DRAFT June 17, 2002

Different Energies on Various Types of Chromosome Aberrations,” Genetika 15, 1046-
1060.

Shimizu, Y., Kato, H., and Schull, W.J., 1990. “Studies of the Mortality of A-Bomb Survivors:
9. Mortality, 1950-1985: Part 2. Cancer Mortality Based on the Revised Doses (DS86),”
Radiat. Res. 121, 120.

Shleien, B., Slaback, L.A., Jr., and Birky, B.K. (eds.), 1998. Handbook of Health Physics and
Radiological Health, Third Edition, Williams & Wilkins, Baltimore, MD.

Sinclair, W.K., 1985. “Experimental RBE Values of High-LET-Radiations at Low Doses and the
Implications for Quality Factor Assignment,” Radiat. Prot. Dosim. 13, 319-326.

Sinclair, W.K., 1996. “The Present System of Quantities and Units for Radiation Protection,”
Health Phys, 70, 781-786.

Stanton, L., Day, J.L., Lightfoot, D.A., Villafana, T., and Rauch, P.L., 1979. “Rapid
Computation of Diagnostic X-Ray Bremsstrahlung Spectra,” Radiol. 130, 477-484.

Storer, J.B., Serrano, L.J., Darden, E.B., Jr., Jernigan, M.C., and Ullrich, R.L., 1979. “Life
shortening in RFM and BALB/c Mice as a Function of Radiation Quality, Dose and Dose
Rate,” Radiat. Res. 78, 122-161.

Storer, J.B., and Ullrich, R.L., 1983. “Life Shortening in BALB/c Mice Following Brief,
Protracted or Fractionated Exposures to Neutrons,” Radiat. Res. 96, 335-347.

Straume, T., and Carsten, A.L., 1993. “Tritium Radiobiology and Relative Biological
Effectiveness,” Health Phys. 65, 657-672.

Straume, T., 1995. “High-Energy Gamma Rays in Hiroshima and Nagasaki: Implications for
Risk and We,” Health Phys. 69, 954-956.

Suyama, L., and Etoh, H., 1985. “Chromosome Effects of Tritium on Lymphocytes of the Telost,
Umbra Limi,” p. 146-156 in Proceedings of the Second Workshop on Tritium
Radiobiology and Health Physics, ed. by H. Matsudaira, T. Yamaguchi, and H. Etoh,
NIRS-M-52, National Institute of Radiological Sciences, Chiba, Japan.

Suzuki, F., Mori, T., Nikaida, O., Suzuki, K., and Watanabe, M., 1989. “Neoplastic
Transformation and Chromosome Aberration Induced by Tritiated Water in Golden
Hamster Embryo Cells,” p. 211-216 in Tritium Radiobiology and Health Physics,
Proceedings of the Third Japan-U.S. Workshop, IPPJ-REV-3, Institute of Plasma Physics,
Nagoya University, Nagoya, Japan.

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Table 21. Summary of 95% confidence intervals of probability distributions of
radiation effectiveness factors for photons’

95% confidence interval of REF,’

Photon energy Exposure 2.5" percentile 50" percentile 97.5" percentile
> 250 keV Acute or chronic - 1.0 -
30-250 keV Acute or chronic 1.0 1.9 AT
<30 keV Acute or chronic 1d 2.4 6.1

“Summary description of probability distributions is given in Table 12. Probability distributions
of REF, apply to all cancers,

5 REF, is radiation effectiveness factor at low doses and low dose rates of reference high-energy
gamma rays.

Table 22. Summary of 95% confidence intervals of probability distributions of
radiation effectiveness factors for electrons‘

95% confidence interval of REF,”

Electron energy Exposure 2.5" percentile 50" percentile 97.5" percentile
> 15 keV Acute or chronic - 1.0 -
< 15 keV* Acute or chronic 1.2 2.4 5.0

“Summary description of probability distributions is given in Table 17. Probability distributions
of REF, apply to all cancers.
EF, is radiation effectiveness factor at low doses and low dose rates of reference high-energy
gamma rays.
“Auger-emitting radionuclides that are incorporated into DNA are excluded. Beta-emitting
radionuclides are included if average energy of continuous spectrum of beta particles is less than 15 keV.

65


DRAFT June 17, 2002

ICRP (International Commission on Radiological Protection), 1991. 1990 Recommendations of
the International Commission on Radiological Protection, ICRP Publication 60, Ann.
ICRP 21, No. 1-3.

ICRP (International Commission on Radiological Protection), 1993. Protection Against Radon-
222 at Home and at Work, ICRP Publication 65, Ann. ICRP 23, No. 2.

ICRP (International Commission on Radiological Protection), 1997. Conversion Coefficients for
Use in Radiological Protection Against External Radiation, ICRP Publication 74, Ann.
ICRP 26, No. 3/4.

ICRU (International Commission on Radiation Units and Measurements), 1986. The Quality
Factor in Radiation Protection, ICRU Report 40, ICRU, Bethesda, MD.

Kamiguchi, M., Tateno, H., and Mikamo, K., 1990. “Dose-Response Relationship for the
Induction of Structural Chromosome Aberrations in Human Spermatozoa After in Vitro
Exposure to Tritium Beta-Rays,” Mutat. Res. 228, 125-131.

