The effects of an inappropriately chosen speed-of-sound in photoacoustic imaging reconstructions are to cause
blurring of images and impairment of contrast. Here we outline a new methodology to measure the speed-of-sound
in a photoacoustic imager with little or no additional cost and without the need to perform extra measurements.
The method uses a strong absorber of light which is placed in the path of the light illuminating the sample.
This acts as a source of ultrasound whose interaction with the sample can be measured at the far-end of the
sample using the same ultrasound detector used for photoacoustics. This yields time-of-arrival measurements of
the ultrasound transient at the multi-element detector. Such measurements are made at various angles around
the sample in a computerized tomography approach. Reconstruction of the time-of-arrival or speed-of-sound
tomogram of the object can be made by implementing a fan-beam projection reconstruction algorithm. We
present the concept and validate the method on a speed-of-sound phantom.
|Name||Proceedings of SPIE|
|Publisher||The International Society for Optical Engineering|
|Conference||Photons Plus Ultrasound: Imaging and Sensing 2007|
|Period||13/02/07 → 15/02/07|