Independent dose validation system for Gamma Knife radiosurgery, using a DICOM-RT interface and Geant4.

Area of Science:

• Medical Physics
• Radiosurgery
• Computational Biology

Background:

• Leksell GammaPlan has limitations in dose estimation for heterogeneous areas in Gamma Knife (GK) radiosurgery.
• Accurate dose distribution is critical for treating conditions like arteriovenous malformations.

Purpose of the Study:

• To develop an independent patient dose validation system for Gamma Knife radiosurgery.
• To enhance dose accuracy in inhomogeneous and complex anatomical regions.

Main Methods:

• Developed a patient-specific model using DICOM-RT interface and Geant4 toolkit.
• Modeled Leksell Gamma Knife Perfexion in Geant4.
• Compared Monte Carlo (MC) algorithm calculations with TMR 10 algorithm and film measurements.
• Evaluated dose distributions using water phantoms and patient simulations.

Main Results:

• MC simulations showed dose differences up to 11% in heterogeneous media with small beam sizes.
• TMR algorithm overestimated dose by ~4% in patient simulations with bony structures.
• Convolution algorithm results closely matched MC algorithm findings.

Conclusions:

• The in-house Monte Carlo simulation system accurately verifies patient doses.
• This system is valuable for patient cases where dose discrepancies are suspected.
• The developed system improves upon existing methods for Gamma Knife dose planning.