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Projects & Publications


One of  the recent projects is a study of the clinical, planning and dosimetric feasibility of external beam dose painting for prostate cancer by Medical Physics and Oncology staff at UHBW (University Hospitals Bristol and Weston NHS Foundation Trust) and NBT (North Bristol NHS Trust), and CRIC Bristol, with support from Above & Beyond. A paper on this subject has been submitted for publication.


1 Prostate anatomy shown on this sagittal CT image

Prostate is in pink between bladder (blue) & rectum brown)


2 Functional MRI images of a prostate showing the dominant intraprostatic lesions (DILs)


3 MRI scanner used in study

4 Treatment planning images showing a patient with 2 DILs with one close to the rectum.

The dose painted dose distribution is shown as a series of lines around each DIL.

Background and purpose

Radiotherapy dose painting is a promising technique which enables dose escalation to dominant intraprostatic lesions (DILs) within the prostate. DILs are areas of higher tumour cell density, and are associated with radioresistance. This study aimed to determine factors affecting treatment feasibility for 20 patients with intermediate and high risk prostate cancer.

Materials & Methods

Patients were imaged using a 3T magnetic resonance imaging (MRI)scanner and identified  DILs were  outlined and the  scan registered with the planning computed tomography (CT) dataset. Plans were produced using two planning systems, and were evaluated dosimetrically to verify that the distribution could be safely delivered.


MRI scans were obtained for 19/20 patients. Fourteen patients had 1-2 DILs (74%) with eleven overlapping the urethra and/or rectum, and one abutting the urethra.

The target boost of 86 Gy was achieved in 6/14 plans but was limited to 82 Gy for one patient due to rectal and urethral constraints, and to 80 Gy for five  patients whose gross target volume (GTV) overlapped or abutted the urethra. For the remaining two patients it was difficult to match CT & MRI images using rigid registration due to changes in internal anatomy between modalities. Dosimetric measurements, made on the plans using an ionization chamber array, gave a satisfactory gamma pass rate at 3%/3mm.


It was feasible to produce dose-painted plans for a boost of 86Gy for approximately half the patients with DILs. The limiting factor was the proximity of organs-at-risk to the boost volumes. For a small proportion of patients, rigid registration between CT and MRI images was not adequate for planning purposes.

For more information on projects the team have done see the Dose Painting Project or the NIHR i4i TRAPS Project


A study of the clinical, planning and dosimetric feasibility of external beam dose painting for prostate cancer SW Blake, A Stapleton, A Brown, S Curtis, J Ash-Miles, E Dennis, S Masson, D Bowers, S Hilman. Submitted for publication in Physics and Imaging in Radiation Oncology 2020.

Beck L, Velthuis JJ, Fletcher S, Haynes JA, & Page RF (2020).  Using a TRAPS upstream transmission detector to verify multileaf collimator positions during dynamic radiotherapy delivery.  Applied Radiation and Isotopes, 156: 1089951.

The Impact of Extended Clinical Hours on a Radiotherapy Physics Service March 2020 update SW Blake, G Chalmers, J Eve, T Millin, S Thomas, A Vinall. 

In-vivo validation of intra-fractional prostate motion during external beam radiotherapy using 4D Trans-Perineal Ultrasound J Aylward, M Skurczynski, P Jacobs, SW Blake. In preparation 2019.

TRAPS upstream transmission detector for tracking mlc positions in VMAT and IMRT radiotherapy fields S. Fletcher (UK), J. Haynes, L. Beck, J. Velthuis, D. Crawford.Electronic Poster EP-1698 at ESTRO 38 2019

Is your department Fire-Proof? - Recovery and lessons learned after the fire at Bristol Oncology Centre. Presentation at IPEM MPEC 25th September 2019

An automated independent Monte-Carlo check for VMAT plans J Cope, University Hospitals Bristol NHS Foundation Trust. Presentation at Adaptive Approaches and Online Monitoring of Radiotherapy Treatment 25th April 2018

Dose painting for prostate cancer with external beam radiotherapy: factors affecting the feasibility of treatment planning and dose delivery SW Blake, S Hilman, A Stapleton, A Brown, S Curtis, M Saunders, J Ash-Miles, E Dennis, R Hartley-Davies S Masson, D Bowers. 2018 UKRCO July 2014 Congress Abstracts.

Page R et al.  Comparison of the TRAPS Upstream Transmission Detector against EPID for Radiotherapy.  Nuclear Science Symposium and Medical Imaging Conference, IEEE abstract 2017.

Feasibility Study: Prostate Dose Painting using External Beam Radiotherapy A Stapleton, University Hospitals Bristol NHS Foundation Trust. Presentation at South West IPEM Regional Scientific Meeting 9th June 2017.

Initial experience with the Elekta Leksell Gamma Knife Icon system: commissioning, QA and workflow S.W. Blake, L. Winch, H. Appleby. 2016 Radiotherapy and Oncology, Volume 119, Supplement 1, S1-S996 Proceedings of ESTRO 35