Optical Coherence Tomography (OCT) allows for real time in vivo tissue imaging analogous to ultrasound, except that it uses light rather than sound waves and has a much greater resolution. It operates at 1300nm (near infrared). Michelson Diagnostics’ Vivosight OCT scanner produces images with a resolution of 7.5 microns to a depth of slightly greater than 1mm. The resolution is equal to the size of a melanocyte. The image extends to about 2mm in depth with progressive degradation of resolution.
Imalux OCT technology is an endoluminal application with a fiberoptic probe that has resolution of 10-20 microns and penetration of 2.5mm. The company at this time does not have products with dermatologic applications in the market. This technology is well represented in research and development for endoluminal applications. It can be followed by an industry website http://www.octnews.org/.
Although Optical Coherence Tomography is an attractive technology, its clinical utility is limited by the relatively shallow imaging. Its high cost (>$100,000) places it as a research tool given lack of meaningful ROI.
Final technology worth mentioning is photoacoustic imaging. It requires intravascular contrast agent, hemoglobin, or melanin for visualization, relying on laser pulses to create thermoelastic expansion and subsequent ultrasonic emission. It produces a remarkable 3-D image with significant depth of penetration up to 7cm enabling full body imaging, also named photoacoustic tomography. Its resolution extends from micro scale of organelle detection to macro scale of tumor imaging. One of its potential applications is identifying methylene blue in lymph nodes for sentinel lymph node biopsy. No commercial application is available at this time.