A procedure being studied in the diagnosis of prostate cancer and in planning prostate cancer treatment. Ultrasound is used to create a map of the prostate so the whole prostate gland can be seen in three dimensions and divided into 24 areas. Needles are then inserted through a template into each of the 24 areas and tissue is removed to be checked under a microscope. Also called transperineal template-guided prostate mapping biopsy.