Dosimetric comparison of deformable image registration and synthetic CT generation based on CBCT images for organs at risk in cervical cancer radiotherapy

Radiation Oncology

Research

Jie Qiu¹  Yongguang Liang¹  Bo Yang¹  Yankui Chang²  Xie George Xu³  Xi Pei⁴ 

[1] Department of Radiation Oncology, Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China;School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, China;School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, China;Department of Radiation Oncology, First Affiliated Hospital of University of Science and Technology of China, Hefei, China;School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, China;Technology Development Department, Anhui Wisdom Technology Co., Ltd., Hefei, China;

关键词: CBCT;    Deformable image registration;    sCT generation;    Dosimetric comparison;    Cervical cancer;   

DOI  :  10.1186/s13014-022-02191-3

 received in 2022-10-10, accepted in 2022-12-27,  发布年份 2022

来源: Springer

【 摘 要 】

ObjectiveAnatomical variations existing in cervical cancer radiotherapy treatment can be monitored by cone-beam computed tomography (CBCT) images. Deformable image registration (DIR) from planning CT (pCT) to CBCT images and synthetic CT (sCT) image generation based on CBCT are two methods for improving the quality of CBCT images. This study aims to compare the accuracy of these two approaches geometrically and dosimetrically in cervical cancer radiotherapy.MethodsIn this study, 40 paired pCT-CBCT images were collected to evaluate the accuracy of DIR and sCT generation. The DIR method was based on a 3D multistage registration network that was trained with 150 paired pCT-CBCT images, and the sCT generation method was performed based on a 2D cycle-consistent adversarial network (CycleGAN) with 6000 paired pCT-CBCT slices for training. Then, the doses were recalculated with the CBCT, pCT, deformed pCT (dpCT) and sCT images by a GPU-based Monte Carlo dose code, ArcherQA, to obtain DoseCBCT, DosepCT, DosedpCT and DosesCT. Organs at risk (OARs) included small intestine, rectum, bladder, spinal cord, femoral heads and bone marrow, CBCT and pCT contours were delineated manually, dpCT contours were propagated through deformation vector fields, sCT contours were auto-segmented and corrected manually.ResultsThe global gamma pass rate of DosesCT and DosedpCT was 99.66% ± 0.34%, while that of DoseCBCT and DosedpCT was 85.92% ± 7.56% at the 1%/1 mm criterion and a low-dose threshold of 10%. Based on DosedpCT as uniform dose distribution, there were comparable errors in femoral heads and bone marrow for the dpCT and sCT contours compared with CBCT contours, while sCT contours had lower errors in small intestine, rectum, bladder and spinal cord, especially for those with large volume difference of pCT and CBCT.ConclusionsFor cervical cancer radiotherapy, the DIR method and sCT generation could produce similar precise dose distributions, but sCT contours had higher accuracy when the difference in planning CT and CBCT was large.

【 授权许可】

CC BY   
© The Author(s) 2023

【 图 表 】

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