Honda Hirofumi, Sasaki Motoharu, Tominaga Masahide, Omoto Kenji, Kido Teruhito
Department of Radiological Technology, Ehime University Hospital, Toon, Ehime, Japan.
Graduate School of Advanced Technology and Science, Tokushima University, Tokushima, Japan.
J Appl Clin Med Phys. 2025 Jul;26(7):e70186. doi: 10.1002/acm2.70186.
The Radixact treatment system is equipped with a delivery analysis feature. This feature enables dose reconstruction using the patient's treatment-planning computed tomography scans and allows verification of the multileaf collimator (MLC) performance before and during treatment. In the Radixact system, the opening time of the MLC leaves is determined based on the treatment plan.
This study aimed to evaluate MLC driving accuracy by assessing the MLC leaf open time (LOT) during treatment.
Using Delivery Analysis version 2.3, we compared the treatment plan LOT with the LOT measured during treatment to determine the average and one standard deviation (%) of the LOT attainment rate. The analysis included comparisons of treated sites across 39 cases: nine prostate, eight pelvic, seven head, six chest, five head and neck (H&N), and four stereotactic body radiation therapy (SBRT) treatment plans.
The average and one standard deviation (%) of the LOT attainment rate for all patients on treatment was 94.56 ± 2.37. The values of each site were as follows: prostate, 95.93 ± 0.68; pelvis, 93.37 ± 2.16; head, 95.05 ± 1.99; chest, 97.61 ± 0.78; H&N, 92.44 ± 1.32; and SBRT, 98.39 ± 0.57. The treatment plans with the lowest attainment rates for each site were as follows: prostate, 95.19 ± 0.39; pelvis, 90.59 ± 0.16; head, 92.20 ± 0.15; chest, 95.76 ± 0.04; H&N, 90.55 ± 0.30; and SBRT, 97.32 ± 0.07. The plans with the largest one standard deviation (%) per site were as follows: prostate, ± 0.97; pelvis, ± 0.26; head, ± 0.57; chest, ± 0.23; H&N, ± 0.30; and SBRT, ± 0.07.
We proposed a simple method for quantitatively analyzing the LOT of an MLC. The average LOT attainment rate and its standard deviation varied by treatment site. Since the standard deviation differed by plan, the LOT attainment rate during treatment should be carefully monitored.
瑞迪克斯（Radixact）治疗系统配备了剂量分析功能。该功能可利用患者的治疗计划计算机断层扫描进行剂量重建，并能在治疗前和治疗期间验证多叶准直器（MLC）的性能。在瑞迪克斯系统中，MLC叶片的开启时间是根据治疗计划确定的。
本研究旨在通过评估治疗期间MLC叶片开启时间（LOT）来评价MLC驱动精度。
使用剂量分析2.3版本，我们将治疗计划中的LOT与治疗期间测量的LOT进行比较，以确定LOT达成率的平均值和一个标准差（%）。分析包括对39例患者不同治疗部位的比较：9例前列腺、8例盆腔、7例头部、6例胸部、5例头颈部（H&N）和4例立体定向体部放射治疗（SBRT）治疗计划。
所有接受治疗患者的LOT达成率平均值和一个标准差（%）为94.56±2.37。各部位的值如下：前列腺，95.93±0.68；盆腔，93.37±2.16；头部，95.05±1.99；胸部，97.61±0.78；头颈部，92.44±1.32；SBRT，98.39±0.57。各部位达成率最低的治疗计划如下：前列腺，95.19±0.39；盆腔，90.59±0.16；头部，92.20±0.15；胸部，95.76±0.04；头颈部，90.55±0.30；SBRT，97.32±0.07。各部位一个标准差（%）最大的计划如下：前列腺，±0.97；盆腔，±0.26；头部，±0.57；胸部，±0.23；头颈部，±0.30；SBRT，±0.07。
我们提出了一种定量分析MLC的LOT的简单方法。LOT达成率的平均值及其标准差因治疗部位而异。由于标准差因计划而异，治疗期间的LOT达成率应仔细监测。
