Silvia Pani

Dr Silvia Pani


Senior Lecturer in Applied Radiation Physics
+44 (0)1483 682276
18 BB 03

Biography

University roles and responsibilities

  • Programme Director, MSc Medical Physics
  • Radiation Protection Supervisor for X-ray laboratories (Physics department)
  • Member of the Departmental Health and Safety Committee

My qualifications

1996
"Laurea" in Physics (MPhys)
University of Trieste (Italy)
2001
PhD in Physics
University of Trieste
2010
Postgraduate Certificate in Academic Practice
University of Surrey

Affiliations and memberships

Fellow of the Higher Education Academy

Courses I teach on

Postgraduate taught

My publications

Publications

Griffiths JA, Metaxas MG, Pani S, Schulerud H, Esbrand C, Royle GJ, Price B, Rokvic T, Longo R, Asimidis A, Bletsas E, Cavouras D, Fant A, Gasiorek P, Georgiou H, Hall G, Jones J, Leaver J, Li G, Machin D, Manthos N, Matheson J, Noy M, Ostby JM, Psomadellis F, van der Stelt PF, Theodoridis S, Triantis F, Turchetta R, Venanzi C, Speller RD (2008) Preliminary images from an adaptive imaging system, PHYSICA MEDICA 24 (2) pp. 117-121 IST EDITORIALI POLGRAFICI INT
Prest M, Vallazza E, Chiavacci M, Mariani R, Motto S, Neri M, Scantamburlo N, Arfelli F, Conighi A, Lengo R, Olivo A, Pani S, Poropat P, Rashevsky A, Rigon L, Tromba G, Castelli E (2001) FROST: a low-noise high-rate photon counting ASIC for X-ray applications, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 461 (1-3) pp. 435-439 ELSEVIER SCIENCE BV
Galbiati A, Metaxas MG, Avset BS, Bergamaschi A, Cavouras D, Evangelou I, Fant A, French MJ, Georgiou H, Hall G, Iles G, Li G, Longo R, Manthos N, Ostby JM, Pani S, Peterzol A, Psomadellis F, Royle GJ, Schulerud H, Speller RD, Van Der Stelt PF, Theodoridis S, Triantis F, Turchetta R (2004) The I-Imas project: End-Users driven specifications for the design of a novel digital medical imaging system, IEEE Nuclear Science Symposium Conference Record 5 pp. 2742-2746
The I-Imas (Intelligent Imaging Sensors) is an EU project whose objective is to design and develop intelligent imaging sensors and evaluate their use within an adaptive medical imaging system specifically tailored to Mammography and Dental Radiology. The system will employ an in line scanning technology approach and proposes the use of CMOS active pixels sensors. The I-Imas sensor will have the capability of processing the data on every pixel and be able to dynamically respond in real time to changing conditions during imaging recording. The result will be to minimise the radiation exposure to areas of low diagnostic information content while extracting the highest diagnostic information from region of high interest. The first phase of the I-Imas project deals with the characterisation of the key features in a medical image that carry the highest content of diagnostic information. With this objective in mind an End-Users Survey has been carried out. We have been distributed a questionnaire to experts in the field of mammography and dental radiology (the dental radiology results will be presented elsewhere): medical physicists, radiologists, radiographers and dentists. From this survey we have collected information about the most useful specifications to be implemented in the I-Imas imaging system. This paper discusses the results from the End-Users survey and considers design implications for the I-Imas sensors. © 2004 IEEE.
Diaz O, Elangovan P, Wells K, Enshaeifar S, Veale M, Wilson M, Seller P, Cernik R, Pani S (2014) Breast CT image simulation framework for optimisation of lesion visualisation, IEEE Nuclear Science Symposium Conference Record pp. 1-5 IEEE
Although X-ray mammography is the gold standard technique for breast cancer detection, it suffers from limitations due to tissue superposition which could either obscure or mimic a breast lesion. Dedicated breast computed-tomography (BrCT) represents an alternative technology with the potential to overcome these limitations. However, this technology is still under investigation in order to study and improve certain parameters (e.g. dose, scattered radiation, etc.). In this work, an image simulation framework is proposed to generate realistic BrCT images and spectral imaging analysis is explored to enhance the contrast of breast lesions. Results illustrated an improvement in contrast between 5 and 10% when the final image is reconstructed using X-ray photons with energies between 21 and 30 keV, in comparison with the reconstructed image from the polychromatic energy spectrum recorded within the image receptor. © 2013 IEEE.
Pani S, Longo R, Dreossi D, Montanari F, Olivo A, Arfelli F, Bergamaschi A, Poropat P, Rigon L, Zanconati F, Dalla Palma L, Castelli E (2004) Breast tomography with synchrotron radiation: preliminary results., Phys Med Biol 49 (9) pp. 1739-1754
A system for in vivo breast imaging with monochromatic x-rays has been designed and built at the synchrotron radiation facility Elettra in Trieste (Italy) and will be operational in 2004. The system design involves the possibility of performing both planar mammography and breast tomography. In the present work, the first results obtained with a test set-up for breast tomography are shown and discussed. Tomographic images of in vitro breasts were acquired using monochromatic x-ray beams in the energy range 20-28 keV and a linear array silicon pixel detector. Tomograms were reconstructed using standard filtered backprojection algorithms; the effect of different filters was evaluated. The attenuation coefficients of fibroglandular and adipose tissue were measured, and a quantitative comparison of images acquired at different energies was performed by calculating the differential signal-to-noise ratio of fibroglandular details in adipose tissue. All images required a dose comparable to the dose delivered in clinical, conventional mammography and showed a high resolution of the breast structures without the overlapping effects that limit the visibility of the structures in 2D mammography. A quantitative evaluation of the images proves that the image quality at a given dose increases in the considered energy range and for the considered breast sizes.
Bergamaschi A, Dreossi D, Longo R, Olivo A, Pani S, Venanzi C, Castelli E (2004) A detection system for clinical breast tomography with synchrotron radiation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 535 (1-2) pp. 88-92 ELSEVIER SCIENCE BV
Olivo A, Arfelli F, Dreossi D, Longo R, Menk RH, Pani S, Poropat P, Rigon L, Zanconati F, Castelli E (2002) Preliminary study on extremely small angle x-ray scatter imaging with synchrotron radiation., Phys Med Biol 47 (3) pp. 469-480
