How proton therapy works

For patients facing many types of cancer, proton therapy can offer a safer, more precise alternative to traditional radiation. Proton beam radiation offers greater precision to destroy cancerous cells and spare healthy tissue, with fewer side effects, largely because the proton beams enter the body and deposit most of their energy directly in the tumor.

History of proton therapy

Proton radiation was first suggested as a treatment for cancer in 1946 by physicist Robert R. Wilson, Ph.D. Early efforts to treat patients began in the 1950s, but it was limited to a few areas of the body. Since then, use of proton therapy has grown, with 28 proton centers in operation in the country. Beaumont is the first proton therapy center in Michigan.

How proton therapy works

Proton therapy uses positive charged hydrogen atom nuclei, also called protons, whose relative mass is about two thousand times higher than that of electrons. In proton beam therapy, protons are accelerated to approximately 230MeV (mega-electron volts), which enables the tumor to reach a depth of about 30 cm inside the body.

The unique feature of protons is that they are able to release significant energy at the end of a proton range which is also called the "Bragg Peak." By using this Bragg Peak, proton beam therapy can accurately release the greatest part of proton energy into the tumor while protecting the healthy tissue behind the tumor.

Because proton therapy is safer and often has fewer side effects, it can be used in conjunction with other treatments, including traditional radiation, chemotherapy, immunotherapy or surgery.

Proton therapy advances at Beaumont

Beaumont's ProteusOne single-room treatment system includes precision technologies. Intensity Modulated Proton Therapy (IMPT) with Pencil Beam Scanning technology and 3-D Cone Beam CT can target a tumor within less than a millimeter.

Pencil Beam Scanning refers to the delivery of protons in a thin beam. Like a pencil, the beam uses back and forth motions to target the treatment area – the shape, size and depth. This technique uses a magnetic field to steer the position of the small proton beam and uses an energy layer selection system to choose the precise depth of the tumor, just like the 3D painting technique used in X-ray therapy.

As leaders in the advancement of radiation oncology treatment, Beaumont radiation oncologists are continually looking for ways to improve patient outcomes and experiences, including developing new methods to deliver proton therapy, such as rotational arc for lung cancer treatment.