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Zero‐Crossing Tracking Technique for Noninvasive Ultrasonic Temperature Estimation
Author(s) -
Ju Kuen-Cheng,
Liu Hao-Li
Publication year - 2010
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.2010.29.11.1607
Subject(s) - medicine , zero crossing , ultrasonic sensor , zero (linguistics) , tracking (education) , acoustics , radiology , electrical engineering , psychology , pedagogy , physics , voltage , linguistics , philosophy , engineering
Objective. The purpose of this study was to investigate the feasibility of a zero‐crossing tracking (ZCT) technique for temperature estimation using ultrasound images. Methods. The backscattered ultrasound radio frequency (RF) echo from a heated region experiences time shifts, which have been identified as causing a gross effect on sound speed changes and thermal expansion. The ZCT technique tracks the shifts in the zero‐crossing instants between preheated and postheated A‐lines to estimate the echo shifts caused by local temperature changes. Compared to the conventional cross‐correlation (CCR) technique, ZCT does not require intensive computational loadings for correlation operations; hence, the computational efficiency could be improved. Phantom experiments were performed to compare the results of temperature estimation by using the ZCT and CCR techniques. Results. The imaging probe was a commercial linear array, and a high‐intensity focused ultrasound transducer was used as a heating source. The acquired RF echo data were processed using the ZCT and CCR techniques. The estimation results of both techniques were similar. However, the ZCT technique yielded up to 7‐fold better computational efficiency than the CCR technique. Conclusions. The ZCT technique has the ability to monitor temperature changes with superior processing speed. This method could be an alternative signal‐processing technique for ultrasonic temperature estimation.