Department of Radiological Technology, Nagoya University Hospital, Nagoya, Aichi, Japan.
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
J Appl Clin Med Phys. 2022 Aug;23(8):e13645. doi: 10.1002/acm2.13645. Epub 2022 Jul 5.
We aim to evaluate the basic characteristics of SRS MapCHECK (SRSMC) for CyberKnife (CK) and establish a dose verification system using SRSMC for the tumor-tracking irradiation for CK. The field size and angular dependence of SRSMC were evaluated for basic characterization. The output factors (OPFs) and absolute doses measured by SRSMC were compared with those measured using microDiamond and microchamber detectors and those calculated by the treatment planning system (TPS). The angular dependence was evaluated by comparing the SRSMC with a microchamber. The tumor-tracking dose verification system consists of SRSMC and a moving platform. The doses measured using SRSMC were compared with the doses measured using a microchamber and radiochromic film. The OPFs and absolute doses of SRSMC were within ±3.0% error for almost all field sizes, and the angular dependence was within ±2.0% for all incidence angles. The absolute dose errors between SRSMC and TPS tended to increase when the field size was smaller than 10 mm. The absolute doses of the tumor-tracking irradiation measured using SRSMC and those measured using a microchamber agreed within 1.0%, and the gamma pass rates of SRSMC in comparison with those of the radiochromic film were greater than 95%. The basic characteristics of SRSMC for CK presented acceptable results for clinical use. The results of the tumor-tracking dose verification system realized using SRSMC were equivalent to those of conventional methods, and this system is expected to contribute toward improving the efficiency of quality control in many facilities.
我们旨在评估 SRS MapCHECK（SRSMC）用于 CyberKnife（CK）的基本特性，并建立使用 SRSMC 对 CK 的肿瘤跟踪照射进行剂量验证的系统。评估了 SRSMC 的射野大小和角度依赖性，以进行基本特性评估。通过 SRSMC 测量的输出因子（OPFs）和绝对剂量与使用 microDiamond 和 microchamber 探测器以及治疗计划系统（TPS）计算的结果进行了比较。通过比较 SRSMC 和 microchamber 评估了角度依赖性。肿瘤跟踪剂量验证系统由 SRSMC 和移动平台组成。使用 SRSMC 测量的剂量与使用 microchamber 和光致变色胶片测量的剂量进行了比较。对于几乎所有射野大小，SRSMC 的 OPFs 和绝对剂量的误差在±3.0%以内，对于所有入射角，角度依赖性在±2.0%以内。当射野尺寸小于 10mm 时，SRSMC 与 TPS 之间的绝对剂量误差趋于增加。使用 SRSMC 测量的肿瘤跟踪照射的绝对剂量与使用 microchamber 测量的剂量一致，误差在 1.0%以内，与光致变色胶片相比，SRSMC 的伽马通过率大于 95%。CK 的 SRSMC 的基本特性呈现出可接受的临床使用结果。使用 SRSMC 实现的肿瘤跟踪剂量验证系统的结果与传统方法等效，该系统有望有助于提高许多设施的质量控制效率。
