Quantitative light microscopic autoradiography. Emulsion sensitivity and latent image fading.

Emulsion sensitivity, latent image fading, and the effects of temperature, humidity, radiation dose and chemography on them were measured for NTB2 autoradiographic emulsion using quantitative methods. Sensitivity of NTB2 emulsion increased as the temperature during exposure increased, with the greatest increase per degree occurring between -20 degrees C. At 4 degrees C, emulsion sensitivity remained constant with time and radiation dose. Direct measurement of latent image fading showed no latent image fading for 60 weeks on slides exposed at 4 degrees C with Drierite. Slides exposed at 27 degrees C showed significant latent image fading and great variation between samples. High humidity decreased emulsion sensitivity and increased latent image fading. No evidence of either positive or negative chemography was found. The practical use of autoradiography requires an internal standard on each slide to correct for fluctuations in temperature and humidity during exposure time.