Development of a 3D optical scanning-based automatic quality assurance system for proton range compensators

Area of Science:

• Medical Physics
• Radiation Oncology
• Quality Assurance

Background:

• Proton therapy requires precise range compensators (RCs) for accurate dose delivery.
• Current quality assurance (QA) methods for RCs can be time-consuming and prone to inaccuracies.

Purpose of the Study:

• To develop and evaluate an automated three-dimensional scanner (3DS)-based system (AutoRCQA) for improved RC QA.
• To assess the accuracy, efficiency, and clinical applicability of the AutoRCQA system.

Main Methods:

• Developed an AutoRCQA system integrating 3DS with custom verification software (3DVS).
• Verified geometrical accuracy by comparing planned RC data (PRC) with measured RC data (MRC) using composite analysis (CA).
• Evaluated detection accuracy using artificial defects and performed clinical tests on seven computerized milling machine (CMM)-RCs, comparing results with manual measurements.

Main Results:

• The AutoRCQA system accurately detected artificial defects.
• Median systematic offsets for CMM-RCs were within 0.08 mm in X/Y directions, with a median distance difference of 0.37 mm.
• The 3DMS showed slightly better thickness agreement than manual measurements (p < 0.05).
• CA pass rates reached 97.97% (1 mm), 99.98% (2 mm), and 100% (3 mm).
• Average net analysis time was 18.01 ± 1.65 min.

Conclusions:

• An automated 3DS-based proton RC QA system (AutoRCQA) has been successfully developed and validated.
• The AutoRCQA system demonstrates potential to enhance both the accuracy and efficiency of RC quality assurance.