Matrixx Evolution在国产联影加速器调强剂量验证中的应用

Application of Matrixx Evolution in Intensity Modulated Dose Verification of Domestic UIH Accelerator

摘要: 目的：研究基于Matrixx Evolution电离室矩阵在最新国产联影uRT-Linac 506C医用直线加速器调强剂量验证中的临床应用。方法：随机选取常德市第一中医医院20例行放疗的肿瘤患者，其中头颈部10例、胸部5例和盆腔部5例。对每例患者分别行VMAT及IMRT计划设计并导出Matrixx矩阵模体的验证计划，分为实际机架角VMAT组、实际机架角IMRT组和机架角归零组IMRT_0。主要分析基于两种通用临床评判标准TG119 (3%/3mm)和TG218 (3%/2mm)三组调强剂量验证γ通过率以及比较常规计算分辨率3 mm和通用临床评判标准下三组Gamma通过率。结果：20例患者三组调强剂量验证γ通过率分别为TG119标准：VMAT (99.65 ± 0.95)%、IMRT (97.85 ± 4.78)%、IMRT_0 (99.97 ± 0.78)%，TG218标准：VMAT (98.81 ± 2.20)%、IMRT (95.79 ± 6.93)%、IMRT_0 (99.92 ± 0.14)%；在TG119评判标准下，任意两组之间γ通过率均无差异(P > 0.05)，在TG218评判标准下，VMAT组与IMRT组通过率差异无统计学意义(P > 0.05)，而IMRT_0组均优于VMAT组与IMRT组(P < 0.05)，平均γ通过率分别高1.12和4.14个百分点。结论：本平台下基于TG119和TG218评判标准，三种剂量验证方式的γ通过率均远远高于95%，符合临床要求，其中IMRT_0组γ通过率最高。剂量验证可根据临床实际灵活选择评判标准和测量方法。

Abstract: Purposes: To study the clinical application of the Matrixx Evolution ionization chamber matrix based on the latest domestic UIH uRT-Linac 506C medical linear accelerator in intensity modulated dose verification. Methods: A total of 20 cancer patients who underwent radiotherapy in the No.1 Traditional Chinese Medicine Hospital in Changde were randomly selected, including 10 cases of head and neck, 5 cases of chest and 5 cases of pelvis. The VMAT and IMRT plans were designed for each patient and the verification plan for the MatriXX matrix model was derived, which was divided into the actual gantry angle VMAT group, the actual gantry angle IMRT group and the gantry angle zeroing group IMRT_0. The gamma pass rate of intensity-modulated dose verification was mainly analyzed based on the two general clinical evaluation criteria TG119 (3%/3mm) and TG218 (3%/2mm) as well as a comparison of three groups of gamma pass rates at the conventional calculation resolution of 3 mm and the general clinical evaluation criteria. Results: The gamma pass rates of the three groups of 20 patients with dose verification were TG119 criteria: VMAT (99.65 ± 0.95)%, IMRT (97.85 ± 4.78)%, IMRT_0 (99.97 ± 0.78)%, TG218 criteria: VMAT (98.81 ± 2.20)%, IMRT (95.79 ± 6.93)%, IMRT_0 (99.92 ± 0.14)%. There was no difference in gamma pass rate between any two groups under the TG119 criterion (P > 0.05), and there was no significant difference in the pass rate between the VMAT group and the IMRT group under the TG218 criterion (P > 0.05), while the IMRT_0 group was better than the VMAT group and the IMRT group (P < 0.05), and the average gamma pass rate was 1.12 and 4.14 percentage points higher, respectively. Conclusion: Based on the evaluation criteria of TG119 and TG218, the gamma pass rates of the three dose verification methods are all much higher than 95%, which meets the clinical requirements in this platform, and the IMRT_0 group is the highest. Actually, dose verification can flexibly select evaluation criteria and measurement methods according to clinical practice.