Validation of Gamma Knife Perfexion Dose Profile Distribution by a Modified Variable Ellipsoid Modeling Technique

Area of Science:

• Medical Physics
• Radiotherapy
• Quality Assurance

Background:

• Gamma Knife radiosurgery demands high precision and accuracy.
• Complex radiation dose gradients necessitate robust quality assurance programs.
• Maintaining radiation dosimetry and geometric accuracy is crucial for patient safety.

Purpose of the Study:

• To investigate the validity of the Leksell Gamma Plan (LGP) 10.1.1 system.
• To assess a modified Variable Ellipsoid Modeling Technique (VEMT) for Gamma Knife Perfexion.
• To ensure the reliability of treatment planning and delivery.

Main Methods:

• Compared LGP 10.1.1 treatment plans with modified VEMT calculations.
• Verified the modified VEMT using Gafchromic EBT3 and EBT-XD films.
• Analyzed dose distributions in a solid water phantom using Full-Width-of-Half-Maximum (FWHM).

Main Results:

• Dose profile distributions evaluated by FWHM showed minimal differences.
• Average difference for LGP was 0.104 mm.
• Average difference for EBT-XD film was 0.130 mm.

Conclusions:

• The modified VEMT demonstrated consistent results.
• Modified VEMT serves as a reliable verification tool.
• This method supports stable testing and operation of the Gamma Knife Perfexion treatment planning system.