Prostate cancer has a slow growth with a potential doubling time ranging from weeks to months (median 42 days) which has led to the hypothesis that prostate cancer will behave more like a late reacting tissue(1). Brenner et al. (2) used data from prostate Low Dose Rate (LDR) permanent seed implants and EBRT series to derive an alpha/beta of approximately 1.5. Many groups have also calculated the alpha/beta ratio to be in the < 3.0 range(3).