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Professor David Bradley


Emeritus Professor
+44 (0)1483 683771
07 BC 04

Academic and research departments

Department of Physics.

Biography

Biography

David Bradley (PhD (USM), MSc (London), BSc (Exeter)) is Professor of Radiation and Medical Physics at the University of Surrey. He has taught and researched in Universities for some 35 years. For some 14 years he Directed MSc programmes in Medical Physics. He was also for six years the Secretary of the International Radiation Physics Society (IRPS). Presently he is Editor-in-Chief of the British Journal of Radiology and Consulting Editor to the Elsevier journals 'Applied Radiation and Isotopes' and 'Radiation Physics and Chemistry'. Dr Bradley is the author of over 250 publications and has made more than 150 presentations at conferences. His interests are in researching the fundamental interactions of radiation in matter as well as their applications in biomedical areas and in industry.

Research interests

Dr Bradley has active research interests in the fundamentals and applications of photon scattering, radioanalytical techniques for determination of trace element concentrations, radiological risks associated with Naturally Occurring Radioactive Material (NORM), the development of synchrotron techniques for characterisation of media, predominantly biological tissues, radiation effects on tissues, and development of silica based luminesence dosimeters.

Research projects of current interest include: the localisation of Zn and Sr in synovial joints, the development of doped radiosensitive glass, the effects of ionizing radiation on extracellular matrix, and near-edge elastic photon scattering from dilute aqueous ions.

Teaching

Module Leader for PHYM018 Radiation Protection

Departmental duties

Course Deputy Director for the MSc Programme in Medical Physics and the MSc Programme in Medical Physics

My publications

Publications

F Issa, AT Abdul Rahman, RP Hugtenburg, David Bradley, Andrew Nisbet (2012)Establishment of Ge-doped optical fibres as thermoluminescence dosimeters for brachytherapy, In: Applied Radiation and Isotopes70(7)pp. 1158-1161 Elsevier

This study aims to establish the sensitive, ~120μm high spatial resolution, high dynamic range Ge-doped optical fibres as thermoluminescence (TL) dosimeters for brachytherapy dose distribution. This requires investigation to accommodate sensitivity of detection, both for the possibility of short range dose deposition from beta components as well as gamma/x-mediated dose. In-air measurements are made at distances close to radionuclide sources, evaluating the fall off in dose along the transverse axis of Ba and Co radioactive sources, at distances from 2mm up to 20mm from their midpoints. Measurements have been compared with Monte Carlo code DOSRZnrc simulations for photon-mediated dose only, agreement being obtained to within 3% and 1% for the Ba and Co sources, respectively. As such, in both cases it is determined that as intended, beta dose has been filtered out by source encapsulation. © 2012 Elsevier Ltd.

NM Noor, M Hussein, DA Bradley, A Nisbet (2010)The potential of Ge-doped optical fibre TL dosimetry for 3D verification of high energy IMRT photon beams, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment619(1-3)pp. 157-162 Elsevier
E Dalah, D Bradley, A Nisbet (2010)Simulation of tissue activity curves of Cu-64-ATSM for sub-target volume delineation in radiotherapy, In: PHYSICS IN MEDICINE AND BIOLOGY55(3)pp. 681-694 IOP PUBLISHING LTD
P Kamali-Zonouzi, A Shutt, Andrew Nisbet, David Bradley (2017)Feasibility of employing thick microbeams from superficial and orthovoltage kVp x-ray tubes for radiotherapy of superficial cancers, In: Radiation Physics and Chemistry140pp. 237-241 Elsevier

Preclinical investigations of thick microbeams show these to be feasible for use in radiotherapeutic dose delivery. To create the beams we access a radiotherapy x-ray tube that is familiarly used within a conventional clinical environment, coupling this with beam-defining grids. Beam characterisation, both single and in the form of arrays, has been by use of both MCNP simulation and direct Gafchromic EBT film dosimetry. As a first step in defining optimal exit-beam profiles over a range of beam energies, simulation has been made of the x-ray tube and numbers of beam-defining parallel geometry grids, the latter being made to vary in thickness, slit separation and material composition. For a grid positioned after the treatment applicator, and of similar design to those used in the first part of the study, MCNP simulation and Gafchromic EBT film were then applied in examining the resultant radiation profiles. MCNP simulations and direct dosimetry both show useful thick microbeams to be produced from the x-ray tube, with peak-to-valley dose ratios (PVDRs) in the approximate range 8.8–13.9. Although the potential to create thick microbeams using radiotherapy x-ray tubes and a grid has been demonstrated, Microbeam Radiation Therapy (MRT) would still need to be approved outside of the preclinical setting, a viable treatment technique of clinical interest needing to benefit for instance from substantially improved x-ray tube dose rates.

NA Zahaimi, MHRO Abdullah, H Zin, ALA Rahman, S Hashim, MI Saripan, MC Paul, DA Bradley, ATA Rahman (2014)Dopant concentration and thermoluminescence (TL) properties of tailor-made Ge-doped SiO2 fibres, In: RADIATION PHYSICS AND CHEMISTRY104pp. 297-301 PERGAMON-ELSEVIER SCIENCE LTD
T Santawamaitre, D Malain, HA Al-Sulaiti, DA Bradley, MC Matthews, PH Regan (2014)Determination of U-238, Th-232 and K-40 activity concentrations in riverbank soil along the Chao Phraya river basin in Thailand, In: JOURNAL OF ENVIRONMENTAL RADIOACTIVITY138pp. 80-86 ELSEVIER SCI LTD
ATA Rahman, NK Abu Bakar, MC Paul, DA Bradley (2014)Ultraviolet radiation (UVR) dosimetry system and the use of Ge-doped silica optical fibres, In: RADIATION PHYSICS AND CHEMISTRY104pp. 129-133 PERGAMON-ELSEVIER SCIENCE LTD
NM Noor, M Hussein, DA Bradley, A Nisbet (2011)Investigation of the use of Ge-doped optical fibre for in vitro IMRT prostate dosimetry, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 819-823 Elsevier
Katie Ley, S.M. Jafari, Annika Lohstroh, Caroline Shenton-Taylor, David Bradley (2019)Thermoluminescent Response of Beta-irradiated Silica Beads, In: Radiation Physics and Chemistry154pp. 32-37 Elsevier

Research into the potential for silica based materials as TLDs continues to increase, harnessing the various advantages that the materials have to offer as a dosimeter, including; affordability, chemical inertness, geometry and size, while producing suitable TL yields. Studies into the possibility of beta source dosimetry open another range of applications for this type of dosimeter, including procedures involving the possibility of in vivo dosimetry (Morino et al., 2002). This work aims to further investigate the properties of a much-studied batch of Mill Hill silica beads of various colours, irradiated with a SR90/Y90 source yielding a dose rate of 0.02 Gy/s, activity 37 MBq and maximum energy of 2.27 MeV, facilitated by the Ris ø TL/OSL reader. The TL yield is compared to that in previous work, with the same set of beads irradiated by a 6 MV photon beam provided by a Varian electron linac (Varian Medical Systems, Palo Alto, CA) X-ray source, delivering a dose of 10 Gy. Present study shows a decrease in the mass normalised TL yield from X-ray to beta source by a factor of 10, assumed to be accounted for by the estimated mean penetration depth of the beta particles in the doped silica beads. Investigating the potential for doped silica beads to be used as a beta source dosimeter a linearity study is reported with a dose range of 5 to 20 Gy. The studies show that all coloured beads except green show a strong conformity to a linear fit of the data over the tested range of doses. Fading studies conducted with clear petite beads (producing the greatest TL yield/mg) for doses of 5 Gy and 20 Gy have shown that the majority of fading occurs within the first hour following irradiation, with a plateau in the fading to approximately 17 % and 22 % loss of signal for 5 Gy and 20 Gy respectively in the interval of 24 hours to 70 hours after irradiation. The decay of the TL yield/mg was fitted to a logarithmic trend of reduction for both the 5 Gy and 20 Gy irradiation, with values of 0.9883 and 0.9705 respectively.

AT Abdul Rahman, A Nisbet, DA Bradley (2011)Dose-rate and the reciprocity law: TL response of Ge-doped SiO2 optical fibers at therapeutic radiation doses, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 891-895
U Akar Tarim, O Gurler, EN Ozmutlu, S Yalcin, O Gundogdu, JM Sharaf, DA Bradley (2012)The energy spectrum of 662 keV photons in a water equivalent phantom, In: Radiation Physics and Chemistry81(7)pp. 745-748 Elsevier

Investigation is made on the energy spectrum of photons originating from interactions of 662 keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm×19 cm×24 cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed using a 51 mm×51 mm NaI(Tl) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100 keV and 210 keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements.

M Begum, AKMM Rahman, HA Abdul-Rashid, WSW Abdullah, NM Noor, MI Zulkifli, SZ Muhamad-Yasin, KA Mat-Sharif, N Tamchek, SNM Nawi, N Wahib, YM Amin, DA Bradley (2013)Thermoluminescence Response of Ge-doped Optical Fiber Dosimeters with Different Core Sizes, In: 2013 IEEE 4TH INTERNATIONAL CONFERENCE ON PHOTONICS (ICP)pp. 290-292
S Hashim, MI Saripan, ATA Rahman, NH Yaakob, DA Bradley, K Alzimami (2013)Effective Atomic Number of Ge-Doped and Al-Doped Optical Fibers for Radiation Dosimetry Purposes, In: IEEE TRANSACTIONS ON NUCLEAR SCIENCE60(2)pp. 555-559 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
E Daar, KS Al Mugren, S Chika, S Barnes, DA Bradley (2015)XRF measurements of Zn, Sr and Pb in archaeological bone, In: X-RAY SPECTROMETRY44(3)pp. 129-134 WILEY-BLACKWELL
Ming Tsuey Chew, Andrew Nisbet, Masao Suzuki, Naruhiro Matsufuji, Takeshi Murakami, Bleddyn Jones, David A. Bradley (2018)Potential lethal damage repair in glioblastoma cells irradiated with ion beams of various types and levels of linear energy transfer, In: Journal of Radiation Researchrry081 Oxford University Press

Glioblastoma (GBM), a Grade IV brain tumour, is a well-known radioresistant cancer. To investigate one of the causes of radioresistance, we studied the capacity for potential lethal damage repair (PLDR) of three altered strains of GBM: T98G, U87 and LN18, irradiated with various ions and various levels of linear energy transfer (LET). The GBM cells were exposed to 12C and 28Si ion beams with LETs of 55, 100 and 200 keV/μm, and with X-ray beams of 1.7 keV/μm. Mono-energetic 12C ions and 28Si ions were generated by the Heavy Ion Medical Accelerator at the National Institute of Radiological Science, Chiba, Japan. Clonogenic assays were used to determine cell inactivation. The ability of the cells to repair potential lethal damage was demonstrated by allowing one identical set of irradiated cells to repair for 24 h before subplating. The results show there is definite PLDR with X-rays, some evidence of PLDR at 55 keV/μm, and minimal PLDR at 100 keV/μm. There is no observable PLDR at 200 keV/μm. This is the first study, to the authors’ knowledge, demonstrating the capability of GBM cells to repair potential lethal damage following charged ion irradiations. It is concluded that a GBM’s PLDR is dependent on LET, dose and GBM strain; and the more radioresistant the cell strain, the greater the PLDR.

S Hashim, SA Ibrahim, SSC Omar, YSM Alajerami, MI Saripan, NM Noor, NM Ung, GA Mahdiraji, DA Bradley, K Alzimami (2014)Photon irradiation response of photonic crystal fibres and flat fibres at radiation therapy doses, In: APPLIED RADIATION AND ISOTOPES90pp. 258-260 PERGAMON-ELSEVIER SCIENCE LTD
DA Bradley, W Kaabar, O Gundogdu, MJ Farquharson, M Janousch, M Bailey, C Jeynes (2010)Synchrotron and ion beam studies of the bone-cartilage interface, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 330-337 ELSEVIER SCIENCE BV
NE Norbani, NAA Salim, A Saat, Z Hamzah, AT Ramli, WMRW Idris, MZ Jaafar, DA Bradley, ATA Rahman (2014)Terrestrial gamma radiation dose rates (TGRD) from surface soil in Negeri Sembilan, Malaysia, In: RADIATION PHYSICS AND CHEMISTRY104pp. 112-117 PERGAMON-ELSEVIER SCIENCE LTD
NH Yaakob, H Wagiran, I Hossain, AT Ramli, DA Bradley, S Hashim, H Ali (2011)Electron irradiation response on Ge and Al-doped SiO2 optical fibres, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
K Asaduzzaman, MU Khandaker, YM Amin, DA Bradley, RH Mahat, RM Nor (2014)Soil-to-root vegetable transfer factors for Ra-226, Th-232, K-40, and Y-88 in Malaysia, In: JOURNAL OF ENVIRONMENTAL RADIOACTIVITY135pp. 120-127 ELSEVIER SCI LTD
AT Abdul Rahman, SF Abdul Sani, DA Bradley (2012)Doped SiO 2 telecommunication fibre as a 1-D detector for radiation therapy dosimetry, In: AIP Conference Proceedings1423pp. 347-353

Present studies concern Ge-doped SiO2 telecommunication fibre as a high spatial resolution 1-D thermoluminescence (TL) system for radiotherapeutic dosimetry. Using tube xray bremsstrahlung sources operating at kilovoltage energies, these fibres have been shown to offer linear response, from < 1Gy up to in excess of 30 Gy. Measurement of the photoelectron dose enhancement resulting from use of a moderately high atomic number medium (iodinated contrast media) demonstrates the fibres to have the local dose sensitivity required of interface dosimetry. In PMMA, the TL yield is ~60% greater in the presence of iodine than in its absence.

MA Alkhorayef, MA Alnaaimi, MA Alduaij, MO Mohamed, SY Ibahim, FA Alkandari, DA Bradley (2015)Toward standardising gamma camera quality control procedures, In: RADIATION PHYSICS AND CHEMISTRY116pp. 95-99 PERGAMON-ELSEVIER SCIENCE LTD
J Cottee, A Lopez-Aviles, K Behzadian, D Bradley, D Butler, C Downing, R Farmani, J Ingram, M Leach, A Pike, L De Propris, L Purvis, P Robinson, A Yang (2016)The Local Nexus Network: Exploring the Future of Localised Food Systems and Associated Energy and Water Supply, In: Sustainable Design and Manufacturing 2016 (Smart Innovation Systems and Technologies). Special Volumepp. 613-624 Springer

This volumes consists of 59 peer-reviewed papers, presented at the International Conference on Sustainable Design and Manufacturing (SDM-16) held in Chania, Crete Greece in April 2016. Leading-edge research into sustainable design and manufacturing aims to enable the manufacturing industry to grow by adopting more advanced technologies, and at the same time improve its sustainability by reducing its environmental impact. SDM-16 covers a wide range of topics from sustainable product design and service innovation, sustainable process and technology for the manufacturing of sustainable products, sustainable manufacturing systems and enterprises, decision support for sustainability, and the study of societal impact of sustainability including research for circular economy. Application areas are wide and varied. The book will provide an excellent overview of the latest research and development in the area of Sustainable Design and Manufacturing.

