Novel optical technique to characterize intact cortical bone

An optical technique based on laser-induced bone autofluorescence was used to characterize intact cortical bone and correlate the results with mechanical test results. The optical system consisted of a nitrogen laser for excitation and a fiber-optic probe to deliver the laser light and acquire the fluorescence spectrum. An unprecedented progressive increase in the width of the autofluorescence peak with aging was observed. It was found that the fracture toughness decreased with age. Since the autofluorescence originates only from the organic phase of the bone, the changes in the mechanical properties of the bone may be attributed to organic phase changes manifested in the fluorescence spectrum.