Image intersification applied to biological problems

Abstract

In many important types of observations in biological research, the information provided by the specimens is in the form of photons-quanta of visible light, u.v., or X-rays. The process of observation becomes one of recording this information in useful form, with as high an efficiency as possible. The problem becomes particularly important when for some reason or other the total number or rate of quanta provided by the specimen is small. Examples of such limitations are included in the following: (i) Processes permitting only low-intensity illumination in order not to interfere with the biological processes under observation. (ii) Processes changing very rapidly and requiring rapid sequence recording. (iii) Processes providing only a limited number of photons per event, such as bioluminescence. (iv) Processes in which radioactive tracers are utilized, and observation of radioactivity is desirable at low specific activity or within short time intervals. (v) X-ray diffraction processes where the specimen is weakly diffracting or where the X-ray intensity must be kept low in order not to damage the specimen. (vi) Processes involving the observation of fluorescence, where the intensity is low because of limitations on the amount of tagging material.