DETERMINING THE AGE OF SKIN BRUISES

摘要

A method of estimating the age of a haematoma involves measuring skin reflectance of both normal and bruised skin. A model is provided that relates haemoglobin and bilirubin content with time after injury, and is used to estimate the haemoglobin and bilirubin distributions as a function of depth, for different times after injury. A photon transport model is then used to simulate reflectance spectra corresponding to the estimated haemoglobin and bilirubin distributions at different times after injury. The photon transport model also takes various input parameters calculated from the measured spectra such as melanin content and blood oxygenation. The age of the haematoma is found by comparing the measured and simulated reflectance spectra and determining the time that gives the best fit. Such a method can be implemented using an integrating sphere (2) and a suitably programmed computer (3). The integrating sphere (2) is placed opposite the skin (1) and collects reflectance spectra of both normal and bruised skin. The computer (3) calculates the various parameters required for the photon transport model from the reflectance spectra. The computer (3) also estimates haemoglobin and bilirubin distributions at different times after injury. The computer (3) then simulates reflectance spectra at different times after injury using the photon transport model. Finally, the measured spectrum and simulated spectra are compared in order to estimate the age of the bruise.