SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY Technical basis of occupational dosimetry- general review Antti Kosunen, Hannu Järvinen STUK 2017 NACP-RPC COURSE Occupational dosimetry in interventional radiology, - cardiology and nuclear medicine 27-29 September 2017 Södersjukhuset, Stockholm, Sweden
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SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Technical basis of occupational dosimetry-general review
Antti Kosunen, Hannu Järvinen STUK
2017 NACP-RPC COURSE
Occupational dosimetry in interventional radiology, -cardiology and nuclear medicine
27-29 September 2017 Södersjukhuset, Stockholm, Sweden
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Occupational dosimetry • Dosimetric quantitities • Basics of personal dosemeters
•Principles of calibration of personal dosemeters • Measurement traceability • Principles of evaluation of uncertainties
Antti Kosunen, 2017
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Physical quantities: • to characterize the reference radiation field • basis for protection and operational quantities
Protection quantities • International Commission on Radiological Protection (ICRP) • related to anatomy of body (organ dose) and to biological
sensitivity of tissues and organs • basis for dose limits • non-measurable (complicated phantom set-up)
Operational quantities • The international Commission on Radiation Units and
Measurements (ICRU) • conservative estimation of protection quantities • measurable
Dosimetric quantities
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Fluence rate , (flux density) Unit: 1/m2 s
Physical quantities
Antti Kosunen, 2017
The absorbed dose, D, is the quotient of de and dm, where de is the mean energy imparted by ionizing radiation to matter of mass dm
The fluence, Φ, is the quotient of dN and dA, where dN is the number of particles incident on a sphere of cross-sectional area dA Unit: 1/m2
dAdN
=Φ
dtdΦ
=ϕ
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
The absorbed dose, D, is the quotient of de and dm, where de is the mean energy imparted by ionizing radiation to matter of mass dm
The kerma, K, (Kinetic energy released per unit mass) The kerma is the expectation value of the energy transferred from uncharged particles to charged particles per unit mass at a point of interest, including radiative-loss of energy but excluding energy passed from one charged particle to another
dmdEK tr=
Unit; J kg-1, The special name is gray (Gy).
Physical quantities
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
The absorbed dose, D, is the quotient of de and dm, where de is the mean energy imparted by ionizing radiation to matter of mass dm
The absorbed dose, D, is the quotient of dε and dm, where dε is the mean energy imparted by ionizing radiation to matter of mass dm
Unit; J kg-1, The special name is gray (Gy).
Physical quantities
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
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Equivalent dose in an organ or tissue, HT
• wR radiation weighting factor for a radiation quality R
• DT,R the average absorbed dose, in the volume of a specified organ or tissue T, due to radiation of type R . • The sum is performed over all types of radiations involved.
• The unit of equivalent dose is J kg-1. The special name sievert (Sv).
Protection quantities
Antti Kosunen, 2017
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Effective dose, E
Protection quantities
• wT tissue weighting factor
• Weighted sum of tissue equivalent doses
• All organs and tissues sensiive by stochastic effects
• The unit of equivalent dose is J kg-1. The special name sievert (Sv).
1=Σ Tw
Antti Kosunen, 2017
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Protection quantities Effective dose, E
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
• Voxel anatomical phantoms representing adult Reference Male and Reference Female
• For whole body irradiations in different geometries the conversion factors are calculated.
• For known exposure geometries effective dose estimates can be made using conv. factors.
Protection quantities Effective dose, E
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Protection quantities Effective dose, E
Picture from ICRP 103
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
• ”The effective dose serves as the basis for the contractual relationship in the regulatory framework, and it has utility in comparative evaluation of alternative work practices.”
• ”The radiation and tissue weighting factors are invariant with respect to age and sex, and hence the weighted sum, the effective dose, is not applicable to a specific individual.”
Protection quantities Effective dose, E
ICRP Publication 116
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Protection quantities Picture from ICRP 103
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Operational quantities, NEW work • Work for renewal of operational quantities is in progress • Final Draft of Joint report by ICRP and ICRU is open for comments • Draft not to be referenced
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Operational quantities
In this presentation operational quantities were presented according to current definitions and practise !
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Operational quantities
• H, dose equivalent in a point in tissue
• D, the absorbed dose in a point
• Q, physical quality factor based on LET dependence of radiation
• Based on definition by ICRU.
• Unit: Jkg-1. The special name is sievert (Sv).
Dose equivalent, H
QDH =
Presenter
Presentation Notes
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
• Q is defined as a function of the unrestricted linear energy transfer, L of charged particles in water:
Operational quantities Dose equivalent, H
• The function is based on considerations of radiobiologicall investigations on cellular and molecular systems and results from animal experimentation.
