In this work, we have developed a selective-plane illumination multispectral optoacoustic tomography (MSOT)
technique for high-resolution whole-body visualization of intact optically diffusive organisms whose sizes may vary
from sub-millimeter up to a centimeter range and beyond. By combining multi-wavelength illumination, the method is
shown capable of resolving tissue-specific expression of fluorescent proteins and other molecular biomarkers located
deep in living optically diffuse tissues.
An essential problem dealing with three-dimensional optoacoustic imaging is the long data acquisition times associated
with recording signals from multiple spatial projections, where signal averaging for each projection is applied to obtain
satisfying signal-to-noise-ratio. This approach complicates acquisition and makes imaging challenging for most
applications, especially for in vivo imaging and multispectral imaging. Instead we employ a herein introduced
continuous data acquisition methodology that greatly shortens recording times over multiple projection angles and
acquires high quality tomographic data without averaging. By this means a two dimensional image acquisition having
270 angular projections only takes about 9 seconds, while a full multispectral three dimensional image can normally take
about 15 minutes to acquire with a single ultrasonic detector. The system performance is verified on tissue-mimicking
phantoms containing known concentrations of fluorescent molecular agent as well as small animals.