Liquid to gas phase transition of dye-loaded PFC nanodroplets (nanobombs, NBs) can be facilitated by the optical absorption of energy of laser pulse. Activation of NBs with laser pulse can produce highly localized longitudinal shear waves (LSW). The advent of LSW elastography has enhanced the ability to measure depth-dependent tissue elasticity. Highly localized NB-induced LSWs propagate through the tissue depth and can discriminate the tissue elasticity gradients along the depth. In this study, we explore the capability of the NB-induced LSWs in discriminating the elasticity properties of multilayered tissue-mimicking phantoms. The NB present in the middle layer of the test phantoms produced LSWs upon the pulse laser excitation, which can provide elasticity information in the sample depth where the NBs are located and the elasticity of layers of the sample on top and bottom of the NB layer.
The heart is the first essential organ that develops during organogenesis. Fetal impaired heart function correlates to functional cardiac anomalies and heart defects in adulthood. Therefore, noninvasive assessment of dynamic functional cardiac events during pregnancy is essential for early diagnosis of cardiac diseases. However, visualization and analysis of the small yet fast-beating embryonic heart require a high-resolution imaging platform to provide reliable volumetric analyses. Optoacoustic (OA) imaging provides excellent optical contrast along with high spatial resolution and has demonstrated an exclusive potential for noninvasive deep-tissue visualization. In this study, we used volumetric OA imaging to visualize the embryonic heart at gestational day (GD) 16.5. The anatomical structure of the embryonic heart and cardiac vasculature was visualized in three orthogonal imaging planes allowing for further quantification and structural measurements. Twenty-five volumes per second temporal resolution of OA imaging enabled assessment of embryonic cardiac dynamics. Using the temporal profile of the time-lapse OA data at different locations of the embryonic heart, the average heart rate of embryos was calculated. This study demonstrated the capability of volumetric OA tomography for noninvasive visualization of the embryonic heart and assessment of cardio dynamics at nearly video rate.
Through chemical modification we developed higher photoacoustic yield molecular contrast agents that will likely enable deep tissue photoacoustic imaging. This talk will be on design and characterization of these contrast agents.
KEYWORDS: Luminescence, Photoacoustic spectroscopy, Absorption, In vivo imaging, Photoacoustic imaging, Tissue optics, Quantum efficiency, Tumors, Near infrared, Cancer
Photoacoustic imaging (PAI) is emerging as a key in vivo imaging technique. Endogenous contrast agents alone are insufficient to obtain high contrast images necessitating a need for synthetic exogenous contrast agents. In recent years a great deal of research has been devoted to the development of nanoparticle based contrast agents with little effort on molecular systems. Here we report on the design and evaluation of BODIPY inspired molecular photoacoustic contrast agents (MPACs). Through chemical modification of the established BODIPY fluorophore, increasing its vibrational freedom and appending with non-emissive functionalities, it is demonstrated that the S0-S1 absorbed excitation energy is redirected towards a nonradiative excited-state decay pathway. Optical and photoacoustic characterization of the modified BODIPY MPACs demonstrates a stronger photoacoustic signal compared to the corresponding fluorescent BODIPY probes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.