Prospects of molecular photoacoustic imaging at 1064 nm wavelength.

An analysis of the photoacoustic (PA) signal from murine tissue in vivo revealed several benefits of contrast-enhanced PA imaging at a wavelength of 1064nm. Of all the wavelengths tested in a range from 710 to 1064nm, the background PA signal from tissue in vivo was lowest and more homogeneous at 1064nm. For blood-laden tissue, the background PA signal was up to 70% less at 1064nm. Furthermore, when plasmonic nanoparticles, such as silver nanoplates, were introduced in vivo as contrast agents, the contrast in PA images at 1064nm increased 38% compared to 750nm. Therefore, contrast-enhanced PA imaging at 1064nm is advantageous because of the low and homogeneous signal from native tissue, enabling high contrast in PA imaging when exogenous, molecularly targeted agents are employed.