The centerpiece of the new Mercy Proton Therapy Center currently under construction at the David C. Pratt Cancer Center, a MEVION S250iTM gantry-mounted proton accelerator, was put into place by McCarthy Building Companies, July 17 at the site at 607 S. New Ballas Road in Creve Coeur, Missouri.
After a journey across seven states, the accelerator was placed through an opening in the vault’s 7-foot, 6-inch-thick concrete lid using a 350-ton crane, the same day it arrived.
A small crowd of leaders from Mercy, McCarthy and Mevion took turns signing the equipment and then watched as the accelerator unit was placed. It was secured inside a three-story high, 60-foot-by-60-foot “vault” treatment room featuring concrete walls ranging from six- to eight-and-a-half feet thick located within the new 17,000-square-foot three-story addition to the David C. Pratt Cancer Center.
Because being as little as one inch off in thickness would result in less radiation shielding, the center was designed and built with extreme precision, with tolerances less than three-quarters-inch wall-to-wall and one-inch floor-to-ceiling.
Construction began in July 2020. The center’s opening is planned for summer 2022.
The world’s only gantry-mounted proton accelerator, the MEVION S250i Hyperscan PBS delivers a highly stable, uniform proton beam that is simple to deliver. The complete unit weighs 300,000 pounds, including the 115,000-pound accelerator, 30,000-pound magnet, 85,000-pound housing and 60,000 pounds of arms and counterweights.
Currently, there are only 37 proton centers in the United States. Proton therapy, which has fewer side effects than traditional cancer treatments and can be used for many types of cancer, uses high-energy beams of protons to precisely deliver radiation to a tumor, reducing or eliminating unwanted radiation exposure to surrounding, healthy tissue. Mercy will make this option available for patients pursuing both research options and traditional clinical care.
