Mahani Leili, Kazemzadeh Arezoo, Saeb Mohsen, Kianinia Mahsa, Akhavan Ali
Department of Radio-Oncology, Seyed-Al-Shohada Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Adv Biomed Res. 2023 Apr 25;12:89. doi: 10.4103/abr.abr_342_21. eCollection 2023.
Multi-leaf collimator (MLC) is one of the efficient and cost-effective methods for protecting sensitive tissues around the target. This study aimed to evaluate the protective effect of MLC on the protection of sensitive organs in patients with left breast cancer.
This study was performed on computed tomography (CT) scans of 45 patients with left breast cancer. Two treatment plans were completed for each patient. Only the heart and left lung were considered organs at risk in the first treatment plan, and in the second treatment plan, the left anterior descending artery (LAD) was also considered the organ at risk. It was covered as much as possible by the MLC. Dosimetric results of tumor and organ at risk (OARs) were extracted from the dose-volume histogram and compared.
The results showed that more LAD coverage by MLC leads to a significant reduction in the mean dose of OARs (-value <0.05). The mean dose for heart, LAD, and left lung decreased by 11%, 7.4%, and 4.9%, respectively. The values of V (volume received the dose of 5 Gy) and V for the lung, V, V, and V30 for LAD, and V, V, V, and V for the heart also decreased significantly (-value <0.05).
In general, better protection of LAD, heart, and lungs can be achieved by maximal shielding organs at risk by MLC in radiation therapy for patients with left breast cancer.
多叶准直器（MLC）是保护靶区周围敏感组织的有效且具成本效益的方法之一。本研究旨在评估MLC对左乳腺癌患者敏感器官的保护作用。
本研究对45例左乳腺癌患者的计算机断层扫描（CT）图像进行分析。为每位患者制定两个治疗计划。在第一个治疗计划中，仅将心脏和左肺视为危及器官，在第二个治疗计划中，左前降支动脉（LAD）也被视为危及器官，并尽可能用MLC覆盖。从剂量体积直方图中提取肿瘤和危及器官（OARs）的剂量学结果并进行比较。
结果显示，MLC对LAD的更多覆盖导致OARs平均剂量显著降低（P值<0.05）。心脏、LAD和左肺的平均剂量分别降低了11%、7.4%和4.9%。肺的V（接受5 Gy剂量的体积）和V值、LAD的V、V、V和V30值以及心脏的V、V、V和V值也显著降低（P值<0.05）。
总体而言，在左乳腺癌患者的放射治疗中，通过MLC对危及器官进行最大程度的屏蔽，可更好地保护LAD、心脏和肺部。
