Effect of radiation on normal brain identified in a landmark study of children with brain tumors

St. Jude Children's Research Hospital (ALSAC)
Tuesday, 8 January 2002

(Memphis, Tennessee, January 8, 2002) The effect of radiation on a child's brain has been measured for the first time in a pioneer study of pediatric brain tumor patients.

The study, published in December's Annals of Neurology, is by scientists at St. Jude Children's Research Hospital in Memphis, led by St. Jude's Dr. Grant Steen. This work should enable doctors to plan radiation therapy so as to spare normal brain areas that could be affected by radiation.

The brain consists of roughly equal parts of white matter and gray matter, with gray matter forming the outer surface of the brain. This study shows that gray matter is resistant to radiation, even at the highest dose of radiation used to treat a brain tumor. Yet white matter, which is made up of nerve fibers, is susceptible to damage during radiation therapy.

"White matter seems more vulnerable to radiation, perhaps more than clinicians would have guessed," Steen added.

While effective in treating brain tumors, the radiation beams doctors use to target the tumor can also damage the normal brain. Using research from this study, doctors can plan therapy so that radiation beams spare white matter as much as possible.

The findings are the result of a three-year study of 33 St. Jude patients using magnetic resonance imaging (MRI). The amounts of radiation absorbed in each type of brain tissue were compared with subtle changes in the MRI results.

St. Jude Children's Research Hospital, in Memphis, Tennessee, was founded by the late entertainer Danny Thomas. The hospital is an internationally recognized biomedical research center dedicated to finding cures for catastrophic diseases of childhood. The hospital's work is supported through funds raised by ALSAC. ALSAC covers all costs not covered by insurance for medical treatment rendered at St. Jude Children's Research Hospital. Families without insurance are never asked to pay.

For more information, or to contact St. Jude Children's Research Hospital (ALSAC), see their website at: www.stjude.org