Browsing ICR Divisions by author "Nill, Simeon"
Now showing items 21-40 of 61
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Dosimetric comparison of automatically propagated prostate contours with manually drawn contours in MRI-guided radiotherapy: A step towards a contouring free workflow?
Sritharan, K; Dunlop, A; Mohajer, J; Adair-Smith, G; Barnes, H; et al. (ELSEVIER IRELAND LTD, 2022-11-01)BACKGROUND: The prostate demonstrates inter- and intra- fractional changes and thus adaptive radiotherapy would be required to ensure optimal coverage. Daily adaptive radiotherapy for MRI-guided radiotherapy can be both ... -
Edge effects in 3D dosimetry: characterisation and correction of the non-uniform dose response of PRESAGE®.
Costa, F; Doran, SJ; Hanson, IM; Adamovics, J; Nill, S; et al. (IOP PUBLISHING LTD, 2020-05-04)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. ... -
An ESTRO-ACROP guideline on quality assurance and medical physics commissioning of online MRI guided radiotherapy systems based on a consensus expert opinion.
Tanadini-Lang, S; Budgell, G; Bohoudi, O; Corradini, S; Cusumano, D; et al. (ELSEVIER IRELAND LTD, 2023-04-01)OBJECTIVE: The goal of this consensus expert opinion was to define quality assurance (QA) tests for online magnetic resonance image (MRI) guided radiotherapy (oMRgRT) systems and to define the important medical physics ... -
Evaluation of a multi-atlas CT synthesis approach for MRI-only radiotherapy treatment planning.
Guerreiro, F; Burgos, N; Dunlop, A; Wong, K; Petkar, I; et al. (ELSEVIER SCI LTD, 2017-03-01)BACKGROUND AND PURPOSE: Computed tomography (CT) imaging is the current gold standard for radiotherapy treatment planning (RTP). The establishment of a magnetic resonance imaging (MRI) only RTP workflow requires the ... -
Evaluation of non-vendor magnetic resonance imaging sequences for use in bladder cancer magnetic resonance image guided radiotherapy.
Chick, J; Alexander, S; Herbert, T; Huddart, R; Ingle, M; et al. (ELSEVIER, 2023-07-01)Hybrid systems that combine Magnetic Resonance Imaging (MRI) and linear accelerators are available clinically to guide and adapt radiotherapy. Vendor-approved MRI sequences are provided, however alternative sequences may ... -
Evaluation of radiotherapy techniques for radical treatment of lateralised oropharyngeal cancers : Dosimetry and NTCP.
McQuaid, D; Dunlop, A; Nill, S; Franzese, C; Nutting, CM; et al. (URBAN & VOGEL, 2016-08-01)AIM: The aim of this study was to investigate potential advantages and disadvantages of three-dimensional conformal radiotherapy (3DCRT), multiple fixed-field intensity-modulated radiotherapy (IMRT) and volumetric-modulated ... -
Evaluation of therapeutic radiographer contouring for magnetic resonance image guided online adaptive prostate radiotherapy.
Adair Smith, G; Dunlop, A; Alexander, SE; Barnes, H; Casey, F; et al. (ELSEVIER IRELAND LTD, 2023-03-01)BACKGROUND AND PURPOSE: The implementation of MRI-guided online adaptive radiotherapy has facilitated the extension of therapeutic radiographers' roles to include contouring, thus releasing the clinician from attending ... -
Evaluation of three presets for four-dimensional cone beam CT in lung radiotherapy verification by visual grading analysis.
Kember, SA; Hansen, VN; Fast, MF; Nill, S; McDonald, F; et al. (BRITISH INST RADIOLOGY, 2016-07-01)OBJECTIVE: To evaluate three image acquisition presets for four-dimensional cone beam CT (CBCT) to identify an optimal preset for lung tumour image quality while minimizing dose and acquisition time. METHODS: Nine patients ... -
Feasibility of magnetic resonance guided radiotherapy for the treatment of bladder cancer.
Hunt, A; Hanson, I; Dunlop, A; Barnes, H; Bower, L; et al. (ELSEVIER IRELAND LTD, 2020-11-01)Whole bladder magnetic resonance image-guided radiotherapy using the 1.5 Telsa MR-linac is feasible. Full online adaptive planning workflow based on the anatomy seen at each fraction was performed. This was delivered within ... -
Feasibility of MR-guided ultrahypofractionated radiotherapy in 5, 2 or 1 fractions for prostate cancer.
Mohajer, J; Dunlop, A; Mitchell, A; Goodwin, E; Nill, S; et al. (ELSEVIER IRELAND LTD, 2021-01-01)The drive towards hypofractionated prostate radiotherapy is motivated by a low alpha/beta ratio for prostate cancer (1 to 3 Gy) compared to surrounding organs at risk, implying an improved therapeutic ratio with increasing ... -
Feasibility of tumour-focused adaptive radiotherapy for bladder cancer on the MR-linac.