Kashima, M., Joshima, H., and Fukutsu, K., 1985. “Induction of Micronuclei and Some Other
Abnormalities in Mouse Bone Marrow Following Tritium Exposure,” p. 246-257 in
Proceedings of the Second Workshop on Tritium Radiobiology and Health Physics, ed. by
H. Matsudaira, T. Yamaguchi, and H. Etoh, NIRS-M-52, National Institute of
Radiological Sciences, Chiba, Japan.

Kocher, D.C., 1981. Radioactive Decay Tables, DOE/TIC-11026, National Technical
Information Service, Springfield, VA.

Land, C., Gilbert, E., Smith, J., Hoffman, F.O., Apostoaei, I, Thomas, B., and Kocher, D.C.,
2002. Report of the NCI-CDC Working Group to Revise the 1985 NIH
Radioepidemiological Tables (in preparation).

Lee, W., Chiacchierini, R.P., Shieien, B., and Telles, N.C., 1982. “Thyroid Tumors Following
‘SIT or Localized X Irradiation to the Thyroid and Pituitary Glands in Rats,” Radiat. Res.
92, 307-319.

Little, J.B., 1986. “Induction of Neoplastic Transformation by Low-Dose-Rate Exposure to
Tritiated Water,” Radiat. Res. 107, 225-233.

Littlefield, L.G., Joiner, E.E., and Hubner, K.F., 1989. “Cytogenetic Techniques in Biological
Dosimetry: Overview and Example of Dose Estimation in 10 Persons Exposed to Gamma
Radiation in the 1984 Mexican “Co Accident,” in Medical Management of Radiation
Accidents, ed. by F.A. Mettler, Jr., C.A. Kelsey, and R.C. Ricks, CRC Press, Boca Raton,
Florida.

70


DRAFT June 17, 2002

Byrne, B.J., and Lee, W.R., 1989. “Relative Biological Effectiveness of Tritiated Water to
Gamma Radiation for Germ Line Mutations,” Radiat. Res. 117, 469-479.

Carnes, B.A., Grahn, D., and Thompson, J.F., 1989. “Dose Response Modeling of the Life
Shortening in a Retrospective Analysis of the Combined Data from the JANUS Program
at Argonne National Laboratory,” Radiat. Res. 119, 39-56.

Carsten, A.L., and Commerford, S.L., 1976. “Dominant Lethal Mutations in Mice Resulting
from Chronic Tritiated Water (HTO) Ingestion,” Radiat. Res. 66, 609-614.

Chopra, C., and Heddle, J.A., 1988. Cytogenetic Measurements of the Relative Biological
Effectiveness of Tritium, INFO-0287, Atomic Energy Control Board, Ottawa, Ontario,
Canada.

CIRRPC (Committee on Interagency Radiation Research and Policy Coordination), 1995.
Neutron Quality Factor, ORAU 95/F-29, CIRRPC, Washington, DC.

Coggle, J.E., 1988. “Lung Tumour Induction in Mice after X-Rays and Neutrons,” Int. J. Radiat.
Biol. 53, 585-598.

Coppola, M., 1993. “Specification of Fast Neutron Radiation Quality from Cell Transformation
Data,” Radiat. Prot. Dosim. 46, 211-212.

Cox, R., and Masson, W.K., 1979. “Mutation and Activation of Cultured Mammalian Celis
Exposed to Beams of Accelerated Heavy Ions. I. Human Diploid Fibroplasts,” Int. J.
Radiat. Biol. 36, 149-160.

Cox, R., Thacker J., Goodhead, D.T., and Munson, R.J., 1977. “Mutation and Inactivation of
Mammalian Cells by Various Ionizing Radiations,” Nature 267, 425.

Dobson, R.L., Straume, T., Carrano, A.V., Minkler, J.L., Deaven, L.L., Littlefield, L.G., and
Awa, A.A., 1991. “Biological Effectiveness of Neutrons from Hiroshima Bomb Replica:
Results of a Collaborative Cytogenetic Study,” Radiat. Res. 142-149.

DOE (U.S. Department of Energy), 1993. “10 CFR Part 835—Occupational Radiation
Protection,” Final Rule, Fed. Registr. 58, 65458-65512; see also Title 10 of Code of
Federal Regulations, which is published annually by U.S. Government Printing Office,
Washington, DC.

Eckerman, K.F., Leggett, R.W., Nelson, C.B., Puskin, J.S., and Richardson, A.C.B., 1999.
Cancer Risk Coefficients for Environmental Exposure to Radionuclides, Federal
Guidance Report No. 13, EPA 402-R-99-001, U.S. Environmental Protection Agency,
Washington, DC.

67


DRAFT June 17, 2002

REFERENCES

Bauchinger, M., 1984. “Cytogenetic Effects in Human Lymphocytes As a Dosimetry System,” p.
15 in Biological Dosimetry, ed. by W.G. Eisert and M.L. Mendelsohn, Springer-Verlag,
Berlin, Germany.

Bocian, E., Ziembia-Zak, E.B., Rosiek, O., and Sablinski, J., 1977. “Chromosome Aberration in
Human Lymphocytes Exposed to Tritiated Water in Vitro,” Curr. Topics Radiat. Res. Q.
12, 168-181.

