An apparatus for acquiring time-resolved measurements from a sample from optical scanning comprises pulsed laser light directed to the sample; a first detector disposed to detect the light after exiting from the sample, the detected light being in the form of a first temporal point spread function (TPSF); a first amplifier to amplify the first TPSF; a first analog-to-digital converted (ADC) to directly digitize the first TPSF; a first buffer connected to the first ADC; a time-pickoff detector to initiate the first ADC to digitize the first TPSF; a clock burst generator initiated by the time-pickoff detector to provide conversion timing to the first ADC; and a computer programmed to fit the digitized first TPSF to a theoretical curve to extract its amplitude, and attenuation and scattering coefficients.A method for acquiring time-resolved measurements from a sample from optical scanning comprises directing a pulse of light onto a surface of the sample; detecting the light that exits from the sample in the form of a temporal point spread function (TPSF); directly digitizing the TPSF; and extracting a transport scattering coefficient and a absorption coefficient from the digitized TPSF.