基于 SBRT 治疗早期肺癌患者的 IGRT 引导成像剂量评估及二次癌症风险的计算机模拟研究。

Evaluation of IGRT-Induced Imaging Doses and Secondary Cancer Risk for SBRT Early Lung Cancer Patients In Silico Study.

机构信息

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.

Department of Engineering, Beijing Jingfang Technologies Co. Ltd, Beijing, China.

出版信息

Technol Cancer Res Treat. 2021 Jan-Dec;20:15330338211016472. doi: 10.1177/15330338211016472.

DOI:10.1177/15330338211016472

PMID:34184567

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8251513/

Abstract

OBJECTIVES

This study performed dosimetry studies and secondary cancer risk assessments on using electronic portal imaging device (EPID) and cone beam computed tomography (CBCT) as image guided tools for the early lung cancer patients treated with SBRT.

METHODS

The imaging doses from MV-EPID and kV-CBCT of the Edge accelerator were retrospectively added to sixty-one SBRT treatment plans of early lung cancer patients. The MV-EPID imaging dose (6MV Photon beam) was calculated in Pinnacle TPS, and the kV-CBCT imaging dose was simulated and calculated by modeling of the kV energy beam in TPS using Pinnacle automatic modeling program. Three types of plans, namely Plan, Plan and Plan, were generated with incorporating doses of EPID, CBCT and no imaging, respectively, for analysis. The effects of imaging doses on dose-volume-histogram (DVH) and plan quality were analyzed, and the excess absolute risk (EAR) of secondary cancer for ipsilateral lung was evaluated.

RESULTS

The regions that received less than 50 cGy were significantly impacted by the imaging doses, while the isodose lines greater than 1000 cGy were barely changed. The DVH values of ipsilateral lung increased the most in Plan, followed by Plan. Compared to Plan on the average, the estimated EAR of ipsilateral lung in Plan increased by 3.43%, while the corresponding EAR increase in Plan was much smaller (about 0.4%). Considering only the contribution of the imaging dose, the EAR values for the ipsilateral lung due to the MV-EPID dose in 5 years,10 years and 15 years were 1.49 cases, 2.09 cases and 2.88 cases per 10PY respectively, and those due to the kV-CBCT dose were about 9 times lower, correspondingly.

CONCLUSIONS

The imaging doses produced by MV-EPID and kV-CBCT had little effects on the target dose coverage. The secondary cancer risk caused by MV-EPID dose is more than 8.5 times that of kV-CBCT.

摘要

目的

本研究对使用电子射野影像装置（EPID）和锥形束 CT（CBCT）作为立体定向体部放射治疗（SBRT）早期肺癌患者的图像引导工具进行了剂量学研究和二次癌症风险评估。

方法

回顾性地将电子射野影像装置（MV-EPID）和千伏锥形束 CT（kV-CBCT）的成像剂量添加到 61 例早期肺癌 SBRT 治疗计划中。MV-EPID 成像剂量（6MV 光子束）在 Pinnacle TPS 中计算，kV-CBCT 成像剂量通过 TPS 中使用 Pinnacle 自动建模程序对 kV 能束建模来模拟和计算。分别生成三种类型的计划，即 Plan、Plan 和 Plan，分别包含 EPID、CBCT 和无成像的剂量，用于分析。分析了成像剂量对剂量体积直方图（DVH）和计划质量的影响，并评估了同侧肺的继发癌症超额绝对风险（EAR）。

结果

受成像剂量影响的区域明显为接收到低于 50 cGy 的区域，而大于 1000 cGy 的等剂量线几乎没有变化。同侧肺的 DVH 值在 Plan 中增加最多，其次是 Plan。与 Plan 相比，Plan 中同侧肺的估计 EAR 增加了 3.43%，而 Plan 中的相应 EAR 增加较小（约 0.4%）。仅考虑成像剂量的贡献，由于 MV-EPID 剂量，5 年、10 年和 15 年时同侧肺的 EAR 值分别为每 10PY 1.49 例、2.09 例和 2.88 例，而由于 kV-CBCT 剂量的 EAR 值则相应降低约 9 倍。