Among the medical physics community, there is nowadays a great interest in the possible implementation of scatter imaging techniques, especially in the field of breast imaging. It is well known that malignant lesions and normal tissue differ in their scattering signatures, and thus scattered radiation can provide a powerful tool to distinguish between the two cases. Up to now, most of the proposed techniques rely on the detection of radiation scattered at angles of the order of a few degrees, which in most cases results in very high contrast values. On the other hand, at those relatively large angles the scattered flux is relatively low with respect to the primary, which often implies the necessity of increasing the dose delivered to the sample in order to achieve sufficient statistics. Furthermore, most of these techniques are based on pencil beam set-ups, which results in an increase of the overall duration of the examination. We propose here an alternative approach based on the detection of radiation scattered at extremely small angles, of the order of approximately 100-200 microrad. This results in a relatively high scattered flux (5-10% of the primary) and in the possibility of utilizing a fan beam geometry, which reduces the acquisition times with respect to pencil beam set-ups. Images of several samples have been acquired, demonstrating that the proposed technique results in an increased contrast with respect to absorption imaging. Possible in vivo implementations of the technique at no dose expense are finally discussed.
Wilson MD, Bell SJ, Seller P, Veale MC, Cernik RJ, Egan CK, Jacques S, Christodoulou C, O'Flynn D, Speller R, Pani S, Sellin PJ, Scuffham J (2013) Multiple module pixellated CdTe spectroscopic X-ray detector, IEEE Transactions on Nuclear Science 60 (2) pp. 1197-1200
A pixellated CdTe detector system comprising 2x2 detector modules has been developed for high energy spectroscopic X-ray imaging applications and has an active area of 16 cm. The detector modules are made from the HEXITEC 80x80 ASIC and 1 mm thick CdTe with Al-Schottky contacts. The CdTe has 250 ¼m pitch pixels with an outer guard ring on the same pitch. The single HEXITEC 80x80 detectors have an average energy resolution (FWHM) of 800 eV at 59.9 keV. Limitations in the multiple module DAQ system mean that the energy resolution of the pixels in the 2x2 detector array is 2.0 keV at 59.9 keV. The spacing between the tiled detector modules is 150 ¼ m which results in an inactive area equivalent to 3 pixels, including the guard ring on the edge of the detectors. The modular detector configuration demonstrates the potential to create large area detector arrays in the future. © 1963-2012 IEEE.
Schena G, Dreossi D, Montanari F, Olivo A, Pani S (2003) Multiple-energy X-ray radiography and digital subtraction for a particle-composition sensor, MINERALS ENGINEERING 16 (7) pp. 609-617 PERGAMON-ELSEVIER SCIENCE LTD
Contardo L, De Luca M, Biasotto M, Longo R, Olivo A, Pani S, Di Lenarda R (2005) Evaluation of the endodontic apical seal after post insertion by synchrotron radiation microtomography, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 548 (1-2) pp. 253-256 ELSEVIER SCIENCE BV
Esbrand CJ, Arvanitis CD, Pani S, Price BD, Griffiths JA, Metaxas M, Royle GJ, Noy M, Leaver J, Longo R, Rokvic T, Turchetta R, Giorgiou H, Schulerud H, Speller RD (2009) Characterisation of the Components of a Prototype Scanning Intelligent Imaging System for Use in Digital Mammography: The I-ImaS System, IEEE TRANSACTIONS ON NUCLEAR SCIENCE 56 (3) pp. 1419-1425 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Seller P, Bell S, Cernik RJ, Christodoulou C, Egan CK, Gaskin JA, Jacques S, Pani S, Ramsey BD, Reid C, Sellin PJ, Scuffham JW, Speller RD, Wilson MD, Veale MC (2011) Pixellated Cd(Zn)Te high-energy X-ray instrument, JOURNAL OF INSTRUMENTATION 6 ARTN C12009
Abrami A, Arfelli F, Barroso RC, Bergamaschi A, Bille F, Bregant P, Brizzi F, Casarin K, Castelli E, Chenda V, Palma LD, Dreossi D, Fava A, Longo R, Mancini L, Menk RH, Montanari F, Olivo A, Pani S, Pillon A, Quai E, Kaiser SR, Rigon L, Rokvic T, Tonutti M, Tromba G, Vaseotto A, Venanzi C, Zanconati F, Zanetti A, Zanini F (2005) Medical applications of synchrotron radiation at the SYRMEP beamline of ELETTRA, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 548 (1-2) pp. 221-227 ELSEVIER SCIENCE BV
Venanzi C, Bergamaschi A, Bruni F, Dreossi D, Longo R, Olivo A, Pani S, Castelli E (2005) A digital detector for breast computed tomography at the SYRMEP beam line, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 548 (1-2) pp. 264-268 ELSEVIER SCIENCE BV
Pani S, Speller R, Royle G, Olivo A (2010) Biomedical Sensors of Ionizing Radiation, In: Jones D (eds.), Biomedical Sensors pp. 129-237 Momentum Pr
Sensors Technology Series Editor-in-Chief's Preface vii Preface ix 1 Biomedical Sensors: Temperature Sensor ... G. Kim Prisk 4 Biomedical Sensors of Ionizing Radiation 129 Robert Speller, Alessandro Olivo, Silvia Pani, and Gary Royle 5 ...
Gambaccini M, Di Domenico G, Fantini A, Sabba N, Taibi A, Tartari A, Tuffanelli A, Zavattini G, Baraldi C, Casnati E, Pani R, Pellegrini R, Soluri A, Cinti MN, Bevilacqua A, Bollini D, Gombia M, Lanconelli L, Pani S, Olivo A, Rigon L, Arfelli F, Longo R, Poropat P, Del Guerra A (2001) Combined CT-SPECT tomography system for breast cancer study, PHYSICA MEDICA 17 (4) pp. 249-252 ISTITUTI EDITORIALI E POLGRAFICI INTERNAZIONALI
Cook EJ, Pani S, George L, Hardwick S, Horrocks JA, Speller RD (2009) Multivariate Data Analysis for Drug Identification Using Energy-Dispersive X-Ray Diffraction, IEEE TRANSACTIONS ON NUCLEAR SCIENCE 56 (3) pp. 1459-1464 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Green FH, Veale MC, Wilson MD, Seller P, Scuffham J, Pani S (2015) Scatter-free breast imaging using a monochromator coupled to a pixellated spectroscopic detector, MEDICAL IMAGING 2015: PHYSICS OF MEDICAL IMAGING 9412 SPIE-INT SOC OPTICAL ENGINEERING
Pani S, Cook E, Horrocks J, George L, Hardwick S, Speller R (2009) Modelling an Energy-Dispersive X-Ray Diffraction System for Drug Detection, IEEE TRANSACTIONS ON NUCLEAR SCIENCE 56 (3) pp. 1238-1241 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Xiao TQ, Bergamaschi A, Dreossi D, Longo R, Olivo A, Pani S, Rigon L, Rokvic T, Venanzi C, Castelli E (2005) Effect of spatial coherence on application of in-line phase contrast imaging to synchrotron radiation mammography, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 548 (1-2) pp. 155-162 ELSEVIER SCIENCE BV
