Low-cost 3D print–based phantom fabrication to facilitate interstitial prostate brachytherapy training program

Purpose: The purpose of this study was to manufacture a realistic and inexpensive prostate phantom to support training programs for ultrasound-based interstitial prostate brachytherapy. Methods and Materials: Five phantom material combinations were tested and evaluated for material characteristics; Ecoflex 00–30 silicone, emulsion silicone with 20% or 50% mineral oil, and regular or supersoft polyvinyl chloride (PVC). A prostate phantom which includes an anatomic simulated prostate, urethra, seminal vesicles, rectum, and normal surrounding tissue was created with 3D-printed molds using 20% emulsion silicone and regular and supersoft PVC materials based on speed of sound testing. Needle artifact retention was evaluated at weekly intervals. Results: Speed of sound testing demonstrated PVC to have the closest ultrasound characteristics of the materials tested to that of soft tissue. Several molds were created with 3D-printed PLA directly or cast on 3D-printed PLA with high heat resistant silicone. The prostate phantom fabrication workflow was developed, including a method to produce dummy seeds for low-dose-rate brachytherapy practice. A complete phantom may be fabricated in 1.5–2 h, and the material cost for each phantom was approximated at $23.98. Conclusions: A low-cost and reusable phantom was developed based on 3D-printed molds for casting. The proposed educational prostate phantom is an ideal cost-effective platform to develop and build confidence in fundamental brachytherapy procedural skills in addition to actual patient caseloads.