Pulsed ultrasound modulated optical tomography with increased optical/ultrasound pulse ratio

An ultrasound modulated optical tomography (UOT) system, comprising:

• an acoustic assembly configured for delivering ultrasound into a target voxel in an anatomical structure;
• an interferometer configured for delivering sample light into the anatomical structure, whereby a portion of the sample light passing through the target voxel is scattered by the anatomical structure as signal light, and another portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light that combines with the signal light to create a sample light pattern, the interferometer further configured for combining reference light with the sample light pattern to generate an interference light pattern;
• a controller configured for operating the acoustic assembly and the interferometer to pulse the ultrasound and the sample light in synchrony, such that only the signal light is frequency shifted by the ultrasound, wherein a duration of each pulse of the ultrasound delivered into the target voxel is within a decorrelation time of the target voxel, and wherein multiple pulses of the sample light are sequentially delivered into the anatomical structure for each pulse of the ultrasound delivered into the target voxel, the controller further configured for operating the interferometer to sequentially modulate the interference light pattern to generate a plurality of different interference light patterns;
• at least one detector configured for detecting the different interference light patterns;
• and
• a processor configured for determining a physiologically-dependent optical parameter of the target voxel based on the detected interference light patterns.