A photoacoustic tomography system for imaging of biological tissues

Abstract

Non-invasive laser-induced photoacoustic tomography (PAT) is a promising imaging modality in the biomedical optical imaging field. This technology, based on the intrinsic optical properties of tissue and ultrasonic detection, overcomes the resolution disadvantage of pure-optical imaging caused by strong light scattering and the contrast and speckle disadvantages of pure ultrasonic imaging. Here, we report a PAT experimental system constructed in our laboratory. In our system, a Q-switched Nd : YAG pulse laser operated at 532 nm with a 8 ns pulse width is used to generate a photoacoustic signal. By using this system, the two-dimensional distribution of optical absorption in the tissue-mimicking phantom is reconstructed and has an excellent agreement with the original ones. The spatial resolution of the imaging system approaches 100 µm through about 4 cm of highly scattering medium.

Variation of the critical feedback level in a 1550nm quantum-dash Fabry-Perot semiconductor laser

“…1, the square of the resonance frequency is plotted as function of the output power (open circles) for the device under study. The experimental dependence of the relaxation oscillation frequency shows a deviation from the expected proportionality on the square root of the optical power, which can be curve-fit to express the gain compression 8 . In this case, the curve-fit leads to a P sat a 17mW and H P a 0.06mW -1 .…”

Simulation study on sensitive detection of small absorbers in photoacoustic tomography

“…The experimental setup in our lab for 2-D photoacoustic imaging is the same as that in the previous paper 8 . A program controls the scanning of the transducers and the data acquisition according to the following sequence: firstly, start the step motor to move the transducers to the designated position, and wait for one second before acquisition to avoid the vibration of transducer; secondly, fire the laser and trigger the data acquisition; thirdly, average the time-dependant signals on the oscilloscope to improve the SNR; finally, save the time-dependent data at this scanning stop.…”

Photoacoustic response of a common starfish tissue

“…In its turn, photoacoustic (PA) spectroscopy is a very powerful tool in investigating interaction of electromagnetic radiation with biological systems [1][2][3][4]. Electronic transitions due to radiation absorption can initiate radiative and non-radiative processes.…”

“…Photoacoustic response of a common starfish tissue 1,2 Guskos N., 2 Majszczyk J., 2 Typek J. , 3 Rybicki J. and 4,5 Padlyak B.…”