Establishment of diagnostic radiology calibrations in an SSDL
Prepared by Miloš Živanović
Background
• Diagnostic radiology is the largest contributor to the total population dose from artificial sources of radiation
• Doses from radiological procedures are usually small, but in some cases, such as interventional procedures, they can even cause deterministic effects
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Background
• Quality Control (QC) checks in diagnostic radiology are performed to ensure the image quality on one side and low dose on the other side
• Testing equipment must be regularly calibrated to ensure accurate measurements
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
International measurement system
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
IAEA TRS 457:2007 , pp. 10
IAEA/WHO SSDL network
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Established in 1976 to ensure traceability of measurements
• Objectives: improve the accuracy of measurements, establish traceability, achieve consistency, foster cooperation
• Membership composed of SSDLs, PSDLs, international organizations
CIPM Mutual Recognition Arrangement
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• National Metrology Institutes and Designated Institutes are signatories of CIPM MRA
• BIPM maintains a database of all signatories and their Calibration and Measurement Capabilities
• Some SSDLs are members of CIPM MRA, but some are not
Abbreviations• SSDL and PSDL – Secondary (Primary) Standards Dosimetry
Laboratory
• NMI – National Metrology Institute
• DI – Designated Institute
• CMC – Calibration and Measurement Capabilities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Important literature• IEC 61267:2005: Medical diagnostic X-ray equipment - Radiation
conditions for use in the determination of characteristics– Definition and establishment of reference radiation qualities
• IAEA TRS 457:2007: Dosimetry in diagnostic radiology : an international code of practice– Code of practice for calibrations of diagnostic radiology equipmenthttps://www.iaea.org/publications/7638/dosimetry-in-diagnostic-radiology-an-international-code-of-practice
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
https://www.iaea.org/publications/7638/dosimetry-in-diagnostic-radiology-an-international-code-of-practice
Important literature• IEC 61674:2012: Medical electrical equipment - Dosimeters
with ionization chambers and/or semiconductor detectors as used in X-ray diagnostic imaging
• IEC 61676:2002: Medical electrical equipment - Dosimetricinstruments used for non-invasive measurement of X-ray tube voltage in diagnostic radiology
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Important literature• BIPM guide to the expression of uncertainty in measurements
(JCGM 100:2008)
• IAEA TECDOC 1585: Measurement Uncertainty, A Practical Guide for Secondary Standards Dosimetry Laboratories
https://www.iaea.org/publications/7913/measurement-uncertainty
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
https://www.iaea.org/publications/7913/measurement-uncertainty
Which services should an SSDL provide?
• Air kerma free-in-air is used for most QC measurements; this quantity is commonly disseminated by PSDLs
𝐾𝐾 =d𝐸𝐸trd𝑚𝑚
• This quantity is the most important quantity for diagnostic radiology calibrations
• Unit: Gy
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Which services should an SSDL provide?
• Kerma area product (PKA) and kerma length product (PKL) are usually established in SSDLs, based on the traceable kerma measurements and length measurements.
• Only 5 laboratories have CMCs in BIPM KCDB for PKAand only 4 for PKL
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Which services should an SSDL provide?
• (Non-invasive) tube voltage measurement
• Practical Peak Voltage is adopted by IEC standards and IAEA TRS 457
• Different quantities are in use, Average Peak Voltage, Average Voltage etc.
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Which services should an SSDL provide?
• Exposure time• Current time product• Total filtration?• HVL measurement?• Beam profile measurement?