Olivo A, Arfelli F, Cantatore G, Longo R, Menk RH, Pani S, Prest M, Poropat P, Rigon L, Tromba G, Vallazza E, Castelli E (2001) An innovative digital imaging set-up allowing a low-dose approach to phase contrast applications in the medical field., Med Phys 28 (8) pp. 1610-1619
Recently, new imaging modalities based on the detection of weak phase perturbations effects, among which are phase contrast and diffraction imaging, have been developed by several researchers. Due to their high sensitivity to weakly absorbing details, these techniques seem to be very promising for applications in the medical field. On the other hand, digital radiology is undergoing a wide diffusion, and its benefits are presently very well understood. Up to now, however, the strong pixel size constraints associated with phase contrast pattern detection limited the possibility of exploiting the advantages of phase contrast in digital radiology applications. In this paper, an innovative setup capable of removing the pixel size constraints, and thus opening the way to low dose digital phase contrast imaging, is described. Furthermore, we introduce an imaging technique based on the detection of radiation scattered at small angles: the information extracted from the sample is increased at no dose expense. We believe that several radiological fields, mammography being the first important example, may benefit from the herein described innovative imaging techniques.
Pani S, Saifuddin SC, Christodoulou C, Veale M, Seller P, Speller RD, Wilson M, Scuffham JW (2011) K-edge subtraction imaging using a pixellated energy-resolving detector, Proceedings of SPIE: Progress in Biomedical Optics and Imaging 7961
Tzaphlidou M, Speller R, Royle G, Griffiths J, Olivo A, Pani S, Longo R (2005) High resolution Ca/P maps of bone architecture in 3D synchrotron radiation microtomographic images, APPLIED RADIATION AND ISOTOPES 62 (4) pp. 569-575 PERGAMON-ELSEVIER SCIENCE LTD
Griffiths JA, Royle GJ, Horrocks JA, Hanby AM, Pani S, Speller RD (2008) Angular dispersive diffraction microCT of small breast tissue samples, RADIATION PHYSICS AND CHEMISTRY 77 (4) pp. 373-380 PERGAMON-ELSEVIER SCIENCE LTD
Schena G, Chiaruttini C, Dreossi D, Olivo A, Pani S (2002) Grade of fine composite mineral particles by dual-energy X-ray radiography, INTERNATIONAL JOURNAL OF MINERAL PROCESSING 67 (1-4) PII S0301-7516(02)00037-6 pp. 101-122 ELSEVIER SCIENCE BV
Scuffham J, Wilson M, Pani S, Duarte D, Veale M, Bell S, Jacques S, Seller P, Sellin P, Cernik R (2012) High resolution dual-tracer brain SPECT with a new high-performance CdTe detector, EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 39 pp. S230-S230 SPRINGER
Pani S (2012) Applications of X-ray diffraction imaging to Mammography, Recent Patents on Medical Imaging 2 (2) pp. 111-119
X-ray diffraction (XRD) imaging appears as an alternative to conventional (transmission) imaging for characterization of breast tissue. The diffraction pattern of a material depends upon its arrangement at the sub-molecular level, which is altered as cancer progresses. For this reason the diffraction patterns of normal and neoplastic tissue have a detectable difference, unlike their X-ray attenuation coefficients, which underpin conventional imaging. This paper presents key studies in the field of single-point characterization of breast tissue using XRD. It then describes the development of XRD imaging and the main approaches used. Existing studies in the field of XRD imaging of breast tissue, both in the Computed Tomography modality, allowing cross-sectional images of an object, and in the planar geometry, are compared. Finally, future developments, including the adaptation to breast tissue analysis of patented diffraction imaging techniques and technologies, are discussed. © 2012 Bentham Science Publishers.
Fabbri S, Taibi A, Longo R, Marziani M, Olivo A, Pani S, Tuffanelli A, Gambaccini M (2002) Signal-to-noise ratio evaluation radiography with synchrotron radiation, PHYSICS IN MEDICINE AND BIOLOGY 47 (22) PII S0031-9155(02)38088-6 pp. 4093-4105 IOP PUBLISHING LTD
Pani R, Soluri A, Scafè R, Pellegrini R, De Vincentis G, Cinti MN, Betti M, Inches R, Garibaldi G, Cusanno F, Gambaccini M, Fantini A, Taibi A, Olivo A, Pani S, Rigon L, Bollini D, Lanconelli N, Del Guerra A (2000) Feasibility study for SPECT mammography based on compact imagers rotating around breast vertical axis, IEEE Nuclear Science Symposium and Medical Imaging Conference 3
The detection limit of invasive carcinoma by standard prone scintimammography appears to be >= 1 cm diameter. Since it is desirable to detect lesions at very earliest stages of growth (0.8 cm or less), the development of prototype scintimammographic systems with improved imaging performances is a primary goal. In this paper we propose a dedicated high resolution breast imaging scanner for SPECT around the Vertical Axis Of Rotation (VAOR) with the breast in prone position. The rotating detector module consists of a compact position sensitive photomultiplier tube (PS-PMTHamamatsu R7600-00-C8 coupled to a CsI(Tl) scintillating array. The compactness is the peculiarity of this detector module to allow the lodging in the breast interspace, to work close to the chest wall and to minimize the tumor to collimator front distance. A preliminary study was performed by a breast phantom and 5 inches small FOV gamma camera with an actual rotation radius of 6.5 cm. Images were reconstructed using a filtered back projection implementation. Tumor SNR from planar images shown very low values; on the contrary reconstructed images strongly enhanced the contrast of a tumor 1 cm sized. A further enhancement was obtained by the compact detector module that was able to achieve higher SNR values for tumor less 1 cm sized).
Longo R, Pani S, Arfelli F, Dreossi D, Olivo A, Poropat P, Quaia E, Rigon L, Zanconati F, Dalla Palma L, Castelli E (2003) Morphological breast imaging: tomography and digital mammography with synchrotron radiation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 497 (1) pp. 9-13 ELSEVIER SCIENCE BV
Peterzol A, Olivo A, Rigon L, Pani S, Dreossi D (2005) The effects of the imaging system on the validity limits of the ray-optical approach to phase contrast imaging, MEDICAL PHYSICS 32 (12) pp. 3617-3627 AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS
