New Tool Allows Radiation Oncologists to Track X-rays in the Body

Dartmouth University researchers started investigating the phenomenon called the Cherenkov effect in 2011

Unlike Superman, radiation oncologists don’t have X-ray vision. When a patient undergoes an X-ray or mammogram, oncologists can’t detect the radiation beam as it passes through bone or soft tissue. If clinicians could see the powerful X-rays, they could see how the rays hit the tumor or how far off they are. The clinicians could stop, make adjustments, and improve accuracy. That ability is getting closer to becoming a reality as oncologists take advantage of the Cherenkov effect.

Dartmouth University researchers started investigating the phenomenon called the Cherenkov effect in 2011. The researchers theorized that by using Cherenkov emissions, a beam of radiation would show how the radiation signals travel through the body, the dose of radiation to the skin, and any errors in dosage.

For the first time in humans, researchers have used the technology with patients. The first case was a female breast cancer patient undergoing radiation.

“Breast cancer is suited for this because the imaging visualizes the superficial dose of radiation to the skin,” said Lesley A. Jarvis, MD, radiation oncologist, Norris Cotton Cancer Center. Skin reactions, similar to sunburn, are a common and bothersome side effect observed during breast radiation. “By imaging and quantitating the surface dose in a way that has never been done before, we hope to learn more about the physical factors contributing to this skin reaction,” said Jarvis.

By seeing the effect of radiation on the body, Norris Cotton Cancer Center radiation oncologists can make adjustments to avoid side effects to the skin. Most radiation patients undergo somewhere between 8—20 sessions. The Cherenkov images of the breast cancer patient showed a hot spot in her underarm, which physicians and physicists could work to prevent in future sessions.

“The actual images show that we are treating the exact correct location, with the appropriate beam modifications and with the precise dose of radiation,” said Jarvis.

This trial showed that the Cherenkov effect is feasible for use real-time during radiation. “We have learned the imaging is easy to incorporate into the patient’s treatment, adding only minimal time to the treatments,” said Jarvis.

Twelve patients are participating in a pilot study, which is almost complete. The research team plans to publish the results in a peer reviewed journal.