*** 96-61055 Mueller This Small Business Innovation Research Phase I project proposes an investigation of the new High-Speed CryoPower concept for magnetic resonance imaging (MRI) power systems, especially their gradient/radio frequency (RF) amplifiers. It introduces herewith a "new technology to reduce the cost of health care without reducing quality of care" by decreasing the equipment size, facilities and operating costs as well as the space requirements of this relatively new imaging modality. By cryogenically cooling the semiconductor devices used and combining them eventually with high temperature superconductors (HTS), substantial enhancements in performance can be expected. Superconductivity and low temperature superconducting magnets enabled Magnetic Resonance Imaging (MRI) thus making possible one of the most successful medical diagnostic tools. But unique high-speed cryogenic power electronics can do even more for the world-wide Public Health Service by drastically reducing the cost, size, weight and air-conditioning requirements of key and expensive power electronic components of an MRI system. In Phase I, a cryogenic miniature switchmode pulse-width modulation (PWM) gradient amplifier (300-600 V, 100-400 A) of high-efficiency will be constructed for a technical/economic assessment. A special and key feature will be high-speed PWM switching (200-500 kHz). MRI systems are uniquely suited for the first implementation of this new concept because (1) the cryogenics is already available, (2) the duty cycles are low, and (3) more gradient power is desirable in general and for angiography and fast-scan MRI in particular. The project has potential for commercial applications in various areas of power electronics. The new concept for Magnetic Resonance Imaging (MRI) systems will promote exports. Potential commercial applications include cost- and size-reduced MRI systems providing improved performance for lower-cost health care, mass screening, etc., especially in rural area s. ***
