<h3>Purpose</h3> An in-house perineal needle-template device was developed to improve the interactive<sup>1</sup> low-dose-rate (LDR) brachytherapy treatment planning process for patients with small prostate volume size. One of the side effects of external beam radiation and androgen deprivation therapies is the significant reduction of the prostate gland volume (target) which can be challenging to plan with a standard 5mm hole spacing template. The new perineal needle template (new template) has additional rows with holes placed in a 2.5mm off-set grid pattern which provided more hole locations to place seeds inside the small prostate periphery region for a more conformal plan while meeting all dosimetric planning goals. <h3>Methods and Materials</h3> Thirty patients with different prostate gland volumes size were selected for this study. These thirty patients received either external beam radiation alone or external radiation combined with androgen deprivation therapy. Patients had LDR interactive planning performed using the new template, BARD I-125 seed model STM1251 (USA, IL), BARD QuickLink Delivery System for the seed train assembly, Oncentra - Prostate (Elekta, Sweden) for the treatment planning software (TPS) and the B-K Medical Ultrasound 3000 (USA, MA) for the internal organs imaging. On implant day (DAY 0), the radiation oncologist (physician) contoured target, urethra and rectum on TPS. The medical physicist proceeded to start the planning on the TPS using the inverse planning option to create plan and dose volume histogram (DVH) as the first iteration. Then, manually adjusted and customized the seeds locations with the MD input for a final DVH evaluation in order to proceed and deliver the implant. The AAPM TG-64<sup>2</sup> dosimetric guidelines were followed and reported. All patients had CT and MRI imaging studies performed approximately 30 days after the implant for a DAY 30 post implant evaluation. Using the Oncentra TPS, both imaging studies were fused, and the prostate, urethra and rectum were contoured. The implanted seeds were registered, and the DAY 0 prescription was used for the post-plan evaluation following the AAPM TG-64 dosimetric guidelines. <h3>Results</h3> Thirty patients were successfully treated using the new template. The new template was modeled in TPS and the ultrasound system. The new template did not affect the calculating time in the TPS and the increased amount of hole locations provided more options for an easier manual optimization "tweaking" to achieve a final plan, especially in the apex location where the target tapers down in size. Initially, physician adaptation to the new template was challenging for the first few cases but rapidly improved as the physician became more familiar with the new hole patterns. <h3>Conclusion</h3> We have successfully designed, built and implemented a new template for brachytherapy LDR treatments of small sizes targets (≤20 cc). The new template has provided a viable option to implant the seeds inside or closer to the target periphery thus improving the interactive planning process significantly.