Bundeswehr Institute of Radiobiology affiliated to the University of Ulm

Transcription

1 Bundeswehr Institute of Radiobiology affiliated to the University of Ulm Radiation exposure case management after incorporation of radioactive materials Support system for internal dosimetry G.Goulko, V.Meineke

2 In RN-Case exposure is possible through: External partial or whole body exposure Contamination of skin Incorporation of radioactive materials through: 2

3 Direct Measurement of exposure (dose) after incorporation is not possible It is possible to measure activity at certain time in: target organs, whole body or excreta It should be taken into account, that: Exposure (dose) builds up over certain time-period Activity intake can be a complicated function of time Activity excretion and decay must be taken into account Therefore: Dose estimation after incorporation requires the measurement of activity in the body or in excreta and bio-kinetic models describing the metabolism Countermeasures (decorporation) could lead to a dose reduction and should be taken into account in the dosimetric calculations Earlier decision making about application of decorporation therapy could increase its effectiveness 3

4 Dose calculations are important for decision making For the management of radiation accidents, especially for the treatment after incorporation of radioactive materials, dose calculation is an important tool for the responsible physician. A prompt and simple prognosis of the expected dose help make an optimal decision about decorporation measures in shortest time. 4

5 Evaluation process after accidental incorporation: 3 levels I. Immediate evaluation on site Tool: Simple (graphic) representation of effective whole-body dose or equivalent dose for the critical organs per 1 Bq of measured activity in whole-body, part of the body or excreta for different times after incorporation II. Fast evaluation with higher reliability on site or in evaluation office (for example in hospital) Tool: Tables with effective dose or equivalent dose per 1 Bq of measured activity in whole-body, part of the body or excreta for different time after incorporation III. Expert evaluation Detailed evaluation with the help of metabolic-dosimetric model calculations taking into account individual circumstances 5

6 Calculations progress: 7 Radionuclides, acute intake Radionuclide Measurement case evaluation countermeasures Adult: body mass = 70 kg Adult: body mass = 70 kg AMAD = Activity Median Aerodynamic Diameter 6

7 241 Am Ingestion: Effective Dose per 1 Bq of Fecesactivity Immediate evaluation: adult, body mass 70 kg Sv 241 Am effective dose per 1 Bq feces activity, Sv E f f e c t i v e Effective dose = 35,3 msv/bq x measured feces-activity D o s e 10 days Time after intake, days 7

8 241 Am ingestion: equivalent dose for bone marrow, bone surface, liver and testes per 1 Bq of feces activity, Sv Immediate decision 1,0E+03 Intake: ingestion Measurement: feces 1,0E+01 Liver Equivalent dose, Sv 1,0E-01 1,0E-03 1,0E-05 Bone surface Red bone marrow Testes It works similarly for bone surface, bone marrow, liver and testes doses 1,0E Time after intake, days 8

9 241 Am inhalation: effective and equivalent bone marrow, bone surface, liver, lung dose per 1 Bq of whole body activity, Sv. Immediate decision 1,0E Am dose after inhalation (AMAD = 5 mkm, solubility = M) for bone marrow, bone surface, liver, as well as effective dose per 1 Bq of whole body activity, Sv/Bq Effective dose, Sv/Bq 1,0E-02 1,0E-03 1,0E-04 liver bone marrow lung dose bone surface effektive dose It works similarly for inhalation 1,0E Time after intake, days 9

10 Calculation table for higher reliability estimations: effective whole-body dose after inhalation of 241 Am Effective in dose Sv per 1 Bq measured whole-body activity Fast evaluation with higher reliability Solubility Effective whole body dose, Sv 24 h Measurement of whole body activity Effective Dose = = 0,202 msv per 1 Bq of measured whole body activity 0,3 2,02E-4 Similar calculation tables are available for the liver, lung, bone surface and bone marrow doses and measurement of lung or feces activity 10

11 Calculation table for higher reliability estimations: effective whole body dose, born surface- and bone marrow- equivalent dose after ingestion of 241 Am, Sv per 1 Bq whole body- or feces- activity Similar calculation tables are available for the intake through the intact skin and wound feces ICRP solubility class ing1 and ing2 11

12 Expert Assessment (Inst.Rad.Bio.): Detailed case evaluation with the help of metabolic model calculations considering individual circumstances Nuclide Acute Chronic IMBA (NRPB, GB): integrated Modules for Bioassay Analysis Main screen define Intake scenarios Lungs Plutonium-239 Urine Faeces Simultaneous fit of bioassay data 138 radionuclides are chosen from periodic system 12

13 What can we do for the dose reduction? Example: countermeasures after (study with test persons) and intake Evaluation is good, therapy is better! Observed mean values ± SD in seven Calculated dependence of the groups with thyroid blockage by KI or SP protective effect of thyroid (Sodium Perchlorate) sorted by the mean blocking on the time of time delay of Intervention (INV) intervention for 131 I. Thin solid line is determined with parameters for the iodine kinetics as published in ICRP-78 and is representative for subjects exceeding 40 yr. of age in the present study. The bold solid line represents the theory based on mean data of the kinetics observed in subjects younger than 25 yr. of age. The lower and upper dashed lines were deduced with the highest and lowest observed values, respectively. H.Hänscheid, Ch.Reiners, G.Goulko, M.Luster, M.Schneider-Ludorff, A.K.Buck, M.Lassmann. Facing the Nuclear Threat: Thyroid Blocking Revisited. J. Clinical Endocrinology and Metabolism, Nov.1, 2011, 96(11):

14 What happens if nothing is done? Thyroid cancer OR (Russia, Belarus): Children (0-15 in 1986) during Chernobyl accident in Case-Control-Study with 276 cases and 1300 controls E.Cardis, A.Kesminiene, V.Ivanov, I.Malakhova, Y.Shibata, V.Krouch, Drozdovich, E.Maceika, I.Zvonova, O.Vlasov, A.Bouville, G.Goulko, M.Hoshi, et al. J. of National Cancer Institute, 2005; 97: : 265-times cited 14

15 Thyroid cancer incidence ( ) in different birth cohorts in 5 northern Ukrainian 6 regions (per 10 5 Person-year) Incidence, Background incidence Age at diagnosis G.Goulko, N.Tronko, T.Bogdanova, K.Henrichs, I.Kayro, V.Shpak, M.Lassmann, Ch.Reiners. Int.J.Low Rad. Vol.2, 3/4, 2006:

16 Radiation risk for thyroid cancer G.Goulko, N.Tronko, T.Bogdanova, K.Henrichs, I.Kayro, V.Shpak, M.Lassmann, Ch.Reiners. Int.J.Low Rad. Vol.2, 3/4, 2006:

17 Thank you for the attention Guennadi Goulko and Viktor Meineke