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DURHAM, N.C. –- Physicians have known that radiation treatments for cancers of the left breast may damage the heart, which lies behind it. But advanced imaging techniques may help plan treatment to avoid such unwelcome side effects.

The potential solution, which will be tested in a clinical trial starting at Duke University Medical Center, is to use imaging techniques that provide a three-dimensional picture of the precise tumor location of the left breast in relationship to the heart. With such images, physicians can aim radiation beams at only the breast and avoid most of the heart, which can be inadvertently hit by radiation.

Physicians do not routinely use this technique, called three-dimensional planning, for breast cancer because they say it is too expensive and time-consuming, especially when the target (the breast) is so easy to hit with conventional radiation planning tools, said Duke's Patricia Hardenbergh, radiation oncologist and trial director.

"While we know that radiation may have toxic effects on the heart, we don't know the extent of the damage nor whether chemotherapy enhances the effects of radiation," she continued. "This clinical trial will be the first to try to answer these questions, and the findings may impact the standard of care for women being treated with radiation for left-sided breast cancer."

The Duke trial is supported by a three-year, $315,000 grant from the Department of Defense under its Idea Award program designed especially for young clinical investigators.

"We plan to exploit newly developed methods of imaging the heart to study the effects of these treatments both in specific areas of the heart hit by radiation and the functioning of the heart as a whole," Hardenbergh said.

With the latest imaging technologies, Hardenbergh plans to document the precise location of radiation damage to the heart and correlate that data with other existing measures of cardiac function.

Prior to receiving treatment, women participating in the trial will receive SPECT (single positron emission computed tomography) scans of their heart, which gives researchers a clear picture of cardiac perfusion. These scans show which areas of the heart are receiving and using oxygenated blood.

Patients also will receive CT (computed tomography) scans at the time of radiation treatment.

"Using the computer, we can superimpose the SPECT and CT images on top of each other and see which areas of the heart are hit by radiation," Hardenbergh explained. "Combining that data with other measures of cardiac function, we hope to quantify the effects of radiation on the heart."

Patients will receive additional scans and tests for up to two years to document any changes in cardiac function related to the breast cancer treatment.

According to the American Cancer Society, about 180,000 new cases of breast cancer will be diagnosed this year; and about 43,000 women will die from the disease.