Z-Tech Breast Scan

The Associated Press reports about a new breast exam system, that potentially one day can replace an uncomfortable and X-radiating mammography. Z-Tech® Inc., the maker of the electrical impendance system, explains its technology:

The measured impedance to the flow of the current reflects the electrical properties of the tissue elements in the current path.
When an area of the breast becomes malignant there is (a) an increase in the volume of fluid in the region and (b) the cell membrane becomes electrically porous, both changes resulting in a decrease in electrical impedance in the cancerous area.
Electrical changes associated with cancer, therefore, can be regarded as a marker that can be detected by a system capable of measuring electrical impedance throughout the breast.
To begin the breast cancer screening test–the Z-Tech breast scan–the subject lies on her back on an examining table. Self-adhesive SuperStellate® Sensors are applied gently to both breasts; here the first sensor, on the left breast, is shown in place.
With the subject lying comfortably, testing is begun. Over 300 combinations of electrodes, one combination at a time, are selected for impedance measurements throughout each breast. The entire procedure is painless, safe, and rapid, and requires only 30 seconds to complete.

Primary breast CA is often just a clump of cells worth a couple of millimeters in diameter. So this test better be extremely sensitive. And then, the test also has to be pretty specific. Breast tissue is often lumpy. Hence the test should identify the normal tissue as such and not alert the physician and patient with a worrisome (false positive) result when the cancer is not really there. (To understand the issues of specificity and sensitivity in medical testing, see this BMJ article.)
Interesting technology, indeed. We will be following up.
More at Z-Tech®…