基于二维半导体矩阵剂量验证系统实施射波刀治疗患者个体化剂量验证研究

Study on the individualized dose verification of patients with CyberKnife treatment based on dose verification system of SRS MapCHECK matrix

目的:利用二维半导体矩阵(SRS MapCHECK)剂量验证系统对射波刀(CK)临床治疗患者计划进行剂量验证,通过对其γ通过率的分析实现肿瘤患者放疗计划的个体化快速验证。方法:选取2021年3月至2023年5月解放军总医院第一医学中心接受CK临床治疗的253例肿瘤患者,CK治疗中头部肿瘤患者121例,肺部肿瘤患者30例、腹部及其他转移肿瘤患者102例,在MultiPlan治疗计划系统中通过计划影像中心重合的方式将患者计划映射至StereoPHAN模体与SRS MapCHEC剂量验证系统组成的一体化模体上,在保证射束数量、方向及机器跳数一致性基础上对每例患者计划进行剂量验证。采用9个不同γ分析标准(1%/1 mm、2%/1 mm、3%/1 mm、1%/2 mm、2%/2 mm、3%/2 mm、1%/3 mm、2%/3 mm和3%/3 mm)对各验证计划进行绝对剂量的全局分析,其中低剂量阈值(TH)设置为10%。结果:253例患者模体验证计划在9个不同分析标准下γ通过率分别为(88.64±5.91)%、(95.43±3.40)%、(97.90±2.06)%、(96.51±2.35)%、(98.15±1.68)%、(99.06±1.12)%、(98.30±1.39)%、(99.09±0.97)%和(99.52±0.63)%;不同部位肿瘤患者除按1%/1 mm标准分析结果外,其他标准γ通过率均>95%。中心点剂量偏差整体分析结果为(-1.30±2.17)%,其中头部肿瘤、腹部及其他转移肿瘤均在-2%左右,而肺部肿瘤在-3%左右;且腹部及其他转移肿瘤偏差最小。Pearson相关性分析显示,靶区体积、最小准直器大小分别与患者整体和头部中心的点剂量偏差均存在一定的相关性。结论:SRS MapCHECK剂量验证系统可简便快捷实现CK治疗患者计划个体化验证。

Objective:A dose verification system of two-dimensional semiconductor matrix(SRS MapCHECK)was used to verify the dose of the clinical treatment plan of patients who underwent CyberKnife(CK),which realized rapid verification for individualization of radiotherapy plans of patients through analyzed theγ-passing rates of them.Methods:A total of 253 patients with tumor who received CK clinical treatment in the First Medical Center of Chinese PLA General Hospital from March 2021 to May 2023 were selected.Among of them,121 cases received CK treatment on head,and 30 cases received that on lung,and 102 cases received CK treatment on abdomen and other metastatic tumor.In the MultiPlan treatment plan system,the plan of patient was mapped to the integrated model composed of StereoPHAN model and SRS MapCHECK matrix dose verification system by the means of the plan image center overlap.The dose verification was conducted on the plan of each patient on the basis of ensuring the consistency of the number of beam,direction of beam and the monitor unit.The differentγanalysis standards(1%/1 mm,2%/1 mm,3%/1 mm,1%/2 mm,2%/2 mm,3%/2 mm,1%/3 mm,2%/3 mm and 3%/3 mm)were adopted to conduct global analysis of absolute dose for each verification plan,and the threshold(TH)of low dose was set as 10%.Results:Theγpassing rates of phantom verification plans of 253 patients were respectively(88.64±5.91)%,(95.43±3.40)%,(97.90±2.06)%,(96.51±2.35)%,(98.15±1.68)%,(99.06±1.12)%,(98.30±1.39)%,(99.09±0.97)%and(99.52±0.63)%under different analysis standards.Theγpassing rates of other standards of patients with tumor on different parts were larger than 95%except the analysis result of 1%1 mm standard.The overall analysis result of the deviation of central point dose was(-1.30±2.17)%,among of which the tumor of head,abdominal tumors and other metastatic tumor were about approximately-2%,while that of lung tumors were approximately-3%.The deviation of abdominal and other metastatic tumor was the minimum.The correlation analysis showed that the target volume and the size of the minimum collimator were respectively correlated to the dose deviation of the center.Conclusion:SRS MapCHECK dose verification system can conveniently and quickly realize the individualized verification for the plan of patients who receive CK treatment.