Performance characteristics of a microreflectometer for measuring autoradiographic grain density

Abstract

An incident light microphotometer for measuring reflectance has been constructed from Wild M20 microscope components and Photovolt 520-M photometer. The instrument measures autoradiographic silver grain densities in either small regions (5-30 pm diameter) or large regions (25-150 pm diameter) with an accuracy of greater than 900b compared to visual grain counts. Grain density measurements can be made in the presence of histological stains. The device speeds the collection of autoradiographic data by a factor of 10 or more, and can be used for 6 or 7 h per day without producing significant strain on the operator.

Chemical microscopy

“…Two papers, one by Entingh (78) and one by Haas (133), are concerned with the use of microeflectometer and a scanning densitometer, respectively, for measuring autoradiogram densities.…”

“…Autoradiography. See under Methods of Microscopy, Microphotometry and Microspectrophotometry (78,133) and Polarized Light Microscopy (115).…”

Quantitative evaluation of autoradiographs by X‐ray spectroscopy

“…The quantitative evaluation of biological autoradiographs is based essentially on the procedure of grain density analysis (Rogers, 1973; Salpeter & McHenry, 1973), reflected-light photometry (Rogers, 1973(Rogers, , 1974 Entingh, 1974), or microdensitometry (Goldstein & Williams, 1971 ;Rogers, 1973). A little explored, though potentially interesting quantitative procedure for autoradiography is the use of X-ray microanalysis for measuring the mass of developed silver present over different regions of a specimen.…”