KS Alzimami, AM Maghraby, DA Bradley (2014)Comparative study of some new EPR dosimeters, In: RADIATION PHYSICS AND CHEMISTRY95pp. 109-112 PERGAMON-ELSEVIER SCIENCE LTD
GA Mandiraji, M Ghomeishi, E Dermosesian, S Hashim, NM Ung, FRM Adikan, DA Bradley (2015)Optical fiber based dosimeter sensor: Beyond TLD-100 limits, In: SENSORS AND ACTUATORS A-PHYSICAL222pp. 48-57 ELSEVIER SCIENCE SA
DA Bradley, W Kaabar, O Gundogdu (2012)Elemental and structural studies at the bone-cartilage interface, In: AIP Conference Proceedings1423pp. 319-326

The techniques μProton-Induced X-and γ-ray Emission, μ-PIXE and μ-PIGE, were used to investigate trace and essential element distributions in sections of normal and osteoarthritic (OA) human femoral head. μ-PIGE yielded 2-D mappings of Na and F while Ca, Z, P and S were mapped by μ-PIXE. The concentration of chondroitin sulphate supporting functionality in healthy cartilage is significantly reduced in OA samples. Localised Zn points to osteoblastic/osteoclastic activity at the bone-cartilage interface. Small-angle X-ray scattering applied to decalcified OA-affected tissue showed spatial alterations of collagen fibres of decreased axial periodicity compared to normal collagen type I.

GA Mahdiraji, FRM Adikan, DA Bradley (2015)Collapsed optical fiber: A novel method for improving thermoluminescence response of optical fiber, In: JOURNAL OF LUMINESCENCE161pp. 442-447 ELSEVIER SCIENCE BV
H Shams, AD Bajoga, N Alazemi, DA Bradley, PH Regan (2016)A preliminary evaluation of naturally occurring radioactivity concentration levels across the State of Kuwait, In: APPLIED RADIATION AND ISOTOPES109pp. 479-481 PERGAMON-ELSEVIER SCIENCE LTD
James Scuffham, M Yip-Braidley, AL Shutt, PJ Hinton, Andrew Nisbet, David Bradley (2016)Adapting clinical gamma cameras for body monitoring in the event of a large-scale radiological incident, In: JOURNAL OF RADIOLOGICAL PROTECTION36(2)pp. 363-381 IOP PUBLISHING LTD

After a release of radionuclides, accidental or otherwise, there will be an urgent need to identify members of the general public who have received a significant intake of radioactive material, sufficient to require medical treatment or further investigation. A large number of people could be contaminated in such an incident. For gamma-ray emitting radionuclides this screening could be carried out using gamma camera medical imaging systems, such as those that are present in many large UK hospital sites. By making a number of simple reversible changes such as removal of collimators, these cameras could be employed as useful additional screening instruments as well as an aid in contamination control. A study was carried out to investigate which systems were present in sufficient number to offer wide scale coverage of UK population centres. Nine gamma cameras (eight dual head and one single head) were assessed using point source and bottle mannequin (BOMAB) phantom measurements so that a mathematical model could be developed for use with the MCNPX Monte Carlo radiation transport code. The gamma camera models were assessed for practical seated and supine geometries to give calibration factors for a list of target radionuclides that could be released in a radiological incident. The minimum detectable activities (MDAs) that were achieved for a five minute measurement demonstrated that these systems are sufficiently sensitive to be used for screening of the general public and are comparable to other body monitoring facilities. While gamma cameras have on-board software that are designed for imaging and provide for a gamma-ray energy range suitable for radionuclides for diagnostic imaging (such as 99mTc), they are not as versatile as custom-built body monitoring systems.

N Alazemi, AD Bajoga, DA Bradley, PH Regan, H Shams (2016)Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait., In: Chemosphere154pp. 55-62 Elsevier

An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the (238)U and (232)Th decay chains and (40)K which. The (238)U and (232)Th chain radionuclides and (40)K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of (238)U, (232)Th and (40)K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively.

Shakardokht Jafari, Clare Gouldstone, Peter Sharpe, Amani Alalawi, David Bradley, Catharine Clark, Andrew Nisbet, Nicholas Spyrou (2018)Low-cost commercial glass beads as dosimeters in radiotherapy
K Wells, DA Bradley (2012)A review of X-ray explosives detection techniques for checked baggage, In: Applied Radiation and Isotopes70(8)pp. 1729-1746

In recent times, the security focus for civil aviation has shifted from hijacking in the 1980s, towards deliberate sabotage. X-ray imaging provides a major tool in checked baggage inspection, with various sensitive techniques being brought to bear in determining the form, and density of items within luggage as well as other material dependent parameters. This review first examines the various challenges to X-ray technology in securing a safe system of passenger transportation. An overview is then presented of the various conventional and less conventional approaches that are available to the airline industry, leading to developments in state-of-the-art imaging technology supported by enhanced machine and observer-based decision making principles. © 2012 Elsevier Ltd.

S Jafari, C Gouldstone, P H G Sharpe, D A Bradley, C H Clark, A Nisbet, N M Spyrou (2018)Characterisation of Glass Beads for Radiotherapy Dosimetry, In: Proceedings of the 7th United Kingdom & Republic of Ireland Postgraduate Conference in Biomedical Engineering and Medical Physicspp. p15-15

Examinations have been made of a low cost commercially available material which is potentially useful as a dosimeter in radiotherapy. An investigation of the thermoluminescent (TL) yield and electron paramagnetic resonance (EPR) signal was performed by irradiating acid-washed glass jewellery beads to MV photons using a medical linear-accelerator and 60Co gamma rays. For comparison, irradiation exposures were also carried out on 5 mm length of Ge-doped optical fibres that have been widely investigated for their TL properties [1]. The dose response was linear for the investigated dose range of 1 to 2500 cGy, with an R2 correlation coefficient of > 0.999 and reproducibility of 1.7%. The results suggest the potential for use of glass beads as TL dosimeters in radiotherapy.

SM Jafari, AI Alalawi, M Hussein, W Alsaleh, MA Najem, RP Hugtenburg, DA Bradley, NM Spyrou, CH Clark, A Nisbet (2014)Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry, In: PHYSICS IN MEDICINE AND BIOLOGY59(22)pp. 6875-6889 IOP PUBLISHING LTD
Anton Johannes Veldhuis, Jane Glover, David Bradley, Kourosh Behzadian, Alma Lopez-Aviles, Julian Cottee, Clare Downing, John Ingram, Matthew Leach, Raziyeh Farmani, David Butler, Andy Pike, Lisa De Propris, Laura Purvis, Pamela Robinson, Aidong Yang (2017)Re-distributed manufacturing and the food-water-energy nexus: Opportunities and challenges, In: Production Planning & Control Taylor & Francis

Addressing the intersection of two important emerging research areas, re-distributed manufacturing (RDM) and the food-energy-water (FEW) nexus, this work combines insights from engineering, business and policy perspectives and explores opportunities and challenges towards a more localised and sustainable food system. Analysis centred on two specific food products, namely bread and tomato paste reveals that the feasibility and potential of RDM vary with the type of food product and the supply chain (SC) components. Physically, energy efficiency, water consumption and reduction of waste and carbon footprint may be affected by scale and location of production activities and potentials of industrial symbiosis. From the business perspective, novel products, new markets and new business models are expected in order for food RDM to penetrate within the established food industry. Studies on policies, through the lens of public procurement, call for solid evidence of envisioned environmental, social and economic benefits of a more localised food system. An initial integrated framework is proposed for understanding and assessing food RDM and the FEW nexus

NA Zahaimi, H Zin, GA Mahdiraji, ALA Rahman, DA Bradley, ATA Rahman (2014)Characterisation of the thermoluminescence (TL) properties of tailor-made Ge-doped silica glass fibre for applications in medical radiation therapy dosimetry, In: 9TH NATIONAL SEMINAR ON MEDICAL PHYSICS (NSMP2014)546ARTN 01201 IOP PUBLISHING LTD
W Kaabar, E Daar, O Gundogdu, PM Jenneson, MJ Farquharson, M Webb, C Jeynes, DA Bradley (2009)Metal deposition at the bone-cartilage interface in articular cartilage, In: APPLIED RADIATION AND ISOTOPES67(3)pp. 475-479 PERGAMON-ELSEVIER SCIENCE LTD
M Ghomeishi, GA Mahdiraji, FRM Adikan, NM Ung, DA Bradley (2015)Sensitive Fibre-Based Thermoluminescence Detectors for High Resolution In-Vivo Dosimetry, In: SCIENTIFIC REPORTS5ARTN 13309 NATURE PUBLISHING GROUP
NM Noor, NA Shukor, M Hussein, A Nisbet, DA Bradley (2012)Comparison of the TL fading characteristics of Ge-doped optical fibres and LiF dosimeters, In: Appl Radiat Isot70(7)pp. 1384-1387 Elsevier

Fading is important in choosing appropriate thermoluminescence (TL) materials for particular applications. Comparison is made herein of changes due to fading in the TL yield of Ge-doped fibres and lithium fluoride (LiF) dosimeters, for varying temperature and dose. The fading is independent of dose for all investigated dosimeters while the loss in TL yield reduces for lower storage temperatures. At room temperature and for 133 days of storage, a maximum signal loss of 5% has been observed for both forms of LiF dosimeter, while 9 and 50μm core diameter Ge-doped fibres produced a loss of 11% and 8%, respectively.

S Al-Nowais, S Doran, A Kacperek, N Krstajic, J Adamovics, D Bradley (2009)A preliminary analysis of LET effects in the dosimetry of proton beams using PRESAGE™ and optical CT, In: Applied Radiation and Isotopes67(3)pp. 415-418
A Palmer, D Bradley, A Nisbet (2012)Physics-aspects of dose accuracy in high dose rate (HDR) brachytherapy: Source dosimetry, treatment planning, equipment performance and in vivo verification techniques, In: Journal of Contemporary Brachytherapy4(2)pp. 81-91 Termedia Publishing House

This study provides a review of recent publications on the physics-aspects of dosimetric accuracy in high dose rate (HDR) brachytherapy. The discussion of accuracy is primarily concerned with uncertainties, but methods to improve dose conformation to the prescribed intended dose distribution are also noted. The main aim of the paper is to review current practical techniques and methods employed for HDR brachytherapy dosimetry. This includes work on the determination of dose rate fields around brachytherapy sources, the capability of treatment planning systems, the performance of treatment units and methods to verify dose delivery. This work highlights the determinants of accuracy in HDR dosimetry and treatment delivery and presents a selection of papers, focusing on articles from the last five years, to reflect active areas of research and development. Apart from Monte Carlo modelling of source dosimetry, there is no clear consensus on the optimum techniques to be used to assure dosimetric accuracy through all the processes involved in HDR brachytherapy treatment. With the exception of the ESTRO mailed dosimetry service, there is little dosimetric audit activity reported in the literature, when compared with external beam radiotherapy verification.

DA Bradley, K Wells (2014)Reprint of: Biomedical applications reviewed: Hot topic areas, In: Radiation Physics and Chemistry95pp. 191-201

Making reference to the British Journal of Radiology and competitor journal titles, we look at the general area of biomedical physics, reviewing some of the associated topics in ionising radiation research attracting interest over the past 2 years. We also reflect on early developments that have paved the way for these endeavours. The talk is illustrated by referring to a number of biomedical physics areas in which this group has been directly involved, including novel imaging techniques that address compositional and structural makeup as well as use of elastically scattered X-ray phase contrast, radiation damage linking to possible pericardial effects in radiotherapy, simulation of microvascularity and oxygenation with a focus of radiation resistant hypoxic tumours, issues of high spatial resolution dosimetry and tissue interface radiotherapy with doses enhanced through use of high atomic number photoelectron conversion media. © 2013 Elsevier Ltd.

N Abuhadi, D Bradley, D Katarey, Z Podolyak, S Sassi (2014)Investigation of the quantitative accuracy of 3D iterative reconstruction algorithms in comparison to filtered back projection method: a phantom study, In: MEDICAL IMAGING 2014: PHYSICS OF MEDICAL IMAGING9033ARTN 90335 SPIE-INT SOC OPTICAL ENGINEERING
F Mohamed, DA Bradley, CP Winlove (2006)Effects of ionizing radiation on extracellular matrix, In: Transactions of the American Nuclear Society95pp. 433-?
SA Ibrahim, SSC Omar, S Hashim, GA Mahdiraji, DA Bradley, AB Kadir, NM Isa (2014)Assessment of Ge-doped optical fibres subjected to x-ray irradiation, In: 9TH NATIONAL SEMINAR ON MEDICAL PHYSICS (NSMP2014)546ARTN 01201 IOP PUBLISHING LTD
B Müller, H Deyhle, DA Bradley, M Farquharson, G Schulz, M Müller-Gerbl, O Bunk (2010)Scanning X-ray scattering: Evaluating the nanostructure of human tissues, In: European Journal of Nanomedicine3(1)pp. 30-33
David Bradley, RP Hugtenburg, Andrew Nisbet, AT Abdul Rahman, F Issa, N Mohd Noor, A Alalawi (2012)Review of doped silica glass optical fibre: Their TL properties and potential applications in radiation therapy dosimetry, In: Applied Radiation and Isotopes71(SUPPL.)pp. 2-11 Elsevier

Review is made of dosimetric studies of Ge-doped SiO telecommunication fibre as a 1-D thermoluminescence (TL) system for therapeutic applications. To-date, the response of these fibres has been investigated for UV sources, superficial X-ray beam therapy facilities, a synchrotron microbeam facility, electron linear accelerators, protons, neutrons and alpha particles, covering the energy range from a few eV to several MeV. Dosimetric characteristics include, reproducibility, fading, dose response, reciprocity between TL yield and dose-rate and energy dependence. The fibres produce a flat response to fixed photon and electron doses to within better than 3% of the mean TL distribution. Irradiated Ge-doped SiO optical fibres show limited signal fading, with an average loss of TL signal of ~0.4% per day. In terms of dose response, Ge-doped SiO optical fibres have been shown to provide linearity to x and electron doses, from a fraction of 1Gy up to 2kGy. The dosimeters have also been used in measuring photoelectron generation from iodinated contrast media; TL yields being some 60% greater in the presence of iodine than in its absence. The review is accompanied by previously unpublished data. © 2012 Elsevier Ltd.

AI Alalawi, Andrew Nisbet, KS Alzimami, David Bradley, RP Hugtenburg, AT Abdul Rahman, MA Barry (2014)Measurement of dose enhancement close to high atomic number media using optical fibre thermoluminescence dosimeters, In: Radiation Physics and Chemistry95pp. 145-147

Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermoluminescence detectors and an X-ray set operating at 250. kVp. Study is made of the dose enhancement factor for various thicknesses of gold; measurements at a total gold thickness of 160. nm (accounting for incident and exiting photons) produces a mean measured dose enhancement factor of 1.33±0.01 To verify results, simulations of the experimental setup have been performed. © 2013 Elsevier Ltd.

