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Radiation Protection in Laboratory work. Mats Isaksson, prof. Department of radiation physics , GU mats.isaksson@radfys.gu.se. Fundamental principles (ICRP). Justification Optimisation Application of dose limits. Fundamental principles (ICRP). Justification

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Radiation Protection in Laboratory work


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    radiation protection in laboratory work

    RadiationProtection in Laboratorywork

    • Mats Isaksson, prof.Departmentofradiationphysics, GUmats.isaksson@radfys.gu.se
    fundamental principles icrp
    Fundamental principles (ICRP)
    • Justification
    • Optimisation
    • Application of dose limits
    fundamental principles icrp 1
    Fundamental principles (ICRP)
    • Justification
    • “Any decision that alters the radiation exposure situation should do more good than harm.”
    fundamental principles icrp 2
    Fundamental principles (ICRP)
    • Optimisation
    • “The likelihood of incurring exposure, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors.”
    • (The ALARA-principle)
    fundamental principles icrp 3
    Fundamental principles (ICRP)
    • Application of dose limits
    • “The total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed the appropriate limits specified by the Commission.”
    • N.B. ”… other than medical exposure of patients…”
    • ICRP-report 103 identifiesthree exposure situations: planned, emergency and existing
    radiation doses 1
    Radiationdoses 1
    • Absorbeddose (unit 1 Gy = 1 J kg-1)
    • Used in e.g. radiationtherapy to specify the dose to the tumor
    • Different radiationqualities(a, b, g, n) can cause different degree of harm – weightingnecessary
    radiation doses 2
    Radiationdoses 2
    • Equivalentdose (unit 1 Sv = 1 J kg-1)
    • Used to calculate the dose to a tissue or organ
    • Weightingfactors for different radiationqualities given by ICRP
    • Can be estimated by measurablequantitiese.g.personaldoseequivalent
    radiation doses 3
    Radiationdoses 3
    • Effectivedose (unit 1 Sv = 1 J kg-1)
    • Used to calculate the wholebodydose that gives the same detriment as the actualpartialbodydose
    • Enables a comparison of risk from different exposure distributions
    radiation doses 3 1
    Radiationdoses 3´
    • Illustration to effectivedose
    radiation doses 4
    Radiationdoses 4
    • Effectivedose (unit 1 Sv = 1 J kg-1)
    • Weightingfactors for different organs and tissues are given by ICRP
    • Can be estimated by measurablequantitiese.g.ambientdoseequivalent
    the bottom line
    ”The bottom line”

    Effectivedose / mSv a-1

    Medical diagnostics

    Caesium-137

    Naturallyoccurring radionuclides in food

    Radon in indoor air

    K in the body

    Soil and building materials

    Cosmic radiation

    Smoker (and ex. smoker)

    Never-smoker

    Reindeer keepers

    Frequent air traveller

    Drinking water problem

    x ray and nuclear medicine
    X-ray and nuclear medicine

    From ”Nuklearmedicin” by Sten Carlsson and Sven-Eric Svensson (available at http://www.sfnm.se/)

    radiation sources
    Radiationsources
    • Radioactivesources
    • Unsealed – liquid, gas, powder
    • Sealed
    • Technicalequipment
    • X-raymachines
    • Accelerators
    x ray equipment
    X-rayequipment

    Generation of x-rays X-rayspectrum

    radiation safety in the lab
    Radiationsafety in the lab
    • Externalirradiation
      • Short range radiation, e.g. a, mostly harmless when the source is outside the body
      • b-emitters may cause severe skin damage if they are in contact with naked skin
    radiation safety in the lab 1
    Radiationsafety in the lab
    • Internalirradiation
      • Radioactive substances in non-sealed sources (gas, liquid, powder) cause special concern
      • Can enter the body through ingestion, inhalation, wounds or through the skin
    radiation safety in the lab 2
    Radiationsafety in the lab
    • Externalirradiation: Factors to be considered
      • Time – more time spent in the radiation field gives a larger radiation dose
      • Distance – inverse square law (for point source)
      • Shielding – shielding material depends on the source (a, b, g)
    radiation safety in the lab 3
    Radiationsafety in the lab
    • Externalirradiation: Inversesquarelaw
    radiation safety in the lab 4
    Radiationsafety in the lab
    • Externalirradiation: Inversesquarelaw
    practical alara
    Practical ALARA
    • Practicebeforeworkingwith the real source
    • Educationbeforework
    • Separateoffice and labwork
    • Wearprotectiveclothing and gloves
    • All labsshould be markedwithsigns
    • Eat, drink etcoutside the lab
    radiation safety in the lab 5
    Radiationsafety in the lab
    • Externalirradiation: Shielding: b-range in mm

    H-3: 19 keV; C-14: 156 keV; S-35: 167 keV; P-32: 1711 keV

    radiation safety in the lab 6
    Radiationsafety in the lab
    • Externalirradiation: Shielding: g HVL in mm

