Table 6.

Optical biopsy

Optical biopsy	Technology	Light source	Information provided	Sensitivity %	Specificity %
Auto-fluorescence spectroscopy	Fluorochromes fluorescence (NAD, FADH)	ultraviolet and visible spectrum light	Distinguish malignant tissue by concentration of (NAD, FADH), re-emit green light	81	100
Enhanced dye fluorescence	Fluorochromes fluorescence (protoporphyrin IX)	ultraviolet and visible spectrum light	Distinguish malignant tissue by high concentration of (protoporphyrin IX), re-emit red light	100	100
Ratio imaging	fluorescence (protoporphyrin IX, NAD, FADH)	ultraviolet and visible blue light	Compare a ratio of red emission of (protoporphyrin IX) from malignant cells with the green emission from normal	from 60 to 97	from 75 to 99%
Raman spectroscopy	Raman vibrational spectroscopy	laser-based spectroscopic technique	enabling chemical characterization	80.5	86.2
Elastic scattering spectroscopy	Elastic scattering (white light reflectance)	pulsed xenon arc lamp	provides optical geometrical information	92	79
Differential path-length spectroscopy	Elastic scattering (white light reflectance)	tungsten-halogen lamp	cell biochemistry, intracellular morphology and microvascular properties such as oxygen saturation and average vessel diameter	69	85
Optical Coherence Tomography	scattered light (Fourier domain mode lock swept source-based) OCT	laser-based	Provide provide high-speed three-dimensional OCT pictures	Subjective image required interpretation	Subjective image required interpretation
Angle-resolved low coherence interferometry (A/LCI)	scattered light to measure the average size of different cell structures	laser-based	delivers direct confirmation of precancerous disease to the physician	100	85