S M Jafari, N M Bates, T Jupp, S F Abdul Sani, A Nisbet, D Bradley (2016)Characterisation of commercial glass beads as TLDs in radiotherapy, In: Radiation Physics and Chemistry137pp. pp181-186 Elsevier
DA Bradley, K Wells (2013)Biomedical applications reviewed: Hot topic areas, In: Radiation Physics and Chemistry

Making reference to the British Journal of Radiology and competitor journal titles, we look at the general area of biomedical physics, reviewing some of the associated topics in ionising radiation research attracting interest over the past 2 years. We also reflect on early developments that have paved the way for these endeavours. The talk is illustrated by referring to a number of biomedical physics areas in which this group has been directly involved, including novel imaging techniques that address compositional and structural makeup as well as use of elastically scattered X-ray phase contrast, radiation damage linking to possible pericardial effects in radiotherapy, simulation of microvascularity and oxygenation with a focus of radiation resistant hypoxic tumours, issues of high spatial resolution dosimetry and tissue interface radiotherapy with doses enhanced through use of high atomic number photoelectron conversion media. © 2012 Elsevier Ltd. All rights reserved.

ATA Rahman, E Bräuer-Krisch, T Brochard, J Adamovics, S Clowes, D Bradley, S Doran (2010)Creation of sophisticated test objects for quality assurance of optical computed tomography scanners, In: Journal of Physics: Conference Series250pp. 215-219
N Mohd Noor, Andrew Nisbet, M Hussein, S Sarene Chu, T Kadni, N Abdullah, David Bradley (2017)Dosimetry Audits and Intercomparisons in Radiotherapy: a Malaysian Profile, In: Radiation Physics and Chemistry140pp. 207-212 Elsevier

Quality audits and intercomparisons are important in ensuring control of processes in any system of endeavour. Present interest is in control of dosimetry in teletherapy, there being a need to assess the extent to which there is consistent radiation dose delivery to the patient. In this study we review significant factors that impact upon radiotherapy dosimetry, focusing upon the example situation of radiotherapy delivery in Malaysia, examining existing literature in support of such efforts. A number of recommendations are made to provide for increased quality assurance and control. In addition to this study, the first level of intercomparison audit i.e. measuring beam output under reference conditions at eight selected Malaysian radiotherapy centres is checked; use being made of 9 µm core diameter Ge-doped silica fibres (Ge-9 µm). The results of Malaysian Secondary Standard Dosimetry Laboratory (SSDL) participation in the IAEA/WHO TLD postal dose audit services during the period between 2011 and 2015 will also been discussed. In conclusion, following review of the development of dosimetry audits and the conduct of one such exercise in Malaysia, it is apparent that regular periodic radiotherapy audits and intercomparison programmes should be strongly supported and implemented worldwide. The programmes to-date demonstrate these to be a good indicator of errors and of consistency between centres. A total of ei+ght beams have been checked in eight Malaysian radiotherapy centres. One out of the eight beams checked produced an unacceptable deviation; this was found to be due to unfamiliarity with the irradiation procedures. Prior to a repeat measurement, the mean ratio of measured to quoted dose was found to be 0.99 with standard deviation of 3%. Subsequent to the repeat measurement, the mean distribution was 1.00, and the standard deviation was 1.3%.

SS Al-Ahbabi, David Bradley, Andrew Nisbet (2013)Tomotherapy evaluation for head and neck cases using two types of phantoms, In: Radiation Physics and Chemistry95pp. 323-325 Elsevier

The use of rotational therapy as an important method of treatment delivery is expected to increase due in a large part to the development and utilisation of tomotherapy. Rotational therapy minimises the occurrence of hotspots and the irradiation of critical organs, providing more uniform dosing while sparing critical organs. Two important characteristics of rotational radiation are its dynamic nature and dosimetric variability in radiation delivery, both of which present a considerable challenge for clinical physicists seeking appropriate tools to meet the demands of quality assurance.In this paper 15 Delivery Quality Assurance (DQA) plans of head and neck patients were assessed for the Hi-Art tomotherapy system using Kodak X-Omat V film and an A1SL Ref F92722 ion chamber versus MapCheck. Absolute dose measurement showed average differences of 3.42. cGy and 98% Gamma (γ) factor for the Cheese phantom technique. For the MapCheck technique the average difference and Gamma factor were 0.74. cGy and 96%, respectively. Gamma (γ) matrix distribution was used to evaluate the difference between measured and calculated dose distribution. © 2013 Elsevier Ltd.

Niki Bardi, Izabela Jurewicz, AK King, Mohammed Alkhorayef, David Bradley, Alan Dalton (2017)X-ray irradiation-induced structural changes on Single Wall Carbon Nanotubes, In: Radiation Physics and Chemistry140pp. 34-37 Elsevier

Dosimetry devices based on Carbon Nanotubes are a promising new technology. In particular using devices based on single wall carbon nanotubes may offer a tissue equivalent response with the possibility for device miniaturisation, high scale manufacturing and low cost. An important precursor to device fabrication requires a quantitative study of the effects of X-ray radiation on the physical and chemical properties of the individual nanotubes. In this study, we concentrate on the effects of relatively low doses, 20 cGy and 45 cGy, respectively. We use a range of characterization techniques including scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to quantify the effects of the radiation dose on inherent properties of the nanotubes. Specifically we find that the radiation exposure results in a reduction in the sp2 nature of the nanotube bond structure. Moreover, our analysis indicates that the exposure results in nanotubes that have an increased defect density which ultimately effects the electrical properties of the nanotubes.

AD Bajoga, N Alazemi, H Shams, Patrick Regan, David Bradley (2016)Evaluation of naturally occurring radioactivity across the State of Kuwait using high-resolution gamma-ray spectrometry, In: Radiation Physics and Chemistry137pp. 203-209 Elsevier

A study of natural radioactivity from 90 different soil samples from the state of Kuwait has been carried out to ascertain the NORM concentration values across the country. The calculated activity concentrations were determined from: (i) the decays of the 226Ra, 214Pb and 214Bi members of the 4n+2 decay chain headed by 238U and; (ii) the 228Ac, 212Pb and 208Tl members of the 4n chain headed by 232Th. The study also included evaluations for the 235U decay chain with the 186 keV doublet transition used together with the measured 4n+2 activity concentration values to determine the 235U/238U isotopic ratios for each sample. The values for the arithmetic mean activity concentrations for 90 separate locations across Kuwait as determined in the current work were 17.2, 14.1, and 368 Bq/kg, with standard deviations of 5.2, 3.7 and 90 Bq/kg for the 238U, 232Th and 40K activity concentrations respectively. Measured isotope ratios for 235U/238U give an arithmetic mean value for all of the samples of 0.045±0.003, consistent with that expected for natural uranium. These results indicate no evidence for a radiologically significant dispersion of additional depleted uranium across the entire State of Kuwait from the 1991 Gulf War.

UA Tarim, EN Ozmutlu, O Gurler, S Yalcin, O Gundogdu, JM Sharaf, DA Bradley (2013)Monte Carlo modelling of single and multiple Compton scattering profiles in a concrete material, In: RADIATION PHYSICS AND CHEMISTRY85pp. 12-17 PERGAMON-ELSEVIER SCIENCE LTD
YM Amin, RH Mahat, RM Nor, MU Khandaker, GH Takleef, DA Bradley (2013)The presence of natural radioactivity and 137Cs in the South China Sea bordering peninsular Malaysia., In: Radiat Prot Dosimetry156(4)pp. 475-480

The presence of natural radioactivity and (137)Cs has been investigated in fresh media obtained from South China Sea locations off the coast of peninsular Malaysia. The media include seafood, sea water and sediment. The samples were collected some weeks prior to the devastating 2011 Tōhoku earthquake and associated tsunami, the occurrence of which precipitated the Fukushima incident. All samples showed the presence of naturally occurring (226)Ra, (228)Ra and primordial (40)K, all at typically prevailing levels. The concentrations of natural radioactivity in molluscs were found to be greater than that of other marine life studied herein, the total activity ranging from 337 to 393 Bq kg(-1) dry weight. The total activity in sea water ranged from 15 to 88 Bq l(-1). Sediment samples obtained at deep sea locations more than 20 km offshore further revealed the presence of (137)Cs. The activity of (137)Cs varied from ND to 0.5 Bq kg(-1) dry weight, the activity increasing with offshore distance and depth. The activity concentrations presented herein should be considered useful in assessing the impact of any future radiological contamination to the marine environment.

DA Bradley, RP Hugtenburg, AL Yusoff (2006)Near-edge elastic photon scattering from dilute aqueous ions, In: RADIATION PHYSICS AND CHEMISTRY75(12)pp. 2129-2135 PERGAMON-ELSEVIER SCIENCE LTD
M Begum, AKMM Rahman, HA Abdul-Rashid, Z Yusoff, M Begum, KA Mat-Sharif, YM Amin, DA Bradley (2015)Thermoluminescence characteristics of Ge-doped optical fibers with different dimensions for radiation dosimetry, In: APPLIED RADIATION AND ISOTOPES100pp. 79-83 PERGAMON-ELSEVIER SCIENCE LTD
P Muthuvelu, RE Ellis, EM Green, D Attenburrow, R Barrett, K Arkill, DB Colridge, CP Winlove, DA Bradley (2007)Microvascularity, blood flow and tissue structure at the subchondral plate using an X-ray fluorescence technique, In: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY271(3)pp. 771-775 SPRINGER

A novel phantom is presented for 'full system' dosimetric audit comparing planned and delivered dose distributions in HDR gynaecological brachytherapy, using clinical treatment applicators. The brachytherapy applicator dosimetry test object consists of a near full-scatter water tank with applicator and film supports constructed of Solid Water, accommodating any typical cervix applicator. Film dosimeters are precisely held in four orthogonal planes bisecting the intrauterine tube, sampling dose distributions in the high risk clinical target volume, points A and B, bladder, rectum and sigmoid. The applicator position is fixed prior to CT scanning and through treatment planning and irradiation. The CT data is acquired with the applicator in a near clinical orientation to include applicator reconstruction in the system test. Gamma analysis is used to compare treatment planning system exported RTDose grid with measured multi-channel film dose maps. Results from two pilot audits are presented, using Ir-192 and Co-60 HDR sources, with a mean gamma passing rate of 98.6% using criteria of 3% local normalization and 3 mm distance to agreement (DTA). The mean DTA between prescribed dose and measured film dose at point A was 1.2 mm. The phantom was funded by IPEM and will be used for a UK national brachytherapy dosimetry audit.

E Daar, W Kaabar, A Nisbet, DA Bradley, E Woods, C Lei (2014)Atomic force microscopy and mechanical testing of bovine pericardium irradiated to radiotherapy doses, In: Radiation Physics and Chemistry96pp. 176-180

Within the context of radiotherapy our work investigates the feasibility of identifying changes in structural and biomechanical properties of pericardium resulting from exposure to penetrating photon irradiation. Collagen fibres extracted from bovine pericardium were chosen as a model of pericardium extracellular matrix as these form the main fibrous component of the medium. Tests of mechanical properties, controlled by the various structural elements of the tissues, were performed on frontal pericardium, including uni-axial tests and atomic force microscopy (AFM). While the irradiated collagen fibres showed no significant change in D-band spacing up to doses of 80. Gy, the fibre width was found to increase by 34±9% at 80. Gy when compared with that for un-irradiated samples. © 2013 Elsevier Ltd.

AD Bajoga, N Alazemi, PH Regan, DA Bradley (2015)Radioactive investigation of NORM samples from Southern Kuwait soil using high-resolution gamma-ray spectroscopy, In: RADIATION PHYSICS AND CHEMISTRY116pp. 305-311 PERGAMON-ELSEVIER SCIENCE LTD
A.A Almahwasi, J.C. Jeynes, M.J. Merchant, D.A. Bradley, P.H. Regan (2016)Delayed persistence of giant-nucleated cells induced by X-ray and proton irradiation in the progeny of replicating normal human fibroblast cells, In: Radiation Physics and Chemistry137pp. 163-168 Elsevier

Ionising radiation can induce giant-nucleated cells (GCs) in the progeny of irradiated populations, as demonstrated in various cellular systems. Most in vitro studies have utilised quiescent cancerous or normal cell lines but it is not clear whether radiation-induced GCs persist in the progeny of normal replicated cells. In the current work we show persistent induction of GCs in the progeny of normal human-diploid skin fibroblasts (AG1522). These cells were originally irradiated with a single equivalent clinical dose of 0.2, 1 or 2 Gy of either X-ray or proton irradiation and maintained in an active state for various post-irradiation incubation interval times before they were replated for GC analysis. The results demonstrate that the formation of GCs in the progeny of X-ray or proton irradiated cells was increased in a dose-dependent manner when measured 7 days after irradiation and this finding is in agreement with that reported for the AG1522 cells using other radiation qualities. For the 1 Gy X-ray doses it was found that the GC yield increased continually with time up to 21 days post-irradiation. These results can act as benchmark data for such work and may have important implications for studies aimed at evaluating the efficacy of radiation therapy and in determining the risk of delayed effects particularly when applying protons.

F Issa, A Nisbet, DA Bradley, RP Hugtenburg (2013)Novel high resolution I brachytherapy source dosimetry using Ge-doped optical fibres, In: Radiation Physics and Chemistry92pp. 48-53

The steep dose gradients close to brachytherapy sources limit the ability to obtain accurate measurements of dose. Here we use a novel high spatial resolution dosimeter to measure dose around a I source and compare against simulations. Ge-doped optical fibres, used as thermoluminescent dosimeters, offer sub-mm spatial resolution, linear response from 10cGy to >1kGy and dose-rate independence. For a I brachytherapy seed in a PMMA phantom, doses were obtained for source-dosimeter separations from 0.1cm up to several cm, supported by EGSnrc/DOSRZznrc Monte Carlo simulations and treatment planning system data. The measurements agree with simulations to within 2.3%±0.3% along the transverse and perpendicular axes and within 3.0%±0.5% for measurements investigating anisotropy in angular dose distribution. Measured and Veriseed™ brachytherapy treatment planning system (TPS) values agreed to within 2.7%±0.5%.Ge-doped optical fibre dosimeters allow detailed dose mapping around brachytherapy sources, not least in situations of high dose gradient. © 2013 Elsevier Ltd.

NH Yaakob, H Wagiran, M Imam Hossain, AT Ramli, DA Bradley, H Ali (2011)Low-dose photon irradiation response of Ge and Al-doped SiO2 optical fibres, In: Applied Radiation and Isotopes69(9)pp. 1189-1192 Elsevier
FCA Da Silva, David Bradley, Patrick Regan, Z Siti Rozaila (2016)Measurement of the total activity concentrations of Libyan oil scale, In: Radiation Physics and Chemistry137pp. 198-202 Elsevier

Twenty-three oil scale samples obtained from the Libyan oil and gas industry production facilities onshore have been measured using high-resolution gamma-ray spectrometry with a shielded HPGe detector, the work being carried out within the Environmental Radioactivity Laboratory at the University of Surrey. The main objectives of this work were to determine the extent to which the predominant radionuclides associated with the uranium and thorium natural decay chains were in secular equilibrium with their decay progeny, also to compare differences between the total activity concentrations (TAC) in secular equilibrium and disequilibrium and to evaluate the measured activities for the predominant gamma-ray emitting decay radionuclides within the 232Th and 238U chains. The oil scale NORM samples did not exhibit radioactive equilibrium between the decay progeny and longer-lived parent radionuclides of the 238U and 232Th series.

