Development of 3-dimensional transperineal ultrasound for image guided radiation therapy of the prostate: Early evaluations of feasibility and use for inter- and intrafractional prostate localization

TPUS provides good imaging of the prostate gland. We noted excellent correlation in gland localization when TPUS is compared with CT scans when comparing routine 3-dimensional positional data. Euclidean distance variation suggests the potential that summation of small errors may in fact lead to significant differences in actual gland positional certainty. The reported difference is within the range of standard planning target volume expansion however requires additional evaluation.