TY - GEN

T1 - Time-shifting correction in optoacoustic tomographic imaging for media with non-uniform speed of sound

AU - Deán-Ben, X. Luís

AU - Ntziachristos, Vasilis

AU - Razansky, Daniel

PY - 2011

Y1 - 2011

N2 - An analysis of the time-shifting correction in optoacoustic tomographic reconstructions for media with an a priori known speed of sound distribution is presented. We describe a modification of the filtered back-projection algorithm, for which the absorbed optical energy at a given point is estimated from the value of the measured signals at the instant corresponding to the time-of-flight between such point and the measuring points. In the case that a non-uniform speed of sound distribution does exist, we estimate the time-of-flight with the straight acoustic rays model, for which acoustic waves are assumed not to change direction as they propagate. The validity of this model is analysed for small speed of sound variations by comparing the predicted values of the time-of-flight with the ones estimated considering the refraction of the waves. Experimental results with tissuemimicking agar phantoms with a higher speed of sound than water showcase the effects of the time-shifting of the optoacoustic signals caused by the acoustic mismatch. The performance of the time-shifting correction relates to the optoacoustic imaging of biological tissues, for which the speed of sound variations are usually lower than 10%.

AB - An analysis of the time-shifting correction in optoacoustic tomographic reconstructions for media with an a priori known speed of sound distribution is presented. We describe a modification of the filtered back-projection algorithm, for which the absorbed optical energy at a given point is estimated from the value of the measured signals at the instant corresponding to the time-of-flight between such point and the measuring points. In the case that a non-uniform speed of sound distribution does exist, we estimate the time-of-flight with the straight acoustic rays model, for which acoustic waves are assumed not to change direction as they propagate. The validity of this model is analysed for small speed of sound variations by comparing the predicted values of the time-of-flight with the ones estimated considering the refraction of the waves. Experimental results with tissuemimicking agar phantoms with a higher speed of sound than water showcase the effects of the time-shifting of the optoacoustic signals caused by the acoustic mismatch. The performance of the time-shifting correction relates to the optoacoustic imaging of biological tissues, for which the speed of sound variations are usually lower than 10%.

KW - Back-projection algorithm

KW - Heterogeneous speed of sound

KW - Optoacoustic tomography

UR - http://www.scopus.com/inward/record.url?scp=79960545749&partnerID=8YFLogxK

U2 - 10.1117/12.889946

DO - 10.1117/12.889946

M3 - Conference contribution

AN - SCOPUS:79960545749

SN - 9780819486875

T3 - Progress in Biomedical Optics and Imaging - Proceedings of SPIE

BT - Novel Biophotonic Techniques and Applications

T2 - Novel Biophotonic Techniques and Applications

Y2 - 22 May 2011 through 24 May 2011

ER -