Boecker, B.B., Hahn, F.F., Muggenburg, B.A., Guilmette, R.A., Griffith, W.C., and McClellan,
R.O., 1988. “The Relative Effectiveness of Inhaled Alpha and Beta Emitting
Radionuclides in Producing Lung Cancer,” p. 1059 in Radiation Protection Practice,
Proceedings of the Seventh International Congress of IRPA, Vol. Il, Pergamon Press,
Sydney, Australia.

Brenner, D.J., 1990. “The Microdosimetry of Radon Daughters and Its Significance,” Radiat.
Prot. Dosim. 31, 399-403.

Brenner, D.J., 1999. “Does Fractionation Decrease the Risk of Breast Cancer Induced by Low-
LET Radiation?,” Radiat. Res. 151, 225-229.

Brenner, D.J., and Amols, H.I., 1989. “Enhanced Risk from Low-Energy Screen-Film
Mammography X Rays,” Brit. J. Radiol. 62, 910-914.

Brewen, J.G., and Luippold, H.E., 1971. “Radiation-Induced Human Chromosome Aberrations:
In Vitro Dose Rate Studies,” Mutat. Res. 12, 305.

Brewen, J.G., Preston, R.L., and Littlefield, L.G., 1972. “Radiation Induced Human
Chromosome Aberrations. IH. Aberration Yields Following an Accidental Whole-Body
Exposure to Co y-Rays,” Radiat. Res. 49, 647.

Broerse, J.J., van Bekkum, D.W., Zoetelief, J., and Zurcher, C., 1991. “Relative Biological
Effectiveness for Neutron Carcinogenesis in Monkeys and Rats,” Radiat. Res. 128, $128-
$135.

Brooks, A.L., 1975. “Chromosome Damage in Liver Cells from Low Dose Rate Alpha, Beta,
and Gamma Irradiation: Derivation of RBE,” Science 190, 1090.

Brooks, A.L., Mewhinney, J.A., and McClellan, R.O., 1972. “The in Vivo Cytogenetic Effects of
252Cf on Liver and Bone Marrow of the Chinese Hamster,” Health Phys. 22, 701-706.

66


DRAFT June 17, 2002

Bone Radiobiology Workshop, UDC-472-136, U.S. Department of Energy, Washington,
DC.

Grogan, H.A., Sinclair, W.K., and Voillequé, P.G., 2000. Assessing Risks of Exposure to
Plutonium, Revision 2, RAC Report No. 5-CDPHE-RFP-1998-FINAL(Rev. 2),
Radiological Assessments Corporation, Neeses, South Carolina.

Grogan, H.A., Sinclair, W.K., and Voillequé, P.G., 2001. “Risks of Fatal Cancer from Inhalation
of Plutonium by Humans: A Combined Four-Method Approach with Uncertainty
Evaluation,” Health Phys. 80, 447.

Hahn, F.F., Griffith, W.C., Boecker, B.B., Muggenberg, B.A., and Lundgren, D.L., 1991.
“Comparison of the Effects of Inhaled “*PuO, and B-Emitting Radionuclides on the
Incidence of Lung Carcinomas in Laboratory Animals,” pp. 916-919 in Proceedings of
IRPA8: Worldwide Achievement in Public and Occupational Health Protection Against
Radiation, 8" International Congress of the International Radiation Protection
Association, Vol. I, Pergamon Press, London.

Harrison, J.D., Khursheed, A., and Lambert, B.E., 2002. “Uncertainties in Dose Coefficients for
Intakes of Tritiated Water and Organically Bound Forms of Tritium by Members of the
Public,” Radiat. Prot. Dosim. 98, 299.

Hei, T.K., Chen, D.J., and Hall, E.J., 1988. “Mutation Induction by Charged Particles of Defined
LET,” Carcinogenesis 9, 1233.

Hunacek, M.M., and Kathren, R.L., 1995. “Alpha Radiation Risk Coefficients for Liver Cancer,
Bone Sarcomas, and Leukemia,” Health Phys. 68, 41-49.

ICRP (International Commission on Radiological Protection), 1960. Recommendations of the
International Commission on Radiological Protection. Report of Committee II on

Permissible Dose for Internal Radiation (1959), Pergamon Press, Oxford, U.K.

ICRP (International Commission on Radiological Protection), 1979. Limits for Intakes of
Radionuclides by Workers, ICRP Publication 30, Part 1, Ann. ICRP 2, No. 3/4.

ICRP (International Commission on Radiological Protection), 1980. Biological Effects of
Inhaled Radionuclides, (CRP Publication 31, Ann. ICRP 4, No. 1-2.

ICRP (International Commission on Radiological Protection), 1987. Lung Cancer Risk from
Indoor Exposures to Radon Daughters, ICRP Publication 50, Ann. ICRP 17, No. 1.

69


DRAFT June 17, 2002

Table 17. Summary of probability distributions of radiation effectiveness factors for
electrons to be used in estimating cancer risks and probability of
causation in accordance with eq. (14), (15), or (16)*

Electron energy Probability distribution of radiation effectiveness factor (REF,)
> 15 keV Single-valued at 1.0 (assumption that such electrons have same
biological effectiveness as reference high-energy gamma rays)”
< 15 keV* Lognormal distribution having a 95% confidence interval between 1.2
and 5.0

“Probability distributions apply to all cancers and at any dose and dose rate.

