Simon Doran

• PhD
• Researcher at Institute of Cancer Research

Background: Evaluating AI-based segmentation models primarily relies on quantitative metrics, but it remains unclear if this approach leads to practical, clinically-applicable tools. Purpose: To create a systematic framework for evaluating the performance of segmentation models using clinically relevant criteria. Materials and Methods: We developed...

Objective. Image quality in whole-body MRI (WB-MRI) may be degraded by faulty radiofrequency (RF) coil elements or mispositioning of the coil arrays. Phantom-based quality control (QC) is used to identify broken RF coil elements but the frequency of these acquisitions is limited by scanner and staff availability. This work aimed to develop a scan-s...

Objectives MAchine Learning In MyelomA Response (MALIMAR) is an observational clinical study combining “real-world” and clinical trial data, both retrospective and prospective. Images were acquired on three MRI scanners over a 10-year window at two institutions, leading to a need for extensive curation. Methods Curation involved image aggregation,...

Introduction New lung nodules observed after prior radical cancer treatment present a complex and increasingly common problem for lung cancer MDTs. Existing research shows lung cancer is common with previous smoking-related cancers, potentially due to shared risk factors or long-term effects of anti-cancer therapies. Radiomics involves computationa...

Background The aim of this work is to evaluate the performance of radiomics predictions for a range of molecular, genomic and clinical targets in patients with clear cell renal cell carcinoma (ccRCC) and demonstrate the impact of novel feature selection strategies and sub-segmentations on model interpretability. Methods Contrast-enhanced CT scans...

Background Large lung nodules (≥15 mm) have the highest risk of malignancy, and may exhibit important differences in phenotypic or clinical characteristics to their smaller counterparts. Existing risk models do not stratify large nodules well. We aimed to develop and validate an integrated segmentation and classification pipeline, incorporating dee...

Recurrence occurs in up to 36% of patients treated with curative-intent radiotherapy for NSCLC. Identifying patients at higher risk of recurrence for more intensive surveillance may facilitate the earlier introduction of the next line of treatment. We aimed to use radiotherapy planning CT scans to develop radiomic classification models that predict...

Introduction Whole-body MRI (WB-MRI) is recommended by the National Institute of Clinical Excellence as the first-line imaging tool for diagnosis of multiple myeloma. Reporting WB-MRI scans requires expertise to interpret and can be challenging for radiologists who need to meet rapid turn-around requirements. Automated computational tools based on...

Glioblastomas are the most common and aggressive malignant primary tumor of the central nervous system in adults. The tumours are quite heterogeneous in its shape, texture, and histology. Patients that have been diagnosed with glioblastoma typically have low survival rates and it can take weeks to perform a genetic analysis of an extracted tissue s...

Introduction The spleen is a lymphoid organ and we hypothesize that clinical benefit to immunotherapy may present with an increase in splenic volume during treatment. The purpose of this study was to investigate whether changes in splenic volume could be observed in those showing clinical benefit versus those not showing clinical benefit to pembrol...

Purpose: XNAT is an informatics software platform to support imaging research, particularly in the context of large, multicentre studies of the type that are essential to validate quantitative imaging biomarkers. XNAT provides import, archiving, processing and secure distribution facilities for image and related study data. Until recently, however,...

Background Most MRI radiomics studies to date, even multi-centre ones, have used “pure” datasets deliberately accrued from single-vendor, single-field-strength scanners. This does not reflect aspirations for the ultimate generalisability of AI models. We therefore investigated the development of a radiomics signature from heterogeneous data origina...

Radiomics refers to the extraction of mineable data from medical imaging and has been applied within oncology to improve diagnosis, prognostication, and clinical decision support, with the goal of delivering precision medicine. The authors provide a practical approach for successfully implementing a radiomic workflow from planning and conceptualiza...

Whole body magnetic resonance imaging (WB-MRI) is the recommended modality for diagnosis of multiple myeloma (MM). WB-MRI is used to detect sites of disease across the entire skeletal system, but it requires significant expertise and is time-consuming to report due to the great number of images. To aid radiological reading, we propose an auxiliary...

Whole body magnetic resonance imaging (WB-MRI) is the recommended modality for diagnosis of multiple myeloma (MM). WB-MRI is used to detect sites of disease across the entire skeletal system, but it requires significant expertise and is time-consuming to report due to the great number of images. To aid radiological reading, we propose an auxiliary...

