Spatial resolution in photon diffusion imaging from measurements of time-resolved transmittance

摘要

Abstract: We have measured time-resolved transmittance of ps laser pulses through scattering suspensions of thickness d employing time- correlated single photon counting. When absorption is neglected time-resolved transmittance and its Fourier transform can be expressed in terms of scaled variables, i.e. time $Theta and angular frequency approximately ega, respectively. We have complemented our investigations on resolution by imaging translucent and absorbing objects embedded in animal tissue in vitro. Objects below the resolution limit, i.e. bars with cross sections 6 mm by 3 mm were detected at the center position of tissue being 4 cm thick. This was achieved by selecting sufficiently short initial time intervals, corresponding to fractions f $LS 0.1, enhancing contrast considerably in this way. !11