Table 1.1-— RELATION OF PARTICLE SIZE TO ORGAN DEPOSITION OF INHALED RADIOACTIVE SILICEQUS DUST IN FEMALE DUTCH RABBITS*¢ particle Beta-gamma activity! above background, d/sec size of dusts u Lungs Stomach 0.47 $.00 13.9 370.0 47,4 33380 9.00 49.9 Small intestine Caecum Large intestine $1.6 31.4 wd 7080 All values represent the mean from four separate azimals exposed simultaneously. All animals were given a single 4-Ar head exposure to the dust and were sacrificed 0 to 1 hr later, $Dust concentration used wae 2 x 10° d/min/m’, @Values shows for beta-gammsa activity were determined from ashed: spectmens of whole organs. Table {.2-—-RATE OF REMOVAL OF PRODIGIOSIN DUST* FROM LUNGS OF NORMAL AND X- IRRADIATED RABBITS Time of Micrograms of prodigiosin per gram of lung tisauet determination (after dust exposure), hr Normal rabdites 0 24 4.0 1.0 32 0.0 48 Irradiated rabbits (7 daye after 800-r whole-body radiation’) ’ 0.6 23 8.0 0.25 0.0 0.0 *Denaity of prodigtosia dust = 1.0, tEach value represente the mean from gix separate antmale. 2250-kvp X-raye having a beam with « half-value layer of 1.98 mm of copper, 160 SESS ; 7 er ee AP ioe Cra oy FF s AE nna, neee ¢ ites Les rr eae f wat .* evars Se ? ~ me 7%) we wwe” ~ -

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