| In the past decade, the reported incidences of prostate cancer have grown dramatically. One widely recognized and effectively viable treatment for early-stage prostate carcinoma is the permanent implantation of radioactive seeds. The prostate boundary is required for implantation and dosage distribution analysis. We propose the use of multiple snakes to improve efficiency as well as a method of visualizing the prostate boundary with associated levels of confidence. Once the prostate boundary has been determined, we propose a new method, Spoke transform, to segment the seeds from the background. The proposed method utilizes and compares the seed and its surrounding region to segment the seeds from the background by incorporating the seed's surrounding regions. This method works with various local backgrounds and seeds with very low signal to noise ratios. After the 2D seed's coordinates have been determined, correcting the seeds' distortions is required. During the image capture of the prostate, the source of geometry distortions is the patient's movements between the projections. We propose a new method that will correct the shifts and rotation. This technique does not require seed matching or pseudo points in the patient's prostate. After correcting the shift distortions, the back projection technique can be used to reconstruct the 3D seed coordinates. The major weakness of the back projection method is that it does not resolve the overlapping seeds in one set of the projection. Additional projections at different angles will resolve the overlapping seeds but the computational overhead increases dramatically. We propose a new approach to 3D seed reconstruction using Hough transformation with multiple projections. Applying the Hough transform parametric equations to describe the path of the seeds, the 3D coordinate of the seed with a valid projection can be verified. The problem of undetected seeds due to superposition can be resolved since this method does not rely on the back projection technique. Our method also has the ability to incorporate additional views without incurring major computing cost. |
