By Vikki Franklin
and Maureen McArthur

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"In the past 12 years, we have adapted that technique and use it in combination with the high energy X-rays available now. Instead of using one large beam of radiation, we used 250 smaller, concentrated pencil-sized beams."

- Mohammed Mohiuddin, M.D., professor and chair, Department of Radiation Medicine, UK College of Medicine

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See related story in the Oct. 1, 1999, issue of the Lexington Herald-Leader.

Results of a study of the Spatially Fractionated Radiation Therapy (GRID therapy) are published in the Sept. 30 issue of the International Journal of Radiation Oncology.

The study’s principal investigator, Mohammed Mohiuddin, M.D., professor and chair, Department of Radiation Medicine, UK College of Medicine, developed the technique about 12 years ago to treat large cancers that tend not to respond to conventional treatment. UK is the only institution in the world offering the treatment.

GRID therapy is based on methods used in the 1950s when a sieve-like device was used to treat small, deeply seated tumors with a high dose of radiation. GRID therapy allows for a five to 10-times greater dose than the daily conventional dose of radiation. Mohiuddin also found that the treatment produces a "bystander effect."

"Using this technique, we’re finding that not only is the direct effect of the radiation good, but it also produces in tumors products that act as agents to kill other cancer cells," he said. Such an effect is not found with conventional treatment.

"In the past 12 years, we have adapted that technique and use it in combination with the high energy X-rays available now," Mohiuddin said. "Instead of using one large beam of radiation, we used 250 smaller, concentrated pencil-sized beams."

In the study, 92 percent of the 70 patients treated with GRID therapy and simultaneous external radiation therapy responded to the treatment. In many cases, the treatment eased pain or helped shrink the tumor so that surgery could be performed.

Also, even with the high doses of radiation used with the technique, few effects of radiation, such as burns, are apparent.

The response in more than 70 patients treated with GRID therapy between 1995 and 1998 has been very dramatic, Mohiuddin said. Nationally, radiation medicine specialists are looking to the technique as a possible way to attack other hard-to-treat cancers.