Olivo A, Rigon L, Arfelli F, Cantatore G, Longo R, Menk RH, Pani S, Prest M, Poropat P, Tromba G, Vallazza E, Castelli E (2000) Experimental evaluation of a simple algorithm to enhance the spatial resolution in scanned radiographic systems., Med Phys 27 (11) pp. 2609-2616
In order to ensure an early diagnosis of breast cancer, an imaging system must fulfil extremely stringent requirements in terms of dynamic range, contrast resolution and spatial resolution. Furthermore, in order to reduce the dose delivered to the patient, a high efficiency of the detector device should be provided. In this paper the SYRMEP/FRONTRAD (SYnchrotron Radiation for MEdical Physics/FRONTier RADiology) mammography project, based on synchroton radiation and a novel solid state pixel detector, is briefly described. Particular relevance is given to the fact that the radiographic image is obtained by means of a scanning technique, which allows the possibility of utilizing a scanning step smaller than the pixel size. With this procedure, a convolution between the real image and the detector point spread function (PSF) is actually acquired: by carefully measuring the detector PSF, it is possible to apply a post-processing procedure (filtered deconvolution), which reconstructs images with enhanced spatial resolution. The image acquisition modality and the deconvolution algorithm are herein described, and some test object images, with spatial resolution enhanced by means of the filtered deconvolution procedure, are presented. As discussed in detail in this paper, this procedure allows us to obtain a spatial resolution determined by the scanning step, rather than by the pixel size.
Bergamaschi A, Prest M, Vallazza E, Arfelli F, Dreossi D, Longo R, Olivo A, Pani S, Castelli E (2003) FROST: an ASIC for digital mammography with synchrotron radiation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 510 (1-2) pp. 51-56 ELSEVIER SCIENCE BV
Olivo A, Arfelli F, Bergamaschi A, Dreossi D, Longo R, Montanari F, Menk RH, Pani S, Poropat P, Rigon L, Vallazza E, Castelli E (2003) Simultaneous acquisition of diffraction, scattering and phase-contrast images by means of a multi-layer edge-on microstrip detector, DIGITAL MAMMOGRAPHY, PROCEEDINGS pp. 48-50 SPRINGER-VERLAG BERLIN
Alkhateeb SM, Abdelkader MH, Bradley DA, Seller P, Veale MC, Wilson MD, Pani S (2013) Energy dispersive X-ray diffraction computed tomography of breastsimulating phantoms and a tissue sample, Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8668
Breast lesions and normal tissue have different characteristics of density and molecular arrangement that affect their diffraction patterns. X-ray diffraction can be used to determine the spatial structure of such tissues at the atomic and molecular level and Energy Dispersive X-Ray Diffraction Computed Tomography (EDXRDCT) can be used to produce 2-dimensional images of cross sections of the samples. The purpose of this work is to use an EDXRDCT system to find the limiting visibility for details that simulate breast lesions. Results are presented for EDXRDCT images of samples of different materials simulating breast tissue contrast and shapes. For simple circular details, the contrast between details and background in the images was measured with the goal of simulating the contrast between real breast tissue components. The limiting visible diameter was measured as a function of detail diameter for different combinations of scanning and geometrical parameters. Images of more complex test objects were assessed in terms of both contrast and accuracy of shape reproduction, evaluating the feasibility of using shape analysis as an additional parameter for lesion identification. The optimum combination of parameters are intended to be applied to the scanning of waxed breast tissue blocks. © 2013 SPIE.
Mills CA, Al-Otaibi H, Intaniwet A, Shkunov M, Pani S, Keddie JL, Sellin PJ (2013) Enhanced x-ray detection sensitivity in semiconducting polymer diodes containing metallic nanoparticles, Journal of Physics D: Applied Physics 46 (27) 275102 Institute of Physics
Semiconducting polymer X-radiation detectors are a completely new family of low-cost radiation detectors with potential application as beam monitors or dosimeters. These detectors are easy to process, mechanically flexible, relatively inexpensive, and able to cover large areas. However, their x-ray photocurrents are typically low as, being composed of elements of low atomic number (Z), they attenuate x-rays weakly. Here, the addition of high-Z nanoparticles is used to increase the x-ray attenuation without sacrificing the attractive properties of the host polymer. Two types of nanoparticles (NPs) are compared: metallic tantalum and electrically insulating bismuth oxide. The detection sensitivity of 5 µm thick semiconducting poly([9,9-dioctylfluorenyl-2,7-diyl]-co-bithiophene) diodes containing tantalum NPs is four times greater than that for the analogous NP-free devices; it is approximately double that of diodes containing an equal volume of bismuth oxide NPs. The x-ray induced photocurrent output of the diodes increases with an increased concentration of NPs. However, contrary to the results of theoretical x-ray attenuation calculations, the experimental current output is higher for the lower-Z tantalum diodes than the bismuth oxide diodes, at the same concentration of NP loading. This result is likely due to the higher tantalum NP electrical conductivity, which increases charge transport through the semiconducting polymer, leading to increased diode conductivity.
Alkhateeb SM, Abdelkader MH, Bradley DA, Pani S (2012) Breast tissue contrast-simulating materials using energy-dispersive X-ray diffraction, Applied Radiation and Isotopes Elsevier
Koutalonis M, Cook EJ, Griffiths JA, Horrocks JA, Gent C, Pani S, George L, Hardwick S, Speller R (2009) Designing an in-field system for illicit drug detection using X-ray diffraction, 2009 IEEE Nuclear Science Symposium Conference Record pp. 862-867 IEEE
