In prostate DWI, low SNR often causes inaccuracy in ADC quantification if not compensated, especially when using surface array coils. Endorectal coils can be used, although associated with substantial setup time, patient discomfort and complications. In this work, a noise bias correction framework was developed and validated in a Monte Carlo simulation, a diffusion phantom, and 14 prostate imaging subjects. Using data acquired with an endorectal coil as a reference, this framework showed improved accuracy of ADC quantification in the prostate when only non-endorectal coils were used. This framework may allow quantitative prostate diffusion imaging without requiring endorectal coils.