From Stockholm to Pittsburgh.

Leksell's conservatism led him to underestimate the demand for new gamma units. When two of his students wanted machines in, respectively, Buenos Aires and Sheffield, there was no possibility for manufacture in Sweden. Arrangements were made for a Swiss company to make two machines that were installed in the two centers but not without problems. Eventually, since the demand was there, arrangements were made to continue manufacture in Sweden by Elekta, the company that still makes them today. When these matters were settled, the first US model was installed in Pittsburgh. This became a crucial development, not only because the machine was now established in the United States but also because of the quality of the publishing from Pittsburgh, which was of the highest quality, honest and believable, and thus a potent impulse in the spread of Gamma Knife treatment.