Based on considerations of the energies of secondary electrons produced by photon interactions
in tissue, 15-60 keV electrons should have the same REF, as 30-250 keV photons (see Table 12).
However, a distribution of REF, greater than unity for 15-60 keV electrons is not adopted in this work,
due to the lack of supporting radiobiological data.

‘Probability distribution of REF, is based on data on RBE for beta particles emitted in decay of
3H. Distribution does not apply to Auger-emitting radionuclides that are incorporated into DNA.

SUMMARY OF REFs FOR DIFFERENT RADIATIONS

Based on evaluations of information on the biological effectiveness of various types of
ionizing radiation, including neutrons, alpha particles, lower-energy photons, and lower-energy
electrons, relative to high-energy photons, we have developed radiation effectiveness factors
(REFs) for the different radiation types for use in calculating the probability of causation of
specific cancers in humans. The REFs developed in this report are applied to estimates of cancer
risk in specific organs or tissues at high acute doses of high-energy gamma rays, which are
obtained mainly from studies in the Japanese atomic-bomb survivors.

The REFs developed in this report are expressed as probability distributions. These
distributions are intended to represent the current state of knowledge of the biological
effectiveness of different radiation types in inducing cancers in humans, taking into account
uncertainties in data on relative biological effectiveness (RBE) obtained from relevant
radiobiological studies and any other judgments involved in evaluating the available information.
The REFs for the different radiations considered in this report are summarized as follows.

Neutrons

The assumed probability distributions of REFs for neutrons are summarized previously in
Table 7. Separate distributions of REFs are developed for solid tumors and leukemias. The
distributions for solid tumors are REFs that represent data on RBE at high acute doses of the
reference high-energy gamma rays, REF, whereas the distributions for leukemias are REFs that

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DRAFT June 17, 2002

Human Lymphocytes Exposed to HTO,” p. 137-142 in Tritium Radiobiology and Health
Physics, Proceedings of the Third Japan-U.S. Workshop, ed. by S. Okada, IPPJ-REV-3,
Institute of Plasma Physics, Nagoya University, Nagoya, Japan.

Muirhead, C.R., Cox, R., Stather, J.W., MacGibbon, B.H., Edwards, A.A., and Haylock, R.G.E.,
1993. “Relative Biological Effectiveness,” pages 126-139 in Documents of the NRPB 4,
No. 4, Nationa! Radiological Protection Board, Chilton, U.K.

Myers, D.K., and Johnson, J.R., 1991. Toxicity and Dosimetry of Tritium: A Review, Atomic
Energy Control Board, Ottawa, Ontario, Canada; see also Myers, D.K., and Johnson, J.R.,
1990. RBE of Tritium and Induction of Myeloid Leukemia and CBA/H Mice, INFO-0360,
Atomic Energy Control Board, Ottawa, Ontario, Canada.

Nakamura, N., Morikawa, N., and Okada, S., 1985. “Dose Rate Effects of Mutation Induction by
Tritiated Water in Mouse Leukemia Cells,” p, 95-100 in Proceedings of the Second
Workshop on Tritium Radiobiology and Health Physics, ed. by H. Matsudaira, T.
Yamaguchi, and H. Etoh, NIRS-M-52, National Institute of Radiological Sciences, Chiba,
Japan.

National Research Council, 1988. Health Risks of Radon and Other Internally Deposited Alpha-
Emitters, BEIR IV, National Academy Press, Washington, DC.

NCRP (National Council on Radiation Protection and Measurements), 1971. Protection Against
Neutron Radiation, Second Edition, NCRP Report No. 38, NCRP, Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements), 1985. A Handbook of
Radioactivity Measurements Procedures, Second Edition, NCRP Report No. 58, NCRP,
Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements), 1990. The Relative
Biological Effectiveness of Radiations of Different Quality, NCRP Report No. 104,
NCRP, Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements), 1991. Conceptual Basis
for Calculations of Absorbed-Dose Distributions, NCRP Report No, 108, NCRP,
Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements), 1993. Limitation of
Exposure to Ionizing Radiation, NCRP Report No. 116, NCRP, Bethesda, MD.

Nomura, T., and Yamamoto, O., 1989. “Jn Vivo Somatic Mutation in Mice Induced by Tritiated
Water,” p. 230-233 in Tritium Radiobiology and Health Physics, Proceedings of the

72


DRAFT June 17, 2002

Lioyd, D.C., Edwards, A.A., Leonard, A., Deknudt, G., Natarajan, A., Obe, G., Palitti, F.,
Tanzarella, C., and Tawn, E.J., 1988. “Frequencies of Chromosome Aberrations Induced
in Human Blood Lymphocytes by Low Doses of X Rays,” Int. J. Radiat. Biol. 53, 49-55.

Lloyd, D.C., Edwards, A.A., and Prosser, J.S., 1986. “Chromosome Aberrations Induced in
Human Lymphocytes by in Vitro Acute X and Gamma Radiation,” Radiat. Prot. Dosim.
15, 83.

Lloyd, D.C., Purrott, R.J., Dolphin, G.W., Bolton, D., Edwards, A.A., and Corp, M., 1975. “The
Relationship Between Chromosome Aberrations and Low-LET Radiation Dose to Human
Lymphocytes,” Int. J. Radiat. Biol. 28, 75-90.

