Because of more rapid dose delivery with HDR compared to LDR brachytherapy (15 minutes vs. 6 months) and more precise control of dose to adjacent critical structures (prostatic and bulbo-membranous urethra and anterior rectal wall), HDR prostate brachytherapy has been associated with more rapid recovery from acute symptoms and a more favorable side effect protocol when used as a boost in combination with external beam radiotherapy. The hypothesis is that this advantage will be maintained when brachytherapy is used as monotherapy without the addition of external beam radiation.