• Many manufacturers offer calibrations or testing in the mentioned quantities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Checklist – what will you need to establish calibrations
• Irradiation room and control room– Restricted access– Appropriate shielding
• X-ray unit with calibration bench and auxiliary equipment– Filters and filter wheels– Lasers for positioning
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Checklist – what will you need to establish calibrations
• Secondary standards traceable to SI• Measurement equipment for ambient conditions,
length, time etc.• Quality system (according to ISO/IEC 17025)• Competent staff• UsersEstablishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Finding users• Establishing calibration service in diagnostic
radiology is expensive (the costs can exceed 500000 euro)
• Needs for calibrations in terms of different quantities and in different radiation qualities should be evaluated
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Existing equipment and facilities
• Equipment for DR calibrations can be used for different types of calibrations (e.g. radiation protection calibrations) and vice versa
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Facilities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Facilities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• At least one irradiation room and one control room should be available
• Room size should be appropriate to avoid scatter from the walls and furniture
Facilities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Walls, door and windows should be appropriately shielded (usually not a big issue for X-ray facilities)
• Access to irradiation room and control room should be restricted
Facilities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Environmental conditions should be monitored and controlled (temperature between 18 °C and 24 °C)
• Temperature change not greater than 1 °C/h
• X-ray unit generator and cooling system might cause significant heating of the room
X-ray unit• F – focus• K1, K2, K3 –
collimators• F1 – additional
filtration• F2 – filter wheel• M – Monitor
chamber• D – detector• B – calibration
bench
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
F
B
X-ray unit• Anode material depends on the application; tungsten is used
for most applications• Anode angle should not be larger than 27° (IAEA TRS 457:
2007) or lower than 9° (IEC 61267:2005)• Liquid cooling of the anode is preferable• Inherent filtration should be lower than the equivalent of 2.5
mm Al. Otherwise, some radiation qualities will not be achievable (IEC 61267:2005, IAEA TRS 457: 2007)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
X-ray unit• Filters should be of 99.9 % purity
• Filter thickness should be known within 0.01 mm (filters for HVL measurements)
• Ripple should be below 10 % (4 % for mammography) (IEC 61267:2005)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
X-ray unit• Apertures should be constructed with appropriate opening
angle (IAEA TRS 457: 2007)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Radiation qualities• Introduction of standard radiation qualities is necessary
because response of every dosimeter (including standards) is dependent on photon energy
• Standard radiation quality is radiation beam with standardized and known properties: target material, PPV, total filtration, first and second HVL
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Radiation qualities• Most complete specification of radiation quality would
include spectral distribution of the photon fluence
• Practically, radiation quality is defined by anode material, total filtration, tube voltage (PPV!), first and second HVL (for mammography qualities, only first HVL is determined)
• Term homogeneity coefficient is often used – ratio of first and second HVL
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Radiation qualities• RQR series – beams emerging from X-ray generator (W target
material, Al filtration)
• RQT series – CT applications (W target material, Al+Cufiltration)
• RQR-M series – mammography applications (Mo target material and filtration)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Determination of HVLs• First step: air kerma is measured without any additional filtration
• Second step: air kerma is measured in the same place, but with added filtration between 0 mm Al and filtration corresponding to air kerma reduction by factor 6 (thicknesses should be concentrated around the values of 1st and 2nd HVL)
• Third step: 1st and 2nd HVL are determined by interpolation between 3 data points very close to the HVL values (not the whole range!)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Determination of HVLs – general radiography
• Homogeneity coefficient should be within ±0.03 of the standard value
• If you position additional filters corresponding to the standard HVL value, air kerma should be within (0.500 ± 0.015) Ka,0
• More information in IAEA TRS 457:2007 appendix 5 or IEC 61267:2005 annex b
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Determination of HVLs -mammography
• In case of RQR-M series, only first HVL is measured
• First HVL should be within 0.02 mm Al of the standard value
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Secondary standards• Reference class ionization chambers • Reference class electrometers• Usually chambers are calibrated together with
electrometer in dosimetry laboratories• Alternatively, ionization chamber can be calibrated
separately in dosimetry laboratory and electrometer in laboratory for electrical quantities
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Secondary standards• Reference class ionization chambers requirements are not well
defined• Clause 4.2 of IEC 61267: 2005 gives the following requirements:
– Dosimeter shall comply with IEC 61674: 2012– Energy dependence shall be within ±3% over the range of the radiation
qualities N-15 to N-200– Dimensions of detector shall be such that it is completely irradiated by the
beam– Sensitivity should be appropriate for measurements with phantoms and
added filters for HVL determination
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Secondary standards• IAEA TRS 457 gives additional requirements, e.g. stability within 0.3%• No clear definition of reference class dosimeter
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
IAEA TRS 457:2007 , pp. 52
QMS• QMS should be established in accordance with ISO/IEC
17025:2017
