MOVEMENT-DETECTION SYSTEM FOR PET SCANNERS

DURING A POSITRON EMISSION TOMOGRAPHY (PET) SCAN, MOVEMENT BY THE SUBJECT OF MORE THAN 1 MM WILL CAUSE NOTICEABLE BLURRING OF THE IMAGE. MOVEMENT WILL ALSO CAUSE ARTIFACTS TO BE INTRODUCED INTO THE IMAGE BECAUSE THE MATRIX FOR CORRECTING FOR GAMMA-RAY ABSORPTION IS DETERMINED FOR A SPECIFIC POSITION. THIS PROPOSAL OUTLINES THE DEVELOPMENT OF A MOVEMENT-DETECTION SYSTEM USING A SMALL ARRAY OF ULTRASONIC TRANSDUCERS THAT TRAIN NARROW BEAMS OF ULTRASOUND ON SELECTED AREAS ON THE SUBJECT IN THE IMAGE VOLUME. MOVEMENTOF THE SUBJECT FROM THE INITIAL POSITION WILL BE DETECTED BY MEASURING THE CHANGE IN TRANSIT TIME OF THE SOUND REFLECTED BACK TO THE TRANSDUCERS. IF MOTION EXCEEDING THE PRESET ACCEPTABLE AMOUNT OCCURS, THE SYSTEM WILL AUTOMATICALLY STOP DATA ACQUISITION AND DISPLAY THE DISPLACEMENTS FOR EACH TRANSDUCER, SO THAT THE OPERATOR CAN MOVE THE SUBJECT BACK INTO POSITION BEFORE RESUMING DATA ACQUISITION. THIS MOVEMENT-DETECTION SYSTEM WILL ALLOW MOREEFFICIENT USE OF THE EXPENSIVE PET SYSTEMS, INSURE BETTER IMAGING, AND HELP ELIMINATE REPEAT INJECTION OF THE SUBJECT WITH RADIOACTIVE ISOTOPES.