One way of smuggling drugs into a country is via the postal and courier services. Automated systems are necessary to scan incoming parcels and make quick decisions on whether they contain drugs or not. Few false positive and negative results are an important requirement for the end users of such a system, as neither parcels containing drugs should be lost nor parcels without drugs should stop the workflow. According to previous studies, x-ray diffraction has demonstrated the potential to meet this requirement, as it has shown high ability in identifying drugs, compared to other methods. This is mainly due to the crystalline pattern of the drugs and their unique diffraction signature. The same technique has also been applied in explosives and calculi identification in the past with great success. In this study, a simulation model was developed simulating energy dispersive x-ray diffraction from the powder diffraction profiles of several materials that could be found in a common parcel. A database containing thousands of such materials has been collected. The aim of this study was to test several possible infield systems for drug identification and decide on the optimum that will be developed in the lab. To this direction, several geometries (including distances, collimation, scattering angles etc.), x-ray spectrum energies and detector energy resolutions (HPGe, CZT, Si and NaI) were tested. A variety of parcel sizes and compositions were designed and simulated and the results were analyzed using Multivariate Analysis (MVA). Results showed that several geometries and detectors can lead to a system with high sensitivity and specificity. The next step of this study is the development of these systems in the lab.
Green FH, Veale MC, Wilson MD, Seller P, Scuffham J, Pani S (2014) A novel approach to scatter-free imaging for the improvement of breast cancer Detection, Journal of Instrumentation 9 (12)
© 2014 IOP Publishing Ltd and Sissa Medialab srl.Compton scattering is one of the main causes of image degradation in X-ray imaging. This is particularly noticeable in mammography where details of interest feature low contrast in comparison to the surrounding tissue. This work shows the feasibility of obtaining scatter-free images by using a quasi-monochromatic X-ray beam and a pixellated spectroscopic detector. This work presents characterisation of the imaging system and quantitative imaging data of a low contrast test object. An improvement in contrast by 8% was observed compared to images obtained including scattered radiation. Comparison with a conventional setup showed an increase in the image quality factor when scatter has been removed.
Venanzi C, Bergamaschi A, Dreossi D, Longo R, Olivo A, Pani S, Castelli E (2004) A digital detection system for synchrotron radiation breast tomography, 2004 IEEE Nuclear Science Symposium Conference Record, Vols 1-7 pp. 4654-4656 IEEE
Pasini A, Baruffaldi F, Bettuzzi M, Brancaccio R, Casali F, Cornacchia S, Lanconelli N, Morigi MP, Di Nicola E, Pani S, Perilli E, Romani D, Rossi A (2004) A CCD-based high resolution CT system for analysis of trabecular bone tissue, IEEE Nuclear Science Symposium Conference Record 4 pp. 2273-2277
This paper illustrates the effectiveness of a new multi-slice CT system to study the trabecular bone tissue. The system is capable of acquiring 3D images of 5600×5600×52 voxels on specimens up to 130 mm with a spatial resolution of 22.5 micrometers. This new detector is coupled to a CCD intensified camera (EBCCD) and was patented by the University of Bologna. The CT acquisitions were performed with an experimental setup at Elettra facilities at beamline SYRMEP. The reconstructed images were sections containing the femoral head, femoral neck and trochantere. The used spatial resolution allows to visualize also thin trabeculae, which typically lie in a range below 100 microns. The morphometric trabecular characterization parameters as BV/TV, Tb.Th, Tb.Sp, Tb.N were calculated over three regions of interest. The local variations in trabecular and cortical structure of the examined bone are clearly visible at a level not obtainable with medical CT scanners. The quality of the reconstructed cross sections images confirm that this investigation technique is an advanced tool for high resolution three-dimensional imaging of bone structure. © 2004 IEEE.
Scuffham JW, Wilson MD, Duarte DD, Veale MC, Bell S, Seller P, Pani S, Sellin PJ, Cernik RJ (2012) Evaluation of a new small-pixel CdTe spectroscopic detector in dual-tracer SPECT brain imaging, IEEE Nuclear Science Symposium Conference Record pp. 3115-3118
Simultaneous dual-tracer brain imaging has the potential to shorten patient pathways in the diagnosis of neurodegenerative diseases, but the poor spectral resolution of conventional gamma cameras limits the utility of this technique. Solid state detectors offer improved capability to distinguish between two radioisotopes, but the technology has yet to be fully evaluated in the field of scintigraphic neuroimaging. We present imaging results for a new small-pixel CdTe detector in simultaneous dual-radioisotope scintigraphy of a brain phantom containing Tc-99m and I-123. Quantitative comparison is made with images of the same phantom obtained using a conventional gamma camera. We show that the CdTe detector offers improved scatter rejection and greatly reduced cross-talk between the energy windows. In addition, the new detector is able to resolve low-energy fluorescence x-rays from the source, which could be incorporated into SPECT reconstruction algorithms. Details of the planned development of the detector into a clinical demonstrator are discussed. © 2012 IEEE.
Pani S, Arfelli F, Bravin A, Cantatore G, Longo R, Olivo A, Poropat P, Rigon L, Tromba G, Castelli E, Fantini A, Tartari A, Gambaccini M, Pani R, Bollini D, Del Guerra A (2000) Tomographic imaging with synchrotron radiation, PHYSICA MEDICA 16 (3) pp. 155-159 ISTITUTI EDITORIALI E POLGRAFICI INTERNAZIONALI
Speller R, Pani S, Tzaphlidou M, Horrocks J (2005) MicroCT analysis of calcium/phosphorus ratio maps at different bone sites, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 548 (1-2) pp. 269-273 ELSEVIER SCIENCE BV
Schulerud H, Thielemann J, Kirkhus T, Kaspersen K, Østby JM, Metaxas MG, Royle GJ, Griffiths J, Cook E, Esbrand C, Pani S, Venanzi C, Speller RD, Van Der Stelt PF, Gang L, Turchetta R, Fant A, Theodoridis S, Georgiou H, Hall G, Noy M, Jones J, Leaver J, Triantis F, Asimidis A, Manthos N, Pani S, Longo R, Bergamaschi A (2007) Adaptive image content-based exposure control for scanning applications in radiography, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 4678 LNCS pp. 543-552
