dosimetry for medical application of ionizing radiations: calibration requirements and clinical...
TRANSCRIPT
DOSIMETRY FOR MEDICAL APPLICATION OF IONIZING RADIATIONS:
Calibration requirements and clinical applications
Olivera Ciraj-Bjelac, Milojko Kovacevic, Danijela Arandjic, Djordje LazarevicVinca Institute of Nuclear SciencesRadiation and Environmental Protection DepartmentLaboratory for Radiation MeasurementsBelgrade, [email protected]
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Content
Global trends in medical exposures Dosimetric quantities and units Dosimetry in diagnostic radiology
Metrology and calibration requirements Clinical application
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Medical exposure contributes 99% of man-made radiation exposure to humans
The concept of risk is used to quantify possible detrimental effects
Medical exposure to ionizing radiation
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
0.61
0.0020.005
0.0020.005
mSv
Medical
Nuclear weapons
Occupational
Chernobyl
Atmospheric nuclear tests
Total dose from man-made sources of radiation> 0.61 mSv
Medical: 0.6 mSv (> 99.97%)
Source: United Nations Scientific Committee for Effect of Atomic Radiation (UNSCEAR), 2010
Dose?
Medical exposure to ionizing radiation
The role of dosimetry is to determine the amount of radiation received by a person from the radiological examination
Dosimetry in diagnostic radiology
Patient dose assessment Establishment of Diagnostic Reference Levels
(DRL), optimisation of protection Assessment of x-ray equipment performance
Standards of good practice Assessment of radiation detriment
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Global trend
3,6 billion radiological examinations in the period 1997-2007
Increase of 50% compared to previous decade Significant increase of CT practice:
Examination frequency Dose per examination
Interventional procedures
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Depends on the examination type Variations for the same type of procedure
0.02- 0.05 mSv@2 mSv @ 100CxR
5-20 mSv400- 1000 CxR
Dose to patient
50 chest radiographies= annual natural background radiation dose
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Problems
Dose for the same examination type varies up to 2 orders of magnitude
Increased utilization of high-dose procedures
CT
Interventional procedures
Increase of probability for stochastic effects, in particular in the case of the repeated examinations
Possible radiation injuries in high-dose procedures
Effects
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Vinc
a In
stitu
te o
f Nuc
lear
Sci
ence
s Ra
diati
on a
nd E
nviro
nmen
tal P
rote
ction
Lab
orat
ory
ww
w.v
inca
.rs
Radiation injuries
10
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
ICRP 85
Basic metrology elements
International Measurements System (IMS)
Framework for dosimetry in diagnostic radiology
Consistency in radiation dosimetry
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
International Measurements System (IMS)
Bureau International des Poids et Mesures (BIPM)
National Primary Standard Dosimetry Laboratories (PSDL)
Secondary Standards Dosimetry Laboratories (SSDL)
Users performing measurements
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Traceability chain
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Metrology and traceability
Dosimeters used to determine doses received by individuals
Measurements need to be traceable though an unbroken chain of comparisons to national and international standards
Traceability is needed to ensure accuracy and reliability
Legal and economic implications
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Role of the SSDL
The prime function: to provide a service in metrology
Designated by the competent national authorities
SSDL-Secondary standards, calibrated against the primary standards of laboratories participating in the IMS
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Journal of the ICRU Vol 5No 2 (2005) Report 74
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Dosimetric quantities in units in diagnostic radiology Basic dosimetric quantity: Air kerma
Easy to measure Calibration:
Dosimeters calibrated in terms of air kerma Clinical application:
Quantities derived from air kerma for different imaging modalities
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Dosimetric quantities
Basic dosimetric quantities Application specific dosimetric quantities
Quantities for risk assessment
Conversion coefficient for tissue and organ dose assessment
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Energy fluenceUnit:J/m2
KermaUnit:J/kg, Gy
Absorbed doseUnit:J/kg, Gy
dadR
trtr
dmdE
K
en
dmd
D
Basic dosimetric quantities
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Basic dosimetric quantities
Charged-particle equilibrium Absence of bremsstrahlung losses
trenDK
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Application specific dosimetric quantities
Quantity Symbol Unit Equation
Incident air kerma Ki Gy
Entrance -surface air kerma Ke Gy
Air-kerma area product PKA Gym2
Air-kerma length product PKL Gym
X-ray tube output Y(d) Gy/As
BKK ie
A
KA dxdyyxKP ),(
L
airKL dzzKP )(
Ita PdKdY /)()(
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Application specific dosimetric quantities: computed tomography
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Quantity Symbol Unit Equation
CT air-kerma index (free in air) Ca,100 Gy
CT air-kerma index (in standard phantom)
CPMMA, 100 Gy
Weighted CT air kerma index Cw Gy
Normalized weighted CT air kerma index nCw Gy/As
Air-kerma length product PKL Gym
Application specific dosimetric quantities: computed tomography
pPMMAcPMMAW CCC ,100,,100, 231
50
50100, )(
1dzzK
TCa
It
VOLVOLn
WWVOL
PC
C
pC
INT
CC
j
ItjjVOLjnKL PlCP
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Quantities describing risk
Organ and tissue dose Equivalent dose Effective dose
Dose-conversion coefficients for assessment of organ and tissue doses
quantityionnormalisat
quantitydosimetricc
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
The Use of Effective Dose (E)
E is a risk-related quantity and should only be used in the low-dose range
Primary use: to demonstrate compliance with dose limits in regulation, for prospective planning of radioprotection
Not for: detailed retrospective dose and risk assessments after exposure
of individuals epidemiological studies, neither in accidents.
