Contemporary IGRT/IMRT design. In this figure we illustrate customized "dominant intraprostatic lesion" (DIL) prostate IMRT dose coverage - the concept of concentrating maximum dose very focally within identified dominant cancer lesions, while also covering the entire prostate target volume with a dose sufficient to sterilize any smaller cancer deposits that may not be seen by imaging. In this figure the dominant lesions are covered within the orange isodose lines and the entire prostate is covered by the red isodose lines, which also include 3-6 mm of added margin to sterilize any cells that may have leaked outside of the prostate capsule. Advanced MRI diagnostic techniques make this customized prostate and tumor mapping possible, state-of-the-art IMRT computer planning allows the differential concentration of dose to exactly match the highest cancer cell burden, and contemporary image guidance (IGRT) allows the delivery of each daily treatment with a very high degree of accuracy.