OCT diagnostics: gathering the data

03 Aug 2009

Clinical study to evaluate optical imaging for pre-operative diagnosis of early forms of skin cancer.

Michelson Diagnostics, the UK manufacturer and developer of optical-coherence-tomography (OCT) imaging systems, has initiated an in vivo trial of its VivoSight multibeam OCT probe. At least 100 patients will be scanned as part of the initial early-stage study.

The trial is a collaboration between researchers at Michelson and Ludwig Maximilians University in Munich, Germany. Together they're working to evaluate VivoSight's ability to differentiate premalignant and early malignant lesions, as well as to demarcate non-melanoma skin cancers before planned surgical excision.

OCT is a non-invasive, interferometric optical imaging technique that "could play an important role in the pre-operative diagnostics of early carcinomas in the skin", according to Gordon McKenzie, Michelson Diagnostics' medical applications director.

The VivoSight probe is designed for use on external tissue – for example, imaging of skin microstructure – with an isotropic resolution of better than 10 µm to a depth of up to 2 mm. Scan rates vary from 6.5 fps to 35 fps, depending on the scan width, which, in turn, can be varied up to 5 mm. The probe has full xy scanning capability, enabling rapid capture of 3D TIFF format image stacks up to 5 ×  5 mm with a pixel size of 4 7µm.

"Right now, because the common imaging systems such as ultrasound, CT and MR don't have sufficient sensitivity for early forms of skin cancer, the early recognition of tumours of the skin relies solely on medical inspection, on epiluminescence microscopy and on subsequent biopsy," explained McKenzie.

Those procedures are expensive and time-consuming, claims McKenzie. What's more, single biopsies may not lead to the correct diagnosis, because lesions commonly occur in multiple locations, and they can also occur over large regions before they become invasive at selected areas.

McKenzie added: "With the help of 3D mapping and structured surveillance using OCT, information may be obtained in a non-invasive manner over the extension, the structure, and the possible dignity (benign or malignant) of such lesions without needing to take an invasive biopsy. If, for example, the distinction between dysplasia and early invasive carcinoma was possible, then subsequent treatment, such as the kind of resection, PDT [photodynamic therapy] or other forms of local therapy, can be better planned."

The VivoSight OCT probe is on sale in Europe for clinical use, but is currently only available for non-clinical applications within the US.