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Efficiency and Dose Planning Comparisons between the Perfexion and 4C Leksell Gamma Knife Units

Aims: We analyzed the efficiency of the Leksell Gamma Knife Perfexion (LGK PFX) in the treatment of multiple metastases and benign tumors. We also compared treatment planning conformity between LGK PFX and LGK 4C for benign tumors. Method: Over a 6-week interval, 37 patients (21 with multiple brain metastases and 16 with benign tumors) underwent radiosurgery using LGK PFX at the University of Pittsburgh. We created dose plans for all patients using Leksell Gamma Plan for LGK PFX and LGK 4C. The same doses were prescribed for both LGK PFX and LGK 4C. Results: No significant difference was observed between LGK 4C and LGK PFX for total beam-on time. The median reduction in setup time on the LGK PFX was 53 min per patient (range 19–125 min) for multiple metastases. The median reduction in setup time on the LGK PFX for benign tumors was 16 min per patient (range 5–53 min). There was no significant difference in the dose conformality between LGK 4C and LGK PFX. Conclusions: This study demonstrated that in addition to its enhanced cranial reach, LGK PFX provided a significant improvement in efficiency for patients with multiple brain metastases. For benign tumor radiosurgery LGK PFX provided improvement in efficiency without a significant difference in conformality.