The facility is expected to treat about 40 people a year. The LBL effort involved a multidisciplinary team, including radiation oncologist Joe Castro, physicist Tim Renner, electronic engineer Mark Nyman, software engineer R.P. Singh, and mechanical technician Mario Cepeda. In essence, the team replicated the program at UC Davis using the 70 MeV Crocker Nuclear Laboratory Cyclotron. Treating an eye tumor with the Crocker Lab's proton beam can save not only lives but unlike conventional surgery, the eye itself. Unlike x-rays, proton beams can avoid damaging the healthy tissue surrounding a tumor.
Protons deposit almost all of their radiation dose near the end of their tracks, where they stop.
Treatment requires locking in place the patient's head and fixing its position so that the beam strikes the target tumor with absolute precision. That's where the unique skills of technician Cepeda came in. His contribution was to build a device to precisely position the patient during treatment. Since limited funds existed to design a device, Castro and Renner turned to Cepeda. Mario took it upon himself to design and build this chair.