MILC routine QA with a 2D diode array
10.3760/cma.j.issn.0254-5098.2009.02.037
- VernacularTitle:二维半导体探测器阵列在多叶准直器日常质量保证中的应用
- Author:
Pan MA
;
Jianrong DAI
;
Jie SHI
- Publication Type:Journal Article
- Keywords:
Two-dimension diode array;
Multileaf collimator;
Positioning error;
Quality assurance
- From:
Chinese Journal of Radiological Medicine and Protection
2009;29(2):217-220
- CountryChina
- Language:Chinese
-
Abstract:
Objective To design leaf patterns for Multileaf Collimator(MLC)routine quality assurance(OA)with a 2D diode array.Methods According to the detector distribution characteristic of the 2D diode array and basillg on the"picket fence"pattern,design the"stepwise"pattern.For each diode involving MLC QA,a calibration curve of relative output versus leaf positioning error was measured through delivering a set of patterns with different intentionally introduced positioning errors.When this proposed technique was delivered,the referenced patterns were exposed,and the calibration curves were used as a mean to quantitative determination of the leaf possible positioning errors through the detector readings.Results Compared with the"picket fence"pattern,the"stepwise"pattern not only had a high detecting efficiency,but also increased the dosimetric sensidvity to leaf positioning error.A 1 mm Ieaf positioni.error corresponds to a dose variation of 25% for the"stepwise"pattern,while for the"picket fence"pattern the same positioning error just causes a 17% dose vailation.Conclusions The new"stepwise"pattern is more efficient to be carried out,and more sensitive to sub-millimeter changes of leaf positioning.