AS Habib, AL Shutt, PH Regan, MC Matthews, H Alsulaiti, DA Bradley (2014)Characterization of naturally occurring radioactive materials in Libyan oil pipe scale using a germanium detector and Monte Carlo simulation, In: RADIATION PHYSICS AND CHEMISTRY95pp. 352-355 PERGAMON-ELSEVIER SCIENCE LTD
K. Ley, S.M. Jafari, A. Lohstroh, D.A. Bradley (2019)Investigations of thermoluminescent silica beads of different manufacturers and colours, In: Radiation Physics and Chemistry155pp. 178-183 Elsevier

Increased interest in silica based materials for use in medical thermolumiscence (TL)-based dosimetry has led to investigations of tailoring different types of technologies for specific uses. Here we study a low-cost approach to the harnessing of this emerging dosimetry technique, utilising commercially manufactured doped silica beads. The beads have been previously studied using two well-established TLD Reader systems, namely the HARSHAWand TOLEDO brands, and are now being studied making use of a RisØ TL/OSL system, a more modern and also highly sensitive facility. Characterisation studies have been conducted and results from this have been compared against that of existing literature including glow-curves and colour study TL-yield responses. The outcome confirms that colourless beads produce the highest yield when observing the 2.7 eV electron trap of silica based materials with TLD techniques. Investigations have also been made concerning the batch homogeneity of coloured beads from two different manufacturers, Mill Hill, Japan and Toho Czech, and different physical finishes of the silica beads, transparent or frosted. Studies also show that the colourless beads displaying the best batch homogeneity overall are those produced by Mill Hill Japan, measured by the percentage difference from the average TL yield, with the clear petite beads displaying the best homogeneity.

AL Palmer, D Bradley, A Nisbet (2014)Evaluation and implementation of triple-channel radiochromic film dosimetry in brachytherapy, In: JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS15(4)pp. 280-296 MULTIMED INC
SM Jafari, TJ Jordan, M Hussein, David Bradley, CH Clark, Andrew Nisbet, NM Spyrou (2014)Energy response of glass bead TLDs irradiated with radiation therapy beams, In: RADIATION PHYSICS AND CHEMISTRY104pp. 208-211 PERGAMON-ELSEVIER SCIENCE LTD

Glass beads are a novel TL dosimeter in radiotherapy. An important characteristic of TL dosimeters is their energy response, especially when intended for use in radiotherapy applications over a wide range of energies (typically from X-rays generated at 80 kVp up to 25 MV photon and MeV electron beams). In this paper, the energy response of glass beads (Mill Hill, Japan) is investigated for their TL response to kV X-rays from an orthovoltage radiotherapy unit and also for MV photon and MeV electron beams from a medical linear accelerator. The experimental findings show that for photon and electron beams, the TL response of this particular glass bead, normalised to unity for 6 MV X-rays (TPR20/10¼0.670), decreases to 0.9670.02 for 15 MV X-rays (TPR20/10¼0.761) and to 0.9570.01 for 20 MeV electron beams (R50,D¼8.35 cm). This compares favourably with other TLD materials such as LiF and also alanine dosimeters that are readout with an EPR system. For kV X-rays, the response increases to 4.5270.05 for 80 kV X-rays (HVL¼2.4 mm Al) which approaches 3 times that of LiF TLDs and 5 times that of alanine. In conclusion, the particular glass beads, when used as a dosimeter material, show a relatively small energy dependence over the megavoltage range of clinically relevant radiation qualities, being clearly advantageous for accurate dosimetry. Conversely, the energy response is significant for photon beam energies covering the kV range. In both circumstances, in dosimetric evaluations the energy response needs to be taken into account.

D Malain, PH Regan, DA Bradley, M Matthews, T Santawamaitre, HA Al-Sulaiti (2010)Measurements of NORM in beach sand samples along the Andaman coast of Thailand after the 2004 tsunami, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 441-445
SM Jafari, DA Bradley, A Alalawi, CH Clark, A Nisbet, NM Spyrou, CA Gouldstone, PHG Sharpe, TJ Jordan (2014)Low-cost commercial glass beads as dosimeters in radiotherapy, In: Radiation Physics and Chemistry97pp. 95-101

Recent developments in advanced radiotherapy techniques using small field photon beams, require small detectors to determine the delivered dose in steep dose gradient fields. Commercially available glass jewellery beads exhibit thermoluminescent properties and have the potential to be used as dosimeters in radiotherapy due to their small size (

AT Abdul Rahman, RP Hugtenburg, SF Abdul Sani, AI Alalawi, F Issa, R Thomas, MA Barry, Andrew Nisbet, David Bradley (2012)An investigation of the thermoluminescence of Ge-doped SiO(2) optical fibres for application in interface radiation dosimetry., In: Applied Radiation and Isotopes70(7)pp. 1436-1441

We investigate the ability of high spatial resolution (∼120μm) Ge-doped SiO(2) TL dosimeters to measure photoelectron dose enhancement resulting from the use of a moderate to high-Z target (an iodinated contrast media) irradiated by 90kVp X-rays. We imagine its application in a novel radiation synovectomy technique, modelled by a phantom containing a reservoir of I(2) molecules at the interface of which the doped silica dosimeters are located. Measurements outside of the iodine photoelectron range are provided for using a stepped-design that allows insertion of the fibres within the phantom. Monte Carlo simulation (MCNPX) is used for verification. At the phantom medium I(2)-interface additional photoelectron generation is observed, ∼60% above that in the absence of the I(2), simulations providing agreement to within 3%. Percentage depth doses measured away from the iodine contrast medium reservoir are bounded by published PDDs at 80kVp and 100kVp.

CJ Moger, R Barrett, P Bleuet, DA Bradley, RE Ellis, EM Green, KM Knapp, P Muthuvelu, CP Winlove (2007)Regional variations of collagen orientation in normal and diseased articular cartilage and subchondral bone determined using small angle X-ray scattering (SAXS), In: OSTEOARTHRITIS AND CARTILAGE15(6)pp. 682-687 W B SAUNDERS CO LTD
Shakardokht Jafari, Nicholas Bates, T Jupp, S F Abdul Sani, Andrew Nisbet, David Bradley (2016)Commercial glass beads as TLDs in radiotherapy produced by different manufacturers, In: Radiation Physics and Chemistry137pp. pp181-186 www.elsevier.com

While commercial jewellery glass beads offer the basis of novel radiotherapy TL dosimetry (Jafari et al. 2014a,b,c, 2015a,b), detailed study of TL variation is required for the products from various manufacturers. Investigation is made for glass beads from four manufacturers from four countries: China (Rocaille), Japan (Mill Hill), Indonesia (TOHO™) and Czech Republic (Czech). Sample composition was determined using an energy-dispersive X-ray unit coupled to a scanning electron microscope. Values of mass attenuation coefficient, μ/ρ, as a function of photon energy were then calculated for photons of energy 1 keV to 10 MeV, using the National Institute of Standards and Technology XCOM program. Radiation and energy response were determined using X-rays generated at accelerating potentials from 80 kVp to 6 MV (TPR20/10¼0.670). All bead types showed TL to be linear with dose (R240.999). Glow curve dosimetric peaks reached a maximum value at 300 °C for the Toho and 290 °C for the Czech and Mill Hill products but was between 200–250 °C for the Rocaille product. Radiation sensitivity following mass normalisation varied within an order of magnitude; Toho samples showed the greatest and Rocaille the least sensitivity. For the Toho, Czech, Rocaille and Mill Hill samples the energy responses at 80 kVp were 5.0, 4.0, 3.6 and 3.3 times that obtained at 6 MV. All four glass bead types offer potential use as TL dosimeters over doses commonly applied in radiotherapy. Energy response variation was o1% at 6 MV but significant variation was found for photon beam energies covering the kV range; careful characterisation is required if use at this range is intended.

E Daar, W Kaabar, C Lei, JL Keddie, A Nisbet, DA Bradley (2010)AFM and uni-axial testing of pericardium exposed to radiotherapy doses, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 874-877 Elsevier
NM Noor, M Hussein, DA Bradley, A Nisbet, T Kadni (2014)Characterization of Ge-doped optical fibres for MV radiotherapy dosimetry, In: Radiation Physics and Chemistry98pp. 33-41

Ge-doped optical fibres offer promising thermoluminescence (TL) properties together with small physical size and modest cost. Their use as dosimeters for postal radiotherapy dose audits of megavoltage photon beams has been investigated. Key dosimetric characteristics including reproducibility, linearity, dose rate, temperature and angular dependence have been established. A methodology of measuring absorbed dose under reference conditions was developed. The Ge-doped optical fibres offer linearity between TL yield and dose, with a reproducibility of better than 5%, following repeated measurements (n=5) for doses from 5cGy to 1000cGy. The fibres also offer dose rate, angular and temperature independence, while an energy-dependent response of 7% was found over the energy range 6MV to 15MV (TPR of 0.660, 0.723 and 0.774 for 6, 10 and 15MV respectively). The audit methodology has been developed with an expanded uncertainty of 4.22% at 95% confidence interval for the photon beams studied. © 2013 Elsevier Ltd.

H Al-Sulaiti, T Nasir, KS Al Mugren, N Alkhomashi, N Al-Dahan, M Al-Dosari, DA Bradley, S Bukhari, M Matthews, PH Regan, T Santawamaitre, D Malain, A Habib (2012)Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry., In: Appl Radiat Isot70(7)pp. 1344-1350

This study is aimed at the determination of the activity concentrations of naturally occuring and technologically enhanced levels of radiation in 34 representative soil samples that have been collected from an inshore oil field area which was found to have, in a previous study, the highest observed value of 226Ra concentration among 129 soil samples. The activity concentrations of 238U and 226Ra have been inferred from gamma-ray transitions associated with their decay progenies and measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the values of the activity concentrations associated with the naturally occuring radionuclide chains for all the samples collected from NW Dukhan. Discrete-line, gamma-ray energy transitions from spectral lines ranging in energy from ∼100 keV up to 2.6 MeV have been associated with characteristic decays of the various decay products within the 235.8U and 232Th radioactive decay chains. These data have been analyzed, under the assumption of secular equilibrium for the U and Th decay chains. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented. The weighted mean value of the activity concentrations of 226Ra in one of the samples was found to be around a factor of 2 higher than the values obtained in the previous study and approximately a factor of 10 higher than the accepted worldwide average value of 35 Bq/kg. The weighted mean values of the activity concentrations of 232Th and 40K were also deduced and found to be within the worldwide average values of 30 and 400 Bq/kg, respectively. Our previous study reported a value of 201.9±1.5Stat.±13Syst.Bq/kg for 226Ra in one sample and further investigation in the current work determined a measured value for 226Ra of 342.00±1.9Stat.±25Syst.Bq/kg in a sample taken from the same locality. This is significantly higher than all the other investigated soil samples in the current and previous works. Notably, the Th levels in the same sample are within the worldwide average expectations, implying that the increased 226Ra concentration arises from TENORM processes.

MU Khandaker, NB Wahib, YM Amin, DA Bradley (2013)Committed effective dose from naturally occuring radionuclides in shellfish, In: RADIATION PHYSICS AND CHEMISTRY88pp. 1-6 PERGAMON-ELSEVIER SCIENCE LTD
T Santawamaitre, D Malain, HA Al-Sulaiti, M Matthews, DA Bradley, PH Regan (2011)Study of natural radioactivity in riverbank soils along the Chao Phraya river basin in Thailand, In: SORMA XII 2010: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 920-924 Elsevier
YM Abubakar, Matthew Taggart, Abdullah Alsubaie, Abdulaziz Alanazi, Amjad Alyahyawi, Annika Lohstroh, A Shutt, Shakardokht Jafari, David Bradley (2016)Characterisation of an isotropic neutron source: a comparison of conventional neutron detectors and micro-silica glass bead thermoluminescent detectors, In: Radiation Physics and Chemistry140pp. 497-501 Elsevier

As a result of their thermoluminescent response, low cost commercial glass beads have been demonstrated to offer potential use as radiation dosimeters, providing capability in sensing different types of ionising radiation. With a linear response over a large range of dose and spatial resolution that allows measurements down to the order of 1 mm, their performance renders them of interest in situations in which sensitivity, dynamic range, and fine spatial resolution are called for. In the present work, the suitability of glass beads for characterisation of an AmericiumBeryllium (241AmBe) neutron source has been assessed. Direct comparison has been made using conventional 3He and boron tri-fluoride neutron detectors as well as Monte Carlo simulation. Good agreement is obtained between the glass beads and gas detectors in terms of general reduction of count rate with distance. Furthermore, the glass beads demonstrate exceptional spatial resolution, leading to the observation of fine detail in the plot of dose versus distance from source. Fine resolution peaks arising in the measured plots, also present in simulations, are interesting features which based on our best knowledge have previously not been reported. The features are reproduced in both experiment and simulation but we do not have a firm reason for their origin. Of greater clarity is that the glass beads have considerable potential for use in high spatial resolution neutron field characterisation, subject to the availability of a suitable automated TLD reader.

Shakardokht Jafari, G. Distefano, J. Lee, C. Gouldstone, H. Mayles, D. A. Bradley, N. M. Spyrou, A. Nisbet, C. H. Clark (2015)Feasibility of using glass bead TLDs for a postal dosimetry audit of MV radiotherapy photon beams, In: Proceedings of the 8th UK Radiation Oncology Conference (UKRO) Varian Medical Systems, Inc.
H Al-Sulaiti, N Alkhomashi, N Al-Dahan, M Al-Dosari, DA Bradley, S Bukhari, M Matthews, PH Regan, T Santawamaitre (2011)Determination of the natural radioactivity in Qatarian building materials using high-resolution gamma-ray spectrometry, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 915-919 Elsevier
AL Palmer, A Nisbet, D Bradley (2013)Verification of high dose rate brachytherapy dose distributions with EBT3 Gafchromic film quality control techniques, In: PHYSICS IN MEDICINE AND BIOLOGY58(3)pp. 497-511 IOP PUBLISHING LTD
DA Bradley, AZ Aziz, AJ Knapton, HA Abdul-Rashid, AKMM Rahman, YM Amin, RM Nor, MJ Maah, R Mahat (2013)Optically Stimulated Luminescence in Beta Irradiated Ge-doped Optical Fibre, In: 2013 IEEE 4TH INTERNATIONAL CONFERENCE ON PHOTONICS (ICP)pp. 38-40 IEEE
DA Bradley, SM Jafari, AS Siti Shafiqah, N Tamcheck, A Shutt, Z Siti Rozaila, SF Abdul Sani, SN Sabtu, A Alanazi, G Amouzad Mahdiraji, HA Abdul Rashid, MJ Maah (2015)Latest developments in silica-based thermoluminescence spectrometry and dosimetry., In: Appl Radiat Isot

Using irradiated doped-silica preforms from which fibres for thermoluminescence dosimetry applications can be fabricated we have carried out a range of luminescence studies, the TL yield of the fibre systems offering many advantages over conventional passive dosimetry types. In this paper we investigate such media, showing emission spectra for irradiated preforms and the TL response of glass beads following irradiation to an (241)Am-Be neutron source located in a tank of water, the glass fibres and beads offering the advantage of being able to be placed directly into liquid. The outcomes from these and other lines of research are intended to inform development of doped silica radiation dosimeters of versatile utility, extending from environmental evaluations through to clinical and industrial applications.

