Improving quality assurance for assembled COMS eye plaques using a pinhole gamma camera

Area of Science:

• Medical Physics
• Radiotherapy Quality Assurance
• Ophthalmology

Background:

• Brachytherapy eye plaques are used for ocular melanoma treatment.
• Accurate seed placement and strength verification are critical for effective and safe treatment.
• Existing quality assurance methods may have limitations in precision and scope.

Purpose of the Study:

• To design and validate a novel quality assurance system for brachytherapy eye plaques.
• To ensure precise verification of seed location and radioactive strength.
• To improve the accuracy and reliability of ocular radiotherapy.

Main Methods:

• A system combining a pinhole camera with computed radiography (CR) for seed imaging and relative strength measurement.
• Use of a source strength jig and survey meter for estimating total seed activity.
• Optimization of plaque-to-pinhole distance and utilization of different magnification scales.

Main Results:

• The system can differentiate seed activities greater than 10% within a specific time-activity range.
• Autoradiographs confirm seed count, proper seating, relative activity distribution, and potentially seed integrity.
• The source strength measurement system achieves a 5% uncertainty for plaque activities between 10-80 mCi.

Conclusions:

• The developed quality assurance system effectively verifies seed location and strength in brachytherapy eye plaques.
• This system enhances the reliability of ocular radiotherapy by ensuring accurate seed parameters.
• The findings support the integration of this QA system into clinical practice for improved patient outcomes.