Measurement system of optical properties of vertebra bones on near-infrared spectrum

Near-infrared spectrum scattered from biological tissue can be used to characterize the optical properties of the tissues. If the optical properties of different parts of vertebra bones are different, a new navigation method in pedicle screw insertion surgery can be proposed. The goal of this study is to develop an optical measurement method which can detect the optical properties of vertebra bones on near-infrared spectrum. A 2.0-mmdiameter steel probe containing two 200-micron diameter optic fibers was used to deliver light and collect light spectrum from the surface of vertebra bones. In experiment, the integrated pig vertebra bones were split. The steel probe was put on the different position of the anatomical section and the spectrum was detected at each point. The optical properties deduced from the spectrum were distinguished between the cortical bones and cancellous bones in the trajectory of pedicle screw placement.