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
ICRU sphere phantom • Aproximates the human body / scattering and attenuation of
radiation • For all types of radiation in area monitoring (ambient and directional dose equivalents)
• Sperical phantom with 30 cm diameter
• Density 1g/cm-3
• Composition (mass %): 76,2 % oxygen
11,1 % carbon 10,1 % hydrogen 2,6% nitrogen
Operational quantities
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
The ambient dose equivalent, H*(d), at the point in a radiation field, is the dose equivalent that would be produced by the corresponding expanded and aligned field, in the ICRU sphere at a depth, d, on the radius opposing the direction of the aligned field
Unit: Jkg-1. The special name is sievert (Sv).
Antti Kosunen, 2017
Operational quantities
Expanded and aligned radiation field
Picture from: Calibration of radiation protection monitoring instruments , IAEA Safety reports Series No.16, 2000
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
The directional dose equivalent, H’(d, Ω), at the point in a radiation field, is the dose equivalent that would be produced by the corresponding expanded radiation field, in the ICRU sphere at a depth, d, on the radius in a specific direction, Ω.
Unit: Jkg-1. The special name is sievert (Sv).
Antti Kosunen, 2017
Operational quantities
Expanded radiation field
Picture from: Calibration of radiation protection monitoring instruments , IAEA Safety reports Series No.16, 2000
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
The personal dose equivalent, Hp(d), at the point in a radiation field, is the dose equivalent in ICRU tissue at depth d below a specified point on a body. Unit: Jkg-1, The special name is sievert (Sv).
Antti Kosunen, 2017
To produce backscatter eq. to body calibrations of dosimeters on phantoms
Operational quantities
Definition on ”a body”
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Part of body d (mm) Whole body 10 Skin, hands, wrist, feet 0,07 Lens of the eye 3
Operational quantities: Specified depth d
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Operational quantities - summary
• Hp(0,07) has been used instead of Hp(3) for dose to the lens of eye
• Standards to test and calibrate eye dosimeters for Hp(3) are in progress
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Relations of protection and operational quantities
Antti Kosunen, 2017
• Generally and for photon radiation Hp(10) overestimates the effective dose, especially with low < 100 kV range • Depends on irradiation geometry for effective dose
Hp(10)/E
Picture from EC, radiation protection No 160. Technical recommendations for Monitoring Individuals Occupationally E xposed to External Radiation, 2009
Presenter
Presentation Notes
Could be designde without response to backscatter, directly proportional fo Hp. Backscatter from dosemeter itself Radiation protection No 160
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Protection quantities (ICRP): • Mean absorbed dose in an organ or tissue DT , [Gy] • Equivalent dose in an organ or tissue HT , [Sv] • Effective dose E , [Sv]
Phantom models, definitions by ICRP Calculated using weighting factors
Calculated using Q(L) and phantom models (Sphere, slab). Validated by measurements H=QD
Compared by measurements and Calculations in anthropomorfic phantoms
Antti Kosunen, 2017
Family of dosimetric quantities
Actual measurand, device specific
Calibration, type tests
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Passive personal dosemeters
Passive: No power circuitry or inbuild software (to directly indicate the value of quantity) • Thermoluminescence dosimetry, TLD • Optically stimulated luminescence, OSL • Radiophotoluminescence, RPL • Film
• Direct ion storage dosemeters (DIS); passive
as separate readout device is required
Dosemeter photos by Maaret Lehtinen
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Passive personal dosemeters
Thermoluminescence dosimetry TLD Optically stimulated luminescence OSL Both are based on similar basic principle: • Electron-hole pairs produced by ionizing radiation are trapped at specific energy levels at the conduction band in the crystal
⇒ Free charge carrier can be released by heating (TLD) or ⇒ by optical stimulation (OSL) ⇒ Return of free charge to valence band emits extra energy by light
⇒ Emitted light intensity is proportional to ionization ie. to Absorbed dose
Antti Kosunen, 2017
Presenter
Presentation Notes
REFERENSSI
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Passive personal dosemeters TLD and OSL
• Crystals used for dosimetry are small in size, storing the dose for
read-out • Separate reader is required: - TLD: heating of crystal typically by hot nitrogen gas flow + readout of
light - OSL. Different stimulation techniques, light sources: lasers, LEDs,
lamps • Personal dosimeter has typically several crystals with diffrent filters - Separation of different dose quantities Hp(10) and Hp(0,07) Similar phosphor materials : TLD: LiF:Mg,Ti, CaF2:Mn, CaSO4:Mn, (Li2B4O2:Mn). OSL: Al2O3:C in routine use for personal dosimetry.
