Semmelweis University Faculty of Dentistry Budapest Studium Radiation

Semmelweis University Faculty of Dentistry, Budapest Studium: Radiation Protection/Strahlenschutz, 2017/2018 PUBLIC EXPOSURES (Strahlendosen für die Bevölkerung) Gabriella Taba, Semmelweis Univ. , Radiation Protection Service 8. marc. 2018, FOK szemináriumi terem, 1. emelet, 1088 Budapest, Szentkirályi u. 47. 1

External and Internal Radiation Dose Radiation Units: Exposure (CLINICAL) Absorbed Dose (CLINICAL) Equivalent Dose (RADIATION PROTECTION) Effective Dose (RADIATION PROTECTION) Dose rate τ ˚ ∫ D(t) dt Committed dose: 0 According to regulation: τ = 50 y (adults), 70 y (children) τ time 2

Categories of Exposures (with respect to the regulation) • Occupational exposures (Berufliche …) • Public (incl. : Medical? ) exposures • (Non-human Biota exposures ? ) 3 https: //www. clpgroup. com/Nuclear. Energy/Eng/images/science/3_2_1 a. jpg

NCRP Report 160: Ionizing Radiation Exposure of the Population of the United States 4

Sources of Public Exposures • Natural Exposure (Natürliche…) annual impact: 2. 5 m. Sv effective dose (external + internal) • Artificial Exposure (Künstliche …) annual impact: 1. 7 m. Sv effective dose (mainly due to medical, X-ray diagnostics) 5

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Natural: Cosmogene and terrestrial radionuclides Univerzum (ions, α-, β-, n-, müon- … radiation) Atmosphere n γ Raindr. Earth Surface γ 7

Cosmogenic isotopes are created when elements in the atmosphere or earth by high energy particles. 9, 400 years of cosmic radiation and solar activity from ice cores and tree rings Friedhelm Steinhilbera, 1, Jose A. Abreua 2, Jürg Beera , Irene Brunnera , Marcus Christlb , Hubertus Fischerc , Ulla Heikkiläd , Peter W. Kubikb , Mathias Manna , Ken G. Mc. Crackene , Heinrich Millerf , Hiroko Miyaharag , Hans Oerterf , and Frank Wilhelmsf 8

Areas of high natural background 9

Terrestrial exposure: natural radioactive decay series (r. nuclides mainly in soil) Thorium serie Th-232 T=14 mrd y . . . Rn-220 . . . Rn-219 . . . Rn-222 32 s . . . Pb-208 stabile . . . Pb-207 stabile . . . Pb-206 stabile Actinium serie U-235 T=0. 72 mrd y 3, 9 s Uranium serie U-238 T=4. 5 mrd y 3, 8 day Main processes: Rn-emanation: deliberation of Rn molecules from chem. -phys. binding in solid phase of soil (to gas form in soil) 10 Rn-exhalation: outflow of Rn gas from soil to atmosphere.

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Rn-222 concentrations indoor and outdoor In winter: due to small ventilation, the Rn-gas accumulates indoor „cultural man”: 80 % indoor Living room (indoor) Outdoor, air: 100 -500 Bq/m 3 Rn-222 (noble gas) ventilation 5 -10 Bq/m 3, to height of nearly 200 -300 m α Ra-226 Rn-222 exhalation soil 500 -2000 Bq/m 3 Rn-222 12 emanation

https: //www. sum. kit. edu/radon-messen. php 13

Rn-conc. due to periodic ventilation, for short (minutes) time intervals • CRn (Bq/m 3) Short and periodic ventilations, 5 -6 hourly 300 200 100 6 h 9 h 12 h 15 h 18 h 14

Radon in the house and protection 15 http: //mr-radon. ca/wordpress/wp-content/uploads/2014/01/how. Radon. Enters. House. png

Artificial exposures • The main sources of the impact are: contamination of air, soil, vegetation etc. in the close environment of: nuclear power plants (NPP) and isotope labs, due to discharges of radionuclides • contamination of spring waters in the close environment of Radioactive Repositories • Nuclear weapons tests • Naturally Occurring Radioactive Material • Medical patient: X-ray diagnostic tests, therapy 16

https: //en. wikipedia. org/wiki/Nuclear_weapons_testing#/media/File: Worldwide_nuclear_testing. svg 17

Tritium activity concentration on the surface earth 18

Sr-90 activity concentration in teeth and milk teeth year 19

Transport, migration of radionuclides discharged from NPP/isotope lab. Exposure pathways (Expositionspfaden) external expos. inhalation Vegetables Atmosph Source Soil intakes Feeding vegetation irrigation Surface water Sediment water plants, fishes Man Animals, anim. prod. intakes external expos. • A radioaktív anyag migrációja a bioszférában és besugárzási útvonalak az ember esetén (szaggatott nyíl a sugárzás, folyamatos nyíl a radioaktív anyag terjedését jelöli) 20

