Abstract: A placement plan is developed for the placement of radioactive seeds in a prostrate for brachytherapy. The placement plan is made available to an intraoperative tracking interface which also shows a live ultrasound image of the needle or catheter placement in the prostate. The difference in the x-y plane between the planned and actual locations of the needle or catheter is calculated, and from that difference, the error in position of each seed is calculated. The seeds are moved, or the operator changes the number of seeds, and the dose is recalculated. A small column of ultrasound images is taken, and each seed located in the column of images is given a confidence level. If the confidence level exceeds a threshold set by the operator, the dosimetry is recalculated. Periodically throughout the seed placement, fluoroscopic x-rays are taken, and the seed coordinates are matched to the x-ray image.