Thermally modulated photoacoustic imaging (TMPI) is reported here for contrast enhancement when using nanoparticles as contrast agents. Exploiting the excellent sensitivity of the photoacoustic (PA) process on temperature and the highly selective heating capability of nanoparticles under electromagnetic field, the PA signals stemming from the nanoparticles labeled region can be efficiently modulated whereas those from highly light absorptive backgrounds are minimally affected. A coherent difference imaging procedure reduces the background signal and thus improves the imaging contrast. Phantom experiments with super-paramagnetic iron oxide nanoparticles (SPIONs) as contrast agents and alternating magnetic fields for heating are demonstrated. Further improvements toward clinical applications are also discussed.
© 2014 Optical Society of America
Original Manuscript: February 17, 2014
Revised Manuscript: April 15, 2014
Manuscript Accepted: May 3, 2014
Published: June 4, 2014
Xiaohua Feng, Fei Gao, and Yuanjin Zheng, "Thermally modulated photoacoustic imaging with super-paramagnetic iron oxide nanoparticles," Opt. Lett. 39, 3414-3417 (2014)