An interactive treatment planning system for ophthalmic plaque radiotherapy

Area of Science:

• Ophthalmology
• Medical Physics
• Radiation Oncology

Background:

• Brachytherapy with episcleral plaques is an alternative to enucleation for ocular tumors.
• While early results are promising, late complications leading to vision loss remain a challenge.
• The Collaborative Ocular Melanoma Study (COMS) is evaluating this treatment, specifying Iodine-125 (125I).

Purpose of the Study:

• To develop a microcomputer-based treatment planning system for ophthalmic plaque brachytherapy.
• To enable precise dosimetric calculations to correlate with complications and optimize plaque design.
• To support the evaluation of brachytherapy for choroidal melanoma and other eye tumors.

Main Methods:

• Developed an interactive, 3D, solid-surface, color-graphic treatment planning system.
• The system supports 125I and Iridium-192 (192Ir) seeds as anisotropic line sources.
• Calculates dose distributions in various cross-sections and spherical surfaces, accounting for collimation effects.

Main Results:

• The system allows detailed study of shielding effectiveness near plaque edges.
• Dose distributions can be calculated and displayed on spherical surfaces as 3D projections or funduscopic diagrams.
• Interactive editing enables rapid addition of new plaque designs.

Conclusions:

• Precise dosimetric calculations are crucial for understanding and mitigating complications in ophthalmic plaque brachytherapy.
• The developed treatment planning system offers detailed dose visualization and design flexibility.
• This tool can aid in optimizing brachytherapy techniques for better patient outcomes in ocular tumor treatment.