SU-E-T-453: Optimization of Dose Gradient for Gamma Knife Radiosurgery
Medical Physics
|May 19, 2017
Summary
This study introduces tools for optimizing stereotactic radiosurgery (SRS) collimator and dose selection. The findings help clinicians achieve better dose gradients and target coverage in GammaKnife treatments.
Area of Science:
- Neurosurgery
- Radiation Oncology
- Medical Physics
Background:
- Stereotactic radiosurgery (SRS) aims to ablate target tissue while sparing critical normal structures.
- Optimizing dose gradients is crucial for effective SRS, particularly in intracranial procedures.
- GammaKnife 4C with updated physics data in GammaPlan v10.1 requires refined planning tools.
Purpose of the Study:
- To develop tools for selecting optimal collimation and prescription (Rx) isodose lines for single isocenter intracranial SRS.
- To improve the dose gradient and target coverage in GammaKnife treatments.
- Utilize updated GammaPlan v10.1 physics data for enhanced treatment planning.
Main Methods:
- Created single isocenter intracranial SRS plans in a head phantom for GammaKnife collimators (4, 8, 14, 18 mm).
- Analyzed dose gradient and Rx treatment volume for isodoses ranging from 99% to 20%.
- Defined dose gradient as the difference in effective radii of spheres for half and full Rx volumes.
Main Results:
- Compiled dosimetric data into a nomogram and graphical plots for easy interpretation.
- Identified optimal Rx isodose lines for sharpest dose gradients: 64% (4 mm), 70% (8 mm), 76% (14 mm), and 77% (18 mm) collimators.
- Determined corresponding target diameters and dose gradient radii for each collimator.
Conclusions:
- Developed tools based on GammaPlan v10.1 dosimetric data for clinical application.
- These tools aid in selecting collimator and Rx isodose line for optimal dose gradient and target coverage.
- Facilitates improved single isocenter intracranial SRS with GammaKnife 4C.
