Geometrical factors in the cardiac nuclear probe

The design of the collimator for the assessment of left ventricular function with a non-imaging detector is considered. When certain simplifying assumptions are made concerning the distribution of the background and the ventricular activity, the statistical variation in the calculated ventricular count rate is examined for various detector-collimator combinations. For detectors with sufficient diameter to give reasonably low counting errors it is shown that the focused multihole type of collimator is preferable and the optimum parameters of this are given. It is shown that when the simplifying assumptions are relaxed there is still a preference for the use of a focused multihole collimator.