Previous work has shown that PRESAGE® can be used successfully to perform 3D dosimetric measurements of complex radiotherapy treatments. However, measurements near the sample edges are known to be difficult to achieve. This is an issue when the doses at air-material interfaces are of interest, for example when investigating the electron return effe...

Background: Endogenous hormones are associated with breast cancer risk, but little is known about their role on breast-tissue composition, a strong risk predictor. This study aims to investigate the relationship between growth and sex hormone levels and breast-tissue composition in young nulliparous women. Methods: A cross-sectional study of 415...

Mammographic % density, the proportion of fibroglandular tissue in the breast, is a strong risk factor for breast cancer, but its determinants in young women are unknown. We examined associations between magnetic resonance imaging (MRI) breast-tissue composition at age 21 years and prospectively-collected measures of body size and composition from...

Purpose: To compare two methods of automatic breast segmentation with each other and with manual segmentation in a large subject cohort. To discuss the factors involved in selecting the most appropriate algorithm for automatic segmentation and, in particular, to investigate the appropriateness of overlap measures (e.g., Dice and Jaccard coefficien...

To compare two methods of automatic breast segmentation with each other and with manual segmentation in a large subject cohort. To discuss the factors involved in selecting the most appropriate algorithm for automatic segmentation and, in particular, to investigate the appropriateness of overlap measures (e.g., Dice and Jaccard coefficients) as the...

An accurate value for the saturation dose of PRESAGE® is important in elucidating the mechanism of the so-called quenching phenomenon in the 3-D dosimetry of proton beams. This quantity is difficult to obtain, because it involves measuring the optical density of a set of very highly attenuating samples. We present a novel method that makes use of t...

Purpose To assess the repeatability of apparent diffusion coefficient (ADC) estimates in extracranial soft-tissue diffusion-weighted magnetic resonance imaging across a wide range of imaging protocols and patient populations. Materials and Methods Nine prospective patient studies and one prospective volunteer study, performed between 2006 and 2016...

Background: Breast density, the amount of fibroglandular tissue in the adult breast for a women’s age and body mass index, is a strong biomarker of susceptibility to breast cancer, which may, like breast cancer risk itself, be influenced by events early in life. In the present study, we investigated the association between pre-natal exposures and b...

Density assessment and lesion localization in breast MRI require accurate segmentation of breast tissues. A fast, computerized algorithm for volumetric breast segmentation, suitable for multi-centre data, has been developed, employing 3D bias-corrected fuzzy c-means clustering and morphological operations. The full breast extent is determined on T1...

Purpose: To determine whether quantitation of T2* is sufficiently repeatable and sensitive to detect clinically relevant oxygenation levels in head and neck squamous cell carcinoma (HNSCC) at 3T. Materials and methods: Ten patients with newly diagnosed locally advanced HNSCC underwent two magnetic resonance imaging (MRI) scans between 24 and 168...

Purpose: To evaluate the diagnostic sensitivity of computed diffusion-weighted (DW)-MR imaging for the detection of breast cancer. Materials and methods: Local research ethics approval was obtained. A total of 61 women (median 48 years) underwent dynamic contrast enhanced (DCE)- and DW-MR between January 2011 and March 2012, including 27 with br...

Synchrotron microbeam radiation therapy (MRT) is an advanced form of radiotherapy for which it is extremely difficult to provide adequate quality assurance. This may delay or limit its clinical uptake, particularly in the paediatric patient populations for whom it could be especially suitable. This study investigates the extent to which new develop...

Methods of monitoring drug toxicity in off-target organs are very important in the development of effective and safe drugs. Standard 2-D techniques, such as histology, are prone to sampling errors and can miss important information. We demonstrate a novel application of optical computed tomography (CT) imaging to quantitatively assess, in 3-D, the...

Radical chemo-radiotherapy (CRT) is an effective organ-sparing treatment option for patients with locally advanced head and neck cancer (LAHNC). Despite advances in treatment for LAHNC, a significant minority of these patients continue to fail to achieve complete response with standard CRT. By constructing a multi-modality functional imaging (FI) p...

Chemical dosimeters, including PRESAGE® as used in optical CT, exhibit significant quenching effects in response to proton irradiation and this may limit their widespread uptake. This study performs careful measurements of the observed quenching of a recently developed variant of PRESAGE® in a 60 MeV proton beam and uses them to attempt an empirica...

