Projects & Publications
Projects
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.
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1 Prostate anatomy shown on this sagittal CT
image
Prostate is in pink between bladder (blue)
& rectum brown)
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2 Functional MRI images of a prostate showing the dominant
intraprostatic lesions (DILs)
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| 3 MRI scanner used in study |
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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.
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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.
Results
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.
Conclusions
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
Publications
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
