Methods of improving brain dose estimates for internally deposited radionuclides .

Autor:	Leggett RW; Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6038, United States of America., Tolmachev SY; Washington State University, Richland, WA, United States of America., Avtandilashvili M; Washington State University, Richland, WA, United States of America., Eckerman KF; Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6038, United States of America., Grogan HA; Cascade Scientific, Bend, OR, United States of America., Sgouros G; The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America., Woloschak GE; Northwestern University Chicago, Chicago, IL, United States of America., Samuels C; Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6038, United States of America., Boice JD Jr; National Council on Radiation Protection and Measurements, Bethesda, MD, United States of America.; Vanderbilt University, Nashville, TN, United States of America.
Jazyk:	angličtina
Zdroj:	Journal of radiological protection : official journal of the Society for Radiological Protection [J Radiol Prot] 2022 Jul 21; Vol. 42 (3). Date of Electronic Publication: 2022 Jul 21.
DOI:	10.1088/1361-6498/ac7e02
Abstrakt:	The US National Council on Radiation Protection and Measurements (NCRP) convened Scientific Committee 6-12 (SC 6-12) to examine methods for improving dose estimates for brain tissue for internally deposited radionuclides, with emphasis on alpha emitters. This Memorandum summarises the main findings of SC 6-12 described in the recently published NCRP Commentary No. 31, 'Development of Kinetic and Anatomical Models for Brain Dosimetry for Internally Deposited Radionuclides'. The Commentary examines the extent to which dose estimates for the brain could be improved through increased realism in the biokinetic and dosimetric models currently used in radiation protection and epidemiology. A limitation of most of the current element-specific systemic biokinetic models is the absence of brain as an explicitly identified source region with its unique rate(s) of exchange of the element with blood. The brain is usually included in a large source region called Other that contains all tissues not considered major repositories for the element. In effect, all tissues in Other are assigned a common set of exchange rates with blood. A limitation of current dosimetric models for internal emitters is that activity in the brain is treated as a well-mixed pool, although more sophisticated models allowing consideration of different activity concentrations in different regions of the brain have been proposed. Case studies for 18 internal emitters indicate that brain dose estimates using current dosimetric models may change substantially (by a factor of 5 or more), or may change only modestly, by addition of a sub-model of the brain in the biokinetic model, with transfer rates based on results of published biokinetic studies and autopsy data for the element of interest. As a starting place for improving brain dose estimates, development of biokinetic models with explicit sub-models of the brain (when sufficient biokinetic data are available) is underway for radionuclides frequently encountered in radiation epidemiology. A longer-term goal is development of coordinated biokinetic and dosimetric models that address the distribution of major radioelements among radiosensitive brain tissues. (© 2022 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights reserved.)
Databáze:	MEDLINE
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