Milk-based material improves imaging

Milk does the body good, especially when it comes to detecting human ailments. In a new development by UW–Madison researchers, concentrated milk provides a tissue-mimicking material that could improve medical imaging.

Physicians rely on magnetic resonance imaging and ultrasound to detect birth defects in fetuses, blocked blood flow and tumors. To ensure the highest quality of performance, the greatest accuracy and the best resolution of images, radiologists calibrate the machines by using phantoms — liter-sized boxes containing water-based gels designed to mimic the structure and properties of human tissue.

“Phantoms can tell you what the limitations are of particular machines,” explains Ernest Madsen, a professor of medical physics.

But, as Madsen points out, some of the materials used in phantoms don’t mimic tissue adequately because of limited physical properties that affect how ultrasound waves travel through tissue, interact with it and, ultimately, image it.

To develop a better model, Madsen and his colleague Gary Frank concentrated cow’s milk — which has many of the same properties as human tissue — and mixed it with a hot solution that congeals into a gel. They added a preservative, creating a product with a shelf life of more than 10 years.

“In making phantoms, we try to represent the patients,” Madsen says. “By developing more realistic tests of performance, we not only allow the periodic monitoring of the imaging quality of hospital ultrasound machines, but also contribute to advances in imaging technology.”

The milk-based material, patented by the Wisconsin Alumni Research Foundation, is already contained in thousands of phantoms distributed to hospitals and research laboratories worldwide.