I-ImaS (Intelligent Imaging Sensors) is a European project which has designed and developed a new adaptive X-ray imaging system using on-line exposure control, to create locally optimized images. The I-ImaS system allows for real-time image analysis during acquisition, thus enabling real-time exposure adjustment. This adaptive imaging system has the potential of creating images with optimal information within a given dose constraint and to acquire optimally exposed images of objects with variable density during one scan. In this paper we present the control system and results from initial tests on mammographic and encephalographic images. Furthermore, algorithms for visualization of the resulting images, consisting of unevenly exposed image regions, are developed and tested. The preliminary results show that the same image quality can be achieved at 30-70% lower dose using the I-ImaS system compared to conventional mammography systems. © Springer-Verlag Berlin Heidelberg 2007.
Scuffham JW, Pani S, Seller P, Sellin PJ, Veale MC, Wilson MD, Cernik RJ (2015) Imaging of Ra-223 with a small-pixel CdTe detector, JOURNAL OF INSTRUMENTATION 10 ARTN C01029 IOP PUBLISHING LTD
Pani S, Royle G, Speller R, Castoldi A, Galimberti A, Guazzoni C (2007) Use of a novel controlled drift detector for diffraction enhanced breast imaging, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 573 (1-2) pp. 133-136 ELSEVIER SCIENCE BV
Bergamaschi A, Arfelli F, Dreossi D, Longo R, Olivo A, Pani S, Rigon L, Castelli E (2005) Edge on silicon microstrip detectors for medical imaging, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 549 (1-3) pp. 199-204 ELSEVIER SCIENCE BV
Olivo A, Pani S, Dreossi D, Montanari F, Bergamaschi A, Vallazza E, Arfelli F, Longo R, Rigon L, Castelli E (2003) A multilayer edge-on single photon counting silicon microstrip detector for innovative imaging techniques in diagnostic radiology, REVIEW OF SCIENTIFIC INSTRUMENTS 74 (7) pp. 3460-3465 AMER INST PHYSICS
Pani S, Saifuddin SC, Ferreira FIM, Sellin PJ, Scuffham JW, Stratmann P, Wilson MD, Veale MC, Bell S, Seller P, Cernik RJ (2012) Optimization of K-edge subtraction imaging using a pixellated spectroscopic detector, IEEE Nuclear Science Symposium Conference Record pp. 3063-3066
Conventional K-edge subtraction imaging is based around the acquisition of two separate images at energies respectively below and above the K-edge of a contrast agent. This implies increased patient dose with respect to a conventional procedure and potentially incorrect image registration due to patient motion. © 2012 IEEE.
Griffiths JA, Royle GJ, Speller RD, Horrocks JA, Olivo A, Pani S, Longo R, Spencer SH, Robbins MS, Clifford DP, Hanby AM (2003) Diffraction enhanced breast imaging: Assessment of realistic system requirements to improve the diagnostic capabilities of mammography, IEEE Nuclear Science Symposium Conference Record 5 pp. 3230-3234
A detectable difference in x-ray diffraction data of healthy and diseased breast tissues has been observed This information can be used to generate images with a higher contrast than that of conventional transmission mammography. A diffraction enhanced breast imaging (DEBI) system that simultaneously combines transmission and diffraction breast images is currently being developed. This paper presents the imaging system requirements for a clinical DEBI system. The DEBI imaging system employs a phosphor coated L3Vision CCD camera. The DEBI principle has been assessed at the SYRMEP synchrotron beamline (Elettra, Trieste) and with a purpose built mammographic x-ray imaging unit Diffraction enhanced images have been obtained of realistic breast tissue phantoms, consisting of 4cm thick slabs of excised breast tissue containing embedded carcinomas. The images were obtained at pre-determined momentum transfer values, allowing some tissue characterization to be achieved during imaging, as well as optimizing image contrast. This paper presents the current state of the project The spatial resolution of the diffraction images have been studied using test phantoms and suggestions are made for the collimation systems necessary for a clinical system. A correction procedure applied to the diffraction images is also presented.
Pani S, Cook EJ, Horrocks JA, Jones JL, Speller RD (2010) Characterization of breast tissue using energy-dispersive X-ray diffraction computed tomography, APPLIED RADIATION AND ISOTOPES 68 (10) pp. 1980-1987 PERGAMON-ELSEVIER SCIENCE LTD
Pani R, Cinti MN, Scafè R, Soluri A, Pellegrini R, De Vincentis G, Trotta G, Betti M, Burgio N, Ciavola C, Garibaldi F, Cusanno F, Zavattini G, Di Domenico G, Bollini D, Lanconelli N, Olivo A, Pani S, Rigon L, Del Guerra A (2000) Imaging evaluation of CsI(Tl) arrays for scintimammography, IEEE Nuclear Science Symposium and Medical Imaging Conference 3
Recently the application of small imagers in nuclear medicine is growing, particularly in scintimammography. In this paper we propose the use of the Hamamatsu R7600-C8 Position Sensitive Photomultiplier Tube (PSPMT) for detection image optimization in scintimammography through the evaluation of image performances of detector pixellation and its interaction with a collimator lattice . To this aim, a number of CsI(Tl) scintillating arrays with different pixel size and thickness were coupled to the same PSPMT. Considering the very high intrinsic spatial resolution, a look up table was realized to correct accurately the gain non uniformities. The results show an overall energy resolution FWHM, from flood field irradiation source, in close agreement with the individual crystal response and an uniformity response within ± 10%. Finally an analysis of tumor signal to noise ratio (SNR) as a function of detection pixellation was performed, utilizing a breast phantom. Tumor SNR values are highest for 5 mm thick CsI(Tl) arrays but shown slight differences with pixel size. The best tumor SNR value for 6 cm breast thick was obtained with 1.5 × 1.5 mm2 crystal pixel size. The collimator used was a low energy all purpose, parallel hole collimator with 22 mm length, 1.5 mm hexagonal hole, 0.2 mm Pb septa, currently utilized in scintimammography.
Gambaccini M, Fantini A, Marchesini R, Sabba N, Sartori L, Tuffanelli A, Taibi A, Pani S, Olivo A, Rigon L, Arfelli F, Longo R, Bollini D, Pani R, Del Guerra A (2000) Development of a small-field quasi-monochromatic computer tomography system, PHYSICA MEDICA 16 (3) pp. 161-164 ISTITUTI EDITORIALI E POLGRAFICI INTERNAZIONALI
Del Gerra A, Di Domenico G, Fantini A, Gambaccini M, Milano L, Sabba N, Taibi A, Tartari A, Tuffanelli A, Zavattini G, Pani R, Pellegrini R, Soluri A, Cinti MN, Bevilacqua A, Bollini D, Gombia M, Lanconelli N, Arfelli F, Longo R, Olivo A, Pani S, Poropat P, Rigon L (2003) A dedicated system for breast cancer study with combined SPECT-CT modalities, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 497 (1) pp. 129-134 ELSEVIER SCIENCE BV
