A comparison between two-dimensional ion chamber array and EDR2 film for intensity modulated planning of helical tomotherapy
10.3760/cma.j.issn.1004-4221.2011.04.020
- VernacularTitle:二维电离室阵列与EDR2胶片在螺旋断层治疗计划剂量验证中的应用研究
- Author:
Chuanbin XIE
;
Shouping XU
;
Zhongjian JU
;
Xiangkun DAI
;
Ruigang GE
;
Hanshun GONG
- Publication Type:Journal Article
- Keywords:
Helical tomotherapy;
Two-dimensional ion chamber array;
Film;
Dose verification;
γ criteria
- From:
Chinese Journal of Radiation Oncology
2011;20(4):330-333
- CountryChina
- Language:Chinese
-
Abstract:
Objective The aim of this work is to compare the performances of EDR2 film dosimetry with two-dimensional ion chamber array (2DICA) in quality assurance (QA) procedures and to investigate the origin of possible discrepancies between the two methods.Methods A 2DICA, I′mRT MatriXX and MULTICube equivalent solid water phantom from IBA Company were used to verify the dose distribution of 15 tomotherapy plan cases.The combined phantom which includes EDR2 film on the array was set up to measure the dose distribution from coronal and sagittal orientations.After the irradiation, the dose distributions of 2DICA and film were compared with those calculated in the planning system for verification.The results and efficiency were evaluated independently in the two methods.Results The mean number of points satifying γ parameter ≤1 in the coronal and sagittal planes was 97.00%±1.56%& 95.98%±2.52%(t=-2.22,P=0.043) and 98.28%±1.55%& 95.42%±1.99%(t=0.75,P=0.464) of the 15 cases respectively for 2DICA and EDR2 film.The ratio of more than 90% and 95% were 93.3% and 66.7%.The results we presented show a very good agreement between the two methods when used to assess the dose distribution between calculated and measured doses,and a certain degree of correlation (r=0.14,P=0.001).Conclusions The 2DICA may effectively replace both film and ion chamber dosimetry in routine IMRT QA.The good agreement between 2DICA and EDR2 film may give a possible check regularly just as a gold standard.
