Prevalence and Trends of Gamma Knife Centers in the United States

Purpose: To evaluate the number of currently active Gamma Knife centers in the United States and installation patterns over time, and to compare the number of skull-base surgeons by state.

Materials/Methods: The official Elekta Gamma Knife Web site was used to locate the currently active Gamma Knife centers in the United States. The total number was determined for each state. A literature search was then done for each center to determine the model being used and the date it was installed or upgraded. The North American Skull-Base Society registry was used to evaluate the number of skull base surgeons by state.

Results: There are currently 113 active Gamma Knife centers in the United States. The states with the largest number of centers include California (12), Texas (9), and Pennsylvania (8). Data regarding year of installment or upgrade was available for 102 centers. The majority (56%) of centers were installed or upgraded during the years 2011–2016. 34% were installed or upgraded during 2006–2010, and 10% during 2000–2005. The majority of current units are the Perfexion model (81%). Thus far, there are nine centers which have ordered or installed the newly available Icon model. The states with the largest number of skull based surgeons were California (53), New York (39), Pennsylvania (25), and Texas (22).

Conclusion: There are a large number of Elekta Gamma Knife centers currently active in the United States, the majority of which have been installed or updated in the past 6 years despite the advent of frameless SRS. As the new Elekta Icon model has frameless treatment capability, there may be an even further increase in the rates of upgrades and/or installation in the near future. As expected, the states with the largest number of Gamma Knife centers did have a large number of skull-base surgeons as well.