A Alanazi, M Alkhorayef, K Alzimami, I Jurewicz, N Abuhadi, A Dalton, DA Bradley (2016)Carbon nanotubes buckypaper radiation studies for medical physics applications., In: Appl Radiat Isot

Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In such circumstance, dosimeters with atomic number similar to human tissue are needed. Carbon nanotubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nanotubes (SWCNTs) buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2Gy. This finding suggests that carbon nanotubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance.

BACKGROUND: Detection of buried improvised explosive devices (IEDs) is a delicate task, leading to a need to develop sensitive stand-off detection technology. The shape, composition and size of the IEDs can be expected to be revised over time in an effort to overcome increasingly sophisticated detection methods. As an example, for the most part, landmines are found through metal detection which has led to increasing use of non-ferrous materials such as wood or plastic containers for chemical based explosives being developed. METHODOLOGY: Monte Carlo simulations have been undertaken considering three different commercially available detector materials (hyperpure-Ge (HPGe), lanthanum(III) bromide (LaBr) and thallium activated sodium iodide (NaI(Tl)), applied at a stand-off distance of 50 cm from the surface and burial depths of 0, 5 and 10 cm, with sand as the obfuscating medium. Target materials representing medium density wood and mild steel have been considered. Each detector has been modelled as a 10 cm thick cylinder with a 20 cm diameter. PRINCIPAL FINDINGS: It appears that HPGe represents the most promising detector for this application. Although it was not the highest density material studied, its excellent energy resolving capability leads to the highest quality spectra from which detection decisions can be inferred. CONCLUSIONS: The simulation work undertaken here suggests that a vehicle-born threat detection system could be envisaged using a single betatron and a series of detectors operating in parallel observing the space directly in front of the vehicle path. Furthermore, results show that non-ferrous materials such as wood can be effectively discerned in such remote-operated detection system, with the potential to apply a signature analysis template matching technique for real-time analysis of such data.

W Kaabar, O Gundogdu, A Laklouk, O Bunk, F Pfeiffer, MJ Farquharson, DA Bradley (2010)mu-PIXE and SAXS studies at the bone-cartilage interface, In: APPLIED RADIATION AND ISOTOPES68(4-5)pp. 730-734 PERGAMON-ELSEVIER SCIENCE LTD
S Hashim, DA Bradley, MI Saripan, AT Ramli, H Wagiran (2010)The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons, In: APPLIED RADIATION AND ISOTOPES68(4-5)pp. 700-703
A Alawiah, S Bauk, MW Marashdeh, MZN Nazura, HA Abdul-Rashid, Z Yusoff, W Gieszczyk, MN Noramaliza, FRM Adikan, GA Mandiraji, N Tamchek, SZ Muhd-Yassin, KA Mat-Sharif, MI Zulkifli, N Omar, WSW Abdullah, DA Bradley (2015)The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays, In: APPLIED RADIATION AND ISOTOPES104pp. 197-202 PERGAMON-ELSEVIER SCIENCE LTD
AKMM Rahman, HT Zubair, M Begum, HA Abdul-Rashid, Z Yusoff, NM Ung, KA Mat-Sharif, WSW Abdullah, GA Mahdiraji, YM Amin, MJ Maah, DA Bradley (2015)Germanium-doped optical fiber for real-time radiation dosimetry, In: RADIATION PHYSICS AND CHEMISTRY116pp. 170-175 PERGAMON-ELSEVIER SCIENCE LTD
AI Alalawi, A Nisbet, KS Alzimami, DA Bradley, AT Abdul Rahman, MA Barry, RP Hugtenburg (2013)Measurement of dose enhancement close to high atomic number media using optical fibre thermo luminescence dosimeters, In: Radiation Physics and Chemistry

Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermo luminescence detectors and an X-ray set operating at 250 kVp. Study is made of the dose enhancement factor for various thickness of gold; measurements at a total gold thickness of 160 nm produces a mean dose enhancement factor of 3.19. To verify results, simulations of the experimental setup have been performed. © 2013 Elsevier Ltd. All rights reserved.

G.W. Grime, S.F. Abdul Sani, Vladimir Palitsin, A.S. Siti Shafiqah, M.J. Maah, Amjad Alyahyawi, D.A. Bradley (2019)Simultaneous microbeam IBA and beam-induced luminescence analysis of strained doped silica fibre radiation dosimeters, In: Radiation Physics and Chemistry155pp. 173-177 Elsevier

We demonstrate that the simultaneous combination of ion beam analysis (IBA) and ion beam induced luminescence (IL) can reveal valuable information concerning the performance of strained doped silica fibre thermoluminescence microdosimeters. The micron scale spatial resolution and low detection limits of IBA allow the lateral distribution of dopant elements to be mapped and then correlated with the distribution of prompt radioluminescence. Measurement of the decay of the IL signal with dose provide information concerning the saturation of the subsequent TL signal at high doses. MeV ion beams can deposit relatively high energy in localized, well-quantified small volumes and so this method is valuable for studying high dose effects in TL dosimeters. We describe a simple modification of the target chamber microscope which enables sensitive low background light detection in two wavelength bands and present preliminary results from three types of germanium doped silica fibre dosimeter.

S Saeed Al-Ahbabi, DA Bradley, M Beyomi, Z Alkatib, S Adhaheri, M Darmaki, A Nisbet (2012)A comparison of protocols for external beam radiotherapy beam calibrations., In: Appl Radiat Isot70(7)pp. 1331-1336

A number of codes of practice (CoP) for electron and photon radiotherapy beam dosimetry are currently in use. Comparison is made of the more widely used of these, specifically those of the International Atomic Energy Agency (IAEA TRS-398), the American Association of Physicists in Medicine (AAPM TG-51) and the Institute of Physics and Engineering in Medicine (IPEM 2003). All are based on calibration of ionization chambers in terms of absorbed dose to water, each seeking to reduce uncertainty in delivered dose, providing an even stronger system of primary standards than previous air-kerma based approaches. They also provide a firm, traceable and straight-forward formalism (Radiology, 1996). Included in making dose assessments for the three CoP are calibration coefficients for a range of beam quality indices. Measurements have been performed using clinical photon and electron beams, the absorbed dose to water being obtained following the recommendations given by each code. Electron beam comparisons have been carried out using measurements for electron beams of nominal energies 6, 9, 12, 16 and 20 MeV. Comparisons were also carried out for photon beams of nominal energies 6 and 18 MV. For photon beams use was made of NE2571 cylindrical graphite walled ionization chambers, cross-calibrated against an NE2611 Secondary Standard; for electron beams, PTW Markus and NACP-02 plane-parallel chambers were used. Irradiations were made using Varian 600C/2100C linacs, supported by water tanks and Virtual Water™ phantoms. The absorbed doses for photon and electron beams obtained following these CoP are all in good agreement, with deviations of less than 2%. A number of studies have been carried out by different groups in different countries to examine the consistency of dosimetry codes of practice or protocols. The aim of these studies is to confirm that the goal of those codes is met, namely uniformity in establishment of dosimetry of all radiation beam types used in cancer therapy in the world, and this is one of the studies.

EC Ismail, W Kaabar, D Garrity, O Gundogdu, O Bunk, F Pfeiffer, MJ Farquharson, DA Bradley (2010)X-ray phase contrast imaging of the bone-cartilage interface, In: APPLIED RADIATION AND ISOTOPES68(4-5)pp. 767-771 PERGAMON-ELSEVIER SCIENCE LTD
O Gundogdu, E Nirgianaki, EC Ismail, PM Jenneson, DA Bradley (2007)Benchtop phase-contrast X-ray imaging, In: APPLIED RADIATION AND ISOTOPES65(12)pp. 1337-1344 PERGAMON-ELSEVIER SCIENCE LTD
SM Alkhateeb, MH Abdelkader, DA Bradley, P Seller, MC Veale, MD Wilson, S Pani, RM Nishikawa, BR Whiting, C Hoeschen (2013)Energy dispersive X-ray diffraction computed tomography of breast-simulating phantoms and a tissue sample, In: MEDICAL IMAGING 2013: PHYSICS OF MEDICAL IMAGING8668ARTN 8pp. ?-? SPIE-INT SOC OPTICAL ENGINEERING
NM Noor, MA Jusoh, AFA Razis, A Alawiah, DA Bradley (2015)Flat Ge-doped Optical Fibres for Food Irradiation Dosimetry, In: NATIONAL PHYSICS CONFERENCE 2014 (PERFIK 2014)1657
SFA Sani, GW Grime, V Palitsin, GA Mahdiraji, HAA Rashid, MJ Maah, DA Bradley (2015)Micro-PIXE analysis of doped SiO2 fibres intended as TL dosimeters for radiation measurements, In: X-RAY SPECTROMETRY44(2)pp. 33-40 WILEY-BLACKWELL
J Loveland, O Gundogdu, E Morton, K Wells, DA Bradley (2010)Phase contrast imaging: Effect of increased object-detector distances at X-ray diagnostic and megavoltage energies, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 625-629 Elsevier
A Alawiah, S Bauk, HA Abdul-Rashid, W Gieszczyk, S Hashim, GA Mandiraji, N Tamchek, DA Bradley (2015)Potential application of pure silica optical flat fibers for radiation therapy dosimetry, In: RADIATION PHYSICS AND CHEMISTRY106pp. 73-76 PERGAMON-ELSEVIER SCIENCE LTD
MU Khandaker, K Asaduzzaman, SM Nawi, AR Usman, YM Amin, E Daar, DA Bradley, H Ahmed, AA Okhunov (2015)Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca, In: PLOS ONE10(6)ARTN epp. ?-? PUBLIC LIBRARY SCIENCE
A Alawiah, S Bauk, MW Marashdeh, KS Ng, HA Abdul-Rashid, Z Yusoff, W Gieszczyk, MN Noramaliza, GA Mahdiraji, N Tamchek, SZ Muhd-Yassin, KA Mat-Sharif, MI Zulkifli, MJ Maah, SSC Omar, DA Bradley (2015)Thermoluminescence glow curves and deconvoluted glow peaks of Ge doped flat fibers at ultra-high doses of electron radiation, In: RADIATION PHYSICS AND CHEMISTRY113pp. 53-58 PERGAMON-ELSEVIER SCIENCE LTD
David Bradley, A S Siti Shafiqah, Z Siti Rozaila, S N Sabtu, S F Abdul Sani, A H Alanazi, Shakardokht Jafari, G Amouzad Mahdiraji, F R Mahamd Adikan, M J Maah, Andrew Nisbet, N Tamchek, H A Abdul Rashid, M Alkhorayef, K Alzimami (2016)Developments in production of silica-based thermoluminescence dosimeters, In: Radiation Physics and Chemistry137pp. 37-44 http://www.elsevier.com/

This work addresses purpose-made thermoluminescence dosimeters (TLD) based on doped silica fibres and sol–gel nanoparticles, produced via Modified Chemical Vapour Deposition (MCVD) and wet chemistry techniques respectively. These seek to improve upon the versatility offered by conventional phosphor-based TLD forms such as that of doped LiF. Fabrication and irradiation-dependent factors are seen to produce defects of differing origin, influencing the luminescence of the media. In coming to a close, we illustrate the utility of Ge-doped silica media for ionizing radiation dosimetry, first showing results from gamma-irradiated Ag-decorated nanoparticles, in the particular instance pointing to an extended dynamic range of dose. For the fibres, at radiotherapy dose levels, we show high spatial resolution (0.1 mm) depth-dose results for proton irradiations. For novel microstructured fibres (photonic crystal fibres, PCFs) we show first results from a study of undisturbed and technologically modified naturally occurring radioactivity environments, measuring doses of some 10 s of μGy over a period of several months.

F Issa, NAA Latip, DA Bradley, A Nisbet (2010)Ge-doped optical fibres as thermoluminescence dosimeters for kilovoltage X-ray therapy irradiations, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 834-837 Elsevier
OD Gonçalves, DA Bradley (2013)ISRP-12: The 12th International Symposium on Radiation Physics, In: Radiation Physics and Chemistry
YSM Alajerami, S Hashim, SK Ghoshal, DA Bradley, M Mhareb, MA Saleh (2014)Copper doped borate dosimeters revisited, In: JOURNAL OF LUMINESCENCE155pp. 141-148 ELSEVIER SCIENCE BV
SFA Sani, GA Mahdiraji, ASS Shafiqah, GW Grime, V Palitsin, SJ Hinder, N Tamchek, HAA Rashid, MJ Maah, JF Watts, DA Bradley (2015)XPS and PIXE Analysis of Doped Silica Fibre for Radiation Dosimetry, In: JOURNAL OF LIGHTWAVE TECHNOLOGY33(11)pp. 2268-2278 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
A Alawiah, MS Alina, S Bauk, HA Abdul-Rashid, W Gieszczyk, MN Noramaliza, GA Mandiraji, N Tamchek, MI Zulkifli, DA Bradley, MW Marashdeh (2015)The thermoluminescence characteristics and the glow curves of Thulium doped silica fiber exposed to 10 MV photon and 21 MeV electron radiation, In: APPLIED RADIATION AND ISOTOPES98pp. 80-86 PERGAMON-ELSEVIER SCIENCE LTD
NNH Ramli, H Salleh, GA Mahdiraji, MI Zulkifli, S Hashim, DA Bradley, NM Noor (2015)Characterization of amorphous thermoluminescence dosimeters for patient dose measurement in X-ray diagnostic procedures, In: RADIATION PHYSICS AND CHEMISTRY116pp. 130-134 PERGAMON-ELSEVIER SCIENCE LTD
S Hashim, SSC Omar, SA Ibrahim, WMSW Hassan, NM Ung, GA Mandiraji, DA Bradley, K Alzimami (2015)Thermoluminescence response of flat optical fiber subjected to 9 MeV electron irradiations, In: RADIATION PHYSICS AND CHEMISTRY106pp. 46-49 PERGAMON-ELSEVIER SCIENCE LTD
MSA Fadzil, NNH Ramli, MA Jusoh, T Kadni, DA Bradley, NM Ung, H Suhairul, NM Noor (2014)Dosimetric characteristics of fabricated silica fibre for postal radiotherapy dose audits, In: 9TH NATIONAL SEMINAR ON MEDICAL PHYSICS (NSMP2014)546ARTN 01201 IOP PUBLISHING LTD
DA Bradley, S Hashim, MI Saripan, K Wells, WL Dunn (2011)Photon signature analysis using template matching, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 466-469 Elsevier
E Dermosesian, GA Mahdiraji, FRM Adikan, DA Bradley (2015)Improving thermoluminescence response through the fabrication of novel microstructured fibers, In: RADIATION PHYSICS AND CHEMISTRY116pp. 135-137 PERGAMON-ELSEVIER SCIENCE LTD
Amjad Alyahyawi, A. Dimitriadis, S.M. Jafari, A. Lohstroh, A. Alanazi, A. Alsubaie, C.H. Clark, A. Nisbet, D.A. Bradley (2019)Thermoluminescence measurements of eye-lens dose in a multi-centre stereotactic radiosurgery audit, In: Radiation Physics and Chemistry155pp. 75-81 Elsevier

Stereotactic radiosurgery (SRS), a non-invasive therapeutic technique, seeks delivery of elevated doses of ionizing radiation to precisely defined targets while at the same time preserving surrounding tissue viability. SRS was developed for treatment of various functional abnormalities, extending also to benign and malignant lesions (the latter sometimes referred to as stereotactic body radiation therapy, SBRT). Local tumour control for single and multiple brain metastases at low complication rates is one such outcome. Notable commercial SRS platforms include Gamma Knife and the linac-based systems, Novalis and Cyberknife. Such systems use imaging techniques that include computed tomography (CT) and magnetic resonance imaging (MRI) in localizing SRS targets, down to a small fraction of one mm. With a wide range of platforms for delivery of SRS, greater investigation and standardization is called for. Present work concerns a multi-centre dosimetric audit (20 centres in all), investigating the range of SRS machines and techniques for a single brain metastasis using a series of small dimension detectors (1.55 mm and less) and an anthropomorphic head phantom. With the lens as one of the more radiosensitive tissues, the aim has been to determine the scattered radiation lens dose received during an SRS treatment, as well as the imaging dose received during planning-stage CT-scanning. Custom-designed holders were fabricated to carry three types of thermoluminescence dosimeters: Ge-doped silica fibres, silica glass beads and TLD-100, the latter as a reference dosimeter (being also of larger dimension than the silica-based dosimeters). For reproducible placement of the TLD holders, a bespoke 3D-printed goggle insert was produced for the head phantom. International guidance is to seek reduction in lens dose down to 0.5 Gy. Present results show lens dose values below 0.5 Gy, albeit sometimes to modest degree, there being need to continue to exercise associated due care in SRS planning and delivery.

