3D Printing a Clinically Available Solution From Plaster‐Based Positives in Superficial Radiation Therapy

INTRODUCTION: This study compares two techniques for creating lead shielding masks to replace the current process for superficial/orthovoltage (SXT) facial radiotherapy: Plaster Cast Positive Mould (PCPM), Computed Tomography (CT) Scanned 3D Print (CT3DP), and Optical Scan 3D Print (OS3DP). The aim is to determine the most accurate and practical method, particularly where PCPM facilities are unavailable. METHODS: From July 2022 to January 2023, twelve patients underwent facial SXT treatment using all three techniques. PCPM used alginate impressions reinforced with plaster. OS3DP employed the Skanect Structure Sensor for optical scanning and PLA 3D printing. CT3DP used CT imaging processed via Varian Eclipse and Adaptiiv 3D Bolus software. Accuracy was retrospectively assessed through surface mesh comparisons, manual point measurements, and blind preference testing. RESULTS: CT3DP showed the highest accuracy, with a mean maximum deviation of 14.8 mm and average surface difference of 2.6 mm, compared to 17.0 mm and 3.4 mm for OS3DP. Manual measurements highlighted better alignment at the eyebrows with CT3DP. In blind testing, 81.4% of participants preferred CT3DP over OS3DP. PCPM was the most time-intensive, taking 16 h to complete, vs. six hours for the 3D printing methods. CONCLUSION: CT3DP offers greater accuracy, efficiency, and clinical preference compared to OS3DP and PCPM. Despite requiring a CT scan and associated imaging dose, its precision and reproducibility make it a strong candidate to replace PCPM in routine clinical practice.