Ultrasound guided placement of transperineal prostatic afterloading catheters

A new method of performing temporary prostate brachytherapy which does not require an open laparotomy is described.

This procedure allows dynamic visualization of the placement of 13-gauge (I-125) or 17-gauge (Ir-192) afterloading catheters into the prostate gland via saggital ultrasound imaging. The image enables visualization of the entire path of the catheter as well as cephalad gland movement. The prostate gland, seminal vesicles, bladder neck, urethra, and rectum are easily identified and implanted, if desired, during the procedure. This procedure has been used in 34 patients as an interstitial boost for locally advanced (T2b, T3) prostatic carcinoma following external beam therapy as a means to safely deliver higher doses to the gland. Another eight patients have undergone this procedure as salvage following failure of prior radical prostatectomy or external beam therapy.

Very customized dosimetry has been obtained using this technique as a result of the optimal catheter placement achieved under ultrasound guidance, particularly with I-125. Although it is too early to evaluate efficacy, the procedure has been well tolerated and is associated with minimal morbidity to date.

This new procedure seems to be an excellent means of safe delivery of higher doses to the gland compared to conventional external beam therapy. Due to the ability to cover the seminal vesicles as well as the afterloading nature of this procedure, a more customized implant is obtained relative to most permanent techniques, and open laparotomy is not required.