Non-invasive diagnosis, small instruments can judge cancer

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Some diseases are difficult to diagnose at an early stage, leaving many patients vulnerable to missing the best time for treatment, especially cancer. Skin cancer is the most common human malignancy and is usually diagnosed by visual inspection, followed by biopsy and histological examination. Researchers have tried to develop automatic classification systems in the past, but achieving this has not been easy due to the wide variation in the appearance of skin lesions.

Currently, the incidence of malignant melanoma is increasing, with approximately 232,000 new cases and 55,500 deaths worldwide each year. Melanoma can be cured if detected early, but many cases are diagnosed when it is more advanced and more difficult to treat.

In an effort to simplify skin cancer diagnosis, a team of researchers from the Stevens Institute of Technology announced today that they have successfully demonstrated the effectiveness of a new non-invasive skin cancer detection tool .

It's a new device that uses millimeter-wave imaging technology -- the same technology used by airport security scanners -- to scan patients' skin to detect whether they have skin cancer. Millimeter-wave rays harmlessly penetrate about 2 millimeters of human skin, so the team's imaging technique provides a clear 3D map of skin damage.

Specifically, healthy tissue reflects millimeter waves differently than cancerous tissue, so cancer could theoretically be detected by monitoring the contrast of light reflected back from the skin . While these studies are a useful proof of concept, they were only performed on tissue samples under laboratory conditions, not on living patients.

To bring this approach into clinical practice, the researchers used algorithms to fuse signals captured by multiple different antennas into a single ultra-high-bandwidth image, reducing noise and quickly capturing high-resolution images of even the smallest mole or blemish . Now, the new study shows that the system has the ability to differentiate between healthy and cancerous tissue in humans. The study noted that the device could return results in about 20 seconds.

The researchers recruited 71 patients with 136 suspicious skin lesions. After evaluation with the new high-resolution millimeter-wave imaging device, the researchers biopsied the lesions. The results showed that the new imaging device was incredibly accurate in identifying benign and malignant lesions. This initial test showed that the system had a specificity of 98% (meaning that 2% of its results were false positives) and a sensitivity of 97% (meaning it accurately detected all but 3% of malignant cancers) .

Only one in every 30 skin cancer lesions is now malignant, the researchers said. So this new device isn't meant to replace biopsies, but to add an extra tool to a doctor's diagnostic arsenal to avoid such a large number of unnecessary biopsies. Currently, researchers are now working to miniaturize the system, making it a low-cost handheld device.