Antti Kosunen, 2017
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Passive personal dosemeters
Some advantages of TLD (depends on material) • Sensitive for low doses of few microGy
• Commersicially available
• Reuseable after annealing procedure, low cost per dosemeter
• Commercial automatic, rapid readers with interfaced software
Antti Kosunen, 2017
TLD Practical materials requires impuries to create lattice defects / optimal traps for electrons - Light emitted for specific temperatures => clow curve - Specific clow peaks for result.
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Passive personal dosemeters
Some advantages of OSL Dosimeters • Result can be read out at room temperature. • No need of correction factors for individual elements. • Dosemeters can be re-analysed several times. • No sensitive for changes in temperature => minimal fading during storage
Antti Kosunen, 2017
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Passive personal dosemeters
Film • Radiation interaction on film (AgBr) change the
light transmission through film
• Transmisson measured by densitometer and converted to optical density.
• Energy dependence is pronouinced for lower photon energies
• Requires developing/prosessing of film.
• Dosemeters: Filters to separate Hp(10) and Hp(0,07)
Film personal dosemeter. These film dosemeters were used in Finland untill middle of 1990s.
Presenter
Presentation Notes
REFERENSSI
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Passive personal dosemeters
DIS- Direct Ion Storage
• Charge / current produced by ionization is measured by ionization chamber principle
• Modified analog memory element as an ionization chamber
• Also MOSFET detectors
• Separate reader device
• Digital memory for storage of Information
• Results are not zeroed during read-out. Can be read several times Antti Kosunen, 2017
Photo provided by Matti Vuotila/ Mirion-Rados
Presenter
Presentation Notes
REFERENSSI
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
• Hp(3), eye lens, • Hp(0,07), finger, wrist • Operating principles typically TLD (…OSL, RPL) • Beeta and photons.
Eye lens and extremity dosemeters
Antti Kosunen, 2017
Photo: finger dosemeters on ISO rod calibration phantom. Calibration by beeta standard irradiator
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Active personal dosemeters, APDs
• Body dosemeters, mainly Hp(10), some also Hp(0,07)
• Has powered electronic circuitry and associated software for visible or audible indication of integrated dose and/or dose rate
• Preset visual and audible alarms
• Often used as supplementary dosemeters to the passive dosemeter
• Approved APDs for official exposure control exist in some countries.
• Challenges. - Response to pulsed radiation (false counting, if counting for external radiation pulses) - Angular dependence
Antti Kosunen, 2017
EC, radiation protection No 160. technical recommendations
Presenter
Presentation Notes
European Commission, radiation protection No 160. technical recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, Directorate-general for Energy and Transport directorate H- Nuclear Energy Unit H.4-Radiation protection, 2009
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Active personal dosemeters, APDs
Challenge with pulsed radiation, high dose rate, Recommendations for interventional radiology /cardiology: • Regular calibration for Hp(10) preferably with X-rays in a calibration
laboratory
• ADP tool to optimize and reduce exposure and wear above the apron
• ADP not recommeded for legal dose record … today more advanced ADPs are available…
Optimization of RAdiation protection for MEDical staff (ORAMED), 2008…
Antti Kosunen, 2017
Presenter
Presentation Notes
European Commission, radiation protection No 160. technical recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, Directorate-general for Energy and Transport directorate H- Nuclear Energy Unit H.4-Radiation protection, 2009
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
The personal dose equivalent, phantoms
Antti Kosunen, 2017
Body: ISO water slab 300mm*300mm*150mm with PMMA walls Wrist: ISO water pillar with PMMA walls Finger: ISO PMMA rod Eye lens: Head phantom (Behrens, PTB)
Operational quantities -calibration The ambient and directional dose equivalent: Calibration of dose/ doseratemeters in air
Photo on left at STUK. Schematic picture of phantoms from:, IAEA Safety reports Series No.16, 2000
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Operational quantities -calibration
• For calibration of eye lens dosemeters, the fluence - dose to eye lens conversion data exist., Hp(3)
• International standards expected.
• PMMA head phantom for calibration has been introduced
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY Antti Kosunen, 2017
Figure from: J. Böhm et. al., ISO recommended reference radiations for the calibration and proficiency testing of dosemeters and dose rate meters used in radiation protection, Radiation Protection Dosimetry Vol. 86, No 2, 1999
Operational quantities -calibration
ISO reference radiation fields
Quantification of radiation fields in terms of air kerma
Conversion to operational quantities: ISO tabulated Conversion factors
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY Antti Kosunen, 2017
Measurement traceability
• Traceability of measurement: Unbroken chain of measurements/calibrations with their uncertainty evaluations at each step.
