Beta-emitting Radionuclides Research Articles

Radiation-Induced Pulmonary Fibrosis: Study of Changes in Collagen Constituents in Different Lung Regions of Beagle Dogs after Inhalation of Beta-Emitting Radionuclides

Pulmonary collagen turnover (synthesis, degradation, and accumulation) was studied in 40 dogs injured by inhalation exposure to ${}^{90}{\rm Y}$ ( $T_{{\textstyle\frac{1}{2}}}{\rm eff}$ 2.6 days, Ē = 0.9 MeV), ${}^{91}{\rm Y}$ (50 days, 0.59 MeV), ${}^{144}{\rm Ce}$ (170 days, 1.29 MeV), or90 Sr (370 days, 1.13 MeV) in fused aluminosilicate particles. Cerium-144 and90 Sr in fused particles produced more uniform patterns of pulmonary damage than did ${}^{90}{\rm Y}$ or ${}^{91}{\rm Y}$ in fused particles. Fibrosis was more severe in the intermediate than in the peripheral or hilar regions of the lungs of dogs exposed to ${}^{90}{\rm Y}$ in fused particles. That observation was consistent with the relatively greater radiation dose delivered to the peribronchiolar region during the early clearance of ${}^{90}{\rm Y}$. Collagen synthesis and degradation responses in the peripheral and hilar regions of animals exposed to ${}^{91}{\rm Y}$ and in the intermediate area of90 Sr indicated the presence of previously...

Acute Toxicity of Beta-Emitting Radionuclides That May Be Released in a Reactor Accident and Ingested

Suckling, weanling, and adult rats received /sup 106/Ru--/sup 106/Rh by gavage and adult beagle dogs ingested /sup 106/Ru--/sup 106/Rh to determine the toxicity of this high-energy (1.4 MeV av) ..beta..-emitting nuclide pair. The LD/sub 50/'s for suckling, weanling, and adult rats were 1.5, 18, and 9.0 mCi/kg, respectively. Adult rats were given /sup 147/Pm by gavage to determine if a low-energy (0.06 MeV av) ..beta.. emitter could also cause death by damaging the bowel. The LD/sub 50/ of /sup 147/Pm in rats was about 5 Ci/kg. The calculated radiation doses absorbed in the target cells at the LD/sub 50/ level were approximately the same for the two radionuclides (3500 rad), although the doses at the mucosal surface differed widely. The LD/sub 50/ for /sup 106/Ru--/sup 106/Rh in dogs was about 3.5 mCi/kg. Dosimeters placed beneath the mucosa in dogs indicated that the radiation dose to the target cells that caused death from /sup 106/Ru--/sup 106/Rh was about the same as it was for rats. The signs of intestinal injury, their duration, and the probabilities of tissue repair were much different in the dog than in the rat. The midcolon and lower colon of dogs were usually denuded at focal sitesmore » after ingestion of 2.5 to 4.0 mCi/kg, and frequently that damage was irreversible. The fatal consequence of severe mucosal damage was averted in two dogs by colectomy and an ileorectal anastomosis.« less

Liquid scintillation alpha counting and spectrometry and its application to bone and tissue samples: [formula omitted], Chemical Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830.

The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1 – absence of effects (stress recognition), 2 – activation (adaptive response), and 3 – inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure.

Altered Collagen Metabolism in Radiation-Induced Interstitial Pulmonary Fibrosis

Pulmonary fibrosis is an end-stage result of diverse forms of lung injury which may result from many occupational injuries or environmental pollutants. Pulmonary irradiation has been shown to cause lung fibrosis. Proposed construction of additional light water and breeder reactors for our nation’s energy future will greatly increase the worldwide inventories of radionuclides. The most likely route of internal deposition of radionuclides in man is through inhalation exposure, creating a potential health hazard at both industrial and environmental levels. 1 McClellan RO Barnes JE Boecker BB et al. Toxicity of beta-emitting radionuclides inhaled in fused clay particles –An experimental approach. in: Nettesheim P Hanna Jr, MG Deatherage Jr, JW Morphology of Experimental Respiratory Carcinogenesis. USAEC Symposium Series No. 21 (CONF-700501). December 1970: 395-415 Google Scholar Initially, this fibrosis represents a reparative process; however, excessive deposition of connective tissue can cause serious physiologic dysfunction. A better understanding of the pathogenesis of pulmonary fibrosis may ultimately lead to improved preventive measures and better treatment of fibrosis.

