A Gamma Knife uses a radioactive source to treat brain tumors. Every seven years, the source loses effectiveness and needs to be replaced. Every fifteen years, the equipment that houses the source is changed to keep up with new technology. This project entailed replacing both, inside a two-foot-thick concrete vault in the middle of a hospital made up of turn-of-the-century building. To work on this project, workers needed an extensive background check to deem them “sufficiently trustworthy and reliable” to be around the source. The project involved removing one of vault walls and the existing 25-ton treatment machine, then installing a new machine through a roof hatch. The new machine was the 100th machine ever made, and the twenty-two ton lead housing was painted gold for the occasion. HVAC, electrical and security upgrades were done throughout the suite. The new interior finishes to the vault were upgraded with new flooring and millwork as well as a backlit sky image to simulate a roof skylight, which helps ease the mind of the patient as they go through treatment.