An iterative approach to the analysis of EM autoradiographs. I. The method.

An iterative scheme is described for determing the most appropriate "model" for dividing micrographs of EM autoradiographs into identified items of known relative specific activities in such a way that the dispersion of silver grains over the autoradiographs is fully and satisfactorily explained. A trial model is first set up for which, using a square matrix of estimates of notional cross-fire between the chosen items, a "solution" is obtained. The quality of the model is then tested using extended cross-fire data contained in rectangular matrix. If the model is shown to be unsatisfactory, an improved model (of tissue subdivision) is postulated and the whole process repeated until the model is deemed to be satisfactory. The computations are such that the data can be processed rapidly on the laboratory bench using a small machine. The logical estimation of errors is facilitated by this approach.