Patterns of practice for adaptive and real-time radiation therapy part II: interfractional changes
Bertholet, J. Distefano, G. Noble, D. Bel, A. VanLeeuwen, R. Roggen, T. Duchateau, M. Thornqvist, S. Garibaldi, C. Tilly, N.
Bertholet, J.
Distefano, G.
Noble, D.
Bel, A.
VanLeeuwen, R.
Roggen, T.
Duchateau, M.
Thornqvist, S.
Garibaldi, C.
Tilly, N.
Citations
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Abstract
Purpose or Objective
The patterns of practice for adaptive and real-time
radiotherapy (POP-ART RT) study aims to determine to
what extent and how these methods are used in clinical
practice and to understand the barriers to
implementation. Here we report on part II: ART to address
interfractional anatomical changes.
Material and Methods
An institution-specific questionnaire developed during the
2nd ESTRO physics workshop was distributed worldwide.
The focus was both on current practice and wishes for
implementation. Therefore, centres not doing ART were
encouraged to participate.
ART was defined as the use of more than one plan per
target per treatment course to counteract the negative
dosimetric impact of interfractional anatomical changes
using: 1) online daily replanning 2) online plan libraries 3)
offline protocols (action levels or scheduled surveillance
scans) or 4) offline adaption ad-hoc (e.g. due to weight
loss).
Respondents were asked if and which type of ART was used
in their centre for selected tumor sites, which imaging
modality was used to guide adaption (more than one
response possible), what type of quality assurance (QA)
was performed on the adapted plan (more than one
response possible) and what type of software was used for
the adaptive procedure.
Respondents were asked if they wished 1) to
change/expand their use of ART for sites already treated
using ART or 2) implement ART for new tumor site(s) and
to rank barriers to implementation in order of importance.
Results
The questionnaire was filled out by 177 centres from 40
countries. The percentages of centres using ART for
selected sites are shown in Table 1. Offline ad-hoc adaption was used in 50% of the centres, mainly for head
and neck cancer; however, online or offline ART protocols
were only used in 31% of the centres.
CBCT/MVCT was the main imaging modality used for
adaption (Fig. a). Of the 11 centres using online daily
replanning, one used CT while others used MR. Three
centres reported “poor mask fitting” as a reason for head
and neck ad-hoc adaption.
Pre-treatment phantom measurements and secondary
dose calculations were the most common QA methods
(>50% of centres using ART). EPID/in vivo dosimetry, log
files and post-treatment phantom measurements were
used in 21%, 16% and 11% of centres respectively.
While 92% of centres used commercial software, 19% of
centres used (also) in-house software due to lack of
functionalities and/or cost.
Figure b shows the state and wishes for ART
implementation and further use. Two thirds of centres
wished to implement ART for a new tumor site, of which
40% have plans to do it in the next 2 years (Fig. c).
Human/financial resources and technical limitations were
reported as the main barriers while reimbursement was
considered a minor hindrance Conclusion
Online adaption is currently only used in the pelvis with
plan library being prevalent for bladder cancer. Many
centres wish to implement or expand their use of ART but
are limited by human/financial resources and technical
limitations.
Description
Date
2020
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Bertholet J, Distefano G, Noble D, Bel A, VanLeeuwen R, Roggen T, et al. PD-0311: Patterns of practice for adaptive and real-time radiation therapy part II: interfractional changes. Radiotherapy and Oncology . 2020 Nov;152:S162–3.