Cylindrical diameters method far calibrating section thickness in serial electron microscopy

An estimate of section thickness is required for measuring structures in se rial section microscopy, Mean section thickness is estimated reliably by av eraging the ratios of the diameters of cylindrical objects, such as mitocho ndria, to the number of sections they span. This cylindrical diameters meth od improves the accuracy of section thickness as inferred from the colour o f sections floating in water. The cylindrical diameters method gives the sa me answer as that obtained by the minimal folds method. It is preferable be cause it can be done in a series that has no folds that can distort and obs cure the objects that are being measured.