Title :
Non-invasive in-vivo temperature mapping of ultrasound heating using fluorine-based magnetic resonance imaging agents
Author :
Webb, A.G. ; Smith, N.B. ; Ellis, D.S. ; O´Brien, William D., Jr.
Author_Institution :
Magnetic Resonance Eng. Lab., Illinois Univ., Urbana, IL, USA
Abstract :
The aim of this study was to investigate the feasibility of using fluorine based magnetic resonance to measure accurately hepatic heating from a focused ultrasound transducer in rats. This new method uses the temperature dependence of the difference in fluorine chemical shifts within a single molecule to provide internal compensation for complicating physiological effects. Female Sprague-Dawley rats were exposed to 5 minutes of CW irradiation at 1.37 MHz from a focused transducer. Theoretical calculations based on the monopole source solution to the bio-heat transfer equation gave a volume-averaged temperature rise of 2.1°C. Preliminary experiments using protein encapsulated perfluorooctylbromide targeted to the liver gave an empirical rise of 2.0±0.4°C
Keywords :
biomedical NMR; biomedical ultrasonics; chemical shift; fluorine; hyperthermia; liver; temperature measurement; 1.37 MHz; 5 min; F; bioheat transfer equation; complicating physiological effects; female Sprague-Dawley rats; fluorine chemical shifts; fluorine-based magnetic resonance imaging agents; focused ultrasound transducer; hepatic heating; monopole source solution; noninvasive in-vivo temperature mapping; protein encapsulated perfluorooctylbromide; ultrasound heating; volume-averaged temperature rise; Chemicals; Equations; Heating; Magnetic resonance; Proteins; Rats; Temperature dependence; Ultrasonic imaging; Ultrasonic transducers; Ultrasonic variables measurement;
Conference_Titel :
Ultrasonics Symposium, 1995. Proceedings., 1995 IEEE
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-2940-6
DOI :
10.1109/ULTSYM.1995.495863
