SU-E-T-196：瓦里安Clinac 21EX直线加速器容积调强放射治疗的调试

SU-E-T-196: Commissioning for Volumetric Modulated Radiation Therapy on Varian Clinac 21EX.

作者信息

Yada R, Hayashi N, Matsunaga T, Nozue M, Sai H, Yamada K, Yamanaka R, Kato Y, Muraki Y

机构信息

Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka.

Graduate school of Medical Science, Kanazawa University, Kanazawa, Ishikawa.

出版信息

Med Phys. 2012 Jun;39(6Part12):3748. doi: 10.1118/1.4735255.

DOI:10.1118/1.4735255

PMID:28517818

Abstract

PURPOSE

Recently the volumetric arc therapy (VMAT) technology such as RapidArc is widely distributed in Japan. These technologies are normally provided by the high spec linear accelerator such as Trilogy, Novalis Tx, Synergy, et al. The specific DICOM-file is generally used for commissioning of these technologies. On the other hand, we had to apply RapidArc into historic linear accelerator. This title expresses an experience how we performed the commissioning of RapidArc with the old linear accelerator.

METHODS

Two Varian's linear accelerators "Clinac 21EX" equipped with Millenium multi-leaf collimator and a Varian's treatment planning system "Eclipse ver.8.9" were used for this study. The commissioning for RapidArc was performed in energy 4,6,10,15 MV (Max-DR: 250, 600, 400, 600 MU/min). Commissioning procedure composed two categories: the general machine QA for DMLC-IMRT procedure and the specific RapidArc QA procedure. In RapidArc QA procedure, we modified DICOM-file to apply into the potential spec of Clinac 21EX optimally. The specific MLC-motion sequence and the gantry rotation speed were created by the dedicated programs (Shaper and DicomEdit, Varian) for RapidArc QA procedure. Each tolerance value was defied by the data from daily/monthly QA and the paper by Ling et al.

RESULTS

As the results of the general machine QA procedure, the variance of radiation output during static/dynamic gantry rotation was less than 1%. The deference of fence tests during static/dynamic gantry rotation and RapidArc were less than 1 mm in each. However, the results of the RapidArc QA were worse than the latest machine (especially variable gantry speed) and it was careful to define tolerance level.

CONCLUSION

The procedure of commissioning for RapidArc on historic linear accelerator was proposed. Several minor revisions for DICOM-file should be required for suitable commissioning and it may ensure the tolerance limit for gantry/MLC-leaf motion speeds.

摘要

目的

近期，容积弧形调强放疗（VMAT）技术，如RapidArc，在日本广泛应用。这些技术通常由高规格直线加速器提供，如Trilogy、Novalis Tx、Synergy等。特定的DICOM文件一般用于这些技术的调试。另一方面，我们不得不将RapidArc应用于老旧直线加速器。本文介绍了我们如何使用老旧直线加速器进行RapidArc调试的经验。

方法

本研究使用两台配备Millenium多叶准直器的Varian直线加速器“Clinac 21EX”以及一台Varian治疗计划系统“Eclipse ver.8.9”。在4、6、10、15 MV能量下进行RapidArc调试（最大剂量率：250、600、400、600 MU/分钟）。调试程序分为两类：适用于动态多叶准直器调强放疗（DMLC-IMRT）程序的一般机器质量保证（QA）和特定的RapidArc QA程序。在RapidArc QA程序中，我们对DICOM文件进行修改，以使其最佳地适用于Clinac 21EX的潜在规格。特定的多叶准直器运动序列和机架旋转速度由用于RapidArc QA程序的专用程序（Shaper和DicomEdit，Varian公司）生成。每个公差值由每日/每月QA数据以及Ling等人的论文确定。