Arfelli F, Bonvicini V, Bravin A, Cantatore G, Castelli E, Palma LD, Michiel MD, Fabrizioli M, Longo R, Menk RH, Olivo A, Pani S, Pontoni D, Poropat P, Prest M, Rashevsky A, Ratti M, Rigon L, Tromba G, Vacchi A, Vallazza E, Zanconati F (2000) Mammography with synchrotron radiation: phase-detection techniques., Radiology 215 (1) pp. 286-293
The authors evaluated the effect on mammographic examinations of the use of synchrotron radiation to detect phase-perturbation effects, which are higher than absorption effects for soft tissue in the energy range of 15-25 keV. Detection of phase-perturbation effects was possible because of the high degree of coherence of synchrotron radiation sources. Synchrotron radiation images were obtained of a mammographic phantom and in vitro breast tissue specimens and compared with conventional mammographic studies. On the basis of grades assigned by three reviewers, image quality of the former was considerably higher, and the delivered dose was fully compatible.
Pani S, Arfelli F, Dreossi D, Montanari F, Longo R, Olivo A, Poropat P, Zanconati F, Dalla Palma L, Castelli E (2002) Breast tomography with synchrotron radiation, MEDICAL IMAGING 2002: PHYSICS OF MEDICAL IMAGING 4682 pp. 228-235 SPIE-INT SOC OPTICAL ENGINEERING
Abdelkader MH, Alkhateeb SM, Bradley DA, Pani S (2012) Development and characterization of a laboratory based X-ray diffraction imaging system for material and tissue characterization., Appl Radiat Isot 70 (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.
Longo R, Olivo A, Arfelli F, Cantatore G, Pani S, Poropat R, Prest M, Rigon L, Vallazza E, Castelli E, Palma LD, Menk R, Tromba G (2001) Improvements in digital mammography with synchrotron radiation, IWDM 2000: 5TH INTERNATIONAL WORKSHOP ON DIGITAL MAMMOGRAPHY pp. 65-71 MEDICAL PHYSICS PUBLISHING
Castoldi A, Guazzoni C, Galimberti A, Hartmann R, Pani S, Royle G, Stueder L (2007) Application of controlled-drift detectors in diffraction enhanced Imaging of tissues, IEEE TRANSACTIONS ON NUCLEAR SCIENCE 54 (5) pp. 1474-1480 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Wilson MD, Dummott L, Duarte DD, Green FH, Pani S, Schneider A, Scuffham JW, Seller P, Veale MC (2015) A 10 cm x 10 cm CdTe Spectroscopic Imaging Detector based on the HEXITEC ASIC, JOURNAL OF INSTRUMENTATION 10 ARTN P10011 IOP PUBLISHING LTD
Bergamaschi A, Arfelli F, Dreossi D, Longo R, Olivo A, Pani S, Rigon L, Vallazza E, Venanzi C, Castelli E (2004) High-speed single photon counting read out electronics for a digital detection system for clinical synchrotron radiation mammography, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 518 (1-2) pp. 415-417 ELSEVIER SCIENCE BV
Griffiths JA, Speller RD, Royle GJ, Horrocks JA, Olivo A, Pani S, Longo R, Dreossi D, Spencer SH, Robbins MS, Clifford DP, Hanby AM (2003) X-Ray diffraction CT of excised breast tissue sections: First results from elettra, IEEE Nuclear Science Symposium Conference Record 4 pp. 2330-2334
The scattering properties of breast tissue have been suggested as a diagnostic tool in the early detection of breast cancer. To aid in the development of a clinical imaging system based upon these properties, a series of breast tissue samples have been subjected to diffraction microCT using the SYRMEP beamline at Elettra, Italy. Using 18 keV photons, both transmission and diffraction CT data sets were collected using a specially designed microCT system. This system was based around a finely collimated, x-ray sensitive L3Vision CCD camera and a simple rotary stage controlled using Lab View software. The images were reconstructed using routines developed in IDL. This paper presents both transmission and diffraction CT images of three samples. The samples were excised breast tissue sections known to contain either tumour, normal tissue adjacent to the tumour or a mixture of each. The results demonstrate that diffraction microCT can be used to evaluate the structure of breast tissue tumours. Registration of the transmission and diffraction CT images demonstrated that both techniques showed the same principle features in the sample and allowed the main components to be identified. However, the diffraction images demonstrated an average increase in image contrast over the transmission images. Further improvements in the collimator design used in the experiments will need to be made if detailed structure is to be seen.
Pani S, Saifuddin S, Ferreira FIM, Henthorn N, Sellers P, Sellin PJ, Stratmann P, Veale M, Wilson M, Cernik R (2017) High energy resolution hyperspectral X-ray imaging for low-dose contrast-enhanced digital mammography, IEEE Transactions on Medical Imaging 36 (9) pp. 1784-1795 IEEE
Contrast-enhanced digital mammography (CEDM) is an alternative to conventional X-ray mammography for imaging dense breasts. However, conventional approaches to CEDM require a double exposure of the patient, implying higher dose and risk of incorrect image registration due to motion artifacts.
A novel approach is presented, based on hyperspectral imaging, where a detector combining positional and high-resolution spectral information (in this case based on Cadmium Telluride) is used. This allows simultaneous acquisition of the two images required for CEDM. The approach was tested on a custom breast-equivalent phantom containing iodinated contrast agent (Niopam 150®).
Two algorithms were used to obtain images of the contrast agent distribution: K-edge subtraction (KES), providing images of the distribution of the contrast agent with the background structures removed, and a dual-energy (DE) algorithm, providing an iodine-equivalent image and a water-equivalent image. The high energy resolution of the detector allowed the selection of two close-by energies, maximising the signal in KES images and enhancing the visibility of details with low surface concentration of contrast agent. DE performed consistently better than KES in terms of contrast-to-noise ratio of the details; moreover, it allowed a correct reconstruction of the surface concentration of the contrast agent in the iodine image.
Comparison with CEDM with a conventional detector proved the superior performance of hyperspectral CEDM in terms of the image quality/dose trade-off.
Davis A, Palmer A, Pani S, Nisbet A (2017) Assessment of the variation in CT scanner performance (image quality and Hounsfield Units) with scan parameters, for image optimisation in radiotherapy treatment planning, Physica Medica: European Journal of Medical Physics 45 pp. 59-64 Elsevier, for Associazione Italiana di Fisica Medica and European Federation of Organisations for Medical Physics
Purpose:

