Is a weekly qualitative picket fence test sufficient? A proposed alternate EPID-based weekly MLC QA program.
J Appl Clin Med Phys
; 23(8): e13699, 2022 Aug.
Article
em En
| MEDLINE
| ID: mdl-35856943
ABSTRACT
PURPOSE:
Well-designed routine multileaf collimator (MLC) quality assurance (QA) is important to assure external-beam radiation treatment delivery accuracy. This study evaluates the clinical necessity of a comprehensive weekly (C-Weekly) MLC QA program compared to the American Association of Physics in Medicinerecommended weekly picket fence test (PF-Weekly), based on our seven-year experience with weekly MLC QA.METHODS:
The C-Weekly MLC QA program used in this study includes 5 tests to analyze (1) absolute MLC leaf position; (2) interdigitation MLC leaf position; (3) picket fence MLC leaf positions at static gantry angle; (4) minimum leaf-gap setting; and (5) volumetric-modulated arc therapy delivery. A total of 20,226 QA images from 16,855 tests (3,371 tests × 5) for 11 linacs at 5 photon clinical sites from May 2014 to June 2021 were analyzed. Failure mode and effects analysis was performed with 5 failure modes related to the 5 tests. For each failure mode, a risk probability number (RPN) was calculated for a C-Weekly and a PF-Weekly MLC QA program. The probability of occurrence was evaluated from statistical analyses of the C-Weekly MLC QA.RESULTS:
The total number of failures for these 16,855 tests was 143 (0.9%) 39 (27.3%) for absolute MLC leaf position, 13 (9.1%) for interdigitation position, 9 (6.3%) for static gantry picket fence, 2 (1.4%) for minimum leaf-gap setting, and 80 (55.9%) for VMAT delivery. RPN scores for PF-Weekly MLC QA ranged from 60 to 192 and from 48 to 96 for C-Weekly MLC QA.CONCLUSION:
RPNs for the 5 failure modes of MLC QA tests were quantitatively determined and analyzed. A comprehensive weekly MLC QA is imperative to lower the RPNs of the 5 failure modes to the desired level (<125); those from the PF-Weekly MLC QA program were found to be higher (>125). This supports the clinical necessity for comprehensive weekly MLC QA.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Aceleradores de Partículas
/
Radioterapia de Intensidade Modulada
Tipo de estudo:
Qualitative_research
Limite:
Humans
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article