Mitchell, A; Ingle, M; Smith, G; Chick, J; Diamantopoulos, S; et al. (ELSEVIER IRELAND LTD, 2022-07-01)Bladder tumour-focused magnetic resonance image-guided adaptive radiotherapy using a 1.5 Tesla MR-linac is feasible. A full online workflow adapting to anatomy at each fraction is achievable in approximately 30 min. ... -
First evaluation of the feasibility of MLC tracking using ultrasound motion estimation.
Fast, MF; O'Shea, TP; Nill, S; Oelfke, U; Harris, EJ (WILEY, 2016-08-01)PURPOSE: To quantify the performance of the Clarity ultrasound (US) imaging system (Elekta AB, Stockholm, Sweden) for real-time dynamic multileaf collimator (MLC) tracking. METHODS: The Clarity calibration and quality ... -
Geometric and dosimetric evaluations of atlas-based segmentation methods of MR images in the head and neck region.
Kieselmann, JP; Kamerling, CP; Burgos, N; Menten, MJ; Fuller, CD; et al. (IOP Publishing, 2018-07-11)Owing to its excellent soft-tissue contrast, magnetic resonance (MR) imaging has found an increased application in radiation therapy (RT). By harnessing these properties for treatment planning, automated segmentation methods ... -
Interim Toxicity Analysis From the Randomized HERMES Trial of 2- and 5-Fraction Magnetic Resonance Imaging-Guided Adaptive Prostate Radiation Therapy.
Westley, RL; Biscombe, K; Dunlop, A; Mitchell, A; Oelfke, U; et al. (ELSEVIER SCIENCE INC, 2024-03-01)PURPOSE: Ultrahypofractionated radiation therapy (UHRT) is an effective treatment for localized prostate cancer with an acceptable toxicity profile; boosting the visible intraprostatic tumor has been shown to improve ... -
Interobserver variation of clinical oncologists compared to therapeutic radiographers (RTT) prostate contours on T2 weighted MRI.
Adair Smith, G; Dunlop, A; Alexander, SE; Barnes, H; Casey, F; et al. (Elsevier BV, 2023-03-01)The implementation of MRI-guided online adaptive radiotherapy has enabled extension of therapeutic radiographers' roles to include contouring. An offline interobserver variability study compared five radiographers' and ... -
Investigating the effect of a magnetic field on dose distributions at phantom-air interfaces using PRESAGE® 3D dosimeter and Monte Carlo simulations.
Costa, F; Doran, SJ; Hanson, IM; Nill, S; Billas, I; et al. (IOP PUBLISHING LTD, 2018-02-26)Dosimetric quality assurance (QA) of the new Elekta Unity (MR-linac) will differ from the QA performed of a conventional linac due to the constant magnetic field, which creates an electron return effect (ERE). In this work ... -
Iterative framework for the joint segmentation and CT synthesis of MR images: application to MRI-only radiotherapy treatment planning.
Burgos, N; Guerreiro, F; McClelland, J; Presles, B; Modat, M; et al. (IOP PUBLISHING LTD, 2017-06-07)To tackle the problem of magnetic resonance imaging (MRI)-only radiotherapy treatment planning (RTP), we propose a multi-atlas information propagation scheme that jointly segments organs and generates pseudo x-ray computed ... -
Lung stereotactic body radiotherapy with an MR-linac - Quantifying the impact of the magnetic field and real-time tumor tracking.
Menten, MJ; Fast, MF; Nill, S; Kamerling, CP; McDonald, F; et al. (ELSEVIER IRELAND LTD, 2016-06-01)BACKGROUND AND PURPOSE: There are concerns that radiotherapy doses delivered in a magnetic field might be distorted due to the Lorentz force deflecting secondary electrons. This study investigates this effect on lung ... -
Magnetic resonance imaging sequence evaluation of an MR Linac system; early clinical experience.
Eccles, CL; Adair Smith, G; Bower, L; Hafeez, S; Herbert, T; et al. (Elsevier BV, 2019-12-16)OBJECTIVES: To systematically identify the preferred magnetic resonance imaging (MRI) sequences following volunteer imaging on a 1.5 Tesla (T) MR-Linear Accelerator (MR Linac) for future protocol development. METHODS: ... -
Magnetic Resonance Imaging-Guided Adaptive Radiation Therapy: A "Game Changer" for Prostate Treatment?
Pathmanathan, AU; van As, NJ; Kerkmeijer, LGW; Christodouleas, J; Lawton, CAF; et al. (ELSEVIER SCIENCE INC, 2018-02-01)Radiation therapy to the prostate involves increasingly sophisticated delivery techniques and changing fractionation schedules. With a low estimated α/β ratio, a larger dose per fraction would be beneficial, with moderate ...