Angled Gantry CT Technique Halves Breast Radiation Exposure

An innovative angled gantry approach to coronary computed tomography (CT) angiography reduced radiation exposure to the breast by more than 50%, according to a study.

In December 2008, Ethan Halpern, M.D., associate professor of radiology at Jefferson Medical College of Thomas Jefferson University (Philadelphia, PA, USA), presented the study at the 94th scientific assembly and annual meeting of the Radiological Society of North America (RSNA), in Chicago, IL, USA. "Radiation dose to the breast during coronary CT is especially a concern for young women as the dose may increase the risk for breast cancer,” Dr. Halpern said. "Physicians are working diligently to reduce the patient radiation dose related to coronary CT.”

Dr. Halpern and colleagues retrospectively reviewed 100 consecutive coronary CT angiography images that were obtained with a 64 detector helical scanner. They evaluated sagittal images to (1) define the position of the breasts and the gantry angulation required to perform a CT examination parallel to the long axis of the heart; and (2) determine the reduction in breast exposure to radiation that might be accomplished by imaging the heart with an angled gantry acquisition.

The standard axial imaging plane for coronary CT angiography required a 6.5 cm ± 1.8 cm overlap with the lower breast. The overlap with the lower breast using the angled scan was reduced in half to 3.2 cm ± 1.6 cm (p < 0.001). "Angled gantry is a feasible technique for coronary CT angiography that reduces radiation exposure to the breast by 50%,” Dr. Halpern said. "These results warrant the development of machines that can perform this technique.”

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Jefferson Medical College of Thomas Jefferson University