Lucia Florescu

Dr Lucia Florescu


Lecturer in Medical Imaging
+44 (0)1483 686045
15 BA 00

About

Research

Research interests

Supervision

Postgraduate research supervision

Teaching

Publications

LUCIA MAGDALENA FLORESCU, MATTHEW JOHN FAULKNER, Vadim A Markel, John C Schotland (2019)Nonreciprocal Broken-Ray Tomography: Applications to Fluorescence Optical Imaging
Matthew Faulkner, Lucia Florescu (2019)Optical-CT with Incomplete Data for Applications to Radiation Dosimetry, In: Proceedings of Imaging and Applied Optics 2019 (COSI, IS, MATH, pcAOP)

Numerical experiments were performed to analyse the effect of data loss at the edges of the sample on the accuracy of optical-CT reconstruction, in the context of applications to radiation dosimetry.

Matthew J. Faulkner, John C Schotland, Vadim A Markel, Lucia Florescu (2022)Image reconstruction in non-reciprocal broken-ray tomography, In: Journal of the Optical Society of America A39(9)pp. 1621-1633 Optica Publishing Group

Optical methods of biomedical tomographic imaging are of considerable interest due to their non-invasive nature and sensitivity to physiologically important markers. Similarly to other imaging modalities, optical methods can be enhanced by utilizing extrinsic contrast agents. Typically, these are fluorescent molecules, which can aggregate in regions of interest due to various mechanisms. In the current approaches to imaging, the intrinsic (related to the tissue) and extrinsic (related to the contrast agent) optical parameters are determined separately. This can result in errors, in particular, due to using simplified heuristic models for the spectral dependence of the optical parameters. Recently, we have developed the theory of non-reciprocal broken-ray tomography (NRBRT) for fluorescence imaging of weakly scattering systems. NRBRT enables simultaneous reconstruction of the fluorophore concentration as well as of the intrinsic optical attenuation coefficient at both the excitation and the emission wavelengths. Importantly, no assumption about the spectral dependence of the tissue optical properties is made in NRBRT. In this study, we perform numerical validation of NRBRT under realistic conditions using the Monte Carlo method to generate forward data. We demonstrate that NRBRT can be used for tomographic imaging of samples of up to four scattering lengths in size. The effects of physical characteristics of the detectors such as the area and the acceptance angle are also investigated.

Lucia Florescu, Matthew Faulkner, Vadim A Markel, John C Schotland (2020)Fluorescence Optical Tomography of Mesocopic Systems, In: Proceedings of Clinical and Translational Biophotonics (Translational, Microscopy, OCT, OTS, BRAIN) Optica Publishing Group

We present a tomographic imaging technique based on angularly-selective measurements of fluorescent light that enables for the first time simultaneous reconstruction of the attenuation coefficient at two energies and of the contrast-agent concentration.

Lucia Florescu, Vadim A Markel, John C Schotland (2018)Nonreciprocal broken ray transforms with applications to fluorescence imaging, In: Inverse Problems34(9)094002 IOP Publishing

Broken ray transforms (BRTs) are typically considered to be reciprocal, meaning that the transform is independent of the direction in which a photon travels along a given broken ray. However, if the photon can change its energy (or be absorbed and re-radiated at a different frequency) at the vertex of the ray, then reciprocity is lost. In optics, non-reciprocal BRTs are applicable to imaging problems with fluorescent contrast agents. In the case of x-ray imaging, problems with single Compton scattering also give rise to non-reciprocal BRTs. In this paper, we focus on tomographic optical fluorescence imaging and show that, by reversing the path of a photon and using the non-reciprocity of the data function, we can reconstruct simultaneously and independently all optical properties of the medium (the intrinsic attenuation coefficients at the excitation and the fluorescence frequency and the concentration of the contrast agent). Our results are also applicable to inverting BRTs that arise due to single Compton scattering.