Microwave mammography.Most women over the age of 40 are intimately acquainted with mammography mammography, diagnostic procedure that uses low-dose X rays to detect abnormalities in the breasts. The early diagnosis of breast cancer made possible by the routine use of mammography for screening women increases a woman's treatment alternatives and improves her , which uses X rays to hunt for breast tumors. This potentially life-saving procedure is uncomfortable under the best of circumstances--which is why William T Joines thinks women may warm to a microwave alternative. The system that he's developing at Duke University in Durham, N.C., aims to locate mammary tumors For mammary tumors in humans, see . A mammary tumor is a tumor originating in the mammary gland. It is a common finding in older female dogs and cats that are not spayed, but they are found in other animals as well. with at least the same resolution as today's diagnostic devices. Yet because there's no need to tightly compress the breast during imaging, the risk of pain or bruising bruising discoloration and actual hemorrhage at the site of injury, and a serious disadvantage in the meat trade. In the first 12 hours after injury the bruise is bright red, at 24 hours it is dark red, at 24 to 36 hours it loses its firm consistency and becomes watery and at 3 or would be eliminated. Women "should feel nothing," Joines says. His technology relies on the fact that microwaves respond somewhat differently when passing through healthy tissue and tumors. Compared with an equal volume of healthy breast tissue, a tumor tumor: see neoplasm. not only dissipates about six times as much of the signal's energy, but also slows the signal's passage. As Joines envisions the new procedure, a women would lie face down on a table with a cutaway section containing a well of warm fluid. This liquid, which could be a mix of salt water and alcohol, mimics healthy tissue's ability to transmit a microwave signal. Once a breast is immersed im·merse tr.v. im·mersed, im·mers·ing, im·mers·es 1. To cover completely in a liquid; submerge. 2. To baptize by submerging in water. 3. in the liquid, a small transmitter would send a beam of microwaves into the well. An array of detectors surrounding the container would then monitor the signal, triangulating any points where the beam slows or weakens--spots that might pinpoint cancers. In tests using materials that mimic the microwave-signal attenuation Loss of signal power in a transmission. Attenuation The reduction in level of a transmitted quantity as a function of a parameter, usually distance. It is applied mainly to acoustic or electromagnetic waves and is expressed as the ratio of power densities. and velocity in normal tissue and tumors, the system detected modeled tumors just 2 millimeters in diameter. Joines hopes soon to begin validation tests using tissue from breast-surgery patients. |
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