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Emerging Biomedical Imaging
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
The learning objectives are to help students to understand mathematically the physics principles governing the imaging techniques derived from photoacoustic effect and to introduce students to clinical situations that photoacoustic imaging may have potential usage.
Photoacoustic Neuroimaging
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Lihong V. Wang, Jun Xia, Junjie Yao
The photoacoustic effect, first discovered by Alexander Bell in 1880 (Bell 1880), refers to the formation of sound waves following light absorption in an object. The conversion of optical energy to acoustic energy allows visualization of deep tissue optical absorption with acoustically defined spatial resolution. Starting in the 1990s, with the advent of short-pulsed lasers and high-sensitivity ultrasound transducers, the photoacoustic effect began to be utilized for biomedical imaging (Kruger 1994, Karabutov et al. 1996, Oraevsky et al. 1997, Wang et al. 2002). In 2003, Wang et al. (2003a,b) reported the first functional photoacoustic tomography (PAT), which imaged hemodynamic response noninvasively in the rat brain. Since then, the field has been growing rapidly, and PAT is now becoming an important neuroimaging modality (Wang 2009, Hu and Wang 2010, Wang and Hu 2012, Xia and Wang 2013).
Oxygen Measurement
Published in Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod, The Primary FRCA Structured Oral Examination Study Guide 1, 2017
Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod
Photoacoustic spectroscopy: Based on the photoacoustic effect, which was discovered by Alexander Graham Bell in his search for a means of wireless communication.Photoacoustic effect is the conversion between light and sound waves.Materials exposed to non-visible portions of the light spectrum (i.e. infrared and ultraviolet light) can produce acoustic waves.By measuring the sound at different wavelengths, a photoacoustic spectrum of a gas sample can be recorded and used to identify the components within that sample.This effect can be used to study solids, liquids and gases.
A randomized, single-blind, study evaluating a 755-nm picosecond pulsed Alexandrite laser vs. a non-ablative 1927-nm fractionated thulium laser for the treatment of facial photopigmentation and aging
Published in Journal of Cosmetic and Laser Therapy, 2018
Monica Serra, Krista Bohnert, Neil Sadick
While the number of subjects was limited, and the 755 nm group received double the amount of treatments compared to the 1927 nm group, the data indicate that the new generation picosecond lasers can effectively target and treat photopigmentation and signs of aging, with minimal downtime. As picosecond laser energy results in a combined photothermal/photoacoustic effect to the tissue, the overall thermal damage to the tissue is reduced, accounting for less side effects. At the same time the energy absorption is great enough to stimulate pigment degradation and stimulation of neocollagenesis, which leads to its clinical effects (17).
Recent advances in ultrasound-triggered therapy
Published in Journal of Drug Targeting, 2019
Chaopin Yang, Yue Li, Meng Du, Zhiyi Chen
Photoacoustic imaging (PAI), a novel imaging modality based on photoacoustic effect, also shows great promise in biomedical applications. By converting pulsed laser excitation into ultrasonic emission, PAI combines the advantages of optical imaging and ultrasound imaging, which benefits rich contrast, high resolution and deep tissue penetration [132].