Lubin, J.H., Boice, J.D., Jr., Edling, C., Hornung, R.W., Howe, G., Kunz, E., Kusiak, R.A.,
Morrison, H.L., Radford, E.P., Samet, J.M., Tirmarche, M., Woodward, A., and Yao,
S.X., 1995. “Radon-Exposed Underground Miners and Inverse Dose-Rate (Protraction
Enhancement) Effects,” Health Phys. 69, 494-500.

Mays, C.W., and Finkel, M.P., 1980. “RBE of «-Particles vs. B-Particles in Bone Sarcoma
Induction,” p, 401 in Proceedings of the 5" International Congress of IRPA, Vol. I,
Israel Health Physics Society, Jerusalem, Israel.

Matsuda, Y., Yamada, T., and Tobari, 1, 1985, “Chromosomal Effects of Tritium in Mouse
Zygotes Fertilized in Vitro,” p. 193-206 in Proceedings of the Second Workshop on
Tritium Radiobiology and Health Physics, ed. by H. Matsudaira, T. Yamaguchi, and H.
Etoh, NIRS-M-52, National Institute of Radiological Sciences, Chiba, Japan.

Miller, R.C., Geard, C.R., Brenner, D.J., Komatsu, K., Marino, S.A., and Hall, E.J., 1989.
“Neutron-Energy-Dependent Oncogenic Transformation of C3H10T'% Mouse Cells,”
Radiat. Res. 117, 114-127.

Miller, R.C., Marino, S.A., Napoli, J., Shah, H., Hall, E.J., Geard, C-R., and Brenner, D.J., 2000.
“Oncogenic Transformation in C3H10T% Cells by Low-Energy Neutrons,” Int. J. Radiat.
Biol. 76, 327-333.

Mole, R.H., and Davids, J.A.G., 1982. “Induction of Myeloid Leukaemia and Other Tumours in
Mice by Irradiation with Fission Neutrons,” pages 31-42 in Neutron Carcinogenesis,

Commission of the European Communities, Luxembourg.

Mole, R.H., Papworth, D.G., and Corp, M.J., 1983. “The Dose Response X-Ray Induction of
Myeloid Leukaemia in Male CBA/H Mice, Br. J. Cancer 47, 285-291.

Morimoto, K., Ogawa, Y., Okayama, A., Shirakawa, T., and Miura, K., 1989. “Development of
the Monitoring System for Human Exposure to Tritium: Chromosome Aberrations in

71


DRAFT June 17, 2002

Edwards, A.A., 1997. “Relative Biological Effectiveness of Neutrons for Stochastic Effects,”
Documents of the NRPB 8, No. 2, National Radiological Protection Board, Chilton, U.K.

Edwards, A.A., 1999. “Neutron RBE Values and Their Relationship to Judgements in
Radiological Protection,” J. Radiol. Prot. 19, 93-105.

Edwards, A.A., Lloyd, D.C., and Prosser, J.S., 1985. “The Induction of Chromosomal
Aberrations in Human Lymphocytes by Accelerated Charged Particles,” Radiat. Prot.
Dosim. 13, 205-209.

Edwards, A.A., Lloyd, D.C., and Prosser, J.S., 1990. “The Induction of Chromosomal
Aberrations in Human Lymphocytes by 24 keV Neutrons,” Radiat. Prot. Dosim. 31, 265-
268.

Edwards, A.A., Purrott, R.J., Prosser, J.S., and Lloyd, D.C., 1980. “The Induction of
Chromosome Aberrations in Human Lymphocytes by Alpha-Radiation,” Int. J. Radiat.
Biol. 38, 83-91.

EPA (U.S. Environmental Protection Agency), 1994. Estimating Radiogenic Cancer Risks, EPA
402-R-93-076, EPA, Washington, DC.

EPA (U.S. Environmental Protection Agency), 1999. Estimating Radiogenic Cancer Risks.
Addendum: Uncertainty Analysis, EPA 402-R-99-003, EPA, Washington, DC.

Fabry, L., Leonard, A., and Wambersie, A., 1985. “Induction of Chromosome Aberrations in G,
Human Lymphocytes by Low Doses of Ionizing Radiations of Different Quality,” Radiat.
Res. 103, 122.

Gragtmans, N.J., Myers, D.K., Johnson, J.R., Jones, A.R., and Johnson, L.D., 1984. “Occurrence
of Mammary Tumors in Rats After Exposure to Tritium Beta Rays and 200-kVp X-
Rays,” Radiat. Res. 99, 636-650.

Grahn, D., Lombard, L. S., and Carnes, B. A., 1992. “The Comparative Tumorigenic Effect of
Fission Neutrons and Cobalt-60 y-rays in the B6CF1 Mouse, Radiat. Res. 129, 19-36.

Griffith, W.C., Boecker, B.B., Cuddihy, R.G., Guilmette, R.A., Hahn, F.F., McClellan, R.O.,
Muggenberg, B.A., and Snipes, M.B., 1987. “Preliminary Radiation Risk Estimates of
Carcinoma Incidence in the Lung as a Function of Cumulative Radiation Dose Using
Proportional Tumor Incidence Rates,” p. 196 in Inhalation Toxicology Research Institute
Annual Report, LMF-120, National Technical Information Service, Springfield, VA.

