A MEMS based handheld confocal microscope with Raman spectroscopy for in-vivo skin cancer diagnosis

Both Confocal Microscopy and Raman Spectroscopy have shown potential for diagnosis and differentiation of cancerous and normal skin. Many current studies utilizing these techniques use large bench-top microscopes, and are not suited for in-vivo diagnosis in a clinical setting. We have developed a microscope which combines confocal reflectance imaging with Raman spectroscopy into a compact handheld probe, allowing images and Raman spectra to be taken in-vivo. The compact design of this handheld unit is largely due to the use of a MEMS mirror which scans the illumination laser light in two dimensions to produce the confocal reflectance image of the skin. An integrated CCD camera provides a large area view of the skin surface which helps to guide the location of the confocal reflectance image area. Using this probe, in-vivo confocal reflectance images and Raman spectra of normal skin have been obtained with axial resolutions of 4 mu m for the confocal channel and 10 mu m for the Raman channel. This paper presents the instrument design and optical characteristics, including representative in-vivo images and Raman data from normal skin tissue.