An innovative optical technology that can distinguish between different types of skin cancer melanoma has been developed in the laboratory of Professor Abraham Katzir of the Raymond and Beverly Sackler Faculty of Exact Sciences at Tel Aviv University. The method, which is rapid, non-invasive, and painless, was tried successfully on about one hundred patients in a major hospital in Israel.
The findings have been published in the journal Medical Physics.
Professor Katzir says that immediate diagnosis can save lives in the case of melanoma. He goes on to explain that when a suspicious lesion is found on the skin during a routine examination, it is removed in a minor surgical procedure and sent to a laboratory for testing. A pathologist diagnoses the lesion and determines whether it is melanoma. In most cases in which melanoma is discovered early when it is still superficial and less than one-millimetre-thick and it is removed, the patient recovers. Late diagnosis, when the melanoma is more than one millimetre thick, significantly reduces the chances of recovery and is life-threatening.
“The idea that guided us in developing the technology was that in the visible range, there are various substances, having various colors, which are not characteristic of each substance. But in the infrared region, which the eye cannot see, various substances have different ‘colors’ of a sort, depending on the chemical makeup of each substance,” says Professor Katzir. “We figured that with the help of devices that can identify these ’colors,’ healthy skin and each of the benign and malignant lesions would have different ’colors,’ enabling us to identify melanoma.”
Professor Katzir’s research group developed special optical fibers that are transparent in the infrared spectrum and also developed a system, based on these fibers, which is suitable for the requirements of evaluating skin. The researchers connected one end of this type of fiber to a device that measures the “colors” in the infrared spectrum, and touched the other end lightly, for several seconds, to a lesion on a patient’s skin. The fiber made it possible to determine the infrared “color” of the lesion immediately.
Clinical trials were carried out on suspicious lesions in about one hundred patients. With the help of the new system, physicists performed measurements of the “color” of each lesion before it was removed and sent to a pathology laboratory. The researchers showed that all of the lesions that were determined by pathologists as being of a certain type, such as melanoma, had a characteristic “color” in the infrared. Each lesion of a different type had a different “color.”
“This technology gives us a kind of ‘fingerprint’ that makes a clear diagnosis of the various lesions possible, by measuring their characteristic ’colors,’” says Professor Katzir. “In this way, lesions can be diagnosed using a non-invasive optical method, and the physician and the patient receive the results automatically and immediately. This is unlike the test that is routinely used, which involves surgery, and the pathological diagnosis takes a long time.” Following the success of the study, the researchers plan to confirm the evaluation method on hundreds of patients.
“Melanoma is life-threatening cancer, so it is very important to diagnose it early on, when it is still superficial,” Professor Katzir concludes. “The innovative system will enable every dermatologist to determine the character of a suspicious lesion automatically, and particularly if it is melanoma. This system has the potential to cause a dramatic change in the field of diagnosing and treating skin cancer, and perhaps other types of cancer as well. The challenge will be to make this technology, which is still expensive, something that canbe used in every hospital or clinic.”