• QA/QC procedures should be established (e.g. ionization chamber stability checks)
• Many procedures are similar to equivalent procedures used for calibrations of radiation protection and radiation therapy equipment
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Uncertainty budget• IAEA TECDOC 1585 is an excellent starting point (together
with IAEA TRS 457)
• At least uncertainty components over 0.1% should be included in the budget
• Uncertainty components below 0.1% should be evaluated and care should be taken that they remain under 0.1%
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Uncertainty budget• Reference chamber calibration factor is usually the largest
contribution to the uncertainty
• Other components likely to be over 0.1%: reference chamber stability, radiation quality, beam uniformity, chamber positioning, electrometer calibration factor (if calibrated separately)
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Uncertainty budget• Other components that should be evaluated: ambient
temperature and pressure, repeatability of standard and user dosimeter indication, resolution of user dosimeter, leakage, saturation, electrometer linearity…
• Combined uncertainty below 3% (k=2, p=0.95) should be achievable
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Proving competence• Audits• Intercomparisons (in particular key and
supplementary comparisons)• Accreditation• CMCs in BIPM KCDB database
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Intercomparisons• Key and supplementary comparisons are usually
required to publish CMCs in KCDB• These comparisons are available to NMIs and DIs
only• The frequency of these comparisons is once in 5 or
10 years
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Intercomparisons• IAEA organizes bilateral comparisons for SSDL
network members (these comparisons can be used to support CMCs!)
• Bilateral or multilateral comparisons can be organized between SSDLs
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Basic calibration procedure
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Calibration is usually performed in one of the three ways:• calibration by substitution• calibration by substitution with monitor• calibration using reference monitor chamber
Basic calibration procedure
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Usually a distance of 1 meter is used• Field size should be large enough to irradiate the wholedetector, but small enough to minimize scatter
• Dosimeter reference point and orientation are usuallystated by the manufacturers
• Some user dosimeters are sensitive to change in ambientconditions
User dosimeter settings
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Settings should be stated in calibration certificate (e.g.ionization chamber voltage and polarity)
• Some semiconductor detectors’ indications are sensitiveto device settings (e.g. anode material, high voltage etc.)
• Special care should be taken to match detector settings tocalibration conditions
User dosimeter settings
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Software for multimeters can be very complicated• Some settings can be ambiguous• Some software applications are (partially) black box,causing different indications when using differentapplications
• In some cases, user should be consulted on theappropriate settings
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Unsealed transmission monitorchambers should be used
• The chamber should be largerthan the largest beam size
• Monitor chamber should add aslittle filtration as possible
• Leakage current should be under2% of the maximum indication ofthe most sensitive current range
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Substitution method with monitor• monitor chamber is used to correct for variations of X-ray output• this is the method of choice when high accuracy and low measurement uncertainty are required• use of two thermometers is recommended (if you use one, you don’t need to perform correction for temperature and pressure!) … = …
𝑄𝑄ref𝑇𝑇𝑃𝑃0𝑇𝑇0𝑃𝑃
𝑄𝑄T𝑇𝑇𝑃𝑃0𝑇𝑇0𝑃𝑃
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Reference monitor chamber
• Monitor chamber can be calibrated in terms of air kerma and used as a reference chamber
IAEA TRS 457: 2007
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Reference monitor chamber• monitor chambers are very sensitive to changes in
radiation energy, so this influence should be estimated• monitor chambers are basically operating as KAP-meters,
so increasing the beam size increases the signal• calibration factor for monitor chamber is valid only for
one specific distance
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Reference monitor chamber
• reproducibility of the setup for user instrument calibration (moving the filter wheel, moving the collimators etc.) introduces additional uncertainty
• dose rate can be different then during monitor chamber calibration (additional uncertainty is introduced)
Monitor chamber
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
Other uses of monitor chambers
• Irradiation of passive dosimeters• Indication of beam on-off status• Indication of the shutter position• Quality control
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Kerma area product is defined as the air-kermaintegral over the irradiated area in X-ray beam in theplane perpendicular to the beam axis
• In homogenous beam, PKA = KaA
𝑃𝑃KA = �𝐴𝐴
𝐾𝐾(𝑥𝑥,𝑦𝑦)dxdy
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Additional collimator is required for calibrations of KAP-meters
• Circular or square collimator with diameter between 40 mm and 60 mm should be used
• Suitable distance from the focus for collimator positioning is 950 mm
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Air kerma is measured in the reference point WITH collimator 4 in place
• Field size is calculated based on the collimator 4 size and collimator and detector distances from the focus
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• KAP-meters can be calibrated for transmitted radiation, in which case KAP-meter is positioned in position 1 during reference measurements
• If a KAP-meter is calibrated for incident radiation, reference measurements are done without KAP-meter in position 1
• In both cases, measurements with user KAP-meter are performed in position 2
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• How to know when to calibrate KAP-meter for transmitted and when for incident radiation?