Griffith, W.C., Boecker, B.B., Gillett, N.A., et al., 1991. “Comparison of Risk Factors for Bone
Cancer Induced by Inhaled *SrCl, and **PuO,,” in Proceedings of EULEP/DOE Joint

68


DRAFT June 17, 2002

Table 20. Summary of 95% confidence intervals of probability distributions of
radiation effectiveness factors for alpha particles’

95% confidence interval of REF,°

Cancer type Exposure? 2.5" percentile 50" percentile _ 97.5" percentile
Solid tumors Chronic 3.4 18 101
Leukemias Chronic 1.0 41 42

“Summary description of probability distributions is given in Table 9.

Pall exposures to alpha particles emitted by radionuclides are assumed to be chronic.

REF, is radiation effectiveness factor at low doses and tow dose rates of reference high-energy
gamma rays.

Photons

The assumed probability distributions of REFs for photons at low doses and low dose
rates, REF,, are summarized previously in Table 12. The biological effectiveness of photons of
energy greater than 250 keV is assumed to be the same as that of high-energy gamma rays, and
probability distributions‘of REF, greater than unity are applied at energies of 30-250 keV and
less than 30 keV. The assumed distributions of REF, are applied to all cancer types.

The 50" percentile (median) and the 95% confidence interval (2.5" and 97.5" percentiles)
of the assumed probability distributions of REF, for photons are given in Table 21.

Electrons

The assumed probability distributions of REFs for electrons at low doses and low dose
rates, REF,, are summarized previously in Table 17. The biological effectiveness of electrons of
energy greater than 15 keV is assumed to be the same as that of high-energy gamma rays, and a
probability distribution of REF, greater than unity is applied at energies less than 15 keV, except
Auger-emitting radionuclides that are incorporated into DNA are excluded. The assumed
distribution of REF, at low energies is applied to all cancer types.

The 50" percentile (median) and the 95% confidence interval (2.5" and 97.5" percentiles)
of the assumed probability distributions of REF, for electrons are given in Table 22.

64


DRAFT June 17, 2002

Thacker, J., Stretch, A., and Stephens, M.A., 1979. “Mutation and Inactivation of Cultured
Mammalian Cells Exposed to Beams of Accelerated Heavy Ions. H. Chinese Hamster
V79 Cells,” Int. J. Radiat. Biol. 36, 137-148.

Thomas, B.A., and Hoffman, F.O., 2000. The Estimate of Excess Lifetime Risk of Cancer
Incidence Associated with Discrete Routine Releases of Tritiated Water Vapor (HTO)
from the National Tritium Labelling Facility at Lawrence Berkeley National Laboratory,
SOR/TR-003-900, SENES Oak Ridge, Inc., Oak Ridge, TN.

Thompson, D.E., Mabuchi, K., Ron, E., Soda, M., Tokunaga, M., Ochikubo, S., Sugimoto, S.,
Ikeda, T., Terasaki, M., Izumi, S., and Preston, D.L., 1994. “Cancer Incidence in Atomic
Bomb Survivors. Part I: Solid Tumors, 1958-1987,” Radiat. Res. 137, S17-S67.

Turner, J.E., 1995. Atoms, Radiation, and Radiation Protection, Second Edition, John Wiley &
Sons, New York.

Ueno, A.M., Furuno-Fukushi, I, and Matsudaira, H., 1982. “Induction of Cell Killing,
Micronuclei and Mutation to 6-Thioguanine Resistance After Exposure to Low Dose-
Rate Gamma Rays and Tritiated Water in Cultured Mammalian Cells (L5178Y),” Radiat.
Res. 91, 447-456.

Ueno, A.M., Furuno-Fukushi, L, and Matsudaira, H., 1989. “Cell Killing and Mutation to 6-
Thioguanine Resistance After Exposure to Tritiated Amino Acids and Tritiated
Thymidine in Cultured Mammalian Cells,” p. 200-210 in Tritium Radiobiology and
Health Physics, Proceedings of the Third Japan-U.S. Workshop, ed. by S. Okada, IPPJ-
REV-3, Institute of Plasma Physics, Nagoya University, Nagoya, Japan.

Ullrich, R.L., 1980. “Effects of Split Doses of X-Rays or Neutrons on Lung Tumor Formation in
RFM Mice,” Radiat. Res. 83, 138-145.

Ullrich, R.L., 1984. “Tumor Induction in BALB/c Mice after Fractionated or Protracted
Exposures to Fission Spectrum Neutrons,” Radiat. Res. 97, 587-597.

Ullrich, R.L., Jernigan, M.C., Cosgrove, G.E., Satterfield, L.C., Bowles, N.D., and Storer, J.B.,
1976. “The Influence of Dose and Dose Rate on the Incidence of Neoplastic Disease in
REM Mice after Neutron Irradiation,” Radiat. Res. 68, 115-131.

Ullrich, R.L., Jernigan, M.C., and Storer, J.B., 1977, “Neutron Carcinogenesis Dose and Dose-
Rate Effects in BALB/c Mice,” Radiat. Res. 72, 487-498.

Ullrich, R.L., Jernigan, M.C., and Adams, L.M., 1979, “induction of Lung Tumors in RFM Mice
after Localized Exposures to X-Rays or Neutrons,” Radiat. Res. 80, 464-473.

