PORTABLE NUCLEAR VENTRICULAR EJECTION FRACTION MONITOR

AN IMPORTANT GOAL OF THE NASA MEDICAL SCIENCES PROGRAM IS TO MAINTAIN THE HEALTH OF THE ASTRONAUTS BOTH BEFORE AND DURING THE SPACE MISSIONS. TWO OF THE MOST IMPORTANT CLINICAL PARAMETERS ARE THE LEFT AND RIGHT HEART EJECTION FRACTIONS. THESE PARAMETERS, WHICH ARE SO CENTRAL TO GOOD VASCULAR PERFORMANCE ARE ALSO ONES WHICH COULD BE STRONGLY EFFECTED BY THE STRESS AND GRAVITY EFFECTS OF THE FLIGHTS. RECENT PRELIMINARY STUDIES DEMONSTRATED THE POSSIBILITY OF CONSTRUCTING A PORTABLE NUCLEAR CARDIOLOGY VENTRICULAR FUNCTION MONITOR. THIS VESTLIKE DEVICE CAN MEASURE THE HEART OUTPUT ON A BEAT BY BEAT BASIS OVER AN EXTENDED PERIOD OF TIME AND STORE THE INFORMATION ON A MINIATURE CASSETTE FOR ANALYSIS. DESPITE SOME IMPRESSIVE DEMONSTRATIONS OF SUCCESS, THE IMPLEMENTATION OF THIS CONCEPT ENCOUNTERED SERIOUS DIFFICULTIES WITH THE NUCLEAR SENSOR AND ELECTRONICS MINIATURIZATION. THIS STUDY INVESTIGATES THE POSSIBILITY OF MAKING A MONITOR OF COMPACTNESS AND RUGGEDNESS SUFFICIENT FOR SPACE FLIGHT. IN PHASE I A VERY SENSITIVE, COMPACT, RUGGEDIZED, SOLID STATE, NUCLEAR PROBE IS DEVELOPED USING THE NEW LARGE AREA SILICON AVALANCHE PHOTODIODE. IN PHASE II THIS PROBE WOULD BE INCORPORATED INTO THE CONSTRUCTION OF A COMPACT FIELD PROTOTYPE CARDIAC MONITOR SUITABLE FOR RIGOROUS TESTING AT NASA MEDICAL FACILITIES.