Background With the advent of the transrectal ultrasound probe as a means to visualize the prostate, Holm et. al. developed the transperineal approach toward prostate brachytherapy 9. This closed technique affords needle placement into the prostate with real-time ultrasound imaging while the patient is in the lithotomy position. The isotope is then introduced through the needles directly into the prostate. This allows a more uniform implantation of the prostate gland since the needles can be inserted parallel to each other, unobstructed by the pubic arch. Over the last decade, this technique has been refined and popularized, especially by the Seattle group 10. A conceptually similar approach using CT-scans instead of ultrasonography was developed by Wallner and colleagues at MSKCC 11. In the intervening 10 years, there has been exponential growth in the number of patients treated with ultrasound-guided permanent prostate brachytherapy with estimations of 40,000 implants performed in the USA in 2001 12. It is believed that permanent prostate brachytherapy with advanced biplane-transrectal ultrasonography (TRUS), perineal guidance systems, treatment planning computers and post-implant CT-scanning has enhanced our ability to perform an adequate implant with associated biochemical control rates that are as good as radical prostatectomy or high-dose external beam radiation 13, 14. Nonetheless, a review by the American Brachytherapy Society (ABS) of physician practices that perform prostate brachytherapy identified that there is tremendous variation associated with the indications, technique, treatment regimens and dosimetry 15. As more centers perform prostate brachytherapy, we must remember that the lessons learned during the retropubic experience so as not to repeat them. Patient Evaluations and Indications Prior to making recommendations for treatment, all therapeutic options, including radical prostatectomy, external beam radiation, brachytherapy, androgen deprivation and watchful waiting, should be fully explained to the patient (Table 1). When considering prostate brachytherapy, all patients require a diagnosis of adenocarcinoma of the prostate with a detailed pathology report inclusive of Gleason grade and score. Clinical staging requires a digital rectal exam, and in general, patients being considered for permanent prostate brachytherapy should have disease clinically confined to the gland (T1,T2, 1997 AJCC staging system) 16. Patients with known metastatic disease are not candidates for permanent prostate brachytherapy of the prostate. Work-up may include a bone-scan, pelvic CT scans, and MRI, but based on the low sensitivity and specificity of these tests with low risk prostate cancer, these tests are considered optional. Currently, there are no individual tests to absolutely determine the extent of a patient’s disease. Patients who have been treated for benign prostatic hypertrophy with a transurethral resection of the prostate (TURP) pose potential problems when treated with permanent prostate brachytherapy. A fresh TURP defect may lead to excessive morbidity and inadequate seed geometry 17. In general, a preimplant ultrasound is required for these patients to assess the TURP defect relative to the planned seed locations. Further, it has been reported that patients with a previous TURP may experience prolonged post-implant dysuria and are at risk of urethral necrosis 18. Current protocols for permanent prostate brachytherapy which place seeds peripherally in the prostate gland, may not cause the high rates of urethral necrosis originally reported 19. After a patient has been assessed and is deemed eligible for an implant, an initial assessment of the prostate volume is required. The purpose of this is to establish a preplan 20. If using an intraoperative technique, the preimplant volume assessment allows one to determine the total isotope activity required. It has been reported that patients with large volume glands that exceed 60 cc are difficult to implant and when using the preloaded needle technique it is advised that a pubic arch study be performed to determine if interference will limit the needle path. Pubic arch interference is not as much an issue with the intraoperative technique, as patient positioning is not as critical, allowing the brachytherapist to extend the patients hips into exaggerated lithotomy position, rotating the pelvic floor away from the anterior part of the prostate gland. Using this approach, Stone et. al. have reported their experience implanting patients with prostates larger than 60 cc with excellent post-implant dosimetry 21. While prostate volume reductions of 35% or more have been reported with LHRH agonist therapy over a 3-4 month duration, these patients have a higher incidence of post-implant urinary morbidity 22. In a recent study reported by Crook et. al. examining the incidence of acute retention following an implant failed to identify any relief for patients that had their prostate volumes reduced with hormones, and in fact those patients had higher rates of retention 23. Therefore, while a large prostate volume may not be an absolute contraindication for permanent prostate brachytherapy, the issues of pubic arch interference and increased post-implant symptoms require one to consider all the ramifications when developing an implant plan. Other relative contraindications for permanent prostate brachytherapy include patients with high American Urological Association (AUA) urinary scores assessing benign prostatic hypertrophy symptoms 24, 25. In this setting, pre-implant treatment with an alpha-blocking medication may decrease the risk of post-implant retention and urinary symptoms. Nonetheless, a patient with a high AUA score coupled with an enlarged prostate gland should be evaluated very carefully for permanent prostate brachytherapy and be advised of the increased risk of post-operative urinary morbidity. 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