SEP 14, 2019 11:10 AM PDT

What is Photoacoustic Imaging?

WRITTEN BY: Daniel Duan

In the last decade, photoacoustic tomography has slowly emerged as a versatile, radiation-free imaging modality that bears great potentials for basic research and clinical diagnostic applications.

Its underlying principle is the photoacoustic effect—sound waves arise following light absorption in a material. 

To use this imaging method, a technician illuminates the tissue of interest with a short-pulse, non-ionizing laser at close proximity. Chromophores within the tissue absorb the photonic energy of specific wavelengths and start to vibrate. The vibration of these molecules causes the expansion of the tissue structure, which can generate acoustic waves for detection.

These acoustic signals are in the ultrasound range, which allows them to propagate through several thin layers of tissues with minimal scattering, and get detected by a tomographic array. Image-reconstructing programs with advanced algorithms convert the detected signals 2-dimensional or even 3-dimensional images, providing researchers or physicians anatomy and pathology information about the examined tissue.

Different chromophores, such as deoxygenated hemoglobin and its oxygenated counterpart, have distinct absorption profile with wavelength-dependent strength in response to multi-spectral laser pulses. 

On top of the two forms of hemoglobin, photoacoustic imaging can also detect melanin, lipid, collage, water, and contrast agents specifically designed to locate various biomarkers.

Source: Seeker

About the Author
Master's (MA/MS/Other)
Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
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