ABSTRACT
Of the various kinds of emanations from radioactive materials, photons alone have a range in tissue great enough to escape so that they can be detected externally. Electrons or beta-minus particles of high energy can create bremsstrahlung in interactions with tissue, but the radiation emanates from the site of the interaction, not the site of the beta ray’s production. Positrons or beta-plus particles annihilate with electrons to create gamma rays so that they can be detected (see Chap. 14). For certain radionuclides, the emanation being detected is x-rays, in the 50-to 100-keV energy range.
