3D-CRT、IMRT 和 VMAT 用于小儿肾母细胞瘤侧野照射：XCAT 体模的比较计划研究。

3D-CRT, IMRT and VMAT for flank irradiation due to pediatric Wilms tumor: A comparative planning study with XCAT phantoms.

机构信息

Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, 71003 Iraklion, Crete, Greece.

Department of Radiation Oncology, University Hospital of Iraklion, 71110 Iraklion, Crete, Greece.

出版信息

Phys Med. 2022 Nov;103:89-97. doi: 10.1016/j.ejmp.2022.10.002. Epub 2022 Oct 17.

DOI:10.1016/j.ejmp.2022.10.002

PMID:36257232

Abstract

PURPOSE

To compare the dosimetric parameters and radiogenic risks from 3D-CRT, IMRT and VMAT for flank irradiation due to pediatric Wilms tumor.

METHODS

Two computational XCAT phantoms simulating an average 5- and 10-year-old patient were used. Four different planning target volumes (PTVs) for right flank (RF) and left flank (LF) irradiation with or without paraaortic lymph nodes (LNs) and eight surrounding organs-at-risk (OARs) were contoured on the phantoms' CT sections. Forty-eight 3D-CRT, IMRT and VMAT plans were created using 6 and 10-MV photons on the two phantoms. The target coverage index (TCI), homogeneity index (HI), conformity index (CI), conformation number (CN) and OAR exposure were determined through dose-volume histogram (DVH) analysis. Second cancer risks were estimated using a non-linear model and DVH data.

RESULTS

The IMRT and VMAT for LF + LN and RF + LN irradiation reduced the radiation dose to four to six out of the eight OARs compared to 3D-CRT. Conventional treatment provided a better organ sparing for RF and LF irradiation. The IMRT and VMAT led to superior planning parameters in respect to 3D-CRT for all PTVs and both patient's ages (3D-CRT: TCI = 59.80 % - 82.26 %, CI = 0.55-0.81, CN = 0.40-0.64, HI = 1.11-1.15; IMRT: TCI = 96.04 % - 99.72 %, CI = 0.85-0.91, CN = 0.85-0.88, HI = 1.03-1.05; VMAT: TCI = 96.02 % - 99.69 %, CI = 0.86-0.91, CN = 0.85-0.89, HI = 1.03-1.06). The excess-absolute-risk for developing secondary small intestine, liver and stomach malignancies from 3D-CRT were (7.99-19.32) × 10, (0.29-3.83) × 10 and (0.37-4.50) × 10 persons-year, respectively. The corresponding risks from intensity modulated techniques reached to 22.26 × 10, 4.58 × 10 and 5.42 × 10 persons-year.

CONCLUSIONS

This dataset related to plan quality, radiation dose and risks to OARs allows the selection of the proper treatment technique for flank irradiation based on the patient's age and target site.

摘要

目的

比较儿童肾母细胞瘤侧野照射的 3D-CRT、调强放疗（IMRT）和容积旋转调强放疗（VMAT）的剂量学参数和放射性风险。

方法

使用两个模拟平均 5 岁和 10 岁患者的计算型 XCAT 体模。在体模 CT 切片上勾画了 4 种不同的右（RF）和左（LF）侧野照射计划靶区（PTV），包括是否包括主动脉旁淋巴结（LNs）和 8 个周围危及器官（OARs）。在两个体模上使用 6 和 10-MV 光子为两个体模生成 48 个 3D-CRT、IMRT 和 VMAT 计划。通过剂量体积直方图（DVH）分析确定靶区覆盖率指数（TCI）、均匀性指数（HI）、适形指数（CI）、适形度指数（CN）和 OAR 暴露情况。使用非线性模型和 DVH 数据估计第二原发癌症风险。

结果

与 3D-CRT 相比，LF+LN 和 RF+LN 照射的 IMRT 和 VMAT 降低了 4 到 6 个 OAR 的辐射剂量。常规治疗对 RF 和 LF 照射提供了更好的器官保护。IMRT 和 VMAT 为所有 PTV 和两个患者年龄（3D-CRT：TCI=59.80%-82.26%，CI=0.55-0.81，CN=0.40-0.64，HI=1.11-1.15；IMRT：TCI=96.04%-99.72%，CI=0.85-0.91，CN=0.85-0.88，HI=1.03-1.05；VMAT：TCI=96.02%-99.69%，CI=0.86-0.91，CN=0.85-0.89，HI=1.03-1.06）的计划参数更优。3D-CRT 治疗导致小肠、肝脏和胃发生第二原发恶性肿瘤的超额绝对风险分别为（7.99-19.32）×10、（0.29-3.83）×10 和（0.37-4.50）×10 人年。强度调制技术的相应风险分别达到 22.26×10、4.58×10 和 5.42×10 人年。