Radiofrequency-induced Thermoacoustic Tomography
Radiofrequency-induced thermoacoustic tomography has been
explored to image biological tissue. Short radiofrequency pulses
irradiate tissue to generate acoustic waves by thermoelastic expansion.
The radiofrequency-induced thermoacoustic waves are detected with a
focused ultrasonic transducer.The time-domain signal from the ultrasonic
transducer represente a one -dimensional image along the acoustic axis
of the ultrasonic transducer, similar to an ultrasonic A-scan. Scanning
the system perpendicularly to the acoustic axis of the ultrasonic
transducer generates multi-dimensional images.
This imaging technique furnishes a new contrast mechanism. It is capable
of penetrating thick (several centimeters) biological tissues with less
than mm spatial resolution. Because cancer tissue and normal tissue
have very different responses, to radiofrequency, this technique has great
potential in early breast cancer diagnosis.
M. Pramanik, M. Swierczewska, D. Green, B. Sitharaman, and L. V. Wang, "Single-walled carbon nanotubes as a multimodal—thermoacoustic and photoacoustic—contrast agent,"
Journal of Biomedical Optics 14 (3), 03401801–08 (Jun. 2009). [PDF]
M. Pramanik, G. Ku, C. H. Li, and L. V. Wang, "Design and evaluation
of a novel breast cancer detection system combining both
thermoacoustic (TA) and photoacoustic (PA) tomography," Medical
Physics 35, 2218–2223 (Jun. 2008).[PDF]
G. Ku, B. D. Fornage, X. Jin, M.
Xu, K. K. Hunt, and L.-H. Wang, "Thermoacoustic and
photoacoustic tomography of thick biological tissues toward
breast imaging," Technology in Cancer Research and Treatment 4
(5), 559-566 (Oct. 2005).[PDF]
M. Xu and L.-H. Wang, "Universal
back-projection algorithm for photoacoustic-computed tomography,"
Physical Review E 71 (1): 016706 (Part 2, Jan. 2005).[PDF]
Y. Xu, L.-H. Wang, G. Ambartsoumian
and P. Kuchment, "Reconstructions in limited-view thermoacoustic
tomography," Medical Physics 31 (4), 724–733
M. Xu and L.-H. Wang, "Analytic
explanation of spatial resolution related to bandwidth and
detector aperture size in thermoacoustic or photoacoustic
reconstruction," Physical Review E 67 (5), 056605, 1-15 (May