K Ley, S.A Hashim, A Lohstroh, C Shenton-Taylor, D.A Bradley (2021)Fading and residual responses for thermoluminescent dosimetry of silica beads irradiated using a high-dose electron-beam, In: Radiation Physics and Chemistry (Oxford, England : 1993)182109366 Elsevier Ltd

Thermoluminescent (TL) glow-curves of 10 different coloured Toho Japan bead types have been obtained using a Risø TL/OSL reader studied for a fading period of 6 months as well as for residual dosimetry for fading up to 16 months after irradiation. For the entirety of the delay period studied the Frosted beads showed the largest TL response followed by Pink and Rose beads. Pink beads showed the best fit to the second order polynomial fit applied to the observed fading. In a more detailed dose curve fitted for a 6 month delay between irradiation and readout in order to determine the nature of the TL response as a function of increasing dose, it was found to follow the same trend for all bead colours. The residual TL response was also studied for beads that showed a large TL response. In these studies all colours showed similar dose response curves to those for the 1st readout, with Pink beads showing the best agreement to the fit applied to model fading. •TL response measured for electron beam irradiation of 1 kGy to 250 kGy, for 10 colours of beads.•The fading effect on TL response was studied in depth for Pink beads over a 16-month period.•Greatest TL produced from Pink and Frosted beads, Green and Lime beads show no correlation.•A detailed comparison of dose dependence with a 6 month fading time was evaluated for Pink beads.•All beads were evaluated for residual dosimetry at a fading time of 3 weeks.

AL Palmer, DA Bradley, A Nisbet (2014)Dosimetric audit in brachytherapy, In: BRITISH JOURNAL OF RADIOLOGY87(1041)ARTN 2pp. ?-? BRITISH INST RADIOLOGY
K Asaduzzaman, MU Khandaker, YM Amin, Z Zainuddin, MS Farook, DA Bradley (2015)MEASUREMENT OF RADIOACTIVITY AND HEAVY METAL LEVELS IN EDIBLE VEGETABLES AND THEIR IMPACT ON KUALA SELANGOR COMMUNITIES OF PENINSULAR MALAYSIA, In: RADIATION PROTECTION DOSIMETRY167(1-3)pp. 165-170 OXFORD UNIV PRESS
SJ Doran, AT Abdul Rahman, E Bräuer-Krisch, T Brochard, J Adamovics, A Nisbet, D Bradley (2013)Establishing the suitability of quantitative optical CT microscopy of PRESAGE® radiochromic dosimeters for the verification of synchrotron microbeam therapy., In: Phys Med Biol58(18)pp. 6279-6297

Previous research on optical computed tomography (CT) microscopy in the context of the synchrotron microbeam has shown the potential of the technique and demonstrated high quality images, but has left two questions unanswered: (i) are the images suitably quantitative for 3D dosimetry? and (ii) what is the impact on the spatial resolution of the system of the limited depth-of-field of the microscope optics? Cuvette and imaging studies are reported here that address these issues. Two sets of cuvettes containing the radiochromic plastic PRESAGE® were irradiated at the ID17 biomedical beamline of the European Synchrotron Radiation facility over the ranges 0-20 and 0-35 Gy and a third set of cuvettes was irradiated over the range 0-20 Gy using a standard medical linac. In parallel, three cylindrical PRESAGE® samples of diameter 9.7 mm were irradiated with test patterns that allowed the quantitative capabilities of the optical CT microscope to be verified, and independent measurements of the imaging modulation transfer function (MTF) to be made via two different methods. Both spectrophotometric analysis and imaging gave a linear dose response, with gradients ranging from 0.036-0.041 cm(-1) Gy(-1) in the three sets of cuvettes and 0.037 (optical CT units) Gy(-1) for the imaging. High-quality, quantitative imaging results were obtained throughout the 3D volume, as illustrated by depth-dose profiles. These profiles are shown to be monoexponential, and the linear attention coefficient of PRESAGE® for the synchrotron-generated x-ray beam is measured to be (0.185 ± 0.02) cm(-1) in excellent agreement with expectations. Low-level (

M Begum, AKMM Rahman, HA Abdul-Rashid, WSW Abdullah, NM Noor, MI Zulkifli, SZ Muhamad-Yasin, KA Mat-Sharif, N Tamchek, SNM Nawi, N Wahib, YM Amin, DA Bradley (2013)Thermoluminescence response of Ge-doped optical fiber dosimeters with different core sizes, In: 4th International Conference on Photonics, ICP 2013 - Conference Proceedingpp. 291-293

Thermoluminescence (TL) properties of five different core diameter of 6 mol% germanium (Ge) doped optical fibers have been investigated for the purpose of TL dosimetry. The optical fiber dosimeter TL properties is compared with commercially available TLD-100 chips (LiF:Mg,Ti). Samples were irradiated using Cobalt-60 standard radiation source ranging from 1Gy to 10 Gy. These fibers show good linear dose response up to 10 Gy. Highest core diameter of Ge doped optical fiber (core 100 μm) provides the best response among all fibers. We observe the larger core fiber show better response than smaller core fiber. The relative sensitivity of 100 μm core optical fiber is 0.26 ± 0.04 with respect to TLD-100 chip. © 2013 IEEE.

Anne Skeldon, G Chaffey, David Lloyd, V Mohan, DA Bradley, A Nisbet (2012)Modelling and detecting tumour oxygenation levels., In: PLoS One7(6)pp. e38597-?

Tumours that are low in oxygen (hypoxic) tend to be more aggressive and respond less well to treatment. Knowing the spatial distribution of oxygen within a tumour could therefore play an important role in treatment planning, enabling treatment to be targeted in such a way that higher doses of radiation are given to the more radioresistant tissue. Mapping the spatial distribution of oxygen in vivo is difficult. Radioactive tracers that are sensitive to different levels of oxygen are under development and in the early stages of clinical use. The concentration of these tracer chemicals can be detected via positron emission tomography resulting in a time dependent concentration profile known as a tissue activity curve (TAC). Pharmaco-kinetic models have then been used to deduce oxygen concentration from TACs. Some such models have included the fact that the spatial distribution of oxygen is often highly inhomogeneous and some have not. We show that the oxygen distribution has little impact on the form of a TAC; it is only the mean oxygen concentration that matters. This has significant consequences both in terms of the computational power needed, and in the amount of information that can be deduced from TACs.

A Alawiah, AM Intan, S Bauk, HA Abdul-Rashid, Z Yusoff, MR Mokhtar, WSW Abdullah, KAM Sharif, GA Mahdiraji, FRM Adikan, N Tamchek, NM Noor, DA Bradley (2013)Thermoluminescence characteristics of flat optical fiber in radiation dosimetry under different electron irradiation conditions, In: MICRO-STRUCTURED AND SPECIALTY OPTICAL FIBRES II8775UNSP 87750 SPIE-INT SOC OPTICAL ENGINEERING
AI Alalawi, SM Jafari, MA Najem, A Nisbet, M Hussein, KS Alzimami, DA Bradley, NM Spyrou, W Alsaleh, RP Hugtenburg, CH Clark, F Abolaban (2014)Preliminary investigations of two types of silica-based dosimeter for small-field radiotherapy, In: Radiation Physics and Chemistry104pp. 139-144

Two thermoluminescent dosimeters (SiO-GeO doped fibres and glass beads (GB)) were used to measure small photon field doses and compared against GAFCHROMIC film, a small ionisation chamber (RK-018) and a p-type silicon diode (SCANDITRONIX, F1356), as well as Monte Carlo simulations with FLUKA and BEAMnrc/DOSXYZnrc. Ge-doped SiO fibres have been shown by this group to offer a viable system for use as dosimeters. The fibres and GB offer good spatial resolution (~120μm and 2mm respectively), large dynamic dose range (with linearity from tens of mGy up to well in excess of many tens of Gy), are non-hygroscopic and are of low cost. Measurements of beam profiles for field sizes of 10mm×10mm, 20mm×20mm, 30mm×30mm, 40mm×40mm, and 100mm×100mm were carried out. Through the use of a customised solid water phantom, doped optical fibres and GBs were placed at defined positions along the x-and y-axes to allow accurate beam profile measurement. The maximum difference between FWHM measurements was 1.8mm. For penumbra measurements (measured between 80% and 20% isodoses), the maximum difference was

E Dalah, David Lloyd, D Bradley, A Nisbet (2009)Computational simulation of tumour hypoxia as applied to radiation therapy applications, In: IFMBE Proceedings25(1)pp. 64-66

It has long been appreciated that hypoxia plays a significant role in tumour resistance to radiotherapy treatment, chemotherapy treatment and also in surgery. For present interests, it is noted that tumour radio-sensitivity increases with the increase of oxygen concentration across tumour regions. A theoretical representation of oxygen distribution in 2D vascular architecture using a reaction diffusion model enables relationships between tissue diffusivity, tissue metabolism, anatomical structure of blood vessels and oxygen gradients to be characterized quantitatively. We present a refinement to the work of Kelly and Brady (2006) and demonstrate the significant effect of the role of the venules supply on the microcirculation process at the intracellular level. With our representation of the two latter forces, the model is being developed to simulate the uptake of various PET reagents, such as 64Cu-ATSM, to demonstrate their potential use in radiation therapy treatment planning as an indicator of tumour hypoxic regions.

H Al-Sulaiti, T Nasir, PH Regan, D Bradley, K Al-Mugren, N Alkhomashi, N Al-Dahan, M Al-Dosari, SJ Bukhari, M Matthews, T Santawamaitre, D Malain, A Habib (2014)Effect of the grain size of the soil on the measured activity and variation in activity in surface and subsurface soil samples, In: Pakistan Journal of Scientific and Industrial Research Series A: Physical Sciences57(3)pp. 129-138

Correlation between grain size and activity concentrations of soils and concentrations of various radionuclides in surface and subsurface soils has been measured for samples taken in the State of Qatar by gamma-spectroscopy using a high purity germanium detector. From the obtained gamma-ray spectra, the activity concentrations of the 238U (226Ra) and 232Th (228Ac) natural decay series, the long-lived naturally occurring radionuclide 40K and the fission product radionuclide 137Cs have been determined. Gamma dose rate, radium equivalent, radiation hazard index and annual effective dose rates have also been estimated from these data. In order to observe the effect of grain size on the radioactivity of soil, three grain sizes were used i.e., smaller than 0.5 mm; smaller than 1 mm and greater than 0.5 mm; and smaller than 2 mm and greater than 1 mm. The weighted activity concentrations of the 238U series nuclides in 0.5-2 mm grain size of sample numbers was found to vary from 2.5±0.2 to 28.5±0.5 Bq/kg, whereas, the weighted activity concentration of 40 K varied from 21±4 to 188±10 Bq/kg. The weighted activity concentrations of 238U series and 40 K have been found to be higher in the finest grain size. However, for the 232Th series, the activity concentrations in the 1-2 mm grain size of one sample were found to be higher than in the 0.5-1 mm grain size. In the study of surface and subsurface soil samples, the activity concentration levels of 238 U series have been found to range from 15.9±0.3 to 24.1±0.9 Bq/kg, in the surface soil samples (0-5 cm) and 14.5±0.3 to 23.6±0.5 Bq/kg in the subsurface soil samples (5-25 cm). The activity concen- trations of 232Th series have been found to lie in the range 5.7±0.2 to 13.7±0.5 Bq/kg, in the surface soil samples (0-5 cm) and 4.1±0.2 to 15.6±0.3 Bq/kg in the subsurface soil samples (5-25 cm). The activity concentrations of 40K were in the range 150±8 to 290±17 Bq/kg, in the surface soil samples (0-5 cm) and 129±7 to 299±14 Bq/kg, in the subsurface soil samples (5-25 cm). The activity concentrations of 238U series, 232Th series and 40K in the surface and deep soil samples are approximately same. The 137Cs activity concentration levels in surface soil samples in four sites were found to be higher than those observed for the soil samples that been collected at a depth of 5-25 cm. They ranged from 1.65±0.22 to 19.0±0.9 Bq/kg, in the surface soil samples (0-5 cm) and 0.5±0.2 to 15.4±0.7 Bq/kg, in the subsurface soil samples (5-25 cm).

YM Amin, MU Khandaker, AKS Shyen, RH Mahat, RM Nor, DA Bradley (2013)Radionuclide emissions from a coal-fired power plant, In: APPLIED RADIATION AND ISOTOPES80pp. 109-116 PERGAMON-ELSEVIER SCIENCE LTD
E Daar, L King, A Nisbet, Rex Thorpe, DA Bradley (2010)Viscosity changes in hyaluronic acid: Irradiation and rheological studies, In: APPLIED RADIATION AND ISOTOPES68(4-5)pp. 746-750
S Hashim, S Al-Ahbabi, DA Bradley, M Webb, C Jeynes, AT Ramli, H Wagiran (2009)The thermoluminescence response of doped SiO2 optical fibres subjected to photon and electron irradiations, In: APPLIED RADIATION AND ISOTOPES67(3)pp. 423-427 PERGAMON-ELSEVIER SCIENCE LTD

Dose distribution measurement in clinical high dose rate (HDR) brachytherapy is challenging, because of the high dose gradients, large dose variations, and small scale, but it is essential to verify accurate treatment planning and treatment equipment performance. The authors compare and evaluate three dosimetry systems for potential use in brachytherapy dose distribution measurement: Ge-doped optical fibers, EBT3 Gafchromic film with multichannel analysis, and the radiochromic material PRESAGE(®) with optical-CT readout.