    I-125: 35 keV; Tc-99m: 140 keV; I-131: 365 keV; Y-88: 1836 keV

    radiation safety in the lab 7
    Radiationsafety in the lab
    • Internalirradiation: Factors to be considered
      • Activity – the larger the activity the larger the radiation dose (for a given radionuclide)
      • Radionuclide – amount of energy per disintegration; type of radiation
      • Metabolism – element and chemical form determine the residence time in the body and concentration in organs
    radiation safety in the lab 8
    Radiationsafety in the lab
    • Internalirradiation: Effectivehalf-life
    radiation safety in the lab 9
    Radiationsafety in the lab
    • Classification of radionuclides
      • Class A: very high radiotoxicity (ex. a-emitters: Pb-210, Pu-238, Cf-252,…)
      • Class B: high radiotoxicity (Na-22, Ca-45, Co-56, Co-60, Sr-89, In-114m, I-125, I-131, Cs-137,…)
      • Class C: moderate radiotoxicity (C-14, Na-24, P-32, S-35, Ca-47, Cr-51, Fe-55, Fe-59, Co-57, Co-58, Zn-65, Y-90, I-123, Tl-201…)
      • Class D: lowradiotoxicity (H-3, C-11, Tc-99m,…)
    deterministic effects approximate threshold values
    Deterministiceffects – approximatethresholdvalues
    • >0,1 Gy Effects on embryo and fetus
    • 0,5 Gy Temporarysterility, men
    • 2 Gy Cataract
    • 4 Gy Temporaryhair loss
    • 5 Gy Skin erythema
    • 6 Gy Permanent sterlility, men
    • 8 Gy Pneumonia
    • 2-12 Gy Permanent sterility, women
    deterministic effects whole body irradiation
    Deterministiceffects – wholebodyirradiation
    • Lethaldose (50 % of exposed individualssurvive): 3-4 Gy
    • Acuteradiationsyndrome – bloodforming organs, gastro-intestinaltract & central nervous system
    stochastic effects no threshold
    Stochasticeffects – no threshold
    • Cancer and hereditaryeffects
    • Increasing risk with increasingdose
    • Risk factoronlyapplicable on a population level
    • LNT-hypothesis
    laws and regulations
    Laws and regulations
    • Strålskyddslagen SFS 1988:220
    • Employers obligations
    • Workers obligations
    • Licencedemands
    • Waste handling demands
    • Medical examination
    • Young people
    • Strålskyddsförordningen SFS 1988:293
    relevant regulations ssm
    Relevant regulations (SSM)
    • SSMFS 2010:2 Radioactivewaste
    • SSMFS 2011:2 Clearance of materials, premises, buildings och grounds
    • SSMFS 2008:25 Radiography
    • SSMFS 2008:51 Protection of workers and the public
    • SSMFS 2008:28 Laboratory work with unsealedradioactivesources
    license from ssm for work with ionizing radiation
    License from SSM for work with ionizingradiation
    • Licensee: University of Gothenburg
    • Contact person Annhild Larsson
    • Radiationprotectionexpert (GU) Annhild Larsson
    • Radiationprotectionexpert (Rad. Phys.) Mats Isaksson
    • License valid to 2016-02-07
    ssmfs 2010 2 radioactive waste
    SSMFS 2010:2 Radioactivewaste
    • Revised limits
    • Documentationkept for 5 years
    • Yearlyreportto SSM concerning releases tosewage
    ssmfs 2008 51 dose limits msv
    SSMFS 2008:51: Dose limits (mSv)

    *) Will probably be revisedto20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv

    ssmfs 2008 51 protection of pregnant or breast feeding women
    SSMFS 2008:51: Protectionof pregnant or breastfeedingwomen
    • Women in fertile agesshould be informedof the risks for the fetus
    • Pregnant womenhave the right to be relocated (if not, the effectivedoseto the fetusshould not exceed 1 mSvduring the rest of the pregnancy
    • Breastfeedingwomenshould not be exposedto a risk ofbeingcontaminated in the work
    ssmfs 2008 51 categorization
    SSMFS 2008:51Categorization
    • Protected area (”Skyddat område”)
    • Category B worker
    • localrules (could be given verbally)
    • signswith the text ”skyddat område” and typeof source
    • Category B (max activity per workactivity)
    • Gamma emittingradioniclides: < 100 MBq
    • Beta emitters:
      • < 10 MBqfor beta energy> 0,3 MeV
      • < 100 MBq for beta energy0,1-0,3 MeV
    • No workwithopenradiography
    ssmfs 2008 28 restrictions on activity in laboratory work
    SSMFS 2008:28 Restrictions on activity in laboratorywork

    N.B. Localrestrictionsconcerning max activity at departments

    Arb I: Risk of inhalation

    Arb II: Risk of external and internal exposure; small risk of inhalation

    ssmfs 2008 28 documentation reporting
    SSMFS 2008:28 Documentation/reporting
    • Data whichshould be documented, signed and keptavailable for concernedpersonnel:
    • Received and storedradioactivesubstances, and theiractivities
    • Possession ofcalibrationsources
    • Results from ventilations and contaminationmonitoring
    • Results from personneldosemonitoring and estimationsof internal doses
    thank you for your patience

    Thankyou for yourpatience

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