Abstract
Photoacoustic imaging combines the high contrast of optical imaging with the spatial resolution and penetration depth of ultrasound. This technique holds tremendous potential for imaging in small animals and importantly, is clinically translatable. At present, there is no accepted standard physical phantom that can be used to provide routine quality control and performance evaluation of photoacoustic imaging instruments. With the growing popularity of the technique and the advent of several commercial small animal imaging systems, it is important to develop a strategy for assessment of such instruments. Here, we developed a protocol for fabrication of physical phantoms for photoacoustic imaging from polyvinyl chloride plastisol (PVCP). Using this material, we designed and constructed a range of phantoms by tuning the optical properties of the background matrix and embedding spherical absorbing targets of the same material at different depths. We created specific designs to enable: routine quality control; the testing of robustness of photoacoustic signals as a function of background; and the evaluation of the maximum imaging depth available. Furthermore, we demonstrated that we could, for the first time, evaluate two small animal photoacoustic imaging systems with distinctly different light delivery, ultrasound imaging geometries and center frequencies, using stable physical phantoms and directly compare the results from both systems.
Highlights
Photoacoustic imaging is an emerging modality that exploits the photoacoustic effect to combine the high contrast of optical imaging with the spatial resolution and penetration depth of ultrasound
The technique relies on the absorption of nanosecond laser pulses by tissue chromophores (either endogenous, or administered molecular imaging agent(s)), which produce an increase in temperature and a thermoelastic expansion; after propagating through the tissue, the broadband acoustic waves are detected using ultrasound receivers and images of the absorbed optical energy density can be reconstructed
Since acoustic waves are scattered far less than photons in tissue, photoacoustic signals can be detected at far greater depths than traditional optical imaging techniques, with depths of up to 7 cm reported in living subjects [1]
Summary
Photoacoustic imaging is an emerging modality that exploits the photoacoustic effect to combine the high contrast of optical imaging with the spatial resolution and penetration depth of ultrasound. Since acoustic waves are scattered far less than photons in tissue, photoacoustic signals can be detected at far greater depths than traditional optical imaging techniques, with depths of up to 7 cm reported in living subjects [1]. Our laboratory is currently pursuing photoacoustic molecular imaging for application in small animals, using both bespoke and commercial preclinical imaging devices, combined with novel contrast agents [2,3,4], and is actively involved in clinical translation of the technique, using a transrectal endoscopic photoacoustic device for prostate cancer diagnosis [5]. Physical phantoms for photoacoustic imaging are needed to [6]:
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
