A comparative study of ArcCHECK measurements at actual and zero degree gantry angles for dose verification of intensity-modulated radiotherapy
10.3760/cma.j.issn.1004-4221.2017.01.015
- VernacularTitle:利用ArcCHECK在实际机架角与零机架角的IMRT剂量验证结果比较
- Author:
Renwei JIANG
;
Shuanshuan GUO
;
Shuting CHEN
;
Siyang WANG
;
Zhibin CHEN
- Keywords:
ArcCHECK;
Intensity modulated radiotherapy;
Dose verification
- From:
Chinese Journal of Radiation Oncology
2017;26(1):66-68
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare theγpassing rate between measurements at actual degree gantry angle and zero degree gantry angle for dose verification of intensity?modulated radiotherapy ( IMRT) in the treatment of nasopharyngeal carcinoma ( NPC) and cervical carcinoma. Methods Thirty patients with NPC and thirty patients with cervical carcinoma were randomly chosen from 87 patients with NPC and 54 patients with cervical carcinoma, respectively. Using a gamma criterion of 3 mm/3%, the γ passing rates at actual gantry angle and zero degree gantry angle were measured using ArcCHECK and compared by paired t test. Results The γ passing rate was significantly lower at actual gantry angle than at zero degree gantry angle in patients with NPC or cervical carcinoma ((93.8±3. 6)% vs. (97.8±1. 1)%, P=0. 00;(96.3±2. 1)% vs. (98.2±1. 0)%, P=0. 00). Moreover, the variation range of the γ passing rate at actual gantry angle was larger than that at zero degree gantry angle. Bothγpassing rates at actual gantry angle and zero degree gantry angle were lower in the patients with NPC than in the patients with cervical carcinoma . Conclusions Compared with that at zero degree gantry angle, theγpassing rate at actual gantry angle is closer to reality. Therefore, the actual gantry angle is recommended for dose verification. In order to meet the clinical requirement, a higher standard of γ passing rate should be proposed when zero degree gantry angle is used for dose verification.
