4D-CT reconstruction based on pulmonary average CT values
Issue title: Frontiers in Biomedical Engineering and Biotechnology – Proceedings of the 2nd International Conference on Biomedical Engineering and Biotechnology, 11–13 October 2013, Wuhan, China
Affiliations: Radiotherapy Center, Affiliated Tumor Hospital of Guangzhou Medical University, Guangzhou 510095, China | Department of Biomedical Engineering, Southern Medical University, Guangzhou 510095, China
Note: [] Address for correspondence: Professor ZHANG Shu-xu, Radiotherapy Center, Affiliated Tumor Hospital of Guangzhou Medical University. NO.78 Hengzhigang Road, Guangzhou, 510095, China. Tel: +86-13005110376; Fax: +86-2066673635; E-mail: gthzsx@163.com
Abstract: To date, commercial 4D-CT systems typically depend on an external respiratory monitoring device. Immobilizing patients in a thermoplastic mask while receiving radiotherapy may result in a failure of 4D-CT reconstruction. The aim of this study is to investigate the feasibility of 4D-CT reconstruction based on a method using pulmonary average CT values (ACV) without an external respiratory monitoring device. The ACV of the whole lung assumes cyclical variation during respiration. Phases of CT images were identified by calculating the ACV over time. Subsequently, five sets of 4D-CT images based on a Real-time Position Management (RPM) system were selected to verify the ACV method. The entire lung CT datasets of another sixteen free-breathing patients were acquired in Cine scan mode for multiple couch positions. The phase of every CT image was identified and re-sorted into different phase 4D-CT volumes by analyzing the time dependence of the corresponding ACVs. This paper demonstrates the ACV method using the 4D-CT data sets based on the RPM system. Convenient and reliable 4D-CT reconstruction can be accomplished without any external respiratory monitoring device using ACVs.
Keywords: 4D-CT, image reconstruction, average CT value, respiration phase
