Radiation Safety and Quality Assurance Division, Hospital East, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 2778577, Japan.
Particle Therapy Division, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Chiba, 2778577, Japan.
Radiol Phys Technol. 2022 Sep;15(3):264-270. doi: 10.1007/s12194-022-00665-3. Epub 2022 Jul 12.
In this study, we implemented a practical dosimetry procedure of air kerma for kilovoltage X-ray beams using a 0.6-cc cylindrical ionization chamber, and validated the procedure with the accuracy of the measurements using the 0.6-cc chamber compared to the measurements using a 6-cc chamber and a semiconductor device. In addition, the kerma area products (KAPs) were compared with the dose reference levels of radiology. A modified air kerma formalism using a 0.6-cc cylindrical ionization chamber air kerma formalism with a cobalt absorbed dose-to-water calibration coefficient was implemented. Validation of the formalism showed good agreement between the 0.6-cc chamber and the 6-cc chamber (< 5%), and between the 0.6-cc chamber and the semiconductor device (< 2%) in the 60-120 kV range. The KAPs for four RO machines had difference factors of 0.04-15.4 and 0.01-4.1 from their median and maximum dose reference levels in radiology, respectively.
在这项研究中，我们使用 0.6cc 圆柱形电离室实施了一种实用的千伏 X 射线束空气比释动能剂量学程序，并使用 0.6cc 室与 6cc 室和半导体器件的测量精度对该程序进行了验证。此外，还将比释动能面积乘积 (KAP) 与放射学的剂量参考水平进行了比较。使用钴吸收剂量-水校准系数的 0.6cc 圆柱形电离室空气比释动能公式，实现了一种改进的空气比释动能形式。在 60-120kV 范围内，形式验证表明 0.6cc 室与 6cc 室（<5%）之间，以及 0.6cc 室与半导体器件（<2%）之间具有良好的一致性。对于四台 RO 机，其 KAP 与放射学中位数和最大剂量参考水平相比的差异因素分别为 0.04-15.4 和 0.01-4.1。
