Andor Newton camera powers combined RS-OCT probe capable of both morphological and biochemical characterization of skin cancers.

Fig. 1 – Schematic diagram of the clinical probe. The Raman laser diode (RLD) is band pass filtered (BP) and co-aligned with the OCT beam at dichroic mirror 1 (DC 1). The Raman excitation and OCT beams are directed at the sample via a galvanometer (G) and objective lens (OL) pair that perform a telecentric scan of the OCT beam during imaging. The Raman scatter is separated from the OCT and Raman excitation by dichroic mirror 2 (DC 2), long pass filtered (LP) and detected by the Raman collection (RC) optics. A foam pad (F) is attached to the sample end of the probe for patient comfort. The overall probe size is 4
Skin cancer is the most common form of cancer in humans, with annual rates continuing to climb from their current estimate of just over three million new cases each year. Although all skin cancers share the likelihood of a favorable outcome if early diagnosis and complete resection are achieved, diagnosis is invasive, subjective, lengthy, and expensive, as it involves expert visual inspection, biopsy, and histopathology.

A joint US-Dutch team under the direction of Anita Mahadevan-Jansen of Vanderbilt University (Nashville, TN), has developed a non-invasive probe capable of both morphological and biochemical characterization of skin cancers. The portable instrument combines a Raman spectroscopy (RS) system with an Optical Coherence Tomography (OCT) device and enables sequential acquisition of co-registered OCT and RS data sets. An Andor highresolution, near-infrared-enhanced Newton camera served as the core element of the Raman diagnosis module. The probe will screen large areas of skin up to 15 mm wide to a depth of 2.4 mm with OCT to visualize microstructural irregularities and perform an initial morphological analysis of lesions. The OCT images are then used to identify locations to acquire biochemically specific Raman spectra.

“Due to the inherently weak nature of Raman scattering and the relatively intense background autofluorescence from tissue, collection efficiency is a critical factor in the design of clinical RS probes,” said Chetan A. Patil of Vanderbilt University. “Unlike confocal approaches that emphasize axial resolution, our probe is designed to prioritize collection efficiency. The high sensitivity of the Andor Newton CCD’s back-illuminated, deep-depletion, thermo-electrically cooled design is well suited to the stringent demands of in vivo Raman spectroscopy.

“Having demonstrated the clinical potential of the RS-OCT instrument to rapidly screen at risk patients, we are continuing to develop the dual-modal technique for other applications where non-invasive assessment of both microstructure and biochemical composition are critical to accurate assessment of pathology. The Labview software development kit, which is supplied with the camera and supported directly by Andor, was crucial in the development of our first probe and in our ongoing research,” said Patil.

Fig. 2 – RS-OCT of a nodular basal cell carcinoma over the right temple. a: OCT image of normal skin adjacent to lesion shows hyporeflective subsurface features that are likely sebaceous glands and hair follicles (green arrows). White arrow indicates area where epidermal-dermal boundary is most visible. Red area approximates axis of RS acquisition. b: The OCT image of the BCC shows a set of hypo-reflective regions in the dermis beneath the red arrow, which indicates the axis of RS. It is likely that these features correspond to tumour cell nests based on the pathology. c: The representative histology (10X magnification, scale bar = 150 μm) shows the presence of a number of tumour cell nests (arrows) characteristic of BCC. d: The mean Raman spectra exhibit distinct differences between the BCC and normal in the regions centred at 1,090, 1,300, and 1,440 cm-1.
According to Antoine Varagnat, Product Specialist at Andor, “With its high sensitivity in the NIR enabled by high Quantum Efficiency and deep TE-cooling interface, the Newton Deep-Depletion CCD platform is just the right detector for demanding clinical NIR spectral diagnosis. One also gets the benefit of long-lasting detection performance and reliability with Andor’s UltraVac™ vacuum technology, alongside high speed acquisitions and ease of integration.”

This technology was done by Andor Technology, Belfast, Northern Ireland. For more information, visit http://info.hotims.com/40437-184.

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