Developed by a researcher at the University of Missouri (Columbia, USA), the new invention involves photoacoustics, also known as laser induced ultrasound. The tool utilizes properties of density, light, heat, and color to cause cancer cells to react in a manner that makes them detectable from the surrounding cells. The first step in the testing process is to separate a patient’s blood into white blood cells (WBCs) and red blood cells (RBCs), using a centrifuge. Since melanoma cells are about the same density as WBCs, but less dense than RBCs, they naturally migrate with WBC fraction as the blood separates.

The resulting batch of WBCs, and any cancer cells present, is then pumped through a small glass flow chamber, where the cells are targeted with a short pulse of high-intensity laser light as they swirl by. Since white objects reflect light, the WBCs are not affected, but any cell containing melanin pigment will absorb the light. The intense laser beam heats such a cell rapidly, causing thermo-elastic expansion, which in turn causes the expanding cell to emit a measurable pressure wave. Detection equipment senses this photoacoustic wave and thus locates the cancer cell presence.

“We are attempting to provide a faster and cheaper screening method, which is ultimately better for the patient and the physician,” said device developer John Viator, MD, PhD, an associate professor of biomedical engineering and dermatology. “Combined with the new photoacoustic detection method, physicians will be able to use targeted therapies and personalized treatments, changing the medical management of this aggressive cancer. Plus, if the test is as accurate, as we believe it will be, our device could be used as a standard screening in targeted populations.”

Melanomas occur predominantly in skin, but are also found in other parts of the body, including the bowel, the eye, or any part of the body that contains melanocytes, the cells that produce the dark pigment, melanin, which is responsible for skin color. Worldwide, about 160,000 new cases of melanoma are diagnosed yearly. Melanomas are more prevalent in women, and are particularly common among Caucasians living in sunny climates, with high rates of incidence in Australia, New Zealand, North America, Latin America, and northern Europe. Treatment includes surgical removal of the tumor, adjuvant treatment, chemo- and immune-therapy, or radiation treatment.

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