Progress in lung modeling by the ICRP task group
The Task Group has reviewed the data on: (a) morphology and physiology of the human respiratory tract; (b) inspirability of aerosols and their deposition in anatomical regions as functions of respiratory parameters; (c) clearance of particles within and from the respiratory tract; (d) absorption of different materials in the blood in humans and in animals. Evidence for evaluating the relative sensitivities of different tissues within the respiratory tract, and for defining cells at risk, has also been reviewed. On these grounds, the Task Group proposes a new model which predicts the deposition, retention and systemic uptake of materials, enabling doses absorbed by different respiratory tissues and other body organs to be evaluated. In the proposed model, clearance is described in terms of competition between the processes moving particles to the oropharynx or to lymph nodes and that of absorption into the blood. From studies with human subjects, characteristic rates and pathways are defined to represent mechanical clearance of particles from each region, which do not depend on the material. Conversely, the absorption rate is determined solely by the material: it is assumed to be the same in all parts of the respiratory tract and in other animal species. For several of the radiologically important forms of actinides, adsorption rates can be derived from animal experiments, or, in some cases, directly from human data. Otherwise, default values are used, based on the current D, W, and Y classification system. 22 refs., 14 figs., 1 tab.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6835757
- Report Number(s):
- PNL-SA-15781; CONF-880514-5; ON: DE88015934
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION
AEROSOLS
BODY
CLEARANCE
COLLOIDS
COMPARATIVE EVALUATIONS
DISPERSIONS
DOSE RATES
EXCRETION
FORECASTING
INHALATION
INTAKE
LUNG CLEARANCE
LUNGS
MATHEMATICAL MODELS
MORPHOLOGY
ORGANS
PHYSIOLOGY
RESPIRATORY SYSTEM
SOLS