HYDROACOUSTICS
ANNUAL JOURNAL |
START | NEW VOL 20 | SEARCH | STATISTICS | PAS - GDANSK DIVISION |
pp. 219-228, vol. 19, 2016 Piotr Karwat Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland Tamara Kujawska Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland Wojciech Secomski Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland Barbara Gambin Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland Jerzy Litniewski Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland Key words: HIFU; echo phase shift; parametric imaging; velocity/brightness CNR Abstract: Therapeutic and surgical applications of High Intensity Focused Ultrasound (HIFU) require monitoring of local temperature rises induced inside tissues. It is needed to appropriately target the focal plane, and hence the whole focal volume inside the tumor tissue, prior to thermo-ablative treatment, and the beginning of tissue necrosis. In this study we present an ultrasound method, which calculates the variations of the speed of sound in the locally heated tissue. Changes in velocity correspond to temperature change. The method calculates a 2D distribution of changes in the sound velocity, by estimation of the local phase shifts of RF echo-signals backscattered from the heated tissue volume (the focal volume of the HIFU beam), and received by an ultrasound scanner (23). The technique enabled temperature imaging of the heated tissue volume from the very inception of heating. The results indicated that the contrast sensitivity for imaging of relative changes in the sound speed was on the order of 0.06%; corresponding to an increase in the tissue temperature by about 2°C.
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