From the OE Magazine
Seeing the light
Biopsies may become rare as photon migration imaging develops into a powerfull noninvasive diagnostic tool.
NIR Tissue Interaction
Optics provides an inexpensive and noninvasive means to monitor blood physiology and more. For example, hold a flashlight to your finger; the red light is the only color transmitted. Hemoglobin absorbs blue and green very strongly, but it absorbs red very weakly.
SPIE Resource Page