Whole-Body Photoacoustic Imaging Techniques for Preclinical Small Animal Studies

Abstract

Photoacoustic imaging is a hybrid imaging technique that has received considerable attention in biomedical studies. In contrast to pure optical imaging techniques, photoacoustic imaging enables the visualization of optical absorption properties at deeper imaging depths. In preclinical small animal studies, photoacoustic imaging is widely used to visualize biodistribution at the molecular level. Monitoring the whole-body distribution of chromophores in small animals is a key method used in preclinical research, including drug-delivery monitoring, treatment assessment, contrast-enhanced tumor imaging, and gastrointestinal tracking. In this review, photoacoustic systems for the whole-body imaging of small animals are explored and summarized. The configurations of the systems vary with the scanning methods and geometries of the ultrasound transducers. The future direction of research is also discussed with regard to achieving a deeper imaging depth and faster imaging speed, which are the main factors that an imaging system should realize to broaden its application in biomedical studies.

Recent Advances in Photoacoustic Agents for Theranostic Applications

“…Advances in PAI systems may also be beneficial for biomedical applications of therapeutic agents. To visualize the biodistribution of agents, whole-body PAI systems equipped with multiple or tunable laser wavelengths have been widely developed [ 22 ]. Recently, three-dimensional PA computed tomography (PACT) systems have shown great potential for monitoring the biodistribution of small animals in vivo [ 26 ].…”

“…Photoacoustic imaging (PAI) is a hybrid imaging technique that visualizes the optical absorption properties of biological tissues with ultrasound (US) resolution [ 20 , 21 , 22 ]. Compared to pure optical imaging techniques, PAI can significantly increase the imaging depth while maintaining a relatively good spatial resolution [ 23 ].…”

Contrast Agents for Photoacoustic Imaging: A Review Focusing on the Wavelength Range

“…In vivo visualization of small animals using these contrast agents has been widely studied using various PAI systems [ 115 , 116 , 117 ]. According to the configuration of the PAI system, the penetration depth and spatial resolution of the resulting images are varied [ 118 ].…”

Sound out the impaired perfusion: Photoacoustic imaging in preclinical ischemic stroke

“…Even so, enlarging the detection geometry is the most effective way to mitigate the limited-view problem. For example, a 2D ring detection geometry or a hemispherical detection geometry are reported to produce superior whole-brain imaging, due to larger detection angles ( Kye et al, 2022 ). However, using these detection arrays can introduce a higher cost of the system and also require a more complicated experimental setup.…”