Department of Radiation Oncology, 8091 Zurich, Switzerland.
Med Phys. 2012 Mar;39(3):1351-6. doi: 10.1118/1.3685461.
Pretreatment quality assurance data from four centers, members of the European TrueBeam council were analyzed with different verification devices to assess reliability of flattening filter free beam delivery for intensity modulated radiotherapy (IMRT) and RapidArc (RA) techniques.
TrueBeam(®) (Varian Medical System) is a new linear accelerator designed for delivering flattened, as well as flattening filter free beams. Pretreatment dosimetric validation of plan delivery was performed with different verification devices and responses to high dose rates were tested. Treatment planning was done in Eclipse planning system (PRO 8.9, AAA 8.9). γ evaluation was performed with (dose difference) = 3% and (distance to agreement) = 3 mm scoring the gamma agreement index (GAI, % of field area passing the test). Two hundred and twenty-four patients with 1-6 lesions in various anatomical regions and dose per fraction ranging from 1.8 Gy to 25 Gy were included in the study; 88 were treated with 6 MV flattening filter free (X6FFF) beam energy and 136 with 10 MV flattening filter free (X10FFF) beam. Gafchromic films in solid water, delta(4), arccheck, and matrixx phantom were used to verify the dose distributions. Additionally, point measurements were performed using a PinPoint chamber and a Farmer chamber.
Dose calculation as well as dose delivery was equally accurate for IMRT and RA delivery (IMRT: GAI = 99.3% (±1.1); RA: GAI = 98.8% (±1.1) as well as for the two beams evaluated (X6FFF: GAI = 99.1% (±1.0); X10FFF: GAI = 98.8% (±1.2). Only small differences were found for the four verification devices. A point dose verification was performed on 52 cases, obtaining a dose deviation of 0.34%. The GAI variations with number of monitor units were statistically significant.
The TrueBeam FFF modality, analyzed with a variety of verification devices and planned with Eclipse planning system is dosimetrically accurate (within the specified limits 3 mm/3%) for both X6FFF and X10FFF beam energy.
分析来自欧洲 TrueBeam 委员会四个成员中心的预处理质量保证数据，使用不同的验证设备评估强度调制放疗（IMRT）和 RapidArc（RA）技术中使用非调强适形滤波器自由射束的可靠性。
TrueBeam（®）（Varian Medical System）是一种新的直线加速器，用于输送调强适形和非调强适形滤波器自由射束。使用不同的验证设备对计划交付进行了预处理剂量验证，并测试了对高剂量率的响应。在 Eclipse 计划系统（PRO 8.9，AAA 8.9）中进行治疗计划。使用（剂量差异）= 3%和（协议距离）= 3 毫米进行γ评估，对伽马吻合指数（GAI，通过测试的字段区域的百分比）进行评分。将 224 名患者纳入研究，这些患者在不同解剖区域有 1-6 个病变，每个病变的剂量为 1.8 Gy 至 25 Gy 不等；88 例患者接受 6 MV 非调强适形滤波器自由（X6FFF）束能量治疗，136 例患者接受 10 MV 非调强适形滤波器自由（X10FFF）束能量治疗。使用固体水中的 Gafchromic 胶片、Delta（4）、Arccheck 和 Matrixx 体模来验证剂量分布。此外，还使用 PinPoint 腔室和 Farmer 腔室进行了点测量。
对于 IMRT 和 RA 输送，剂量计算和剂量输送同样准确（IMRT：GAI=99.3%（±1.1）；RA：GAI=98.8%（±1.1），以及评估的两种光束（X6FFF：GAI=99.1%（±1.0）；X10FFF：GAI=98.8%（±1.2））。仅在四个验证设备之间发现了很小的差异。对 52 例进行了点剂量验证，得到剂量偏差为 0.34%。GAI 随监测单元数量的变化具有统计学意义。
使用各种验证设备分析的 TrueBeam FFF 模式，并使用 Eclipse 计划系统进行计划，对于 X6FFF 和 X10FFF 束能量，在规定的 3 毫米/3%范围内，剂量学是准确的。
