Carefully Mixed
Radiation Cocktail Reduces Collateral Damage in Breast Cancer Patients
Behind the Cancer Headlines®
A carefully determined mixture of electron and x-ray beams
precisely treated breast tumors while significantly reducing collateral skin
damage in 78 patients, researchers reported at the annual meeting of the
American Association of Physicists in Medicine in
In treating shallow tumors such as those that occur in the breast, physicians have been turning to mixed-beam radiation therapy (MBRT), which employs separate beams of electrons and photons (x-rays). The two types of radiation complement one another, as electrons generally travel to shallow depths while the x-rays can penetrate to deeper parts of the tumor as needed.
However, each beam interacts in complex ways with its environment, making their exact path to the tumor region hard to predict. Nonetheless, physicists can calculate the probability for a given beam to follow a desired trajectory.
Therefore, Li and Ma use computers to simulate billions of trips of each beam to the unique landscape of each tumor. Gathering the statistics from these billions of trials, they determine the best beam properties and mixtures.
The computer simulations helped oncologists send accurately
targeted doses for 78 breast cancer patients receiving "hypofractionated" treatments, in which the patients
received fewer, but more potent, doses of radiation. The beams delivered all
the radiation within a small margin of the tumor's edge, dramatically reducing
radiation damage to surrounding healthy tissue. The researchers expect their
approach to provide benefits for reducing collateral damage in the treatment of
shallow tumors in the breast, chest wall, and head-and-neck region.
SOURCE:
48th Annual Meeting of the American Association of
Physicists in Medicine,