First clinical experience with the automatic positioning system and Leksell gamma knife Model C. Technical note

Area of Science:

• Neurosurgery
• Medical Technology
• Radiation Oncology

Background:

• The Leksell Gamma Knife is a leading radiosurgery tool.
• The Model C introduced new functionalities, including an automatic positioning system (APS).
• Early adoption and testing were crucial for system refinement.

Purpose of the Study:

• To evaluate the initial clinical experience with the Leksell Model C Gamma Knife.
• To assess the performance and safety of the new automatic positioning system (APS).
• To identify and address any limitations of the Model C, particularly in APS mode.

Main Methods:

• Installation and initial testing of the Leksell Model C Gamma Knife.
• Performance of 163 treatments using manual/trunnion mode.
• Testing and implementation of the automatic positioning system (APS), with 50 treatments performed.
• Analysis of treatment modes (APS alone, hybrid, manual fallback) and reasons for manual conversion.

Main Results:

• Successful implementation of Leksell Model C, with continuous hardware and software adaptation.
• 163 Gamma Knife surgeries (GKS) performed in manual/trunnion mode by end of 1999.
• 50 GKS performed with APS, with 74% using APS exclusively.
• 12% of planned APS treatments required manual conversion due to technical or mechanical issues.
• Identified spatial restrictions in APS mode (e.g., shoulder space) compared to Model B.
• No relevant safety errors occurred during Gamma Knife surgery (GKS) with APS.

Conclusions:

• The Leksell Model C Gamma Knife, particularly with its APS, demonstrates safe and efficient operation.
• Future mechanical modifications aim to resolve spatial limitations in APS mode.
• The system's precision requires critical head frame placement, especially with APS.