In the last cases: organ doses are needed !
ICRP 103, ICRP 105
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Effective Dose in Medical Exposure
The relevant quantity for planning the exposure of patients and risk-benefit assessments is the equivalent dose or the absorbed dose to irradiated tissues.
The assessment and interpretation of E is very problematic when organs and tissues receive only partial exposure or a very heterogeneous exposure (x-ray diagnostics)
E can be of value for comparing doses from different diagnostic procedures similar procedures in different hospitals and countries different technologies for the same medical examination.
ICRP 103, ICRP 105
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Dosimeters in diagnostic radiology
Tube voltage 20-150 keV, various A/F combinations, various modalities
Ionization chambers
Accurate
Good energy dependence
Design for different application (cylindrical, parallel-plate, different volumes..)
Semiconductor dosimeters
Compact
Energy dependant
Others
TLD
OSL
Film (radiochromic)
Scintillation
(kVp meters)
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
PSDL/SSDL user
Dosimetry standards in diagnostic radiology IEC 61674: Dosimeters with
ionization chambers and/or semi-conductor detectors as used in X-ray diagnostic imaging Diagnostic dosimeter:
detector and measuring assembly
IEC 60580: Dose area product meters
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Requirements for dosemeters
User IEC 61674 Ionization chambers Semiconductor
detectors
SSDL Ionization chamber of
reference class
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Calibrations in diagnostic radiology
Air kerma: Radiography and mammography
Kerma-length product Dosimeters in CT
Kerma-area product Radiography and fluoroscopy
PPV: kVp meters
Frequency: according to national regulations V
inca
Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Calibration in diagnostic radiology
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
SSDL with relevant measurement capabilities General requirements: beam qualities, tube
voltage and filtration measurements Dosimeter of reference class (with
electrometer) Calibrated Quality control Traceability for all beam qualities
Auxiliary equipment: electrometers, thermometers, barometers…
Environmental conditions
Equipment
Dosimetry Ionization chambers Position system HV supply for monitor and
reference class ionization chamber
Electrometer
Radiation source X-ray generator, 50-150
kVp, 20-40 kVp Ripple less than 10% for
radiography and less than 4% for mammography
Beam qualities according IEC 61267
“Shutter” mechanism Filters and attenuators Tube voltage meter (ppv,
±1.5%) Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Application Type of chamber
Range tube voltage (kV)
Intrinsic uncertainty
(k=2)Maximum variation
of response (%)
Range of air kerma rate
Unatte-nuated beam
Attenuated beam
General radiography
cylindrical or plane parallel 60-150 3.2 ±2.6 1 mGy/s-
500 mGy/s10 μGy/s-5 mGy/s
Fluoroscopy cylindrical or plane parallel 50-100 3.2 ±2.6 0.1 μGy/s-
100 μGy/s
Mammogra-phy plane parallel 22-40 3.2 ±2.6 10 μGy/s-
10 mGy/s
CT cylindrical 100-150 3.2 ±2.6 0.1 mGy/s-50 mGy/s
Dental radiography
cylindrical or plane parallel 50-90 3.2 ±2.6 1 μGy/s-
10 mGy/s
Reference class dosemeter
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Specification of the x-ray beam
Spectrum X-ray beam quality:
First half-value layer (HVL1) Second half-value layer
(HVL2) Homogeneity coefficient:
Tube voltage Total filtration
2
1
HVL
HVLh
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Radiation beam qualities (IEC 61267)
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Radiation quality Radiation origin Phantom material Application
RQRUnfiltered beam emerging from x-ray assembly
No phantomGeneral radiography, fluoroscopy, dental radiology
RQA Radiation beam from an added filter Aluminium
Measurements behind the patient (on the image intensifier)
RQT Radiation beam from an added filter Copper CT applications (free
in air)
RQR-MUnfiltered beam emerging from x-ray assembly
No phantom Mammography (free in air)
RQA-M Radiation beam from an added filter Aluminium Measurements
behind the patient
Typical calibration set up
X-ray tube window
Focal spot
Shutter
Apertures
Additional filtration
Monitor chamber
Test point
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Calibration procedures
Procedures before calibration (acclimatization, positioning, stabilization…)
Calibration procedures (methods, number of measurements, interval between measurements…corrections…
Procedures following calibration (uncertainty budget, certificate…)
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Dosimetry formalism
Air kerma:
Reference conditions: set of influencing quantities
Influencing condition: quantities that are not subject of mesusremst but have an impact on the result
Air density correction: Beam quality correction:
0,0 QKQ NMMK
i
iQKQ kNMMK0,0
0
0
15.273
15.273
T
T
P
PkTP
QoQQKQQ kNMK ,, 0
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Calibrations of dosemeters for CT
Traditionally, irradiation of the whole volume Contras:
Information on chamber response only Size on active volume only assumed Far from real situation