High Intensity Focused ultrasound (HIFU) is a non-invasive cancer therapy that makes use of the mainly thermal effects of ultrasound to destroy tissue. In order to achieve reliable treatment planning, it is necessary to characterise the ultrasound source (transducer) and to understand how the wave propagates in tissue and the energy deposition in t...

Optical Computed Tomography (CT) is a promising technique for dosimetry of Microbeam Radiation Therapy (MRT), providing high resolution 3D dose maps. Here different MRT irradiation geometries are visualised showing the potential of Optical CT as a tool for future MRT trials. The Peak-to-Valley dose ratio (PVDR) is calculated to be 7 at a depth of 3...

Dosimetry of proton beams using 3D imaging of chemical dosimeters is complicated by a variation with proton linear energy transfer (LET) of the dose–response (the so-called ‘quenching effect’). Simple theoretical arguments lead to the conclusion that the total absorbed dose from multiple irradiations with different LETs cannot be uniquely determine...

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 sys...

Medical image analysis remains a challenging application area for artificial intelligence. When applying machine learning, obtaining ground-truth labels for supervised learning is more difficult than in many more common applications of machine learning. This is especially so for datasets with abnormalities, as tissue types and the shapes of the org...

Purpose: 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 i...

Optical CT is a method that can potentially provide both accurate dosimetry at high spatial resolution and 3-D visualisation over a large field-of-view in a single dataset. The major factors limiting spatial resolution in previous studies are analysed here and it is shown that improvements in equipment specification can overcome many of these. The...

PRESAGE® has previously shown potential for 3D dosimetry of heavy particles. A new formulation has specifically developed for dosimetry of protons/heavy ions. This work provides a preliminary characterization the new formulation of PRESAGE® by measuring optical absorbance and dose response after irradiating by a 62 MeV proton beam for a dose range...

The aim of this study is to present the first experimental validation and quantification of the dose enhancement capability of bismuth oxide nanoparticles (Bi2O3-Nps). A recently introduced multi-compartment 3D radiochromic dosimeter for measuring radiation dose enhancement produced from the interaction of X-rays with metal nanoparticles was employ...

In this article, which accompanies one of the morning "refresher" sessions at the IC3D Dose 2012 conference, a workflow for optical CT scanning is described and the following steps in that workflow are illustrated: sample positioning, refractive index matching, the importance of apparatus cleanliness to the imaging process, the pre-scan and image r...

The aim of this study was to compare the conventional combination of three-dimensional dosimeter (nPAG gel) and readout method (MRI) with other combinations of three-dimensional dosimeters (nPAG gel/PresageTM) and readout methods (optical CT scanners). In the first experiment, the dose readout of a gel irradiated with a four field-box technique was...

Purpose To evaluate the water and tissue equivalence of a new PRESAGE® 3D dosimeter for proton therapy. Methods The GEANT4 software toolkit was used to calculate and compare total dose delivered by a proton beam with mean energy 62 MeV in a PRESAGE® dosimeter, water, and soft tissue. The dose delivered by primary protons and secondary particles wa...

Picture archiving and communication systems (PACS) provide limited flexibility for the development of novel research methods. By contrast, the research model of data access is more flexible but has vulnerabilities in numerous areas. No single monolithic application can fulfill the diverse and rapidly changing needs of the clinical imaging research...

Gold nanoparticles (AuNps), because of their high atomic number (Z), have been demonstrated to absorb low-energy X-rays preferentially, compared with tissue, and may be used to achieve localized radiation dose enhancement in tumors. The purpose of this study is to introduce the first example of a novel multicompartment radiochromic radiation dosime...

Optical computed tomography has now become a well-established method for making empirical measurements of 3D dose distributions in radiotherapy treatment verification. The requirement for effective refractive index matching as part of the scanning process has long been an inconvenience for users, limiting the speed of sample throughput. We propose...

The topic of deep-learning has recently received considerable attention in the machine learning research community, having great potential to liberate computer scientists from hand-engineering training datasets, because the method can learn the desired features automatically. This is particularly beneficial in medical research applications of machi...

In this study, we introduce a novel, robust and accurate computerized algorithm based on volumetric principal component maps and template matching that facilitates lesion detection on dynamic contrast-enhanced MR. The study dataset comprises 24,204 contrast-enhanced breast MR images corresponding to 4034 axial slices from 47 women in the UK multi-c...

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...

Tissue inhomogeneities such as bones or air cavities give rise to significant perturbations of dose during electron radiotherapy. Whilst these can be calculated using a variety of computational methods, accurate experimental verification has hitherto been difficult. In this study, we used 3-D optical computed tomography (CT) dosimetry of PRESAGETM...

