Prostate Edema Characterization Using Image Registration and PCA

Abstract

The purpose of this paper is to develop a method for detailed characterization of edema-induced geometric variation of prostate in permanent prostate brachytherapy. The variation of prostate gland was sampled by 6~8 serial CT scans within a 6-week period from pre-implantation up to 42 days post implantation. The detailed prostate variation was first captured by deformable image registration, augmented with a weighting strategy to deal with the non-matching of image outside prostate. The registration results were then analyzed by principal component analysis (PCA) to quantify the isotropy of prostates and edema-induced changes. The preliminary application of this method to one patient has unveiled dynamic and highly anisotropic prostate variations during edema formation and resolution.