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H. Matsudaira, T, Yamaguchi, and H. Etoh, NIRS-M-52, National Institute of
Radiological Sciences, Chiba, Japan.

Yokoro, K., Yamamoto, O., Seyama, T., Nitta, Y., and Niwa, O., 1989. “Carcinogenic Effect of
Tritiated Water (HTO) in Mice in Comparison with Those of Fission Neutrons and
Gamma-Rays,” p. 233-238 in Tritium Radiobiology and Health Physics, Proceedings of
the Third Japan-U.S. Workshop, ed. by S. Okada, IPPJ-REV-3, Institute of Plasma
Physics, Nagoya University, Nagoya, Japan.

TT



DRAFT June 17, 2002

Table 18. Summary of 95% confidence intervals of probability distributions of
radiation effectiveness factors for neutrons and solid tumors‘

95% confidence interval of REF,’

Neutron energy Exposure 2.5" percentile 50" percentile 97.5" percentile
0.1-2 MeV* Acute 2.0 77 30
Chronic 24 10 47
10-100 keV; Acute 1.2 3.8 18
2-20 MeV Chronic 1.4 Al 28
< 10 keV; Acute 1.1 1.9 11
> 20 MeV Chronic 11 2.4 16

“Summary description of probability distributions is given in Table 7.
REF,, is radiation effectiveness factor at high acute doses of reference high-energy gamma rays.
°REFs for this energy range apply to fission neutrons.

Table 19. Summary of 95% confidence intervals of probability distributions of
radiation effectiveness factors for neutrons and leukemias“

95% confidence interval of REF,’

Neutron energy Exposure 2.5" percentile  50"percentile 97.5" percentile

0.1-2 MeV* Acute 2.0 11 60
Chronic 25 14 91

10-100 keV; Acute 1.3 5.6 36

2-20 MeV Chronic 1.5 TA 55

< 10 keV; Acute 1d 2.8 22

> 20 MeV Chronic 1.2 3.4 34

“Summary description of probability distributions is given in Table 7.

REF, is radiation effectiveness factor at low doses and low dose rates of reference high-energy
gamma rays.

°REFs for this energy range apply to fission neutrons.

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DRAFT June 17, 2002

represent data on RBE at low doses and low dose rates, REF,. When REF, is used to estimate
tisks of solid tumors at any dose and dose rate of neutrons, a dose and dose-rate effectiveness
factor (DDREF) for high-energy gamma rays is not used. REFs at high acute doses of the
reference radiation are not used in estimating cancer risks for any other radiation type.

The probability distributions of REF, for solid tumors and REF, for leukemias are
assumed to depend on neutron energy. Based on the energy dependence of the radiation
weighting factor recommended by the ICRP (see Fig. 7), probability distributions of REFs are
developed for three groups of energies: 0.1-2 MeV (including fission neutrons), 10-100 keV and
2-20 MeV, and less than 10 keV and greater than 20 MeV.

Under conditions of chronic exposure to neutrons, a small correction representing an
inverse dose-rate effect is applied to the probability distributions of REFs for solid tumors and
leukemias. This correction is assumed to be independent of neutron energy.

The 50" percentile (median) and the 95% confidence interval (2.5 and 97.5" percentiles)
of the assumed probability distributions of REFs for neutrons are given in Tables 18 and 19,

Alpha Particles

The assumed probability distributions of REFs for alpha particles are summarized
previously in Table 9. As in the case of neutrons, separate distributions of REFs are developed
for solid tumors and leukemias, except the distribution for solid tumors is not applied in
estimating risks of lung cancer due to inhalation of radon and its short-lived decay products. The
distribution for each cancer type is the REF at low doses and low dose rates of the reference
high-energy gamma rays, REF, The separate probability distributions of REF, for solid tumors
and leukemias are applied at all energies of alpha particles emitted by radionuclides.

In all cases of exposure to alpha particles emitted by radionuclides, a small correction
representing an inverse dose-rate effect under conditions of chronic exposure is applied to the
probability distributions of REF, for solid tumors and leukemias. Acute exposure to alpha
particles emitted by radionuclides is assumed not to occur.

The 50" percentile (median) and the 95% confidence interval (2.5 and 97.5” percentiles)
of the assumed probability distributions of REF, for alpha particles are given in Table 20.

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Third Japan-U.S. Workshop, ed. by S. Okada, IPPJ-REV-3, Institute of Plasma Physics,
Nagoya University, Nagoya, Japan.

NRC (U.S. Nuclear Regulatory Commission), 1991. “10 CFR Part 20 et al —Standards for
Protection Against Radiation,” Fed. Registr. 56, 23360-23474; see also Title 10 of Code
of Federal Regulations, which is published annually by U.S. Government Printing Office,
Washington, DC.

Pomerantseva, M.D., 1964. “The Genetic Activity of Various Types of Ionizing Radiation,”
Radiobiologiya 4, 13.

Prosser, J.S., Lloyd, D.C., Edwards, A.A., and Stather, J.W., 1983. “The Induction of
Chromosome Aberrations in Human Lymphocytes by Exposure to Tritiated Water in
Vitro,” Radiat. Protect. Dosim. 4, 21-26.