• KAP-meters permanently installed on X-ray units should be calibrated for transmitted radiation
• KAP-meters used for in-situ calibrations of other KAP-meters should be calibrated for incident radiation
• KAP-meters used for patient dosimetry and QA/QC – depending on the mode of use
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Calibration factor is practically calculated according to the following formula (example for circular collimator):
𝑁𝑁P =𝐾𝐾a𝑟𝑟2π
𝑑𝑑r𝑑𝑑c
2
𝑀𝑀𝑘𝑘d𝑘𝑘T
where Ka is reference air kerma value, r is the radius of the collimator, drand dc are distances of reference point and collimator (usually 100 cm and 95 cm), M is indication of the KAP-meter, kd is correction for air density and kT correction for indication of transmission monitor chamber.
KAP-meter calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Further uncertainty components should beconsidered:
• collimator distance• collimator dimensions• beam uniformity (more important than in airkerma calibration)
CT-chamber calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Kerma length product is defined as the air-kerma integral overthe line of length L:
𝑃𝑃KL = �𝐿𝐿
𝐾𝐾(𝑧𝑧)dz
• In homogenous beam, PKL = KaL
CT-chamber calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Additional collimator K4 is positioned, usually at 950 mm
• Collimator width should be approximately 2 CT-chamber diameters, and length between 20 and 50 mm
• Field size is calculated based on the K4 length and collimator and detector distances from the focus
CT-chamber calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Reference measurements are performed WITHOUT K4
• Collimator is positioned only for CT-chamber measurements
CT-chamber calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Calibration factor is practically calculated according to the following formula:
𝑁𝑁P =𝐾𝐾a𝑙𝑙
𝑑𝑑r𝑑𝑑c
𝑀𝑀𝑘𝑘d𝑘𝑘T
where Ka is reference air kerma value, l is the length of the collimator along the CT-chamber axis, dr and dc are distances of reference point and collimator (usually 100 cm and 95 cm), M is indication of the CT-chamber and kT correction for indication of transmission monitor chamber.
X-ray tube high voltage• High voltage generator
generates a large potential difference between cathode (C) and anode (A)
• Electrons accelerate on their way to the anode, gaining kinetic energy of eU [keV]
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
http://commons.wikimedia.org/wiki/File:Xraytubeinhousing_commons.png
X-ray tube high voltage• High voltage is used for
beam characterization… but high voltage is usually not constant
• Ideally, a single number could be used for high voltage, and this number would be meaningful for purposes of beam characterization
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
http://commons.wikimedia.org/wiki/File:Xraytubeinhousing_commons.png
X-ray tube high voltage• X-ray generators
produce different waveforms
• How to compare the output of different X-ray machines? How does the high voltage translate into dose rate or radiological image?
