千伏级锥形束CT计算宫颈癌放疗剂量

发布时间：2018-08-05 19:19

【摘要】：目的探讨宫颈癌放疗中采用加速器机载千伏级锥形束CT(kV-CBCT)影像进行剂量计算的准确性和可行性。方法分别于CT模拟机和kV-CBCT上扫描CIRS-062电子密度模体,获得电子密度模体影像及计划CT(pCT)和kV-CBCT的CT值-相对电子密度曲线,采用治疗计划系统计算剂量。选取9例宫颈癌患者的调强治疗计划,并将计划移植至模体和患者的pCT和kV-CBCT影像进行剂量计算,比较剂量差异及剂量分布情况。结果 kV-CBCT的CT值经多次重复测量最大变化≤3%;kV-CBCT的CT值-相对电子密度曲线与pCT相比,低密度组织的差异较小,高密度者差异相对较大。在对模体的剂量计算中,pCT和kV-CBCT的剂量差异为0.7%~2.5%,平均(1.23±0.55)%;而在对宫颈癌患者的剂量计算中,剂量差异为0.5%~1.8%,平均(0.84±0.44)%;剂量分布的一致性均较好。结论宫颈癌放疗中采用kV-CBCT影像进行剂量计算是可行的。
[Abstract]:Objective to investigate the accuracy and feasibility of dose calculation using accelerator airborne KV conical beam CT (kV-CBCT) in cervical cancer radiotherapy. Methods the electron density motifs of CIRS-062 were scanned on CT simulator and kV-CBCT, respectively. The CT values and relative electron density curves of CT (pCT) and kV-CBCT were obtained. The dose was calculated by the treatment plan system. Nine patients with cervical cancer were selected for intensity modulation treatment plan. The dose difference and dose distribution were compared by transplanting the plan to the motif and the pCT and kV-CBCT images of the patients. Results the CT value of kV-CBCT was measured repeatedly. The difference of CT value and relative electron density curve of kV-CBCT was smaller than that of pCT, and the difference of high-density tissue was larger than that of low-density tissue. The dose difference between PCT and kV-CBCT was 0.72.5, average (1.23 卤0.55), but in the dose calculation of cervical cancer patients, the dose difference was 0.5 ~ 1.8 and (0.84 卤0.44), and the consistency of dose distribution was good. Conclusion it is feasible to calculate the dose of cervical cancer by kV-CBCT imaging.
【作者单位】：汕头大学医学院附属肿瘤医院放疗科;
【分类号】：R737.33;R730.44

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