Optoacoustic Tomography

In vivo photothermal flow cytometry: Imaging and detection of individual cells in blood and lymph flow

“…Specifically, a PT deflection module with a position-sensitive photodetector is incorporated to measure bioflow velocity (PT velocimetry [Zharov et al, 2004a]), a PT thermolens module to measure integrated time-resolved PT responses from moving cells [Zharov and Lapotko, 2005], and a PTI module to image moving cells alone or with PT labels (e.g., gold nanoparticles) in combination with a thermolens or phase-contrast imaging technique [Zharov and Lapotko, 2005]. Also, a PA transducer or transducer array allows measurement of PA signals from single cells, either alone or with gold labels, in flow with focused laser beams, as well as measurement of PA signals from cells accumulated at specific sites (vessel wall, surrounding tissue, or specific organ) with a relatively broad laser beam using PA tomography schematics [Oraevsky and Karabutov, 2003].…”

High Sensitivity of In Vivo Detection of Gold Nanorods Using a Laser Optoacoustic Imaging System

“…4 In optoacoustic imaging, tissue is irradiated with a short laser pulse that can be selected at the near-infrared (NIR) region of the spectrum to enhance light penetration and probing of tissue. 5 Within most tissue, light-absorbing components such as hemoglobin of blood absorb photons, transfer energy in the form of heat to surrounding tissue, which then undergoes thermoelastic expansion, resulting in generation of acoustic waves that can be detected on the surface of the tissue using acoustic transducers operating in a wide ultrasonic frequency band.…”

“…By using an array of acoustic transducers and applying filtered back projection algorithms to the time-resolved optoacoustic signals, LOIS renders an image. 4,6 Like the contrast of conventional optical methods, optoacoustic contrast is dependent on the difference in the optical absorption of objects to render an image, but unlike conventional optical methods, it uses ultrasound waves to locate objects. Because ultrasound waves can travel through tissue with minimal scattering and attenuation, LOIS is capable of locating optically absorbing objects deep within tissue.…”

A 2.5-mm outer diameter photoacoustic endoscopic mini-probe based on a highly sensitive PMN-PT ultrasonic transducer

“…Photoacoustic endoscopy (PAE) [1][2][3][4] could be a useful clinical tool because it possesses many of the strengths of photoacoustic tomography (PAT) 1,[5][6][7][8][9][10] . PAT is a novel tomographic imaging technique that reveals optical absorptionbased image contrast by detecting acoustic waves induced by rapid optical absorption of target tissue, called the photoacoustic (PA) effect.…”