To define a method and investigate how the adjustment of scan parameters affected the image quality and Hounsfield units (HUs) on a CT scanner used for radiotherapy treatment planning. A lack of similar investigations in the literature may be a contributing factor in the apparent reluctance to optimise radiotherapy CT protocols.

Method:

A Catphan phantom was used to assess how image quality on a Toshiba Aquilion LB scanner changed with scan parameters. Acquisition and reconstruction field-of-view (FOV), collimation, image slice thickness, effective mAs per rotation and reconstruction algorithm were varied. Changes were assessed for HUs of different materials, high contrast spatial resolution (HCSR), contrast-noise ratio (CNR), HU uniformity, scan direction low contrast and CT dose-index.

Results:

CNR and HCSR varied most with reconstruction algorithm, reconstruction FOV and effective mAs. Collimation, but not image slice width, had a significant effect on CT dose-index with narrower collimation giving higher doses. Dose increased with effective mAs. Highest HU differences were seen when changing reconstruction algorithm: 56 HU for densities close to water and 117 HU for bone-like materials. Acquisition FOV affected the HUs but reconstruction FOV and effective mAs did not.

Conclusions:

All the scan parameters investigated affected the image quality metrics. Reconstruction algorithm, reconstruction FOV, collimation and effective mAs were most important. Reconstruction algorithm and acquisition FOV had significant effect on HU. The methodology is applicable to radiotherapy CT scanners when investigating image quality optimisation, prior to assessing the impact of scan protocol changes on clinical CT images and treatment plans.

Thirimanne Hashini, Jayawardena K, Parnell A, Bandara R, Karalasingam A, Pani Silvia, Huerdler J, Lidzey D, Tedde S, Nisbet Andrew, Mills Chris, Silva Ravi (2018) High sensitivity organic inorganic hybrid X ray detectors with direct transduction and broadband response, Nature Communications 9 2926 Nature Publishing Group
X-ray detectors are critical to healthcare diagnostics, cancer therapy and homeland
security, with many potential uses limited by system cost and/or detector dimensions.
Current X-ray detector sensitivities are limited by the bulk X-ray attenuation of the
materials and consequently necessitate thick crystals (~ 1 mm ? 1 cm), resulting in rigid
structure, high operational voltages and high cost. Here we present a disruptive,
flexible, low cost, broad-band, and high sensitivity direct X-ray transduction technology
produced by embedding high atomic number bismuth oxide nanoparticles in an organic
bulk heterojunction. These hybrid detectors demonstrate sensitivities of 1712 µC mGy-1
cm-3 for ?soft? X-rays and ~30 and 58 µC mGy-1 cm-3 under 6 and 15 MV ?hard? X-rays
generated from a medical linear accelerator; strongly competing with the current solid state detectors, all achieved at low bias voltages (-10 V) and low power, enabling
detector operation powered by coin cell batteries.