Proton Beam Therapy – Radiation Treatment at Siteman Cancer Center

The S. Lee Kling Proton Therapy Center at the Siteman Cancer Center is the only proton therapy center located in Missouri and the surrounding region.

The center houses the world’s first compact proton beam accelerator, called the Mevion S250™ Proton Beam Therapy System. Radiation oncologists and physicists here helped evaluate the system and developed the patient protocols and quality standards for this advanced technology.

Proton beam therapy’s main advantage is that radiation specialists can control radiation beams by:

  • Depth
  • Shape
  • Amount of radiation dose

In other external radiation therapies, radiation beams pass through a patient to a defined location and then exit the body on the other side, leaving deposits of radiation all along their path. Because proton therapy allows for depth control, the majority of radiation is held until the beam hits the precise area targeted. Little to no radiation is delivered past the tumor.

Proton therapy can be used as a solo treatment option or it can be used in combination with other radiation therapies or chemotherapy.

There are only a handful of proton beam therapy centers in the United States, most with large, football field-sized treatment areas. In contrast, the Mevion S250™ system, called a superconducting synchrocyclotron proton accelerator, is much more compact, fitting into about 2,000 square feet. The compact nature of the technology makes it more versatile as well as more cost-effective to use.

The Mevion S250 system, which debuted in late 2013, is ideal for patients with solid tumors that are located near sensitive structures or tissues, such as the eyes, brain or spinal cord. It is particularly beneficial for children, where precise targeting is critical to avoid impacting growing bones or tissues. St. Louis Children’s Hospital and the Siteman Cancer Center are committed to providing proton beam therapy in a way that is sensitive to the needs of children and their families.