Clinical application of gamma knife dose verification method in multiple brain tumors : modified variable ellipsoid...

Area of Science:

• Medical Physics
• Radiation Oncology
• Neurosurgery

Background:

• Leksell Gamma Knife® (LGK) utilizes a single-fraction high-dose strategy, necessitating precise treatment planning.
• Independent verification of Leksell GammaPlan® (LGP) is crucial for patient safety and minimizing treatment errors.
• Existing verification methods lack statistical validation for multiple LGK target treatments.

Purpose of the Study:

• To evaluate the accuracy and statistical agreement of the modified variable ellipsoid modeling technique (MVEMT) for verifying LGP in multiple target treatments.
• To establish MVEMT as a reliable independent tool for LGP verification in radiosurgery.

Main Methods:

• A total of 500 points across 10 patients with multiple brain tumor targets were analyzed.
• Comparison between LGP and MVEMT data included dose at random points, maximal dose points, and target volumes.
• Statistical analysis employed t-tests and Bland-Altman plots to compare the two measurement techniques.

Main Results:

• No statistically significant difference in dose was found at 500 random points between LGP and MVEMT.
• Maximal dose differences between the methods ranged from -2.4% to 6.1%.
• An average distance of 1.6 mm was observed between maximal dose points when comparing LGP and MVEMT.

Conclusions:

• MVEMT demonstrated excellent agreement with LGP for radiosurgery planning involving multiple targets.
• MVEMT serves as a valuable, independent tool for multiple target treatment planning, yielding statistically identical results to LGP.
• MVEMT is suitable for use as a reference dose verification system for multiple brain tumors.