SM Jafari, TJ Jordan, G Distefano, DA Bradley, NM Spyrou, A Nisbet, CH Clark (2015)Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification, In: BRITISH JOURNAL OF RADIOLOGY88(1055)ARTN 20140 BRITISH INST RADIOLOGY
WL Dunn, CJ Solomon, KW Loschke, DA Bradley, WB Gilboy (2007)Ionizing photon methods for standoff bomb detection, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT580(1)pp. 778-781
F Issa, RP Hugtenburg, DA Bradley, A Nisbet (2012)Investigating radionuclide source shielding performance using Ge-doped optical fibre thermoluminescence dosimeters, In: AIP Conference Proceedings1423pp. 401-405
AL Palmer, A Nisbet, DA Bradley (2013)Semi-3D dosimetry of high dose rate brachytherapy using a novel Gafchromic EBT3 film-array water phantom, In: 7TH INTERNATIONAL CONFERENCE ON 3D RADIATION DOSIMETRY (IC3DDOSE)444pp. ?-?
DA Bradley, S Hashim, J Cabello, K Wells, WL Dunn (2010)Photon-induced positron annihilation for standoff bomb detection, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 415-418 ELSEVIER SCIENCE BV
DA Bradley, RP Hugtenburg, S Hashim, OO Okoya, AL Yusoff, AAM Hassan, AT Ramli, H Wagiran (2007)The development of doped radiosensitive glass, In: Solid State Science and Technology909pp. 9-18
R.A.S. Thomas, S. M. Jafari, D. A. Bradley, N. M. Spyrou, A. Nisbet, C.H. Clark (2014)PO-0796: Dosimetric characterisation of glass bead TLDs in proton beams, In: Radiotherapy and Oncology111(1)PO-0796pp. S58-S58 Elsevier

Purpose/Objective: To investigate the feasibility of using glass beads as a novel thermoluminescence dosimeter (TLD) in clinical proton radiotherapy. The glass beads have several physical characteristics which suggest their suitability for use as TLDs in this area: a spherical physical shape with a hole in the middle that facilitate their use in 2D and 3D arrangements; chemically inert nature; small size of 1.5 mm diameter and 1 mm thickness; inexpensive and readily available; reusable; and importantly their TL light transparency with negligible self-attenuation which is very important for high LET beams. Proton beams have high LET and therefore can deposit dose nonuniformly across a detector. Readout of TL detectors can be influenced if any opacity is present causing self-attenuation of TL light [1], [2]. The transparency of glass beads to TL light means the beads have the potential to avoid such issues.

DA Bradley, CJ Moger, CP Winlove (2007)Zn deposition at the bone-cartilage interface in equine articular cartilage, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT580(1)pp. 473-476
AL Palmer, DA Bradley, A Nisbet (2015)Evaluation and mitigation of potential errors in radiochromic film dosimetry due to film curvature at scanning, In: JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS16(2)pp. 425-431 MULTIMED INC
S M Jafari, G Distefano, D Bradley, N M Spyrou, A Nisbet, C H Clark (2014)Validation of glass bead TLDs for radiotherapy treatment verification, In: Radiotherapy and Oncology111(1)PO-0793pp. p317-317 0167-8140
AL Palmer, D Bradley, A Nisbet, P Diez, L Gandon, A Wynn-Jones, P Bownes, C Lee, E Aird, M Bidmead, G Lowe (2015)A multicentre 'end to end' dosimetry audit for cervix HDR brachytherapy treatment, In: Radiotherapy and Oncology114(2)pp. 264-271

Purpose To undertake the first multicentre fully 'end to end' dosimetry audit for HDR cervix brachytherapy, comparing planned and delivered dose distributions around clinical treatment applicators, with review of local procedures. Materials and methods A film-dosimetry audit was performed at 46 centres, including imaging, applicator reconstruction, treatment planning and delivery. Film dose maps were calculated using triple-channel dosimetry and compared to RTDose data from treatment planning systems. Deviations between plan and measurement were quantified at prescription Point A and using gamma analysis. Local procedures were also discussed. Results The mean difference between planned and measured dose at Point A was -0.6% for plastic applicators and -3.0% for metal applicators, at standard uncertainty 3.0% (k = 1). Isodose distributions agreed within 1 mm over a dose range 2-16 Gy. Mean gamma passing rates exceeded 97% for plastic and metal applicators at 3% (local) 2 mm criteria. Two errors were found: one dose normalisation error and one applicator library misaligned with the imaged applicator. Suggestions for quality improvement were also made. Conclusions The concept of 'end to end' dosimetry audit for HDR brachytherapy has been successfully implemented in a multicentre environment, providing evidence that a high level of accuracy in brachytherapy dosimetry can be achieved.

RP Hugtenburg, DW England, DA Bradley (2007)Near-edge elastic photon scattering in amorphous systems, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS263(1)pp. 22-26
DA Bradley, P Muthuvelu, RE Ellis, EM Green, D AttenburrOW, R Barrett, K Arkill, DB Colridge, CP Winlove (2007)Characterisation of mineralisation of bone and cartilage: X-ray diffraction and Ca and SrK alpha X-ray fluorescence microscopy, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS263(1)pp. 1-6
M Begum, AKMM Rahman, HA Abdul-Rashid, Z Yusoff, KA Mat-Sharif, MI Zulkifli, SZ Muhamad-Yasin, NM Ung, ABA Kadir, YM Amin, DA Bradley (2015)Comparison of thermoluminescence response of different sized Ge-doped flat fibers as a dosimeter, In: RADIATION PHYSICS AND CHEMISTRY116pp. 155-159 PERGAMON-ELSEVIER SCIENCE LTD
Amani Alalawi, Shakardokht Jafari, M Najem, K Clark, A Nisbet, F Abolaban, R Hugtenburg, M Hussein, Khalid Alzimami, N Spyrou, D Bradley (2013)Comparison of Ge-doped TL optical fibres and glass beads with ion chamber and Gafchromic film for small field photon dosimetry, In: 1st International Conference on Dosimetry and its Applications - Book of abstractspp. pp1-206 České vysoké učení technické v Praze Fakulta jaderná a fyzikálně inženýrská

Small field (≤ 4 × 4 cm) photon radiotherapy treatments include intensity-modulated radiation therapy (IMRT)and stereotactic body radiation therapy (SBRT). These require small, high spatial resolution dosimeters of adequate dynamic range. In this study, field sizes of 1 cm × 1 cm, 2 cm × 2 cm, 3 cm × 3 cm, 4 cm × 4 cm, and 10 cm × 10 cm have been investigated using commercially available silica-based fibres and glass beads (GB) as TL dosimeters and a Varian linear accelerator operating at 6, 10 and 15 MV. Ge-doped SiO2 fibres have previously been shown by this group to offer a viable system for use as dosimeters. The fibres and GB, offer good spatial resolution (∼120 μm and 2 mm respectively), large dynamic dose range (with linearity from tens of mGy up to well in excess of many tens of Gy), a non-hygroscopic nature and low cost. The main aim of this present work is to investigate the use of Ge-doped optical fibres and GBs as thermoluminescence dosimeters in small photon fields for different photon beam energies, comparing the measurements against Gafchromic films, hospital commissioning data obtained from small ionisation chambers and photon diodes and Monte Carlo simulations with FLUKA and BEAMnrc.

F Mohamed, DA Bradley, CP Winlove (2007)Effects of ionizing radiation on extracellular matrix, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT580(1)pp. 566-569
E Daar, E Woods, JL Keddie, A Nisbet, DA Bradley (2010)Effect of penetrating ionising radiation on the mechanical properties of pericardium, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 356-360
DJ Garrity, AJ De Rosa, DA Bradley, SE Jarman, PM Jenneson, SM Vincent (2010)Development of a prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD), In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 287-290
DA Bradley, RP Hugtenburg, AL Yusoff (2006)At-edge minima in elastic photon scattering amplitudes for dilute aqueous ions, In: RADIATION PHYSICS AND CHEMISTRY75(11)pp. 1676-1682
GA Mahdiraji, E Dermosesian, MJ Safari, FRM Adikan, DA Bradley (2015)Collapsed-Hole Ge-Doped Photonic Crystal Fiber as a Diagnostic Radiation Dosimeter, In: JOURNAL OF LIGHTWAVE TECHNOLOGY33(16)pp. 3439-3445 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
S Hashim, MHA Mhareb, SK Ghoshal, YSM Alajerami, DA Bradley, MI Saripan, N Tamchek, K Alzimami (2015)Luminescence characteristics of Li2O-MgO-B2O3 doped with Dy3+ as a solid TL detector, In: RADIATION PHYSICS AND CHEMISTRY116pp. 138-141 PERGAMON-ELSEVIER SCIENCE LTD
ATA Rahman, DA Bradley, SJ Doran, B Thierry, E Braeuer-Krisch, A Bravin (2010)The thermoluminescence response of Ge-doped silica fibres for synchrotron microbeam radiation therapy dosimetry, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 167-170
MI Saripan, WHM Saad, S Hashim, ATA Rahman, K Wells, DA Bradley (2013)Analysis of Photon Scattering Trends for Material Classification Using Artificial Neural Network Models, In: IEEE TRANSACTIONS ON NUCLEAR SCIENCE60(2)pp. 515-519 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
K Geraki, MJ Farquharson, DA Bradley, O Gundogdu, G Falkenberg (2008)The localisation of biologically important metals in soft and calcified tissues using a synchrotron x-ray fluorescence technique, In: X-RAY SPECTROMETRY37(1)pp. 12-20 JOHN WILEY & SONS LTD
MH Abdelkader, SM Alkhateeb, DA Bradley, S Pani (2012)Development and characterization of a laboratory based X-ray diffraction imaging system for material and tissue characterization., In: Appl Radiat Isot70(7)pp. 1325-1330 Elsevier

Soft tissues feature a degree of short-range order, giving rise to diffraction patterns with broader peaks than crystalline materials. For this reason, an X-ray diffraction system (XRD) for characterization of soft tissue has less stringent requirements in terms of momentum transfer resolution than the one aimed at characterizing crystalline materials. We present results on the characterization of two energy-dispersive XRD systems. The first was based on conical collimation at 5.9° and the second was based on linear collimation at varying angles between 2° and 10°. The systems include a CdTe detector and a W-anode X-ray source. The angular resolution was measured as a function of sample thickness and scattering angle. Preliminary results confirm the effectiveness of the method for the characterization of biological tissues, showing insensitivity to small changes in angular acceptance and sample thickness, also showing it is possible to combine scattering data obtained at different angles.

AS Habib, DA Bradley, PH Regan, AL Shutt (2010)The use of MCNP and gamma spectrometry in supporting the evaluation of NORM in Libyan oil pipeline scale, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 245-251
MJ Farquharson, A Al-Ebraheem, G Falkenberg, R Leek, AL Harris, DA Bradley (2008)The distribution of trace elements Ca, Fe, Cu and Zn and the determination of copper oxidation state in breast tumour tissue using mu SRXRF and mu XANES, In: PHYSICS IN MEDICINE AND BIOLOGY53(11)pp. 3023-3037 IOP PUBLISHING LTD
SM Alkhateeb, MH Abdelkader, DA Bradley, S Pani (2012)Breast tissue contrast-simulating materials using energy-dispersive X-ray diffraction, In: Applied Radiation and Isotopes Elsevier
RP Hugtenburg, F Saeedi, DA Bradley (2007)Modeling dose response to synchrotron X-rays in solid-state and biological systems, In: RADIATION EFFECTS AND DEFECTS IN SOLIDS162(10-12)pp. 765-769
AL Palmer, DA Bradley, A Nisbet (2015)Evaluation and mitigation of potential errors in radiochromic film dosimetry due to film curvature at scanning., In: J Appl Clin Med Phys16(2)pp. 5141-?

This work considers a previously overlooked uncertainty present in film dosimetry which results from moderate curvature of films during the scanning process. Small film samples are particularly susceptible to film curling which may be undetected or deemed insignificant. In this study, we consider test cases with controlled induced curvature of film and with film raised horizontally above the scanner plate. We also evaluate the difference in scans of a film irradiated with a typical brachytherapy dose distribution with the film naturally curved and with the film held flat on the scanner. Typical naturally occurring curvature of film at scanning, giving rise to a maximum height 1 to 2 mm above the scan plane, may introduce dose errors of 1% to 4%, and considerably reduce gamma evaluation passing rates when comparing film-measured doses with treatment planning system-calculated dose distributions, a common application of film dosimetry in radiotherapy. The use of a triple-channel dosimetry algorithm appeared to mitigate the error due to film curvature compared to conventional single-channel film dosimetry. The change in pixel value and calibrated reported dose with film curling or height above the scanner plate may be due to variations in illumination characteristics, optical disturbances, or a Callier-type effect. There is a clear requirement for physically flat films at scanning to avoid the introduction of a substantial error source in film dosimetry. Particularly for small film samples, a compression glass plate above the film is recommended to ensure flat-film scanning. This effect has been overlooked to date in the literature.

S Hashim, DA Bradley, N Peng, AT Ramli, H Wagiran (2010)The thermoluminescence response of oxygen-doped optical fibres subjected to photon and electron irradiations, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 291-294
O Gundogdu, EC Ismail, RM Jenneson, DA Bradley (2009)Making Clear the Imperceptible: In-Line X-ray Phase Contrast Imaging, In: ADVANCED SCIENCE LETTERS2(1)pp. 78-80 AMER SCIENTIFIC PUBLISHERS
JCG Jeynes, M Webb, KJ Kirkby, NF Kirkby, DA Bradley (2009)Proceedings of the First International Conference on Biomedical Applications of High Energy Ion Beams Preface, In: APPLIED RADIATION AND ISOTOPES67(3)pp. 369-370 PERGAMON-ELSEVIER SCIENCE LTD
AT Ramli, DA Bradley, S Hashim, H Wagiran (2009)The thermoluminescence response of doped SiO2 optical fibres subjected to alpha-particle irradiation, In: APPLIED RADIATION AND ISOTOPES67(3)pp. 428-432 PERGAMON-ELSEVIER SCIENCE LTD
MJ Farquharson, A Al-Ebraheem, C Theodorakou, E Ryan, DA Bradley, K Gurusamy, B Davidson (2009)Measurement of K, Fe, Cu and Zn levels in secondary colorectal liver cancer and surrounding normal liver tissue, and their potential as a tissue classifier, In: X-RAY SPECTROMETRY38(2)pp. 81-88 JOHN WILEY & SONS LTD
RP Hugtenburg, AS Adegunloye, DA Bradley (2010)X-ray microbeam radiation therapy calculations, including polarisation effects, with the Monte Carlo code EGS5, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier
D Malain, PH Regan, DA Bradley, M Matthews, HA Al-Sulaiti, T Santawamaitre (2012)An evaluation of the natural radioactivity in Andaman beach sand samples of Thailand after the 2004 tsunami., In: Appl Radiat Isot70(8)pp. 1467-1474

Following the 2004 'Boxing day' tsunami, a determination has been made of the activity concentrations of (226)Ra, (232)Th and (40)K in beach sand samples which have been collected from various locations along the Andaman coast of the Thai peninsula. Use has been made of a HPGe detector-based, low-background gamma-ray counting system. The natural radioactivity levels of (226)Ra, (232)Th and (40)K measured from these samples was found to lie in the range 1.6-52.5, 0.3-73.9 and 2.8-1111.9Bq/kg respectively for the west coast and 3.5-83.1, 4.5-42.0, and 9.6-1376 Bq/kg respectively for the east coast. The radioactivity concentrations of (226)Ra, (232)Th and (40)K along the Andaman coast are comparable to that of the east coast, which was not exposed to the tsunami. The corresponding annual effective dose varies from 1.6-105.9 μSv/y with a mean value of 59.1 ± 0.3 μSv/y, significantly lower than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2000).

