SU‐E‐J‐134: Development of the 4D Cone‐Beam CT Modelling Software to Investigate Effects of Imaging Parameters

Purpose: Four‐dimensional (4D) cone‐beam computed tomography (CBCT) is an adaptive imaging technique which can be improved x‐ray beam delivery accuracy during radiation therapy accompanied organ motions by respiration. However, a major drawback to the technique is that 4D CBCT image quality is affected by several parameters. Therefore, in this study, we implemented a preliminary study that developed a predictive modeling software for investigating effects of applied parameters to 4D CBCT imaging. Methods: The 4D CBCT imaging parameters in this software such as related with geometry, projection data acquisition, and image reconstruction can be selected arbitrarily by user. The software provides digital phantom projection images applied input a practical or virtual respiratory signal if real projections do not exist. The projection images and the signal amplitudes were sorted into ten phase bins ranging from 0% to 90% in this simulation. We employed Feldkamp‐Davis‐Kress (FDK) algorithm based on filtered backprojection (FBP) as a reconstruction method. Results: The program could provide projection images, 4D CBCT reconstruction images, internal target volume and quantitative values for residual motion in each phase. Conclusion: The developed program would be useful to verify quantitatively for effects of 4D CBCT imaging parameters and target motions. In addition, it is possible to simulate without heavy workload for experimental set‐up. This program was supported by the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R and D programs (No. 20120004886) funded by the Ministry of Education, Science and Technology (MEST) and a grant (No. 2012K001141) from the Korea Heavy‐ion Medical Accelerator project grant funded by the Ministry of Education, Science and Technology (MEST) and Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea(NRF)(No.2009‐00420) funded by the Ministry of Education, Science and Technology (MEST) of Korea.