Applied stochastic microdosimetry of internal alpha emitters

Conference · Tue Jul 01 04:00:00 EDT 1980

OSTI ID:6899529

Fisher, D R

Conventional dose averaging fails to account for the random nature of energy deposition in matter by ionizing radiation. Statistical fluctuations in localized dose are greatest for densely ionizing charged particles and small sensitive regions or sites in biological tissues. Biological end-points of irradiation are initially determined by microscopic energy deposition events occurring in cells or cell nuclei. Microdosimetry theory was developed to transcend the limitations imposed by absorbed dose and LET concepts by determining the probability density of specific energies imparted to biological sites for various types and distributions of radiation sources. Potential applications of stochastic microdosimetry in radiation protection are many. Computer methods were recently developed to facilitate calculation of the microdosimetry of internally-deposited radionuclides. For example, we are now able to determine the distribution of doses to single cells in vitro in solution with alpha-emitting particulates. Currently, we are calculating the microdosimetry of inhaled plutonium or other alpha emitters in the pulmonary lung. Our approach utilizes a newly-developed statistical model of the microdistribution of tissue, air space, and the epithelial nuclei in the mammalian lung. These studies should elucidate questions concerning the relative biological effectiveness of hot-spot versus uniformly-distributed activity.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6899529
• Report Number(s): PNL-SA-8321; CONF-800731-5; ON: DE83002683
• Country of Publication: United States
• Language: English

Related Subjects

560152 -- Radiation Effects on Animals-- Animals
61 RADIATION PROTECTION AND DOSIMETRY
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
655003* -- Medical Physics-- Dosimetry
ACTINIDES
ALPHA PARTICLES
ANIMALS
BODY
CHARGED PARTICLES
DISTRIBUTION
DOSIMETRY
ELEMENTS
IN VITRO
INTERNAL IRRADIATION
IRRADIATION
LUNGS
MAMMALS
METALS
MICRODOSIMETRY
ORGANS
PLUTONIUM
RADIATION PROTECTION
RADIONUCLIDE KINETICS
RESPIRATORY SYSTEM
STOCHASTIC PROCESSES
TISSUE DISTRIBUTION
TRANSURANIUM ELEMENTS
VERTEBRATES