eprintid: 1535158
rev_number: 41
eprint_status: archive
userid: 608
dir: disk0/01/53/51/58
datestamp: 2017-01-08 09:27:01
lastmod: 2021-10-04 01:54:02
status_changed: 2017-05-17 14:05:38
type: article
metadata_visibility: show
creators_name: Georgiou, PS
creators_name: Jaros, J
creators_name: Payne, H
creators_name: Allen, C
creators_name: Shah, TT
creators_name: Ahmed, HU
creators_name: Gibson, E
creators_name: Barratt, D
creators_name: Treeby, BE
title: Beam distortion due to gold fiducial markers during salvage high-intensity focused ultrasound in the prostate
ispublished: pub
subjects: WHITT
divisions: UCL
divisions: B02
divisions: C10
divisions: D16
divisions: B04
divisions: C05
divisions: F42
keywords: Science & Technology, Life Sciences & Biomedicine, Radiology, Nuclear Medicine & Medical Imaging, EBRT, fiducial marker, prostate cancer, salvage HIFU, IMAGE-GUIDED RADIOTHERAPY, RADIATION-THERAPY, RADICAL PROSTATECTOMY, NONLINEAR ULTRASOUND, ONCOLOGIC OUTCOMES, CANCER, FAILURE, HIFU, BRACHYTHERAPY, FEASIBILITY
note: © 2016 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
abstract: Purpose High intensity focused ultrasound (HIFU) provides a non-invasive salvage treatment option for patients with recurrence after external beam radiation therapy (EBRT). As part of EBRT the prostate is frequently implanted with permanent fiducial markers. To date, the impact of these markers on subsequent HIFU treatment is unknown. The objective of this work was to systematically investigate, using computational simulations, how these fiducial markers affect the delivery of HIFU treatment. Methods A series of simulations was performed modelling the propagation of ultrasound pressure waves in the prostate with a single spherical or cylindrical gold marker at different positions and orientations. For each marker configuration, a set of metrics (spatial-peak temporal-average intensity, focus shift, focal volume) was evaluated to quantify the distortion introduced at the focus. An analytical model was also developed describing the marker effect on the intensity at the focus. The model was used to examine the marker's impact in a clinical setting through case studies. Results The simulations show that the presence of the marker in the pre-focal region causes reflections which induce a decrease in the focal intensity and focal volume, and a shift of the maximum pressure point away from the transducer's focus. These effects depend on the shape and orientation of the marker and become more pronounced as its distance from the transducer's focus decreases, with the distortion introduced by the marker greatly increasing when placed within 5 mm of the focus. The analytical model approximates the marker's effect and can be used as an alternative method to the computationally intensive and time consuming simulations for quickly estimating the intensity at the focus. A retrospective review of a small patient cohort selected for focal HIFU after failed EBRT indicates that the presence of the marker may affect HIFU treatment delivery. Conclusions The distortion introduced by the marker to the HIFU beam when positioned close to the focus may result in an undertreated region beyond the marker due to less energy arriving at the focus, and an overtreated region due to reflections. Further work is necessary to investigate whether the results presented here justify the revision of the patient selection criteria or the markers’ placement protocol.
date: 2017-02-01
date_type: published
publisher: WILEY
official_url: http://dx.doi.org/10.1002/mp.12044
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
article_type_text: Article
verified: verified_manual
elements_id: 1199180
doi: 10.1002/mp.12044
language_elements: English
lyricists_name: Ahmed, Hashim
lyricists_name: Barratt, Dean
lyricists_name: Georgiou, Panayiotis
lyricists_name: Gibson, Eli
lyricists_name: Shah, Taimur
lyricists_name: Treeby, Bradley
lyricists_id: HUAHM90
lyricists_id: DBARR55
lyricists_id: PGEOR54
lyricists_id: EGIBS90
lyricists_id: TTSHA97
lyricists_id: BTREE66
actors_name: Barczynska, Patrycja
actors_id: PBARC91
actors_role: owner
full_text_status: public
publication: Medical Physics
volume: 44
number: 2
pagerange: 679-693
pages: 15
issn: 2473-4209
citation:        Georgiou, PS;    Jaros, J;    Payne, H;    Allen, C;    Shah, TT;    Ahmed, HU;    Gibson, E;         ... Treeby, BE; + view all <#>        Georgiou, PS;  Jaros, J;  Payne, H;  Allen, C;  Shah, TT;  Ahmed, HU;  Gibson, E;  Barratt, D;  Treeby, BE;   - view fewer <#>    (2017)    Beam distortion due to gold fiducial markers during salvage high-intensity focused ultrasound in the prostate.                   Medical Physics , 44  (2)   pp. 679-693.    10.1002/mp.12044 <https://doi.org/10.1002/mp.12044>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1535158/1/Georgiou_et_al-2017-Medical_Physics.pdf