Averaged dose levels, inc. confidence ranges(natural sources) Sources, pathways Mean values and ranges (m. Sv) Cosmic rays, external, annual effective dose 0. 38 (0. 3 -1. 0) Inhalation and ingestion of cosmogene radionuclides (internal, 0. 012 (0. 008– 0. 02) committed effective dose, annual) Terrestrial, external, annual effective dose, outdoor , indoor 0. 45 (0. 3 -0. 6) 0. 55 (0. 4 -0. 8) Terrestrial, annual internal, committed eff. dose (without Rn and daughters) 0. 27 (0. 2 -0. 5) Terrestrial, annual internal, comitted eff. Dose from the Rn daughters 1. 2 (0. 5 -5. 0) Terrestrial, annual internal, committed equivalent dose to lung, due to 10 Rn daughters Technical Enhanced Natural Occurring Radioactive Material (TENORM): indoor (building material: Ra-226 content) 21

Averaged individual doses to public (artificial sources) Sources, components Mean and range (m. Sv) Medical, external (mainly X-ray diagn), annual effective dose 1. 5 (0. 1 -5) From NPP (1 -5 km far), annual 0. 01 ( - 0. 1) Atomic bombs (Hirosima, Nagaszaki, inside the city area) 100 -5000 Nuclear tests, North hemisphere 0. 1 -2 , South < 0. 01 Chernobyl accident, effective dose within r ≈ 30 km circle 1 -20 Central and West Europe 0. 1 -2 North America 0. 01 Japan 0. 01 South hemisphere < 0. 01 SE X-ray stations, eff. dose by films (-2009, last 3 years): ≈ 0. 5 m. Sv / y SE dentist X-ray stations (last 3 years): < 0. 3 m. Sv / y SE nuclear medic. labs (last 3 years): ≈ 0. 7 m. Sv / év 22

Heart perfusion scintigraphy Tumor scintigraphy Heart perfusion scintigraphy Mammo-scintigraphy Kidney scintigraphy Lkiver spleen scintigraphy Thyroid diagnostic Intervention Angiography Chest CT Abdomen CT Bile test Mammography Chest Limb Medical exposure (patient dose per test) 23

Determination of exposures • External dose: nearly 100 % in medical, dental praxis - X-ray diagn. , Radiation therapy - Meassurement of X-rays (≈ 60 ke. V 20 -150 ke. V): mainly by ionization chamber (energy dependency) • Internal dose: Radioactive isotopes: used as tracers to test the metabolic systems (nuclear medicine), and in internal radioisotope therapy (I-131 to thyroid) Dose assessment: Calculation from measured radionuclide concentration of air and food samples (inhalation and ingestion dose). - α-, β- and γ-ray contamination of whole body, surfaces, samples etc. : special sample processing, detectors: Na. I(Tl), semiconducter ones (Ge, Si) 24

Personel monitoring, dosimeter Hp(10). Personal dose equivalent Ambient dose equivalent H*(10) 25

Whole body counter, determination incorporated radionuclides (geometries used) detector 26

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Na. I scintillation kit and dose rate meters 700 MBq Tc-99 m, bone scint. gh. patient 1 m from body 9, 97 mikro Sv/h On surface the body 92 mikor Sv/h 9, 97 mikor. Sv/h dose rate 28

A Cs-137 in the inhabitants of capital Budapest (measured by: Andrási, A. , (KFKI)) Activ. /body weight Atmospheric nuclear tests (SU-USA: 1945 -1964), later on by less intensity: Fr, Gr. B, China, …) 29

Environmental monitoring, early warning system Continously (mainly by 2 -10 minutes frequency) measured dose rates, usually 1 m heigh from the surface „Rainpeaks”: due to intensive wash out to the surface, from atmosphere, and some patient (bone scint. grp. Tc-99 m) go nearly to the detector 30

Ru-106 2017 okt. —nov. 31

Literature: Basic safety standards. IAEA Safety Series No. 115, Vienna, 1996) Kanyár, B. , G. J. Köteles: Dosimetry and Biological Effects of Ionizing Radiation, Chapter 10, in: Vértes, A. , Z. Klencsar (eds): Handbook of Nuclear Chemistry, Springer, 2010 UNSCEAR Reports (2 -4 yearly, UN New. York, …) EU Radiation Protection No. 136, 2004. European guidelines on radiation protection in dental radiology ICRP (Intern. Comm. on Radiol. Prot. ) Public. No 103, Pergamon P. , New. York, London, 2007. IAEA Tech. Doc Dr. Kanyár Béla presentation 2004 -2013 https: //www. youtube. com/watch? v=rrew 5 Xaqho. Y 32