【摘要】 目的：探讨基于ArcCHECK系统的宫颈癌容积旋转调强放疗(volumetric modulated arc therapy,VMAT)超长靶区剂量验证方法，以保障宫颈癌放疗的精准性。方法：回顾性选取某院2021—2023年期间收治的33例超长靶区(靶区长度≥26 cm)宫颈癌放疗患者，使用VMAT技术进行计划设计，并通过不同验证方法对放疗计划进行剂量验证。首先分别在沿出床方向偏离ArcCHECK系统中心点5和8 cm处采集剂量分布数据，分别命名为Test 1组和Test 2组。随后翻转ArcCHECK系统180°，在沿进床方向偏离ArcCHECK系统中心点8 cm处采集剂量分布数据，命名为Test 3组，使用Merge功能对Test 2组和Test 3组的剂量进行衔接，得到融合后的剂量分布数据，命名为Test 4组。统计Test 1组、Test 2组、Test 4组的机器跳数，对靶区长度、检测点、照射时间进行差异性分析。对比Test 1组、Test 2组和Test 4组的γ通过率、归一点剂量偏差、通过率的置信限(confidence limit,CL)水平与合格率(γ通过率≥95%及γ通过率≥90%)。采用Spearman相关系数对靶区最大横径、靶区长度、靶区体积、机器跳数与计划预计执行时间等参数进行相关性分析。采用SPSS 19.0软件进行统计学分析。结果：3组的机器跳数为(758.76±107.63)MU,3组间的靶区长度、检测点和照射时间差异均有统计学意义(P<0.01)。Test 4组中2%/2 mm的γ通过率未达到90%，在3%/3 mm和3%/2 mm的标准下Test 1组与Test 2组的γ通过率均能达到95%的标准。Test 1组、Test 2组与Test 4组的γ通过率和归一点剂量偏差差异有统计学意义(P均<0.05)。Test 1组在3%/3 mm的标准下超过90%的验证结果满足γ通过率≥95%、超过95%的验证结果满足γ通过率≥90%。机器跳数与最大横径、靶区长度、靶区体积均分别呈正相关(0.337≤r≤0.568,P<0.05)，计划预计执行时间与靶区体积和机器跳数均分别呈正相关(0.457≤r≤0.517,P<0.01)。结论：对于靶区超长的宫颈癌放疗患者，可通过沿出床方向偏离验证设备中心点5 cm的方法完成剂量验证，该方法既能保证验证设备的安全性，同时具有一定的可行性，能够满足临床需求。更多还原

【Abstract】 Objective To explore the ArcCHECK system-based methods for dose verification of ultra-long target for cervical cancer VMAT so as to assure the precision of cervical cancer radiotherapy.Methods A total of 33 patients with ultra-longtarget(target length ≥26 cm)admitted tosomehospitalforcervical cancer VMATfrom 2021 to 2023 wereselected retrospectively, and radiotherapy plans were designed for the patients with VMAT technology and verified dosimetrically with different methods. Firstly, the dose distribution data were collected respectively at 5 and 8 cm away from the center of the ArcCHECK system along the bed exit direction, and enrolled into Group Test 1 and Test 2 respectively. Then the ArcCHECK system was flipped 180°, and the dose distribution data were acquired at 8 cm away from the center along the bed exit direction and included into Group Test 3. Dose merging between Group Test 2 and Test 3 with the Merge function was carried out to obtain the dose distribution data which were divided into Group Test 4. The monitor units of Group Test1, 2 and 4 were summarized, and difference analyses were performed on the length of the target area, detection point and irradiation time. Group Test 1, 2 and 4 were compared in terms of γ pass rate, normalized dose deviation, confidence limit(CL) of pass rate and acceptance rate(γ pass rate ≥ 95% and γ pass rate ≥ 90%). Spearman’s correlation coefficient was used to correlate the parameters such as maximum transverse diameter, length, volume and monitor unit of the target area and expected execution time of the plan. SPSS 19.0 software was used for statistical analysis.Results Group Test 1, 2 and 4 had the monitor unit being(758.76±107.63) MU, and had statistically significant differences in length of the target area,detection point and irradiation time(P < 0.01). In Group Test 4 γ pass rate under 2%/2 mm criterion did not reach 90%,and in Group Test 1 and 2 γ pass rates under 3%/3 mm and 3%/2 mm criteria both amounted to 95%. Group Test 1, 2 and 4 had statistically significant differences in γ pass rate and normalized dose deviation(all P < 0.05). In Group Test 1 there were more than 90% of the verification results where γ pass rate ≥ 95% and more than 95% where γ pass rate ≥ 90%under 3%/3 mm criterion. The monitor unit was positively correlated with the maximum transverse diameter, length and volume of the target area, respectively(0.337 ≤ r ≤ 0.568, P < 0.05), and the expected execution time of the plan was positively correlated with the volume and monitor unit of the target area, respectively(0.457 ≤ r ≤ 0.517, P < 0.01).Conclusion The dose verification method with the target at 5 cm away from the center along the bed exit direction can be applied clinically with high feasibility to the dose verification during the radiotherapy of the cervical cancer VMAT patients with ultra-long target, with the safety of the verification devices ensured effectively.[Chinese Medical Equipment Journal,2025,46(11):39-43]更多还原