DocumentCode :
1422290
Title :
Two-dimensional temperature estimation using diagnostic ultrasound
Author :
Simon, Claudio ; VanBaren, Philip ; Ebbini, Emad S.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
Volume :
45
Issue :
4
fYear :
1998
fDate :
7/1/1998 12:00:00 AM
Firstpage :
1088
Lastpage :
1099
Abstract :
A two-dimensional temperature estimation method was developed based on the detection of shifts in echo location of backscattered ultrasound from a region of tissue undergoing thermal therapy. The echo shifts are due to the combination of the local temperature dependence of speed of sound and thermal expansion in the heated region. A linear relationship between these shifts and the underlying tissue temperature rise is derived from first principles and experimentally validated. The echo shifts are estimated from the correlation of successive backscattered ultrasound frames, and the axial derivative of the accumulated echo shifts is shown to be proportional to the temperature rise. Sharp lateral gradients in the temperature distribution introduce ripple on the estimates of the echo shifts due to a thermo-acoustic lens effect. This ripple can be effectively reduced by filtering the echo shifts along the axial and lateral directions upon differentiation. However, this is achieved at the expense of spatial resolution. Experimental evaluation of the accuracy (0.5/spl deg/C) and spatial resolution (2 mm) of the algorithm in tissue mimicking phantoms was conducted using a diagnostic ultrasound imaging scanner and a therapeutic ultrasound unit. The estimated temperature maps were overlaid on the gray-scale ultrasound images to illustrate the applicability of this technique for image guidance of focused ultrasound thermal therapy.
Keywords :
biomedical ultrasonics; biothermics; echo; radiation therapy; temperature distribution; temperature measurement; HIFU; RF echo; algorithm; backscattered ultrasound; diagnostic ultrasound imaging scanner; focused ultrasound thermal therapy; thermo-acoustic lens; tissue mimicking phantom; two-dimensional temperature distribution; Filtering; Gray-scale; Imaging phantoms; Lenses; Medical treatment; Spatial resolution; Temperature dependence; Temperature distribution; Thermal expansion; Ultrasonic imaging;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/58.710592
Filename :
710592
Link To Document :
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