Back to back autoradiography: a method for ultrastructural analysis of light microscopic autoradiographs.

A method for studying radiolabeled cells is described that combines the simplicity of light microscopic autoradiography with the high resolution of electron microscopy. Serial thin (600 A) and thick (1 micron) sections are placed on Formvar-coated slot grids and glass slides, respectively. Labeled cells are visualized on the thick section by autoradiography and may then be studied in the electron microscope by locating the corresponding fields on the grid. This technique permits accurate ultrastructural identification and analysis of radiolabeled cells, yet avoids the need for electron microscopic autoradiography.