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

Area of Science:

• Medical Physics
• Radiotherapy Technology
• 3D Printing Applications

Background:

• Superficial/orthovoltage (SXT) facial radiotherapy requires custom lead shielding masks.
• Current Plaster Cast Positive Mould (PCPM) methods are time-intensive and may be unavailable.
• Evaluating advanced 3D printing techniques is crucial for improving radiotherapy mask fabrication.

Purpose of the Study:

• To compare the accuracy and practicality of Computed Tomography (CT) Scanned 3D Print (CT3DP) and Optical Scan 3D Print (OS3DP) against Plaster Cast Positive Mould (PCPM) for facial radiotherapy masks.
• To identify the optimal method for SXT facial radiotherapy mask creation, especially where PCPM is not feasible.

Main Methods:

• A comparative study involving twelve patients undergoing facial SXT treatment from July 2022 to January 2023.
• Utilized Plaster Cast Positive Mould (PCPM), Optical Scan 3D Print (OS3DP) with Skanect Structure Sensor, and CT Scanned 3D Print (CT3DP) via Varian Eclipse and Adaptiiv 3D Bolus software.
• Assessed accuracy through surface mesh comparisons, manual measurements, and blind preference testing.

Main Results:

• CT3DP demonstrated superior accuracy with a mean maximum deviation of 14.8 mm and average surface difference of 2.6 mm.
• OS3DP showed deviations of 17.0 mm and 3.4 mm, respectively.
• Blind testing revealed an 81.4% preference for CT3DP, which also proved more time-efficient than PCPM.

Conclusions:

• CT3DP is the most accurate, efficient, and clinically preferred method for fabricating SXT facial radiotherapy masks.
• Despite the need for CT imaging, CT3DP's precision and reproducibility position it as a strong replacement for PCPM in clinical practice.