Laser Optoacoustic Imaging System in Application for Cancer Diagnostics
A.Oraevsky (University of Texas Medical Branch, Galveston, TX, USA); A.A.Karabutov, V.G.Andreev (Moscow State University, Moscow, Russia); P.M.Henrichs (LaserSonix Technologies, TX, USA)
Principles of the optoacoustic tomography, current status of development of the Laser Optoacoustic Imaging System (LOIS) and its applications for cancer detection and characterization will be reviewed based on results of collaborative efforts at the University of Texas Medical Branch, LaserSonix Technologies Incorporated and Moscow State University. The optoacoustic tomography employs laser pulses for effectively generation of transient pressure in cancerous tissue and ultrawide-band ultrasonic transducers for sensitive detection of profiles of optoacoustic signals representing distribution of acoustic sources in tissues. The laser wavelength can be chosen for optimal tissue contrast and penetration depth in tissue. The main advantage of LOIS compared with conventional ultrasound is the enhanced optical contrast between tumors and normal tissue ranging from 200% to 600%. This contrast is defined primarily by increased concentration of deoxygenated blood in microcirculation network of cancerous tissue. Application of two colors of laser pulses matching peaks in optical absorption of oxy- and deoxy- hemoglobin permits differentiation of aggressive malignant tumors from benign lesions. Two modes of the optoacoustic detection, forward mode and backward mode, permit flexibility of the system design for each human organ. Applications of LOIS for cancer detection in the breast, prostate and digestive system will be discussed. Methods for optimization of the system parameters, such as resolution, field of imaging, sensitivity and accuracy of image reconstruction algorithms will be presented.
Section : 9