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Calibration for CT: air kerma length product Cylindrical chamber, 100 mm Non-uniform irradiation Uniform response RQT 9 (120 kVp, HVL: 8.5 mm Al)
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Focal spot
Monitor chamber
Aperture Ionization chamber
w
da
dr
a
rQP d
dMwKN
KL /,
In laboratory (SSDL) Field calibration
Film
10 cm 10 cm
Ref. chamber
KAP
nomQrefQoK
ref
QP M
AkNMN
KA
,,
Calibration for fluoroscopy: air kerma area product
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Cekerevac at al, Poster B3
Calibration in terms of practical peak voltage X-ray tube voltage
measurements Practical Peak Voltage
(ppv):
Property of the whole exposure cycle
Related to image contrast
Invasive or non-invasive measurements
Voltage divider
n
iii
n
iiii
UwUp
WwUUpU
1
1ˆ
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Uncertainty of the reference standard Uncertainty of user’s instrument Uncertainty due to calibration set up Uncertainty of the evaluation procedure
Uncertainty budget
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Uncertainty budget
Air kerma: ± 2.7 % Air kerma length product: ± 3.0 % Air kerma area product: ± 15 % Non-invasive tube voltage measuring devices:
2.5 %
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Goal: minimal uncertainty Assurance and control of traceability Quality manual: technical details, methods, traceability,
uncertainty budget, QC, safety…. Continuous improvements and reviews External peer review/audit
Quality Management System
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Patient dose assessment
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Clinical dosimetry
Direct measurement on patients or phantoms
Indirect measurements on patients or phantoms Output of the X-ray tube,
scaled for exposure and geometry
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Dosimetric quantites
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
BSFKAP
Ke
Quantitiesa) incident air kerma, entrance
surface air kerma and kerma-area product (radiography);
b) kerma-area product and entrance surface air kerma rate (fluoroscopy);
c) incident and entrance surface air kerma (mammography); and
d) kerma-length product (computed tomography)
Patients and phantoms
Patient Real situation
Phantoms Objects that simulate real
patients in terms of interaction of radiation with matter
Easy to perform Standardized
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Radiography
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Fluoroscopy
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Mammography
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Computed tomography
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Patient dose levels
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Uncertainty of clinical dose assessment Radiographers taking the
x-ray images Determining tube output Calculation of individual
patient doses Determining dose to an
average patient
Use of k=2 for expression of uncertainty of dose assessment
Typically >10% and close to 25%*
*if correction for beam quality and for individual patient is not applied
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Form measurements towards risk assessment Conversion coefficients
Conversion of measured quantity into organ doses and effective dose
Ratio of the dose to a specified tissue or effective dose divided by the normalization quantity
Measured using phantoms or calculated using computer models
Voxel phantoms based on images of human anatomy
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Organ dose assesment
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
ICRU 74
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Optimization of protection
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Application of DRLs
Values of measured quantities above which some specified action or decision should be taken Values must be specified Action must be specified
DRLs will be intended for use as a convenient test for
identifying situations where the levels of patient dose are unusually high.
Quantities that are easily measured!
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Diagnostic Reference Levels
Doses to patients from radiographic and fluoroscopic X-ray imaging procedures in the UK—2005 review. HPA RPD-029, HPA; 2007. V
inca
Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Re-cap
Diagnostic radiology is major contribution to total dose from man-made sources of radiation
Dose measurements: population dose assessment, optimization of practice
Application-specific dosimetric quantities (patients, phantoms)
Calibration of dosimeters in the conditions that are similar to the clinical environment, in terms of air kerma kerma-area product kerma-length product V
inca
Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs
Olivera Ciraj-Bjelac, PhD, research associate, dosimetry and radiation physics Milojko Kovacevic, MSc, Head of MDL, radiation physicist Danijela Arandjic, MSc, PhD student, dosimetry and radiation physics Djordje Lazarevic, MSc, PhD student, dosimetry and radiation physics Dragana Divnic, technician Milos Jovanovic, technician Nikola Blagojevic , technician
Vin
ca Inst
itute
of
Nucl
ear
Sci
ence
s R
ad
iati
on a
nd
Envir
onm
enta
l Pro
tect
ion L
ab
ora
tory
ww
w.v
inca
.rs