Plane wave acousto-optic imaging in reflection mode geometry

Abstract

Imaging performance of an acousto-optic system is limited by light fluence rate and acoustic pressure filed distributions characteristics. The system parameters can be shaped by changing relative positions of ultrasound transducer array and optodes. However, in case of many potential clinical applications optimization possibilities in this regard are limited, as a sample is accessible from one side only and using a water tank for coupling is not feasible. We investigate the possibilities of improving performance of an acousto-optic imaging system operating in reflection mode geometry with linear ultrasound array in direct contact with a sample by using plane wave instead of focused ultrasound pulses. Differences in acoustic pressure field distributions for various transducer excitation patterns were determined numerically. Acousto-optic images of phantoms with and without optically absorbing inclusions were acquired by measuring laser speckle contrast decrease due to the light modulation by plane wave and focused ultrasound pulses. The light fluence rate maps reconstructed using plane wave imaging proved more distinct and clear.

Reflection-mode acousto-optic imaging using plane wave ultrasound pulses

“…Some of the initial results related to this study were previously published as an SPIE Proceedings paper. 21 Funding Sources: Grant No. 15228 of NWO Division Applied and Engineering Sciences and the Dutch Cancer Society.…”