A remote EPID-based dosimetric TPS-planned audit of centers for clinical trials: outcomes and analysis of contributing factors.
Radiat Oncol
; 13(1): 178, 2018 Sep 17.
Article
em En
| MEDLINE
| ID: mdl-30223857
ABSTRACT
BACKGROUND:
A novel remote method for external dosimetric TPS-planned auditing of intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for clinical trials using electronic portal imaging device (EPID) has been developed. The audit has been applied to multiple centers across Australia and New Zealand. This work aims to assess the audit outcomes and explores the variables that contributed to the audit results.METHODS:
Thirty audits were performed of 21 radiotherapy facilities, 17 facilities underwent IMRT audits and 13 underwent VMAT audits. The assessment was based on comparisons between the delivered doses derived from images acquired with EPIDs and planned doses from the local treatment planning systems (TPS). Gamma pass-rate (GPR) and gamma mean value (GMV) were calculated for each IMRT field and VMAT arc (total 268 comparisons). A multiple variable linear model was applied to the GMV results (3%/3 mm criteria) to assess the influence and significance of explanatory variables. The explanatory variables were Linac-TPS combination, TPS grid resolution, IMRT/VMAT delivery, age of EPID, treatment site, record and verification system (R&V) type and dose-rate. Finally, the audit results were compared with other recent audits by calculating the incidence ratio (IR) as a ratio of the observed mean/median GPRs for the remote audit to the other audits.RESULTS:
The average (± 1 SD) of the centers' GPRs were 99.3 ± 1.9%, 98.6 ± 2.7% & 96.2 ± 5.5% at 3%, 3 mm, 3%, 2 mm and 2%, 2 mm criteria respectively. The most determinative variables on the GMVs were Linac-TPS combination, TPS grid resolution and IMRT/VMAT delivery type. The IR values were 1 for seven comparisons, indicating similar GPRs of the remote audit with the reference audits and > 1 for four comparisons, indicating higher GPRs of the remote audit than the reference audits.CONCLUSION:
The remote dosimetry audit method for clinical trials demonstrated high GPRs and provided results comparable to established more resource-intensive audit methods. Several factors were found to influence the results including some effect of Linac-TPS combination.Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Planejamento da Radioterapia Assistida por Computador
/
Institutos de Câncer
/
Ensaios Clínicos como Assunto
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Radioterapia de Intensidade Modulada
/
Auditoria Clínica
Tipo de estudo:
Prognostic_studies
Limite:
Humans
/
Male
País/Região como assunto:
Oceania
Idioma:
En
Revista:
Radiat Oncol
Assunto da revista:
NEOPLASIAS
/
RADIOTERAPIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Austrália