COUNT-RATE STATISTICS OF THE GAMMA-CAMERA

The temporal distribution of decay events recorded by a gamma camera i n 'list mode' differs from the Poisson distribution because of dead-ti me effects. We propose a new model for the dead-time behaviour of a ga mma camera. The most important feature of our model is that the loss o f events occurs in pairs or higher multiples due to the so-called 'pil e-up' effect. We analyse the consequences of pile-up for the temporal distribution of events recorded by a gamma camera. The probability dis tribution for the time intervals between events recorded by the camera is calculated from first principles. We construct estimators for the parameter of the new distribution. We distinguish between the estimati on of the total count tate and the estimation of a certain subset of t he total count rate. Computer simulation confirms that our estimators are less influenced by dead-time effects than the standard estimator.