Purrott, R.J., Edwards, A.A., Lloyd, D.C., and Stather, J.W., 1980. “The Induction of
Chromosome Aberrations in Human Lymphocytes by in Vitro Irradiation with a-Particles
from Plutonium-239,” Int. J. Radiat. Biol. 38, 277-284.

Ron, E., Lubin, J.H., Shore, R.E., Mabuchi, K., Modan, B., Pottern, L.M., Scheider, A.B.,
Tucker, M.A., and Boice, J.D., Jr., 1995. “Thyroid Cancer after Exposure to External
Radiation: A Pooled Analysis of Seven Studies,” Radiat. Res. 141, 259-277.

Satow, Y., Lee, J., and Sawada, S., 1989. “Teratogenic Effect of Tritium Water and Tritium
Simulator on Rat Embryos,” p. 280-286 in Tritium Radiobiology and Health Physics,
Proceedings of the Third Japan-U.S. Workshop, ed. by S. Okada, IPPJ-REV-3, Institute
of Plasma Physics, Nagoya University, Nagoya, Japan.

Schmid, E., Regulla, D., Guldbakke, S., Schlegel, D., and Bauchinger, M., 2000. “The
Effectiveness of Monoenergetic Neutrons at 565 keV in Producing Dicentric
Chromosomes in Human Lymphocytes at Low Doses,” Radiat. Res. 154, 307-312.

Searle, A.G., 1984. “Genetic Effects of Tritium in Mammals,” p. 303-310 in Proceedings of the
European Seminar on the Risks from Tritium Exposure, EUR 9056 EN, Commission of
the European Communities, Mol, Belgium.

Searle, A.G., Beechey, C.V., Green, D., and Humphreys, E.R., 1976. “Cytogenetic Effects of
Protracted Exposures to Alpha Particles from “Pu and to Gamma Rays from “Co
Compared in Male Mice,” Mutat. Res. 41, 297-310.

Sevan’kaev, A.V., Zherbin, E.A., Luchnik, N.V., Obaturov, G.M., Kozloo, G.M., Tayatte, E.G.,

and Kapchigasher, S.P., 1979. “Neutron-Induced Cytogenetic Effects in Lymphocytes of
Human Peripheral Blood in Vitro. I. Dose Dependence of the Effects of Neutrons of

73


DRAFT June 17, 2002

Ullrich, R.L., and Preston, R.J., 1987. “Myeloid Leukemia in Male RFM Mice Following
Irradiation with Fission Spectrum Neutrons or y-Rays,” Radiat. Res. 109, 165-170.

Underbrink, A.G., Sparrow, R.C., Sparrow, A.H., and Rossi, H.H., 1970. “RBE of X Rays and
0.43 MeV Monoenergetic Neutrons on Somatic Mutations and Loss of Reproductive
Integrity in Tradescantia Stamen Hairs,” p. 373 in Symposium on Neutrons in
Radiobiology, CONF-691106, Oak Ridge National Laboratory, Oak Ridge, Tennessee;
see also Radiat. Res. 44, 187.

UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), 1982.
Tonizing Radiation: Sources and Biological Effects, Report to the General Assembly, with
Annexes, United Nations, New York.

UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), 2000.
“Epidemiological Evaluations of Radiation-Induced Cancer,” Annex I in Sources and
Effects of Ionizing Radiation, Vol. II, pp. 298-450, United Nations, New York.

Upton, A.C., Randolph, M.L., Conklin, J-W., Kastenbaum, M.A., Slater, M., Melville, G.S.J.,
Conte, F.P., and Sproul, J.A., Jr., 1967. “Late Effects of Fast Neutrons and Gamma Rays
in Mice as Influenced by the Dose Rate of Irradiation: Life Shortening,” Radiat. Res. 32,
493-509.

Upton, A.C., Randolph, M.L., and Conklin, J.W., 1970. “Late Effects of Fast Neutrons and
Gamma-Rays in Mice as Influenced by the Dose Rate of Irradiation: Induction of
Neoplasia,” Radiat. Res. 41, 467-491.

Vulpis, N., 1984. “The Induction of Chromosome Aberrations in Human Lymphocytes by in
Vitro Irradiation with Beta Particles from Tritiated Water,” Radiat. Res. 97, 511-518.

Wolf, C., Lafuma, J., Masse, R., Morin, M., and Kellerer, A.M., 2000. “Neutron RBE for
Induction of Tumors of High Lethality in Sprague-Dawley Rats,” Radiat. Res. 154, 412-
420,

Xiang-yan, Z., Jin-chan, D., Xin-sheng, G., and Lu-xin, W., 1986. “Tritium Beta-Ray and “Co
Gamma-Ray Caused Dominant Lethal Mutation in Mice,” Chinese Med. J. 99, 420-423.

Yamada, T., Yukawa, O., Asami, K., and Nakazawa, T., 1982. “Effect of Chronic HTO Beta or
Co Gamma-Radiation on Pre-implantation Mouse Development in Vitro,” Radiat. Res.
93, 359-369.

Yamaguchi, T., Yasukawa, M., Terasima, T., and Matsudaira, H., 1985. “Malignant Cell

Transformation Induced by Tritiated Water in Mouse 10T Cells,” p, 136-145 in
Proceedings of the Second Workshop on Tritium Radiobiology and Health Physics, ed. by

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