The internal target volume (ITV)-based IMRT method can be used to reduce the effect of respiratory tumor motion. In this study, the effect of tumor motion on the dosimetric accuracy during ITV-based IMRT was investigated. ITV-based IMRT plans for a total of ten cases of liver cancer were prepared in TomoTherapy (Tomo) and volumetric modulated arc therapy (VMAT). Delivery quality assurance (DQA) plans were created using Delta⁴ phantom for the verification of dosimetric accuracy of the established Tomo and VMAT plans. DQA measurements were performed in both the static mode and the Hexa-Motion mode by using the Delta⁴ Hexa-Motion system in Tomo and VMAT. In the static mode, the average gamma passing rate (GPR) using a 3% dose difference/3 mm distance-to-agreement criteria was 99.61% in Tomo and 99.35% in VMAT, which confirmed sufficient dosimetric accuracy in both IMRT methods. For the Hexa-Motion measurement, the average GRP result of 90.93% in Tomo was higher than the result of 82.58% obtained in VMAT. In addition, the difference in the GPR results between the static and the Hexa-motion modes in Tomo was 8.68%, which is approximately 8% less than the 16.77% difference in VMAT. This study verifies that the dosimetric error of ITV-based IMRT due to the tumor motion was larger in VMAT than in Tomo. Also, Tomo can be considered to be more suitable than the conventional LINAC-based VMAT method in terms of the dosimetric accuracy of ITV-based IMRT for the treatment of a moving tumor.

基于内部目标体积（ITV）的IMRT方法可用于减少呼吸道肿瘤运动的影响。在这项研究中，研究了基于ITV的IMRT期间肿瘤运动对剂量精确度的影响。在TomoTherapy（Tomo）和容积调制弧光治疗（VMAT）中准备了基于ITV的IMRT计划，该计划针对总共10例肝癌。使用Delta ^4体模创建了交付质量保证（DQA）计划，以验证已建立的Tomo和VMAT计划的剂量学准确性。通过使用Delta ⁴在静态模式和六边形运动模式下执行DQA测量Tomo和VMAT中的Hexa-Motion系统。在静态模式下，使用3％剂量差异/ 3毫米协议距离标准的平均伽马通过率（GPR）在Tomo中为99.61％，在VMAT中为99.35％，这证实了两种IMRT方法均具有足够的剂量测定精度。对于Hexa-Motion测量，在Tomo中的平均GRP结果为90.93％，高于在VMAT中获得的82.58％。此外，在Tomo中，静态模式和Hexa运动模式之间的GPR结果差异为8.68％，比VMAT中的16.77％差异小大约8％。这项研究证实，由于肿瘤运动而导致的基于ITV的IMRT的剂量学误差在VMAT中比在Tomo中更大。还，