Accurate and Fast Localization of Prostate for External Beam Radiation Therapy

摘要

The development of intensity modulated radiation therapy (IMRT) makes it possible to deliver high precision conformal dose distributions to the target. However, the non-rigid internal motion of the prostate makes it difficult to locate the target precisely during IMRT. In this project, we propose to develop a tomosynthesis-based method for fast and accurate prostate localization during IMRT. The hypothesis of this proposal is that the effective use of 3D information provided by tomosynthesis and the development of a non- rigid tomosynthesis/CT registration technique will enable us to significantly improve the precision of prostate target localization. We have carried a systematic study on the tomosynthesis based prostate localization technique. A number of important milestones have been accomplished, which include (i) implemented a ray-tracing based projector to generate projection data from a digital phantom and analytical FDK image reconstruction algorithm to reconstruct tomosynthesis image; (ii) Developed a statistics -based sinogram smoothing algorithm to suppress noise in projection data and improve image quality in reconstructed image; and (iii) Developed an iterative image reconstruction algorithm with a new prior constraint to improve image quality and resolution in tomographic images. It is expected that these tools will improve the accuracy of the prostate localization for EBRT.