Radiotherapy and Imaging

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    Development and Characterisation of Clinically Relevant Tissue Mimics for an Ultrasound Drug Delivery Phantom
    (Institute of Cancer Research (University Of London), 2024-09-19) Braunstein, L; Ter Haar G; Ter Haar, G; Braunstein, Lisa
    Ultrasound (US) can be used for therapeutic applications, by exploiting the thermal and mechanical effects induced in tissue. Knowledge of the acoustic, thermal and cavitation properties of tissue and tissue mimicking materials (TMMs), which display the properties of different soft tissues, is essential for experimental evaluation of therapeutic US. Furthermore, the use of TMMs to create a US drug delivery phantom, will help in understanding the modalities and physical effects of cavitation. The first two chapters of this thesis will review the current knowledge about therapeutic US, characterisation techniques for relevant acoustic and thermal properties of tissues, and the need for TMMs and phantoms, and potential candidates for these. The thesis will then focus on TMM development, and the methodologies used here for acoustic, thermal and cavitation property characterisation of tissue and TMMs, moving on to the results and their discussion. The sixth chapter will focus on the design, development and set up of a US drug delivery phantom. The final chapter will summarise the overall work and give conclusions, and suggest potential future work
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    A scan-specific quality control acquisition for clinical whole-body (WB) MRI protocols.
    (IOP Publishing Ltd, 2024-06-17) Keaveney, S; Hopkinson, G; Markus, JE; Priest, AN; Scurr, E; Hughes, J; Robertson, S; Doran, SJ; Collins, DJ; Messiou, C; Koh, D-M; Winfield, JM; Doran, Simon
    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-specific QC acquisition and processing pipeline to detect broken RF coil elements, which is sufficiently rapid to be added to the clinical WB-MRI protocol. The purpose of this is to improve the quality of WB-MRI by reducing the number of patient examinations conducted with suboptimal equipment.Approach.A rapid acquisition (14 s additional acquisition time per imaging station) was developed that identifies broken RF coil elements by acquiring images from each individual coil element and using the integral body coil. This acquisition was added to one centre's clinical WB-MRI protocol for one year (892 examinations) to evaluate the effect of this scan-specific QC. To demonstrate applicability in multi-centre imaging trials, the technique was also implemented on scanners from three manufacturers.Main results. Over the course of the study RF coil elements were flagged as potentially broken on five occasions, with the faults confirmed in four of those cases. The method had a precision of 80% and a recall of 100% for detecting faulty RF coil elements. The coil array positioning measurements were consistent across scanners and have been used to define the expected variation in signal.Significance. The technique demonstrated here can identify faulty RF coil elements and positioning errors and is a practical addition to the clinical WB-MRI protocol. This approach was fully implemented on systems from two manufacturers and partially implemented on a third. It has potential to reduce the number of clinical examinations conducted with suboptimal hardware and improve image quality across multi-centre studies.
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    Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial
    (ELSEVIER SCIENCE INC, 2024-06-01) Parker, CC; Kynaston, H; Cook, A; Clarke, NW; Catton, CN; Cross, WR; Petersen, PM; Persad, RA; Pugh, CA; Saad, F; Logue, J; Payne, H; Bower, LC; Brawley, C; Rauchenberger, M; Barkati, M; Bottomley, DM; Brasso, K; Chung, H; Chung, PWM; Conroy, R; Falconer, A; Ford, V; Goh, CL; Heath, CM; James, N; Kim-Sing, C; Kodavatiganti, R; Malone, SC; Morris, SL; Nabid, A; Ong, A; Raman, R; Rodda, S; Wells, P; Worlding, J; Parulekar, WR; Parmar, MKB; Sydes, MR; James, Nicholas
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    Development of daily automated treatment adaptation for MRI-guided radiotherapy of head and neck cancer patients
    (Institute of Cancer Research (University Of London), 2024-08-29) Koteva, V; Oelfke U; Oelfke, U; Koteva, Vesela
    Adaptive radiotherapy (ART) using an MR-Linac enables treatment plans to be adapted daily to account for any observed anatomical changes. To adapt these plans effectively, the regions of interest (ROIs) must be re-delineated on the daily scans, which requires fast organ delineation. Manual delineation, particularly for head and neck cancer (HNC) patients, is subjective and time-intensive task. Following re-delineation, a new treatment plan must be optimised to accommodate the observed anatomical changes. Manual treatment planning requires manually selecting and adjusting the optimisation parameters, a process that is both time-consuming and heavily dependent on the treatment planner's experience. These manual interventions frequently involve trial-and-error iterations, potentially prolonging the planning process and introducing variability in plan quality. Automated contouring and planning methodologies offer a promising solution to these challenges. This thesis aimed to develop and clinically validate an automated approach for treatment adaptation. To accomplish this, a widely adopted network architecture incorporating established segmentation techniques was employed. Additionally, an automated treatment planning tool called Erasmus-iCycle, developed by Erasmus MC in Rotterdam, The Netherlands, was utilised to automatically generate treatment plans for HNC patients undergoing MR-Linac treatment. For the evaluation and validation of the automated structures, first an evaluation on purely geometric features was performed followed by a blind test conducted by a radiation oncologist to assess the clinical acceptability. Subsequently, the dosimetric impact was evaluated. The automated plans were assessed against dosimetric criteria, and the dose-volume histograms achieved by the automated plans were compared to those achieved by manual plans. The auto-segmentation model demonstrated high clinical accuracy and led to minimal dosimetric differences for most structures, all within a segmentation time of under 10 seconds. Additionally, the automated treatment planning yielded good results, producing dose distributions comparable to those of manual plans. Notably, the auto-plans exhibited significant sparing of normal tissue, especially for the brainstem. The integration of auto-segmentation and auto-planning led to the development of clinically acceptable treatment plans, reducing reliance on expert experience, and almost completely eliminating the necessity for manual adjustments and physical presence. This thesis demonstrates the potential of automating contouring and planning for HNC patients on MR-Linacs, showing effective automated contouring, especially for OARs, and comparable plan quality to manual methods. Further research is needed to address limitations such as broader patient population inclusion and clinical deliverability of automated plans, aiming to create an efficient workflow for clinical implementation. Overall, this research provides promising results for automating HNC treatment planning on MR-Linacs, with potential benefits for efficiency and consistency. Continued refinement and integration of automated tools hold promise for advancing radiation oncology and personalised therapy delivery.
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    Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial.
    (Elsevier BV, 2024-06-01) Parker, CC; Kynaston, H; Cook, AD; Clarke, NW; Catton, CN; Cross, WR; Petersen, PM; Persad, RA; Pugh, CA; Saad, F; Logue, J; Payne, H; Bower, LC; Brawley, C; Rauchenberger, M; Barkati, M; Bottomley, DM; Brasso, K; Chung, HT; Chung, PWM; Conroy, R; Falconer, A; Ford, V; Goh, CL; Heath, CM; James, ND; Kim-Sing, C; Kodavatiganti, R; Malone, SC; Morris, SL; Nabid, A; Ong, AD; Raman, R; Rodda, S; Wells, P; Worlding, J; Parulekar, WR; Parmar, MKB; Sydes, MR; RADICALS investigators,; James, Nicholas
    BACKGROUND: Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. METHODS: RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov, NCT00541047. FINDINGS: Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60-69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0-10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612-0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6-75·7) in the short-course ADT group and 78·1% (74·2-81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. INTERPRETATION: Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. FUNDING: Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society.