By Deborah Borfitz
May 19, 2022 | Electrical and computer engineers at Stevens Institute of Technology in Hoboken, New Jersey, together with clinical dermatology specialists at Hackensack University Medical Center (HUMC) in Hackensack, New Jersey, are collaboratively developing a low-cost, handheld imaging device that provides laboratory-grade diagnoses of different types of skin cancer. It should be received as a welcome alternative to skin biopsies, about half of which are unnecessarily done for want of another method for differentiating benign from cancerous tissue, according to Negar Tavassolian, director of the bio-electromagnetics laboratory at Stevens.
The innovation here is the application of millimeter-wave imaging—the same technology used by airport security scanners—to generate high-resolution images of suspicious lesions, she explains. The millimeter-wave rays harmlessly penetrate about 2mm into the skin, with healthy and cancerous tissue reflecting those rays back differently to create a measurable contrast.
Most recently, the development team optimized the hardware enabling real-time in vivo measurements, as reported in Scientific Reports (DOI: 10.1038/s41598-022-09047-6). The portable, benchtop-sized system was used on patients with melanoma, non-melanoma, and benign skin lesions being treated at the Dermatologic, Mohs, and Laser Surgery Center at HUMC.
The large-scale imaging study focused on concerning skin lesions, including malignancies and pre-malignancies requiring treatment (e.g., malignant melanoma, squamous cell carcinoma, basal cell carcinoma, and actinic keratosis) and benign conditions that visually mimic skin cancer (e.g., melanocytic nevi, angiokeratoma, dermatofibroma, solar lentigo, and seborrheic keratosis). The ability of the device to detect the benign lesions, with 97% sensitivity and 98% specificity relative to an invasive biopsy procedure, is more important than its ability to distinguish cancers “because right now everything can be cancer and everybody errs on the side of caution,” stresses Tavassolian.
Aggressive diagnostic efforts have caused the number of biopsies to grow around four times faster than the number of cancers detected, she reports. About 30 benign lesions are being biopsied for every case of skin cancer that’s found.
Researchers used algorithms to fuse signals captured by multiple different antennas into a single ultrahigh-bandwidth image, reducing noise and quickly capturing high-resolution images of even the tiniest mole or blemish. Skin anywhere on the body can be evaluated in seconds, versus 20 minutes with the original setup that accommodated only a thin layer of excised tissue under the probe, as described several years ago in IEEE Transactions on Medical Imaging (DOI: 10.1109/TMI.2019.2902600).
That means the test should prove both useful and practical if deployed during routine clinic visits. Toward that end, large-scale clinical trials will be conducted this year once the technology has been implemented on a single microwave integrated circuit chip to lower the cost of manufacturing the compact system to as little as $100 a piece, says Tavassolian.
The chip will send a signal to a handheld device the size of a dermatoscope, or possibly as small as a cell phone, she continues. It could simply be held over the skin to provide a three-dimensional, magnified image of the scanned lesion as well as indicate if it’s benign, cancerous, or just discoloration of normal skin.
Currently, dermatologists rely on a magnifying dermatoscope to examine and diagnose skin lesions. The new system would offer doctors a comparably priced point-of-care imaging tool, allowing them to visit more patients in different rooms or at different clinics, Tavassolian says.
A 510(k) premarket submission is expected to be made to the U.S. Food and Drug Administration in 2023. The market potential for the device is huge, given that skin cancer is the most prevalent and fastest growing cancer in the country, she notes.
It will have utility not only for detection but removal surgery of cancerous lesions, Tavassolian adds. Future improvements to the algorithm powering the device could significantly improve mapping of lesion margins, ensuring that they neither cut out less than the needed amount of tissue nor more than is necessary. Surgeons currently just rely on their eye.
A startup company, founded by her former student Amir Mirbeik Ph.D., will market the device, says Tavassolian. The early adapters are expected to be dermatology surgeons who are most open to the surgical assistance.