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
IAEA TRS 457:2007 , pp. 257
X-ray tube high voltage• Voltage ripple can be as high as 100 %• If voltage ripple is less than 2 %, the high voltage generator
is considered constant potential
• According to IAEA TRS 457, voltage ripple should be less than 10 % for conventional applications and less than 4 % for mammography
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
PPV definition• Based on the contrast produced by 1 mm thick aluminum on 10 cm
PMMA phantom irradiated by “reference” X-ray tube
• Contrast decreases monotonously with constant potential voltage, so relation between contrast and PPV is unambiguous
• PPV does not depend strongly on total filtration, anode angle and contrast configuration
• PPV is the value of the high voltage of constant potential X-ray tube that would produce the same contrast as the tube under consideration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
PPV measurement
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Û – practical peak voltage
• p(Ui) is the probability of occurence of the voltage Ui(Ui - ΔU/2, Ui + ΔU/2)
• w(Ui) is the weighting function
PPV measurement
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• w(Ui) is approximated by the following formulas:
a) for Ui < 20 kV, w(Ui) = 0
b) for 20 kV ≤ Ui < 36 kV, w(Ui) = exp(aUi2 + bUi + c)
c) for 36 kV ≤ Ui , w(Ui) = dUi4 + eUi3 + fUi2 + gUi + h
IEC 61676: 2002
PPV measurement
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• for mammography beams, w(Ui) is approximated by the following formula:
w(Ui) = exp(kUi4 + lUi3 + mUi2 + nUi + o)
IEC 61676: 2002
PPV measurement
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Û can be measured in three ways:
• invasively
• non-invasively by analyzing wave function
• non-invasively with a calibrated PPV meter
0
10
20
30
40
50
60
70
80
0 5 10 15 20
U (k
V)
Which is the preferred method?
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Û can be measured in three ways:
• invasively
• non-invasively by analyzing wave function
• non-invasively with a calibrated PPV meter
0
10
20
30
40
50
60
70
80
0 5 10 15 20
U (k
V)
PPV calibration
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Reference value divided by user instrument indication• Usually no corrections• How to treat measurement uncertainty?• When non invasive devices are used, usually only the uncertainty of reference instrument calibration factor is considered
Conclusions
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Consider the needs of your (potential) users before you start establishing calibrations of DR dosimeters• Only air kerma calibrations are necessary, but many users will request calibrations in other quantities• Use any equipment that you already have
Conclusions
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• Monitor chambers can help you in many ways and their use is recommended• Calibration procedure is very similar to procedures in radiation protection and radiotherapy• Radiological multimeters based on semiconductor detectors can make you problems
Where to find more information?
Establishment of diagnostic radiology calibrations in an SSDLPrepared by Miloš Živanović
• IAEA TRS 457: 2007
• IEC standards
Thank you for your attention!
Establishment of diagnostic radiology calibrations in an SSDLBackgroundBackgroundInternational measurement systemIAEA/WHO SSDL networkCIPM Mutual Recognition ArrangementAbbreviationsImportant literatureImportant literatureImportant literatureWhich services should an SSDL provide?Which services should an SSDL provide?Which services should an SSDL provide?Which services should an SSDL provide?Checklist – what will you need to establish calibrationsChecklist – what will you need to establish calibrationsFinding usersExisting equipment and facilitiesFacilitiesFacilitiesFacilitiesFacilitiesX-ray unitX-ray unitX-ray unitX-ray unitRadiation qualitiesRadiation qualitiesRadiation qualitiesDetermination of HVLsDetermination of HVLs – general radiographyDetermination of HVLs - mammographySecondary standardsSecondary standardsSecondary standardsQMSUncertainty budgetUncertainty budgetUncertainty budgetProving competenceIntercomparisonsIntercomparisonsBasic calibration procedureBasic calibration procedureUser dosimeter settingsUser dosimeter settingsMonitor chamberMonitor chamberMonitor chamberMonitor chamberMonitor chamberMonitor chamberKAP-meter calibrationKAP-meter calibrationKAP-meter calibrationKAP-meter calibrationKAP-meter calibrationKAP-meter calibrationKAP-meter calibrationCT-chamber calibrationCT-chamber calibrationCT-chamber calibrationCT-chamber calibrationX-ray tube high voltageX-ray tube high voltageX-ray tube high voltageX-ray tube high voltagePPV definitionPPV measurementPPV measurementPPV measurementPPV measurementWhich is the preferred method?PPV calibrationConclusionsConclusionsWhere to find more information?Thank you for your attention!