Evaluation and validation of the convolution algorithm for Leksell Gamma knife radiosurgery.

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiosurgery

Background:

• The Leksell Gamma Knife (LGK) is a stereotactic radiosurgery tool.
• Accurate dose calculation is crucial for effective and safe treatment delivery.
• A new convolution algorithm for LGK requires validation before clinical use.

Purpose of the Study:

• To evaluate the accuracy of the new LGK convolution algorithm.
• To compare the convolution algorithm's performance against the TMR10 algorithm.
• To validate dose calculations in both homogeneous and heterogeneous phantom tissues.

Main Methods:

• Utilized an anthropomorphic head phantom (CIRS) for realistic simulation.
• Employed EBT3 GafChromic films for precise dose measurements.
• Compared measured doses and distributions with calculations from LGK TMR10 and convolution algorithms.

Main Results:

• The convolution algorithm showed strong agreement with measured doses in homogeneous phantom regions.
• Significant discrepancies were observed in heterogeneous regions (e.g., air gaps) with the TMR10 algorithm.
• The convolution algorithm accurately computed dose to water in heterogeneous tissues, within a 2% error margin.

Conclusions:

• The new Leksell Gamma Knife convolution algorithm demonstrates superior accuracy.
• The algorithm effectively handles varying electron densities, crucial for heterogeneous tissues.
• This validated algorithm is suitable for clinical implementation in radiosurgery planning.