Real-time measurement of cardiac stroke volume using Compton backscattered X-rays

A technique which uses Compton backscattered X-rays to provide real-time measurements of stroke volume and cardiac output in the isolated working rat heart preparation is presented. A basic system was assembled and tested on mechanical models. Six isolated rat hearts were studied. Preliminary work shows that this X-ray backscatter detection system responds in a highly linear fashion and can detect rapid (>4 Hz) and small amplitude (<0.1 ml) changes in volume in the isolated and perfused rat heart. The amplitudes of the dynamic backscatter waveforms generally correlate well with directly measured stroke volumes and cardiac output.<
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