Simple index for validity of the evaluation point for dosimetric verification results of intensity-modulated radiation therapy using a Farmer-type ionization chamber.
J Xray Sci Technol
; 26(3): 473-480, 2018.
Article
em En
| MEDLINE
| ID: mdl-29562582
ABSTRACT
PURPOSE:
Based on a retrospective analysis, this study aims to develop a simple index for validity of the evaluation point for the dosimetric verification of intensity-modulated radiation therapy (IMRT).METHODS:
The results for the dosimetric verifications of a total of 69 IMRT plans were analyzed in this study. A Farmer-type ion chamber was used as a dose detector, and a solid water-equivalent phantom was used. Index values were obtained by dividing the difference between the maximum and minimum dosages by the mean dosage of the 69 plans, and the values were classified into five groups with index value <4, 4-8, 8-12, 12-16, and >16. A t-test was used to assess the statistical significance of the mean differences of the absolute values of the relative errors among these groups.RESULTS:
We found that there was no significant difference between the groups with index value <4 and 4-8 (pâ=â0.152); however, there were significant differences between the other groups (pâ<â0.01). In addition, when the index values were smaller than 8, the pass ratio of 3% tolerance was 96.2% and the pass ratio of 5% tolerance was 99.9%. We observed that the smaller the index value, the smaller the uncertainty of the dose measurement.CONCLUSIONS:
The results obtained in this study may prove to be useful for accurate dosimetric verifications of IMRTs when ion chambers are used.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dosagem Radioterapêutica
/
Planejamento da Radioterapia Assistida por Computador
/
Radioterapia de Intensidade Modulada
Tipo de estudo:
Diagnostic_studies
/
Observational_studies
Limite:
Humans
Idioma:
En
Revista:
J Xray Sci Technol
Assunto da revista:
RADIOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Japão