Impact of CT slice thickness on volume and dose evaluation during thoracic cancer radiotherapy
Authors Luo H, He Y, Jin F, Yang D, Liu X, Ran X, Wang Y
Received 15 May 2018
Accepted for publication 26 July 2018
Published 20 September 2018 Volume 2018:10 Pages 3679—3686
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Antonella D'Anneo
Huanli Luo, Yanan He, Fu Jin, Dingyi Yang, Xianfeng Liu, Xueqi Ran, Ying Wang
Department of Radiation Oncology, Chongqing University Cancer Hospital & Chongqing Cancer Institute & Chongqing Cancer Hospital, Chongqing, 400030, China
Introduction: Accurate delineation of targets and organs at risk (OAR) is required to ensure treatment efficacy and minimize risk of normal tissue toxicity with radiotherapy. Therefore, we evaluated the impacts of computed tomography (CT) slice thickness and reconstruction methods on the volume and dose evaluations of targets and OAR.
Patients and methods: Eleven CT datasets from patients with thoracic cancer were included. 3D images with a slice thickness of 2 mm (2–CT) were created automatically. Images of other slice thickness (4–CT, 6–CT, 8–CT, 10–CT) were reconstructed manually by the selected 2D images using two methods; internal tumor information and external CT Reference markers. Structures and plans on 2–CT images, as a reference data, were copied to the reconstructed images.
Results: The maximum error of volume was 84.6% for the smallest target in 10–CT, and the maximum error (≥20 cm3) was 10.1%, 14.8% for the two reconstruction methods, internal tumor information and external CT Reference, respectively. Changes in conformity index for a target of <20 cm3 were 5.4% and 17.5% in 8–CT. Changes on V30 and V40 of the heart were considerable. In the internal tumor information method, volumes of hearts decreased by 3.2% in 6–CT, while V30 and V40 increased by 18.4% and 46.6%.
Conclusion: The image reconstruction method by internal tumor information was less affected by slice thickness than the image reconstruction method by external CT Reference markers. This study suggested that before positioning scanning, the largest section through the target should be determined and the optimal slice thickness should be estimated.
Keywords: computed tomography, slice thickness, thoracic cancer, dose, image reconstruction
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