Institute of Health Biosciences, The University of Tokushima, Tokushima, Japan, 770-8503.
Med Phys. 2011 May;38(5):2467-78. doi: 10.1118/1.3570769.
This paper uses film dosimetry to investigate the relationship between multiple scan parameters of multidetector CT with automatic exposure control (AEC) and the surface dose distribution produced on a chest phantom.
The characteristics of the film used in the film dosimeter were evaluated with regard to linearity, relative film response, and directional dependence. Measurements with an ionization chamber dosimeter and a water phantom were used to evaluate the accuracy of the film dosimeter measurements and to validate the dose profile measurements while changing the tube current, detector dimensions and pitch. When using AEC, the surface dose distribution on the chest phantom was analyzed while changing the detector dimensions and pitch.
The linearity, relative film response, and directional dependence of the film were established. The measurement difference between the film dosimeter and ionization chamber dosimeter was within +/- 5% and the dose profile measurement results were validated. It was found that the surface dose distribution changed helically in the direction of the body axis depending on the scan parameters and the phantom.
Using a film dosimeter, the relationship between various multidetector CT scan parameters and the surface dose distribution on a chest phantom was investigated and clarified.
本研究采用胶片剂量计，通过体模实验研究多层螺旋 CT 自动曝光控制（AEC）多扫描参数与表面剂量分布之间的关系。
评估胶片剂量计的线性、相对胶片响应和方向依赖性等特点。采用电离室剂量计和水模进行测量，以验证胶片剂量计测量的准确性和管电流、探测器尺寸和螺距改变时的剂量分布测量。使用 AEC 时，分析了探测器尺寸和螺距改变时体模表面剂量分布。
建立了胶片的线性、相对胶片响应和方向依赖性。胶片剂量计和电离室剂量计的测量差值在 +/- 5%以内，剂量分布测量结果得到验证。结果表明，根据扫描参数和体模的不同，表面剂量分布在体轴方向呈螺旋状变化。
本研究使用胶片剂量计，研究并阐明了多层螺旋 CT 各种扫描参数与体模表面剂量分布之间的关系。
