Relative biological effectiveness for induction of cancer by protracted alpha versus beta internal irradiation

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Health Physics

OSTI ID:393931

Raabe, O G ^[1]

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1. Univ. of California, Davis, CA (United States)

Three-dimensional dose-rate/time/ response mathematical surfaces describe radiation effects in lifetime studies of beagles after Intake by injection or inhalation of selected radionuclides (including {alpha}-emitters {sup 226}Ra, {sup 239}Pu, {sup 238}Pu, and {sup 241}Am and {Beta}-emitters {sup 90}Sr, {sup 91}Y, and {sup 144}Ce) and in people after intake of {sup 226}Ra. For each effect t{sub m}=K{sub m}d{sup -s}, where t{sub m} is the median elapsed time to death with the specified effect after intake, d is the time-weighted average absorbed radiation dose-rate to the target organ, K{sub m} is the median distribution coefficient, and s is the negative slope parameter. Using maximum likelihood survival regression methods, for fatal cancer induction s was found to be one-third for {alpha} radiation and two-thirds for {beta} radiation. Because the slopes of the response curves for high LET {alpha} emitters differ from those for the low LET {Beta} emitters, the observed relative biological effectiveness, RBE({alpha}/{beta}), varies as a function of time-weighted average dose rate. At high dose rates, this radiation-induced cancer RBE({alpha}/{beta}) is small, but as dose rate goes down, the radiation-induced cancer RBE({alpha}/{beta}) rises without limit; actually the RBE({beta}/{alpha}) for producing radiation-induced cancer approaches zero. For example, for {sup 239}Pu dioxide in lung at 0.1 Gy d{sup -1} vs. {sup 90}Sr, the RBE({alpha}/{beta})=5, while at 1 mGy d{sup -1}, RBE({alpha}/{Beta})=50. The bone cancer RBE({alpha}/{beta})=l at 0.16 Gy d{sup -1} but RBE({alpha}/{beta})=30 at 1 mGy d{sup -1} for {sup 226}Ra/{sup 90}Sr in bone. Since {sup 238}Pu and {sup 239}Pu are about 10 times more effective than {sup 226}Ra in producing bone cancer, the apparent RBE({alpha}/{beta})=300 for plutonium in bone at 1 mG d{sup -1}.

• OSTI ID: 393931
• Report Number(s): CONF-9607135--
• Journal Information: Health Physics, Journal Name: Health Physics Journal Issue: Suppl.6 Vol. 70; ISSN HLTPAO; ISSN 0017-9078
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
99 GENERAL AND MISCELLANEOUS
AMERICIUM 241
BEAGLES
CERIUM 144
DOSE RATES
INHALATION
INJECTION
INTERNAL IRRADIATION
LET
MAN
NEOPLASMS
PLUTONIUM 238
PLUTONIUM 239
RADIOINDUCTION
RADIUM 226
RBE
SKELETON
STRONTIUM 90
YTTRIUM 91