This study presents an investigation of the use of 3-D dosimetry using optical computed tomography to provide verification of synchrotron microbeam radiation therapy (MRT). MRT is based on the remarkable tolerance of normal tissues to high doses of radiation when this dose is constrained to very narrow beams. At beamline ID17 of the European Synchr...

The conference "refresher session" associated with this abstract reviews the main principles of the two most important imaging readout modalities for 3-D dosimetry: MRI and optical CT. Best practices for both these techniques are already described in several different places in the literature, but, for the uninitiated, there are a number of pitfall...

Optical computed tomography (CT) shows great potential for radiation therapy dose verification in 3D. However, an effective quality assurance regime for the various scanners currently available still remains to be developed. We show how the favourable properties of the PRESAGETM radiochromic polymer may be exploited to create highly sophisticated Q...

BACKGROUND With a wealth of functional imaging data being acquired in clinical trials, there is a need to process information in a variety of different formats with research software tools that are not part of the standard radiological workflow. These are created by different groups, on a variety of platforms and are generally not designed to inter...

Measurements of the 62 MeV proton beam at the Clatterbridge Centre for Oncology using the radiosensitive plastic PRESAGETM have previously shown a dependence of the dosimeter sensitivity (dose-response slope) on the linear energy transfer (LET) of the ionising particles. This work focuses on a possible explanation in terms of track structure theory...

In radiation cancer therapy, the aim is to destroy the tumour cells in the treated area while minimizing damage to the surrounding normal tissue. Synchrotron microbeam radiation therapy offers considerable promise in this respect, based on knowledge that normal tissue can tolerate high doses of radiation over small volumes. At the ESRF microbeam ra...

The efficiency of breast density assessment using interactive intensity thresholding applied to intensity uniformity corrected T1-weighted MR images is investigated for 20 healthy women who attended the UK multi-centre study of MRI screening for breast cancer. Mammographic density is estimated on the medial-lateral oblique X-ray mammograms using CU...

X-ray microbeam radiation therapy (MRT) is a novel form of treatment, currently in its preclinical stage, which uses microplanar x-ray beams from a synchrotron radiation source. It is important to perform accurate dosimetry on these microbeams, but, to date, there has been no accurate enough method available for making 3D dose measurements with iso...

Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as...

The current status of optical CT for 3-D radiation dosimetry is reviewed. The technique is first placed in its historical context, pointing out the relationship with other methods of optical imaging and showing how optical-CT has emerged independently in several different fields and under different names. The theoretical background of the method is...

The introduction of optical computed tomography (optical-CT) offers economic and easy to use 3-D optical readout for gel dosimeters. However, previous authors have noted some challenges regarding the accuracy of such imaging techniques at high values of optical density. In this paper, we take a closer look at the 'cupping' artefact evident in both...

This brief work-in-progress outlines two methods that we have attempted for determining the dose at which the linear relation between optical density of a PRESAGE™ dosimeter and the dose deposited breaks down. Both methods were equally successful in mapping the linear relation up to an optical density of approximately 6.25 cm−1 (absorbance 2..5), b...

Laser scanning optical computed tomography (optical CT) is potentially a better technique for analyzing 3-D dosimeters than CCD based dosimetry due to the fact that narrow cone of light passing through the sample is not affected by the refractive index inhomogeneities of surrounding structures. We have previously demonstrated fast laser scanning of...

This paper describes a new device, RadBall™ for mapping environmental radiation fields, as found in the area of nuclear decontamination. The system consists of a specially shaped PRESAGE™ dosimeter, which sits inside a custom-designed lead collimator. This is imaged using optical CT to yield data from which the position of either point sources or e...

Over recent decades, modern protocols of external beam radiotherapy have been developed that involve very steep dose gradients and are thus extremely sensitive to errors in treatment delivery. A recent credentialling study by the Radiological Physics Center at the MD Anderson Cancer Center (Texas, USA) has noted potentially significant inaccuracies...

Anuran vocalizations are valuable in the determination of species identity and have the potential to discriminate intraspecific variation. We developed novel bioacoustic sampling techniques, based on Fast Fourier Transforms, to increase the precision and sensitivity of male advertisement call analysis and applied the method to European water frogs....

