Proton Beam Therapy (PBT): What does a dosimetrist do?
Story by Melissa Abrams
Dosimetrists work with radiation oncologists to make treatment plans come to life, mapping out the prescribed radiation dosage to be delivered in and around the tumor, and determining the necessary angles and depths of the radiation. In addition to treating the patient’s cancer, dosimetrists are concerned with protecting other areas of the body, including sensitive organs and structures, from radiation. With proton beam therapy about to become available in Arizona and Rochester, a team of experienced dosimetrists in Arizona and Rochester have become experts in proton beam therapy.
“Dosimetrists need to understand the differences in the physics of the proton beam and its delivery system, and factor them into treatment plans,” says Jeff Kuball, Radiation Oncology, who is a certified medical dosimetrist in the Proton Beam Therapy Program in Rochester. “Proton beams have many advantages over the current standard technology in some types of cancer, because the particles behave differently. Proton beam therapy is very precise, so the dosimetrist remains involved throughout a patient’s treatment to make adjustments for changes in a patient’s weight or tumor size.”
Rochester cancer patients will begin receiving proton beam therapy in June. Arizona patients will follow in the spring. Proton beam therapy is a significant advance over conventional radiation therapy for certain types of cancer, especially pediatric cancer and those cancers situated near critical structures in the body.
Mayo Clinic’s program uses pencil beam scanning/intensity-modulated proton beams. Shawn Korte, Radiation Oncology, who is a certified medical dosimetrist on the Arizona campus, describes the technology Mayo Clinic’s program uses as a game-changer in delivering radiation therapy with potentially fewer side effects.
‘Like Star Wars’ technology
“Compared to the previous proton therapy technology, ours is like 'Star Wars,'” says Korte. “A few years ago, physicists only dreamed about this.”
Between them, Korte and Kuball have more than three decades of experience in traditional (photon) radiation oncology. Both say they’re pleased to be part of Mayo Clinic’s proton beam therapy team, which is on the brink of providing the most advanced proton beam therapy available.
“It’s exciting to work with the most advanced technology and collaborate with an experienced team that will research, invent and publish the future direction for pencil beam scanning that all proton facilities will follow,” says Korte. “The physics of the proton beam allow us to take the next big step in treating cancer safely with radiation therapy.”
According to Kuball, in most of the qualifying pediatric cases Mayo Clinic has analyzed, proton beam therapy would provide better treatment dose coverage to the tumor and significantly reduce the dose to normal tissue, reducing short- and long-term side effects. “This is what motivates me: knowing that the work I do makes a difference in the lives of patients and their families, now and in the future,” he says.
Dosimetrists collaborate with physicists, physicians, therapists and staff nurses on every patient’s case. “Each patient’s case is a unique, complicated puzzle, requiring us to work together to devise the best solution for our patients,” says Korte.