Evaluation of the accuracy of deformable registration of prostate MRI for targeted prostate cancer radiotherapy
Karthik Krishnan, Rex Min Cheung · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2009
Endorectal MRI provides detailed images of the prostate anatomy and is useful for radiation treatment planning. The endorectal probe (which is often removed during radiotherapy) introduces a large prostate deformation, thereby posing a challenge for purposes of treatment planning. The probe-in MRI needs to be deformably registered to the planning MRI prior to radiation treatment. The goal of this paper is to evaluate a deformable registration workflow and quantify its accuracy and suitability for radiation treatment planning. We use three metrics to evaluate the accuracy of the prostate/tumor segmentations from the registered volume to the gold standard prostate/tumor segmentations: (a) Dice Similarity Coefficient (b) Hausdorff Distance (c) Mean surface distance. These metrics quantify the acceptability of the registration within the prescribed treatment margin. We evaluate and adapt existing methods, both manual and automated, to accurately track, visualize and quantify the deformations in the prostate geometry between the endorectal MRI and the treatment planning image. An important aspect of the work described in this paper is the integration of interactive guidance on the registration process. The approach described in this paper provides users with the option of performing interactive manual alignment followed by deformable registration.