• To assure the absolute value of dose • Calibrations of dosemeters either at accredited laboratory or at national laboratory
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Assessment of uncertainties Follow int. guidance:
ISO/IEC Guide 98 Part 3 Guide to the expression of uncertainty in measurement (ISO: Geneva) (1995). ISO/IEC Guide 98 Part 3-1 Guide to the expression of uncertainty in measurement (GUM)-Supplement 1: Numerical methods for the propagation of, distributions. (ISO: Geneva) (2008). BIPM, IEC, IFCC, ISO IUPAC, IUPAP and OIML. Joint Committee for Guides in Metrology Guide to the expression of uncertainty in measurement,(BIPM:Sèvres) (2008). http://www.bipm.org/utils/ EUROPEAN COMMISSION RADIATION PROTECTION NO 160, Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, 2009
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
Assessment of uncertainties
True value never precisely known Measurement error not precisely known Measurement uncertainty
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Step 1/6. Determination of the model function • Identification of all input quantities
(influence quantities) • Form the measurement model
equation
Step 2/6. Estimation of uncertainties for influence quantities • By standard deviation with
probability density function • Quntification of sub-uncertainties:
- Results from type tests - Resuts from other
tests/experiments
Antti Kosunen, 2017
Assessment of uncertainties, procedure
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
• Contribution of each source of uncertainty to the standard uncertainty of measurement result
• Reliability of the uncertainty estimate (excellent, good, reasonable, rough)
Antti Kosunen, 2017
Step 3/6. Combination of Type A and Type B uncertainties Step 4/6. Propagation/ summation of uncertainties for model function to obtain combined uncertainty - Sensitivity factors - Degrees of freedom Step 5/6. Determination/estimation of expanded uncertainty using coverage factor (for required confidence probability) Step 6/6. Evaluation reliability of uncertainty estimate - Results from intercomparisons - Results from blind test
Assessment of uncertainties, procedure
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
EU 160 report Recommendations Dose ranges based on annual dose limits for public • For Hp(10) for a single field component not below 1 mSv in proportion to the wear period, the combined standard uncertainty < 30% for photon/electron workplace fields and < 50% for neutron fields. • For a measurement of Hp(3) and single field component for a quantity value equal to or greater than 15 mSv in proportion to the wear period, the combined standard uncertainty should < 30%. • For Hp(0.07) for a single field component for a quantity value equal to or greater than 50 mSv in proportion to the wear period, the combined standard uncertainty < 30%. • The combined standard uncertainty for values of assessed annual dose values at or near the dose limit < 20 %, or in a more general probabilistic approach the 95% confidence interval should not exceed 0.67 to 1.5, after all corrections have been made.
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
EU 160 report highlights also the importance of factors affecting on accuracy on field: a) Implemented quality system (general laboratory and staff quality, quality management, software, conformity of equipment used, calibration and internal performance tests) b) routine external performance tests of the dosimetry, periodic inter-comparisons between systems providing similar services. c) determination of the dosimetric characteristics of the system by type-testing d) information on the energy and direction characteristics of the radiation field being measured, plus other factors (environmental conditions, dosemeter wear position,etc.).
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY
Antti Kosunen, 2017
ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2-4). ICRP, 2010. Conversion Coefficients for Radiological Protection Quantities for External Radiation Exposures. ICRP Publication 116, Ann. ICRP 40(2-5). J. Böhm et. al., ISO recommended reference radiations for the calibration and proficiency testing of dosemeters and dose rate meters used in radiation protection, Radiation Protection Dosimetry Vol. 86, No 2, 1999 Calibration of radiation protection monitoring instruments, IAEA Safety reports Series No.16, 2000. European Commission, radiation protection No 160. technical recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, Directorate-general for Energy and Transport directorate H- Nuclear Energy Unit H.4-Radiation protection, 2009. R. Behrens, Compilation of conversion coefficients for the dose to the lens of the eye, radiation protection Dosimetry Vol 174, No.3., 348-370, 2016. The international Commission on Radiation Units and Measurements (ICRU), Fundamental quantities and units for ionizing radiation (revised) , ICRU Report No. 85, Journal of the ICRU, Volume 11, No 1, 2011
References
SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN RADIATION AND NUCLEAR SAFETY AUTHORITY