Calculated beta-ray dose factors for trabecular bone

Mean dose factors have been calculated for those tissues in bone that are relevant to the induction of late irradiation effects; namely, red bone marrow and endosteal tissues lining trabecular bone surfaces. The calculations are based on a Monte Carlo computer method for beta-emitting radionuclides which are distributed uniformly throughout the volume of mineralized bone. Results are given for the radionuclides 14C, 45Ca, 22Na, 18F, 32P, 90Y and 90Sr+90Y (all considered for this purpose as volume-seekers) for seven bones from the adult human skeleton and calculations are also presented of average skeletal dose factors. Where possible, results are compared with those derived from other methods based on simple geometrical models.

Biological detection of reduction in dose at the surface of volume sources containing beta emitters

Dosimetry theory related to volume sources containing uniformly distributed beta-emitting radionuclides predicts a rapid drop in dose at the outer surface to approximately one half of the maximum dose within the volume. Rats were injected with radiocolloids of either 198Au, 113Inm or 99Tcm, to produce liver irradiation from their decay, or their livers were treated with external X-irradiation. After irradiation, a portion of the liver was surgically removed to stimulate cell division in the liver remnant revealing radiation damage in the form of chromosomal aberrations. The percentages of dividing cells with bridges were scored in the outer edges (0.45 mm) of the tissue sections and were compared to levels obtained from the central portion of the liver lobe. No significant difference was observed with X-irradiation or from 99Tcm irradiation. However, irradiation with 198Au and 113Inm (which emit large numbers of energetic electrons) produced significantly fewer aberrations in the outer layer when compared with the central portion.

The Effects of Inhaled 90 Y Fused Clay Aerosol on Pulmonary Function and Related Parameters of the Beagle Dog

Nine Beagle dogs were exposed to aerosols of ${}^{90}{\rm Y}$ in fused clay and examined serially using pulmonary function, clinical, and radiographic evaluations to better describe the pathogenesis of pulmonary damage resulting from the inhalation of beta-emitting radionuclides. The inhalation exposure resulted in initial lung burdens (ILB) of 390 to 920 μCi ${}^{90}{\rm Y}/{\rm kg}$ body weight and cumulative doses to the lung of 4900 to 12,000 rads. The evaluation of pulmonary function included measurements of ventilation, lung mechanics, gas exchange, and parameters obtained under the stresses of treadmill exercise and added external respiratory dead space. Functional alterations appeared in all exposed dogs at approximately 8 wk postinhalation exposure and the severity and rapidity of progression of dysfunction was related to dose. Early functional impairments included defects in the distribution of ventilation and in alveolar-capillary gas exchange. Later, t...

The determination of plutonium-241 in effluents

A method is described for the simultaneous determiantion of plutonium-241 and plutonium alpha-activity. The plutonium is isolated by coprecipitation on barium sulphate followed by extraction into di(2-ethylhexyl)-phosphoric acid, which is incorporated in a liquid scintillator for counting in a liquid scintillation spectrometer. Interferences from alpha- and beta-emitting radionuclides are studied together with interferences from non-radioactive elements. The lower limit of detection is in the region of 1 pCi.

Beta spectrum analysis: a new method to analyze mixtures of beta-emitting radionuclides by liquid scintillation techniques

A description is given of a method to couple a liquid scintillation spectrometer to a multichannel pulse-height analyzer to record beta spectra simultaneously with three different energy ranges. Spectra of tritium, carbon-14 and phosphorus-32 recorded by this method are presented. Analyses of the beta spectra are performed by a least-squares technique, and the results are shown in tabular form.

A continuously monitored recirculating perfusion system for measuring intestinal absorption.

A system was developed for the continuous and simultaneous measurement of water and nutrient (or electrolyte) absorption from the intestine. A recirculating loop (with a reservoir) was kept moving by means of two peristaltic pumps. Water was quantitated by means of a chromogenic nonabsorbed marker and a spectrophotometer. The nutrient (or electrolyte) was present in radiolabeled form and was quantitated by means of a gamma-ray detector. Use of the system was illustrated by the study of22NaCl and75Se-l-selenomethionine. By utilization of a suitable detector, beta-emitting radionuclides may also be used in the perfusing fluid.

A versatile two-element low-background flow-type beta-counter

The use of a simple two-element Geiger counter, for a sensitive measurement of beta activity of solid sources, is discussed. The counter provides information simultaneously on the number of beta-particles which are absorbed in traversing a given thickness of absorber, as well as those which have sufficient energy to emerge through the absorber. These counting rates suffice to determine the maximum energy of the beta-particle if the source contains a pure beta-emitting radionuclide. If the source contains a mixture of two known beta-emitting radionuclides of significantly different E max-values, this information also suffices to determine the individual disintegration rates of the two nuclides.