A robotic system for transrectal needle insertion into the prostate with integrated ultrasound

We have designed a minimally invasive medical device with the capability to insert a needle (or catheter) under transrectal ultrasound (TRUS) image guidance through the rectum and into the surrounding tissue, primarily the prostate. A partial sheath surrounds an ultrasound probe 210° around the circumference in order to remain attached to the probe but minimize interference with the ultrasound image. A needle is inserted through one of two parametric guides on the sheath; which guide depends upon the desired location of the needle and the presence of anatomy to be avoided. Our hypothesis is that by reducing the amount of tissue, muscle, and nerves in the path of the needle, this method, when compared to the perineal approach, improves both the accuracy of the needle placement and the comfort to the patient. Experiments with a custom phantom prostate demonstrate that this device provides target accuracy comparable to the current perineal approach.