DTIC ADA444735: Exploratory Studies of Magnetic Resonance pdf

DTIC ADA444735: Exploratory Studies of Magnetic Resonance

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The goal of this exploratory project was to demonstrate the feasibility of MR (magnetic resonance) detection of thermoelastically generated tissue motion resulting from localized absorption of pulsed microwave power. All of the instrumentation and software control necessary to deliver high power (4 KW) short-duration on (1*s) pulses of continuous 434 MHz RF power synchronized to the MR repetition rate (TR) of the acquisition sequence has been realized. Phantom studies consisting of local absorbers with biologically relevant electromagnetic properties and contrast have been completed which illustrate that displacements of 1-2*m can be generated from the absorption of the pulsed microwave power. MR detection of this small amplitude motion is also evident. although recordings are not sufficiently robust at present because the background motion caused by the natural vibrations of the scanner is much larger creating clutter which makes the microwave induced displacements difficult to detect because they are very near the noise floor of the MR measurement scheme used

• Creator/s: Defense Technical Information Center
• Date: 10/1/2004
• Year: 2004
• Book Topics/Themes: DTIC Archive, Paulsen, Keith D, DARTMOUTH COLL HANOVER NH, *ELECTROMAGNETIC PROPERTIES, *MAGNETIC RESONANCE, *RADIOFREQUENCY POWER, *THERMOELASTICITY, *RADIOLOGY, *BREAST CANCER, COMPUTER PROGRAMS, HIGH POWER, MEASUREMENT, MOTION, INSTRUMENTATION, ABSORPTION, NOISE, ABSORBERS(MATERIALS), MICROWAVES, DISPLACEMENT, VIBRATION, REPETITION RATE

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