Leksell Gamma Knife Icon
Manufacturer: Leksell / Elekta · Modality: Gamma Knife
The current-generation Gamma Knife platform. 192 cobalt-60 sources focused on a single isocenter. Submillimeter precision for intracranial stereotactic radiosurgery: brain metastases, vestibular schwannoma, AVM, trigeminal neuralgia, meningiomas, functional neurosurgery.
Icon added integrated cone-beam CT and real-time motion management to the earlier Perfexion — enabling frameless treatment (vs the traditional rigid skull frame that defined Gamma Knife through the Perfexion era).
What Icon added vs Perfexion
- Integrated CBCT for setup imaging (eliminates MRI-only targeting for select cases)
- Infrared motion monitoring for frameless treatment (HDMM)
- Frameless workflow option — patients without a rigid skull frame; thermoplastic mask + HDMM verification
- Fractionated treatment capability — some lesions now treated in 3-5 fractions instead of single-session
Specs
- 192 Co-60 sources in a tungsten collimator body
- 8 sectors of 24 sources each (programmable collimation)
- Dose rate decreases with source age (Co-60 half-life 5.27 years)
- Integrated CBCT (kV)
- Infrared-based motion tracking (HDMM)
- Leksell Gamma Plan TPS
Cobalt source economics
Co-60 decays at ~1% per month. Source exchange every ~5-7 years is a scheduled capital event ($1-2M typical). Dose rates drop over the inter-exchange cycle → treatment times lengthen; clinicians adjust expectations accordingly.
Clinical positioning
Gold-standard for brain SRS. Competes clinically with:
- Varian Edge (linac-based SRS)
- CyberKnife (robotic SRS, intracranial + extracranial)
- Elekta Versa HD with HexaPOD (linac-based brain SRS)
Gamma Knife's advantage: more non-coplanar beam angles → steeper dose gradient around target → better OAR sparing for some anatomies (deep brainstem, optic-apparatus-adjacent lesions).
Install reality
Gamma Knife install is its own category:
- Specialized vault — lead shielding + permanent cobalt-source housing
- NRC license (Co-60 = sealed source, different than PET tracers)
- Source loading is factory-scheduled + supervised by NRC-authorized personnel
- Institutional commitment — Gamma Knife centers have a dedicated program, not ad-hoc