472 



RADIOISOTOPES IN BIOLOGY AND AGRICULTURE 



Guinea pigs, blood collection, 147-148 

 blood and plasma space, 257 

 management requirements, 129 

 metabolism cages, 129-131 



Hafnium, summary, 250 



Hafnium (Hf*), summary, 250, 448 



Half-life, biologic, 429 



definition, 20, 439 



in double counting, 190 



effective, 431 



{See also individual isotopes) 



equations for, 19-22 



radioactive, definition, 20, 439 



of radiocontaminants, 446-451 



of radioisotopes for activation analysis, 

 416-418 

 Half -thickness (see Half- value layer) 

 Half-time of exchange, 434 

 Half-value layer, 434 



and needed absorber thickness, 93 



table for gamma rays, 94 

 Half-value time, 19 

 Hand-washing procedures, 99-100 

 Hardness (X rays), 434 

 Haversian systems, 343 

 Hazards, of external radiation, 89-91 



of internal radiation, 96-99 

 Health physics, 83, 434 



instrumentation for, 105-107 



laboratory rules, 108-111 

 Heavy water, 434 

 Hematocrit, whole-body, 12 

 Hemoglobin, labeled, 39, 263 

 Histologic methods, autoradiographic, 



328-331 

 Holdback agent, 434 

 Hoods, for carbon-14 work, 123 



gloved-box-type, 124 



for radioisotope work, 121-123 

 Hydrogen 3 (tritium), summary, 251- 



253, 448 

 Hydrolytic reagent, 370 



Immunological studies, 4 



Implant, 434 



Impurities {see Radioactive impurities) 



In vivo counting, with cattle, 193 



methods, 192-195, 256-257, 285, 289, 

 300, 303 

 In vivo studies, survey, 4-5 

 Indium, summary, 254 

 Indium (In*), summary, 254, 448 

 Induced radioactivity, 434 



(See also Radioactivation analysis) 

 infinite thickness, effect on C^-^ sensitiv- 

 ity, 225-226 



Infinite thickness, in self-absorption, 182 

 Inhalation and intratracheal dosage, 147 

 Injection, intramuscular, 144 

 intraperitoneal, 144 

 intratracheal, 146-147 

 intravenous, 144-147 

 subcutaneous, 144 

 Inorganic ions, radioactivation analysis, 



425 

 Inorganic separations by paper chroma- 

 tography, 375, 379-380 

 Insecticides, labeled methyl bromide, 215 

 movement, 4 



paper chromatography, 383 

 Insects, body-fluid circulation, 6 

 labeled. As*, 208 

 Ba*, 211 

 carbon-14, 223 

 Co'^o, Ra226, P32, Sr89, Zr^s, 3 

 Cu^", 243 

 Mn*, 266 



phosphorus-32, 279 

 strontium-89, 304 

 radiation effects of P^a, 69 

 Insensitive time (dead time), 430 

 Instrumentation, for continuous blood 

 counting, 194 

 for gamma counting, 188 

 for hard-beta counting, 187 

 for health physics, 105-107 

 internal counters, 186 

 for ion exchange, 391-393 

 needle counters, 195 

 for paper chromatography, 362-366 

 for paper electrophoresis, 373-375 

 probe counters, 195 

 for radiation protection, 105-107 

 for scanning chromatograms, 368 

 for soft-beta counting, 186 

 solution counting, 187 

 Integral dose (volume dose), 434 

 Integrating dose meter, 434 

 Intensitometer, 434 

 Intensity, 434 

 Interchange, 434 

 Internal counters, 186 



sensitivity for C^^, 225 

 Internal hazards, avoidance of, 98 

 radioactive, 96-99 

 radioisotope groups, 99 

 Internal radiation in tracer studies, 



66-71 

 Intramuscular injection, 144 

 Intraperitoneal injection, 144 

 Intratracheal injection, 146-147 

 Intravenous injection, 144-147 

 Inverse-square law, 93 

 Inversion autoradiography, 338 



