Development of Kinetic and Anatomical Models for Brain Dosimetry for Internally Deposited Radionuclides-0B5B6F33

This Commentary examines current information on the accumulation, distribution, and retention of radionuclides in the brain and the extent to which that information can be used to improve estimates of dose to potentially radiosensitive regions of the brain from internal emitters, with emphasis on high linear-energy transfer alpha particle-emitting radionuclides. Dose estimates for the brain based on explicit brain models reflecting best available biokinetic data are compared with estimates based on the brain models typically used in radiation protection and dose reconstruction. The comparisons indicate that predictions of brain doses based on current models for radionuclides may substantially underestimate or overestimate brain dose projections based on an explicit brain model reflecting best available biokinetic data. Potential improvements in dose estimates for the brain based on more detailed dosimetric models of the brain are also examined. Improved estimates of radiation doses to brain based on more realistic biokinetic and dosimetric representations of the brain would be an important step forward in ongoing epidemiologic research aimed at evaluating dementia, Alzheimer’s, Parkinson’s, motor neuron diseases and cognitive impairment as possible adverse effects of radionuclide depositions in the brain.