Influence of Scanning Conditions on CT Values in Radiotherapy Simulation Positioning
ZHANG Guo-qian1, ZHANG Shu-xu1,YU Hui1, WANG Rui-hao1,LEI Huai-yu2
1.Department of Radiotherapy, Caner Center of Guangzhou Medical University, Guangzhou Guangdong 510095, China;2. Graduate Institute, Guangzhou Medical University, Guangzhou Guangdong 510182, China
Abstract：Objective This study was designed to investigate the influence of scanning conditions on CT values in radiotherapy simulation positioning. Methods CT scanning was performed in the electron density phantom (Model:CIRS 062) in different conditions so as to measure relevant CT values. Then, the influence of changes in the tube current and voltage, slice thickness, pitch, image reconstruction algorithm, height of the scanning bed and scanning sequence to the CT values were evaluated and analyzed. Results The tube current, slice thickness, pitch had neglectable influence (<1%) on CT values.The tube voltage and image reconstruction algorithm showed significant influence on CT values for high-density phantoms; while no obvious influence was seen on those for low-density phantoms. The height of the scanning bed and scanning sequence had influence on CT values at varying degree for phantoms with various densities.Conclusion CT scanning parameters and positioning conditions can result in changes of CT values for image reconstruction of a certain tissue, which was of great value for clinical references.
