A portable cadmium telluride multidetector probe for cardiac function monitoring

A new nuclear stethoscope based on a matrix of small CdTe semiconductor det ectors has been developed for studying the cardiac performance by gamma ven triculography at the equilibrium in rest and stress conditions, in the earl y and recovery phases of the coronary disease and to follow the long-term t herapy. The light-weight probe consists of an array of 64 detectors 5 x 5 x 2 mm grouped in 16 independent units in a lead shielded aluminum box inclu ding 16 preamplifiers. The probe is connected to an electronic box containi ng DC power supply, 16 channel amplifiers, discriminators and counters, two analog-triggering ECG channels, and interface to a PC. The left ventricle activity is, preferentially, detected by using a low-resolution matching co nvergent collimator. A physical evaluation of the probe has been performed, both with static tests and dynamically with a hydraulic home-built model o f bearing heart ventricle paced by a rhythm simulator. The sum of the 16 de tectors activity provided a radiocardiogram (RCC) which well depicted the f illing and ejection of the cardiac beats, allowing to compare the clinicall y relevant parameters of the cardiac performance. proportional variables of the stroke volume (SV), ejection fraction (EF) and ventricular flow-rate w ith the known absolute values programmed on the model. The portable system is now in operation for clinical assessment of cardiac patients. (C) 1999 E lsevier Science B.V. All rights reserved.