Optical CT, using a solid polyurethane (PRESAGE) radiochromic dosimeter, has been used to evaluate dose distributions produced by the microSelectron-HDR Ir-192 source. The anisotropy functions obtained through optical CT are in good agreement with Monte Carlo and previously published results especially at polar angle above 20 degrees. The results i...

PRESAGE is a solid dosimeter based on a clear polyurethane matrix doped with radiochromic components (leuco dyes). On exposure to ionizing radiation a colour change is generated in the dosimeter, and hence an optical absorption or optical density change that can be read out by optical CT. The main focus of present investigations has been to investi...

3D measurement of optical attenuation is of interest in a variety of fields of biomedical importance, including spectrophotometry, optical projection tomography (OPT) and analysis of 3D radiation dosimeters. Accurate, precise and economical 3D measurements of optical density (OD) are a crucial step in enabling 3D radiation dosimeters to enter wider...

Optical computed tomography (optical-CT) of 3D radiation dosimeters is a promising avenue for delivering an economic and reliable quality control of radiotherapy treatments such as intensity modulated radiotherapy, brachytherapy and stereotactic radiosurgery. The main problems in transferring 3D dosimeters to clinical setting have been in (1) the c...

MRI and laser-scanned optical-CT are widely reported as being three-dimensional readout methods for gel dosimetry. This preliminary study of proton irradiation of a PRESAGETM transparent solid plastic dosimeter is presented as a case study to illustrate the potential of a true-3D approach.

In this paper we describe the particular considerations relating to ultra-rapid, true-3D scanners based on charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) imaging detectors. Central to our ability to image dose distributions has been the development of novel materials whose optical properties change in response to radi...

To investigate the feasibility of solid polymer dosimetry as an accurate 3-D dose verification applied to prostatic brachytherapy, the model 6711 Oncoseed TM was selected for a pilot study comparing experimental methods and Monte Carlo simulations. This study is presented as a typical case study of what can be achieved using solid polymer dosimetry...

Optical tomography of gel dosimeters is a promising and cost-effective avenue for quality control of radiotherapy treatments such as intensity-modulated radiotherapy (IMRT). Systems based on a laser coupled to a photodiode have so far shown the best results within the context of optical scanning of radiosensitive gels, but are very slow ( approxima...

Radiotherapy treatment planning relies on the use of geometrically correct images. This paper presents a fully automatic tool for correcting MR images for the effects of B(0) inhomogeneities. The post-processing method is based on the gradient-reversal technique of Chang and Fitzpatrick (1992 IEEE Trans. Med. Imaging 11 319-29) which combines two i...

Since the discovery of X rays radiotherapy has had the same aim - to deliver a precisely measured dose of radiation to a defined tumour volume with minimal damage to surrounding healthy tissue. Recent developments in radiotherapy such as intensity modulated radiotherapy (IMRT) can generate complex shapes of dose distributions. Until recently it has...

Burst is an ultra-rapid imaging sequence that works by excitation of magnetization using a series of regularly spaced, low flip-angle pulses, applied at the same time as a gradient in the read direction. In the original concept, this gradient is constant, and multiple echoes are refocused under a constant-read gradient. This article brings together...

MR images are known to be distorted because of both gradient nonlinearity and imperfections in the B0 field, the latter caused either by an imperfect shim or sample-induced distortions. This paper describes in detail a method for correcting the gradient warp distortion, based on a direct field mapping using a custom-built phantom with three orthogo...

The application of diffusion weighted-magnetic resonance imaging (DW-MRI) studies to biologic processes in vivo is a recent development given that it is 50 years since the ?rst description of the effects of diffusion on the nuclear magnetic resonance (NMR) signal. Although considerable effort has gone into explaining the biology underlying the diff...

Nuclear magnetic resonance (NMR) images often contain data corrupted by intensity variations in field strength due to the sensitivity of the radio frequency (rf) coils used in the NMR scanner. This confounds some of the image processing tasks, such as segmentation, difficult. In this paper, we investigate several approaches to arrive at a quick sim...

This article demonstrates the resolution capabilities of the CCD scanner under ideal circumstances and describes the first CCD-based optical CT experiments on a new class of dosimeter, known as PRESAGE™ (Heuris Pharma, Skillman, NJ).

Preliminary optical density results on irradiated PRESAGE dosimeter are outlined in this article. PRESAGE is a solid dosimeter, based on a clear polyurethane combined with the leuco-dye leuco-malachite green. The purpose of these measurements was a) to obtain spectra for optimizing the wavelength of a new light source for the equipment and b) to ob...