DA Bradley, MJ Farquharson, O Gundogdu, A Al-Ebraheem, EC Ismail, W Kaabar, O Bunk, F Pfeiffer, G Falkenberge, M Bailey (2010)Applications of condensed matter understanding to medical tissues and disease progression: Elemental analysis and structural integrity of tissue scaffolds, In: RADIATION PHYSICS AND CHEMISTRY79(2)pp. 162-175
W Kaabar, O Gundogdu, M Tzaphlidou, M Janousch, D Attenburrow, DA Bradley (2008)Investigation of essential element distribution in the equine metacarpophalangeal joint using a synchrotron radiation micro x-ray fluorescence technique, In: CURRENT ISSUES OF PHYSICS IN MALAYSIA1017pp. 18-24
D Bradley, N Hoggard (2014)Happy New Year from BJR!, In: Br J Radiol87(1033)pp. 20130778-?
S Hashim, YSM Alajerami, AT Ramli, SK Ghoshal, MA Saleh, ABA Kadir, MI Saripan, K Alzimami, DA Bradley, MHA Mhareb (2014)Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides, In: APPLIED RADIATION AND ISOTOPES91pp. 126-130 PERGAMON-ELSEVIER SCIENCE LTD
David Bradley, SF Abdul Sani, AI Alalawi, Shakardokht Jafari, Andrew Nisbet, NM Noor, AR Hairul Azhar, GA Mahdiraji, N Tamchek, S Ghosh, MC Paul, KS Alzimami, MJ Maah (2014)Development of tailor-made silica fibres for TL dosimetry, In: Radiation Physics and Chemistry104pp. 3-9

The Ge dopant in commercially available silica optical fibres gives rise to appreciable thermoluminscence (TL), weight-for-weight offering sensitivity to MV X-rays several times that of the LiF dosimeter TLD100. The response of these fibres to UV radiation, X-rays, electrons, protons, neutrons and alpha particles, with doses from a fraction of 1Gy up to 10kGy, have stimulated further investigation of the magnitude of the TL signal for intrinsic and doped SiO fibres. We represent a consortium effort between Malaysian partners and the University of Surrey, aimed at production of silica fibres with specific TL dosimetry applications, utilizing modified chemical vapour deposition (MCVD) doped silica-glass production and fibre-pulling facilities. The work is informed by defect and dopant concentration and various production dependences including pulling parameters such as temperature, speed and tension; the fibres also provide for spatial resolutions down to

SN Sabtu, RH Mahat, YM Amin, DM Price, DA Bradley, MJ Maah (2015)Thermo luminescence dating analysis at the site of an ancient brick structure at Pengkalan Bujang, Malaysia, In: APPLIED RADIATION AND ISOTOPES105pp. 182-187 PERGAMON-ELSEVIER SCIENCE LTD
EZ Dalah, A Nisbet, D Bradley (2010)Effect of window level on target volume delineation in treatment planning, In: APPLIED RADIATION AND ISOTOPES68(4-5)pp. 602-604
NH Yaakob, H Wagiran, MI Hossain, AT Ramli, DA Bradley, S Hashim, H Ali (2011)Thermoluminescence response of Ge- and Al-doped optical fibers subjected to low-dose electron irradiation, In: Journal of Nuclear Science and Technology48(7)pp. 1115-1117
DA Bradley, GA Mandiraji, M Ghomeishi, E Dermosesian, FRM Adikan, HAA Rashid, MJ Maah (2015)Enhancing the radiation dose detection sensitivity of optical fibres, In: APPLIED RADIATION AND ISOTOPES100pp. 43-49 PERGAMON-ELSEVIER SCIENCE LTD
SF Abdul Sani, AI Alalawi, Andrew Nisbet, David Bradley, H Azhar A R, G Amouzad Mahdiraji, N Tamchek, MJ Maah (2014)High sensitivity flat SiO fibres for medical dosimetry, In: Radiation Physics and Chemistry104pp. 134-138

We describe investigation of a novel undoped flat fibre fabricated for medical radiation dosimetry. Using high energy X-ray beams generated at a potential of 6MV, comparison has been made of the TL yield of silica flat fibres, TLD-100 chips and Ge-doped silica fibres. The flat fibres provide competitive TL yield to that of TLD-100 chips, being some 100 times that of the Ge-doped fibres. Pt-coated flat fibres have then been used to increase photoelectron production and hence local dose deposition, obtaining significant increase in dose sensitivity over that of undoped flat fibres. Using 250kVp X-ray beams, the TL yield reveals a progressive linear increase in dose for Pt thicknesses from 20nm up to 80nm. The dose enhancement factor (DEF) of (0.0150±0.0003)nm Pt is comparable to that obtained using gold, agreeing at the 1% level with the value expected on the basis of photoelectron generation. Finally, X-ray photoelectron spectroscopy (XPS) has been employed to characterize the surface oxidation state of the fibre medium. The charge state of Si2p was found to lie on 103.86eV of binding energy and the atomic percentage obtained from the XPS analysis is 22.41%. © 2014 Elsevier Ltd.

A Campbell, R Rawcliffe, A Guite, JCD Faria, A Mukherjee, MA McLachlan, M Shkunov, DDC Bradley (2016)Charge-Carrier Density Independent Mobility in Amorphous Fluorene-Triarylamine Copolymers, In: ADVANCED FUNCTIONAL MATERIALS26(21)pp. 3720-3729 WILEY-V C H VERLAG GMBH
W Kaabar, E Daar, O Bunk, MJ Farquharson, A Laklouk, M Bailey, C Jeynes, O Gundogdu, DA Bradley (2011)Elemental and structural studies at the bonecartilage interface, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment652(1)pp. 786-790
S Hashim, YSM Alajerami, SK Ghoshal, MA Saleh, MI Saripan, ABA Kadir, DA Bradley, K Alzimami (2014)Dosimetric characteristics of LKB:Cu,P solid TL detector, In: RADIATION PHYSICS AND CHEMISTRY104pp. 36-39 PERGAMON-ELSEVIER SCIENCE LTD
AS Siti Shafiqah, YM Amin, R Md Nor, N Tamchek, MS Khairul Anuar, HA Abdul Rashid, DA Bradley (2015)Properties of ge-doped silica preform by raman spectroscopy, In: ARPN Journal of Engineering and Applied Sciences10(15)pp. 6214-6218

©2006-2015 Asian Research Publishing Network (ARPN).In the present work, the structural modifications of Ge-doped silica preforms due to γ-irradiation at room temperature have been investigated using Raman spectroscopy. The MCVD fabricated preforms labelled as P1 and P2 are distinguishable by the oxidation and thermal history during the fabrication process, in which related to the oxygen bonding of SiO4 tetrahedral. From Raman analysis, the 480 cm-1(D1) and 609 cm-1(D2) peaks are the main network features of pure and doped silica glass, suggest the formation of defect centers in the preforms. The structural modifications of this defects centers are more sensitive in P2, due to the oxygen deficient state of the preform.

NN Zulkepely, YM Amin, RM Nor, DA Bradley, MJ Maah, SNM Nawi, NF Wahib (2015)Preliminary results on the photo-transferred thermoluminescence from Ge-doped SiO2 optical fiber, In: RADIATION PHYSICS AND CHEMISTRY117pp. 108-111 PERGAMON-ELSEVIER SCIENCE LTD
KH Al-Hinai, NB Mohd, NR Zulkepely, RM Nor, YM Amin, DA Bradley (2013)A search for novel thermoluminescent radiation dosimeter media, In: APPLIED RADIATION AND ISOTOPES82pp. 126-129 PERGAMON-ELSEVIER SCIENCE LTD
EZ Dalah, A Nisbet, S Reise, D Bradley (2008)Evaluating commercial image registration packages for radiotherapy treatment planning, In: APPLIED RADIATION AND ISOTOPES66(12)pp. 1948-1953 PERGAMON-ELSEVIER SCIENCE LTD
YSM Alajerami, S Hashim, SK Ghoshal, MA Saleh, T Kadni, MI Saripan, K Alzimami, Z Ibrahim, DA Bradley (2013)The Effect of TiO2 and MgO on the Thermo luminescence Properties of a Lithium Potassium Borate Glass System, In: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS74(12)pp. 1816-1822 PERGAMON-ELSEVIER SCIENCE LTD
S.F. Abdul Sani, R Hammond, Shakardokht Jafari, N Wahab, G Amouzad Mahdiraji, A S Siti Shafiqah, H A Abdul Rashid, M J Maah, H Aldousari, Mohammed Alkhorayef, M Alzimami, David Bradley (2016)Measurement of a wide-range of X-ray doses using specialty doped silica fibres, In: Radiation Physics and Chemistry137pp. 49-55 http://www.elsevier.com/

Using six types of tailor-made doped optical fibres, we carry out thermoluminescent (TL) studies of X-rays, investigating the TL yield for doses from 20 mGy through to 50 Gy. Dosimetric parameters were investigated for nominal 8 wt% Ge doped fibres that in two cases were co-doped, using B in one case and Br in the other. A comparative measurement of surface analysis has also been made for non-annealed and annealed capillary fibres, use being made of X-ray Photoelectron Spectroscopy (XPS) analysis. Comparison was made with the conventional TL phosphor LiF in the form of the proprietary product TLD-100, including dose response and glow curves investigated for X-rays generated at 60 kVp over a dose range from 2 cGy to 50 Gy. The energy response of the fibres was also performed for X-rays generated at peak accelerating potentials of 80 kVp, 140 kVp, 250 kVp and 6 MV photons for an absorbed dose of 2 Gy. Present results show the samples to be suitable for use as TL dosimeters, with good linearity of response and a simple glow curve (simple trap) distribution. It has been established that the TL performance of an irradiated fibre is not only influenced by radiation parameters such as energy, dose-rate and total dose but also the type of fibre.

SNBM Nawi, NFB Wahib, NNB Zulkepely, YBM Amin, UN Min, DA Bradley, RBM Nor, MJ Maah (2015)The Thermoluminescence Response of Ge-Doped Flat Fibers to Gamma Radiation, In: SENSORS15(8)pp. 20557-20569 MDPI AG
E Dalah, D Bradley, A Nisbet (2010)A mathematical approach towards simulating a realistic tissue activity curve of Cu-64-ATSM for the purpose of sub-target volume delineation in radiotherapy, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 283-286
YSM Alajerami, S Hashim, SK Ghoshal, AT Ramli, MA Saleh, Z Ibrahim, T Kadni, DA Bradley (2013)Luminescence characteristics of Li2CO3-K2CO3-H3BO3 glasses co-doped with TiO2/MgO, In: APPLIED RADIATION AND ISOTOPES82pp. 12-19 PERGAMON-ELSEVIER SCIENCE LTD
ASS Shafiqah, YM Amin, RM Nor, N Tamchek, DA Bradley (2015)Enhanced TL response due to radiation induced defects in Ge-doped silica preforms, In: RADIATION PHYSICS AND CHEMISTRY111pp. 87-90 PERGAMON-ELSEVIER SCIENCE LTD
N Wahib, NN Zulkepely, SNM Nawi, YM Amin, YS Ling, SFA Sani, MJ Maah, DA Bradley (2015)Gamma irradiated thermoluminescence response of Ge-doped SiO2 fibre, In: APPLIED RADIATION AND ISOTOPES105pp. 158-162 PERGAMON-ELSEVIER SCIENCE LTD
SA Choulis, Y. Kim, J Nelson, D D Bradley, M Giles, M Shkunov, I McCulloch (2004)High Ambipolar and Balanced Carrier Mobility in Regioregular Poly(3-hexylthiophene), In: Applied Physics Letters85(17) AIP Publishing

The carrier transport of carefully purified regioregular poly(3-hexylthiophene) films was studied using time-of-flight photocurrent measurements. The authors find balanced ambipolar transport with a room-temp. mobility for holes of 3 * 10-4 cm2 V-1 s-1 and for electrons of 1.5 * 10-4 cm2 V-1 s-1 at elec. fields >=105 V/cm. The transport is relatively field independent and weakly temp. dependent, pointing to a high degree of chem. regioregularity and purity. These factors make poly(3-hexylthiophene) attractive for use in a range of electronic applications.

ASS Shafiqah, YM Amin, RM Nor, DA Bradley (2015)Effect of particle size on the thermoluminescence (TL) response of silica nanoparticles, In: RADIATION PHYSICS AND CHEMISTRY117pp. 102-107 PERGAMON-ELSEVIER SCIENCE LTD
AT Abdul Rahman, E Bräuer-Krisch, T Brochard, J Adamovics, SK Clowes, D Bradley, SJ Doran (2011)Sophisticated test objects for the quality assurance of optical computed tomography scanners., In: Phys Med Biol56(14)pp. 4177-4199

Optical computed tomography (CT), in conjunction with radiochromic gels and plastics, shows great potential for radiation therapy dose verification in 3D. However, an effective quality assurance (QA) regime for the various scanners currently available still remains to be developed. We show how the favourable properties of the PRESAGE® radiochromic polymer may be exploited to create highly sophisticated QA phantoms. Five 60 mm diameter cylindrical PRESAGE® samples were irradiated using the x-ray microbeam radiation therapy facility on the ID-17 biomedical beamline at the European Synchrotron Radiation Facility. Samples were then imaged on the University of Surrey parallel-beam optical CT scanner. The sample irradiations were designed to allow a variety of tests to be performed, including assessments of linearity, modulation transfer function (three independent measurements), geometric distortion and the effect of treatment fractionation. It is clear that, although the synchrotron method produces extremely high-quality test objects, it is not practical on a routine basis, because of its reliance on a highly specialized radiation source. Hence, we investigated a second possibility: three PRESAGE® samples were illuminated with ultraviolet light of wavelength 365 nm, using cheap masks created by laser-printing patterns onto overhead projector acetate sheets. There was good correlation between optical densities measured by the CT scanner and the expected UV 'dose' delivered. The results are encouraging and a proposal is made for a scanner test regime based on calibrated and well-characterized PRESAGE® samples.

S Yalcin, O Gurler, O Gundogdu, DA Bradley (2012)A practical method for in-situ thickness determination using energy distribution of beta particles, In: APPLIED RADIATION AND ISOTOPES70(1)pp. 128-132 Elsevier
OB Uwatse, MA Olatunji, MU Khandaker, YM Amin, DA Bradley, M Alkhorayef, K Alzimami (2015)Measurement of Natural and Artificial Radioactivity in Infant Powdered Milk and Estimation of the Corresponding Annual Effective Dose, In: ENVIRONMENTAL ENGINEERING SCIENCE32(10)pp. 838-846 MARY ANN LIEBERT, INC