Skin cancer diagnosis can take weeks, involving referral to a dermatologist for a skin biopsy, and then possibly an invasive sentinel lymph node biopsy under general anaesthetic to find out if the tumour is spreading.
The new technology, developed in a European project led by UK-based Michelson Diagnostics, could dramatically speed up this process by allowing dermatologists to diagnose a malignant melanoma in real time.
The scanner allows dermatologists to view a 3D image of the blood vessels under the skin, up to a depth of 1mm.
The technology is based on Optical Coherence Tomography (OCT), conventionally used in retina scans, in which a laser beam is projected onto tissue and the reflected light is detected by a microscope and used to create a 3D image.
Unlike conventional OCT, however, the new technology, known as dynamic OCT (D-OCT), is able to detect motion within the tissue, according to Jon Holmes, co-founder and chief technology officer of Michelson Diagnostics. This reveals the flicker of light patterns created by moving blood cells against the background of solid tissue.
“Traditional OCT gives you the structure of the tissue, and if there is a tumour you can see it as a shape within that,” said Holmes. “Dynamic OCT, in contrast, detects motion, so it is able to compare two OCT images, taken within a short space of time, looking for differences.”
The system uses algorithms to extract the motion information and reveal the structure of the blood vessels.
Cancers are known to grow their own blood vessels. But unlike the blood vessels in healthy tissue, these vessels tend to grow in an abnormal, disorderly fashion, said Holmes.
“The vessels in normal tissue are like a network, whereas the vessels that feed tumours are more like twisted tree roots,” he said.
This allows the system to detect blood vessels grown by the tumour from within healthy tissue, and there are also hints that the degree of irregularity of the vessels may indicate how far the tumour has progressed, he said.
The technology has been implemented in the company’s VivoSight scanners, which use four beams of infrared laser light to double the image resolution of conventional OCT, providing the detail needed for skin cancer diagnosis.
The VivoSight device already has CE and Food and Drug Administration (FDA) regulatory clearance for clinical use in Europe and the US, although more testing is needed for use in diagnosing malignant melanomas, said Holmes.
The technology was developed in a €2.3m, European Commission-funded project known as Automatic Detection of Vascular Networks for Cancer Evaluation (ADVANCE).