Retrospective dose reconstruction of prostate stereotactic body radiotherapy using cone-beam CT and a log file during VMAT delivery with flattening-filter-free mode
Retrospective dose reconstruction of prostate stereotactic body radiotherapy using cone-beam CT and a log file during VMAT delivery with flattening-filter-free mode
复制标题
锥束CT和记录文件在无滤波平坦化VMAT治疗过程中的剂量重建
DOI：
10.1007/s12194-020-00574-3
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发表时间：
2020-07-12
影响因子：
1.6
通讯作者：
Abe, Osamu
中科院分区：
文献类型：
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作者：
Imae, Toshikazu;Haga, Akihiro;Abe, Osamu
本研究旨在使用锥形束计算机断层扫描（CBCT）和日志文件重建前列腺癌患者立体定向体部放射治疗（VMAT）无滤波器（FFF）模式下单次分割的剂量分布。20例临床局限性前列腺癌患者接受了FFF-VMAT治疗，同时采集了治疗中CBCT（iCBCT）成像的投影图像和日志文件。在每个治疗计划CT（pCT）上，为每个计划靶体积（PTV）规定了5次36.25戈伊的D（95）剂量。使用混合可变形图像配准算法从iCBCT获得变形pCT（dCT）。使用内部软件将日志文件数据转换为Pinnacle（3）数据格式，使用Pinnacle（3）v9.10计算dCT上的剂量分布。通过参考从pCT和dCT计算的变形矢量场进行剂量扭曲。将重建后的剂量分布与原计划进行比较。原始和重建剂量分布之间的剂量差异在等中心点处在3%以内，并且在PTV和器官风险（OAR）区域中观察到。OAR区域的差异相对大于PTV，可能是因为OAR比PTV更变形。因此，我们的方法可以成功地用于重建剂量分布的一个部分，使用iCBCT和日志文件在FFF-VMAT交付。
This study aimed to reconstruct the dose distribution of single fraction of stereotactic body radiotherapy for patients with prostate cancer using cone-beam computed tomography (CBCT) and a log file during volumetric-modulated arc therapy (VMAT) delivery with flattening-filter-free (FFF) mode. Twenty patients with clinically localized prostate cancer were treated with FFF-VMAT, and projection images for in-treatment CBCT (iCBCT) imaging were concomitantly acquired with a log file. A D(95)dose of 36.25 Gy in five fractions was prescribed to each planning target volume (PTV) on each treatment planning CT (pCT). Deformed pCT (dCT) was obtained from the iCBCT using a hybrid deformable image registration algorithm. Dose distributions on the dCT were calculated using Pinnacle(3)v9.10 by converting the log file data to Pinnacle(3)data format using an in-house software. Dose warping was performed by referring to deformation vector fields calculated from pCT and dCT. Reconstructed dose distribution was compared with that of the original plan. Dose differences between the original and reconstructed dose distributions were within 3% at the isocenter and observed in PTV and organ-at-risk (OAR) regions. Differences in OAR regions were relatively larger than those in the PTV, presumably because OARs were more deformed than the PTV. Therefore, our method can be used successfully to reconstruct the dose distributions of one fraction using iCBCT and a log file during FFF-VMAT delivery.