291263.Lecture-EAWorkshop-RanogajecM.ppt

Dosimetry

1. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 1
SOME ASPECTS SOME ASPECTS
OF SOLID STATE DOSIMETRY OF SOLID STATE DOSIMETRY
IN EUROPEIN EUROPE
Mária Ranogajec-Komor
Ruđer Bošković Institute, Zagreb (IRB)
Croatian Radiation Protection
Association (CRPA)

2. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 2
OUTLINEOUTLINE
•IM (Individual monitoring)
Implementation of standards in IM
Integration of dosimetric methods for external
exposure
Quality control and reliability of reported doses
•MD (Medical Dosimetry)
X-ray diagnostic (children)
CT (of head)
•EM (Environmental monitoring)
Dosimetry systems
Intercomparison

3. East Asian Workshop,
Mito, Japan, 2006

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Why is IM, MD and EM important?
Nuclear power
plants in Europe
The art of life lies in a
constant readjustment
to our surroundings.
Okakura Kakuzo
Japanese scholar,
1863-1913

4. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 4
Why is IM, MD and EM important?
•Diagnostic and therapeautic
X-ray units: Most of European
countries are in the 1
st
cathegory
according to the number of
units/1000 inhabitants
UNSCEAR Report to General Assembly,
(New York, UN) (1993).

5. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 5
Why is IM, MD and EM important?
•Other medical and industrial application of
ionising radiation
•Dosimetry research facilities
Database for EU+Schwitzerland, August 2004
http://www.eurados-db.npl.co.uk/EURADOS_facilities_summary_html

6. East Asian Workshop,
Mito, Japan, 2006

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IM: IM: Implementation of standards
•Various standardisation/ accreditation/ approval
bodies are in each country
•The accreditation bodies in Europe operate within
mutual agreements.
•Numerous existing standards (ISO, IEC, IAEA,
national) and documents of relevance like
international recommendations, technical reports
(ICRP, ICRU, IAEA, EUR, RPD, national).
Harmony is needed in standards

7. East Asian Workshop,
Mito, Japan, 2006

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IM: IM: Implementation of standards
•ISO/IEC 17025 represents the best available
techniques for the quality of laboratory work (ISO
and IEC are meant for manufacturers and
industry).
•IEC 1066 (1991) for IM and EM
ISO: International Standard Organization
IEC: International Electrotechnical Committee

8. East Asian Workshop,
Mito, Japan, 2006

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System of IMIM service in Croatia (HR)
STATE OFFICE
OF RP
Registration
ACCREDITED
INSTITUTIONS
USERS
MINISTRY OF
HEALTH
U
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t
Measured dose
Report: overdose, lost
dosimeters, etc.
Database

9. East Asian Workshop,
Mito, Japan, 2006

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A catalogue of IMIM services within
Europe
•Total number of estimated IM services: 200
•Catalogue of dosemeters and dosimetric
services within Europe: 104
Results: The data indicates that the services in
Europe almost exclusively monitor their workers
in terms of personal dose equivalent (H
p(10)).
Calibration: air kerma Personal dose: H
p
(10)

10. East Asian Workshop,
Mito, Japan, 2006

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Data on IMIM dosimetric services
who responded to the questionnaire
Country
code
Services Workers
controlled
Dosimeter system
for photons
B 3 6000 1F, 2TLD
BG 5 12450 1F, 5TLD
CZ 4 20420 2F, 2TLD
D 8 52900 1F, 2TLD, 3V
EST 1 1050 1TLD
F 8 242800
H 2 30000 1F, 1TLD
HR 2 3700 1F, 1TLD
I 12 44170 2F, 10 TLD
PL 3 35000 2F, 3TLD
YU 2 5100 2TLD
29 104 72764030F, 69TLD, 5V
F: film (443 000)
TLD: (273 070)
thermoluminescent
V: various (glass,
electronic, OSL)
(11 570)
6F, 2TLD1 RPL, 5F, 2TLD
F: film (200 000)
RPL: glass
(200000)
TLD: (273 070)
thermoluminescent
V: various (glass,
electronic, OSL)
(11 570)

11. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 11
Data on IM IM dosimetric services in
Croatia (HR) – 2006
Accredited
institution
No of
workers
Dosimeter
system
EKOTEH 2677F
(188 TLD)
IMI 1024F
IRB 1222TLD
Total 46812F, 1 TLD
Data from SRP, D. Kubelka

12. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 12
IM:IM: Electronic dosemeters and
other new developments
Objective:
First evaluation (implementation
and use) of Active Personal
Devices (APD) for IM
•Legal status
•Technical characteristics
•Advantages and disadvantages
Used in NPP – Energy dependence and mechanical
properties critical – differences in intercomparison –
increasingly used

13. East Asian Workshop,
Mito, Japan, 2006

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Inventory of problems of non-dosimetric origin
in individual monitoring that impair the quality
of external dose assessments: lost, mislaid or
damaged dosimeters, failure of processing equipment
including data processing,...
88 services from 26 European countries
participated in the study.
Overview on QC actions and possible sources
of uncertainties was analysed in Europe.
QC and reliability of IMIM systems
(external radiation)

14. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 14
Introducing new dosimetry systems RPL-
(France)
Proposal of WG2 of Eurados
Perspectives in IMIM

15. East Asian Workshop,
Mito, Japan, 2006

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EURADOS (European Radiation Dosimetry)
Membership:
recently 50 voting and 200 associate members
Activity:
several Working Groups
4. Numerical
dosimetry
7. Internal
dosimetry
5. Air crew
dosimetry
6. Computational
dosimetry
3. EM
2. IM1. Irradiation
facilities
9. RP of medical
staff
http://www.eurados-online.de/
8. Complex
mixed fields

16. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 16
Produce every four years a report on
Current state of the art
External photon, beta, neutron
Internal, direct, indirect
Workplace, external, radon, aircrew
Address a special topic
E.g. electronic, neutron, beta, extremity
Organise every four years an intercomparison
Monitoring services external, internal radiation
Organise every four years a workshop
Perspectives in IMIM
Proposal of WG2 of Eurados

17. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 17
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
•X-ray diagnostic
•Therapy
•Nuclear medicine
–conventional radiology
–CT
–interventional radiology
77% Natural radiation
20% Medical irradition
3% Other man-made irradiation

20%
3%
77%

18. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRYMEDICAL DOSIMETRY
1.Dose measurements after the characterisation of
dosimetry systems
2. The exact knowledge of doses delivered to different
organs or to the whole body is needed (patient and
phantom)
•to estimate the exposure of population
•to estimate the risk
•to specify radiation protection measures
•to assess the justification of the procedure
in terms of overall patient benefit and safety
measures

19. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRYMEDICAL DOSIMETRY
The determination of the doses received by
patients in X-ray diagnostics is complicated
•very low doses at low and variable
energies
•considerable variation in radiation
doses delivered to patients (different X-
ray equipment, different personnel)

20. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Use of baby-fix and arrangement of dosimeters

21. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Lateral chest
radiography
(age: under 3 years)
Posteroanterioral (PA) and lateral
chest radiography (age: 3 years and
older)

22. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Age
(years)

Back

Chest
Dose
Thyroid
(mSv)
Armpit

Eye

Gonad
0 - 3 0.12 0.07 0.08 0.05 0.08 0.07
3 - 6 0.17 0.15 0.12 0.10 0.05 0.04
6 - 9 0.31 0.29 0.27 0.13 0.04 0.02
9 - 12 0.36 0.26 0.16 0.17 0.03 0.02
> 12 0.33 0.25 0.20 0.18 0.07 0.03
Mean 0.26 0.20 0.17 0.13 0.05 0.04
SD 0.11 0.09 0.05 0.05 0.02 0.02

Mean value of the surface skin dose measured
on children during X-ray diagnostics of chest

23. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 23
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Standard deviations of dosimetric
measurements
Energy SD (%)
SSDL 80 kev ± 4
routine X-ray
unit
90 kV ± 21
on patients variable ± 100

24. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 24
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Factors
which influence the standard deviation
technical conditions (kV, mAs),
feature of patients (age, height, weight
etc.),
absorption and scattering of radiation,
PA and lateral projection
different X-ray units
working method of personnel.

25. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 25
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
Risk estimation of radiation damage
in X-ray diagnostics of respiratory tract of children
*ICRP, Publ. 60, 1990
**Number of children examined 1 patient with damage

26. East Asian Workshop,
Mito, Japan, 2006

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3. For the risk estimation highly
statistical dose measurements are needed
2.Importance of standardisation of technik and
methods reduction of large
variation in absorbed dose
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
1.The evaluated risks are not alarming all
patient protection measures should be carried
out
SUMMARY

27. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 27
MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
The highest doses result
from CT (in diagnostics)
CT accounts for 2-3% of all
X-ray examinations -
it contributes about 20% of
the population doses.
Important task: radiation
protection of patients.

28. East Asian Workshop,
Mito, Japan, 2006

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MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
Dosimetry: TLD
CT: SOMATOM DR-H SCT-4500TE
(Siemens) (Shimadzu)
Installation: 1987, Hospital A 1994, Hospital B
Condition, number of patients, number of dosimeters

29. East Asian Workshop,
Mito, Japan, 2006

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0
10
20
30
40
50
515253545556575
Dose (mGy)
N
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r

o
f

m
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s
MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
Distribution of radiation doses for both eyes
measured during CT of the head

30. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 30
MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
The ratio of the minimum to the maximum of the
measured surface doses varies by a factor of
4 to 7 (gonades, chest, thyroid).
10-11 (eye lens)

31. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 31
MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
the dose varies according to the position,
size and shape of the patients' bodies;
the distance of the primary X-ray beam from
the organ significantly varies from one
patient to another;
the number of scans varied by a factor of 2;
the total mAs also varied by a factor of 2.
This is understandable when we consider the
following:

32. East Asian Workshop,
Mito, Japan, 2006

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•3 in New Zealand,
•5 in Sweden and the United Kingdom
•3.5 in Japan (depending on the CT scanner unit).
Measured on a hypothetical average adult phantom.
MEDICAL DOSIMETRY-CTMEDICAL DOSIMETRY-CT
•USA: 250 CT systems - typical dose is 22-68 mGy
•Japan: from 18 to 80 mGy (adults).
Factor of dose variations:
Literature (UNSCEAR, 1993):
Surface doses during CT of head:

33. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 33
Dose measurements in medicine - TL and RPL
dosimetry
Benefits:
facilitate the control of X-ray equipment;
identify equipment requiring additional
safety measures;
facilitate patient risk assessment
aid in directing efforts toward reducing
total radiation doses.
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
SUMMARY

34. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 34
From the point of view of radiation protection of
patients, an optimum factor for X-ray
examinations should be decided by considering
not only the image quality but also the
absorbed dose resulting from medical
procedures.
This aim can be achieve
 by frequent dosimetry
 by permanent education of personnel.
MEDICAL DOSIMETRYMEDICAL DOSIMETRY
CONCLUSIONS

35. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 35
ENVIRONMENTAL DOSE ENVIRONMENTAL DOSE
MEASUREMENTMEASUREMENT (EM) (EM)
PROBLEMS:
•society worries about environmental quality
•human activities can increase radiation
dose in the environment
TASK:
•collection of well documented data on
radiation doses in the environment

36. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 36
Environmental radiation
external exposure
Terrestrial Cosmic
Dubrovnik, Croatia
Fujijama, Japan
EMEM

37. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 37
EMEM
REQUIREMENTS for dose measurements:
•to measure the man-made contribution to
environmental radiation (1:10)
•to follow the changes in natural environmental
radiation (Early Warning Network Systems)
•under variable environmental conditions (UV
sunlight, humidity, temperature)
SOLUTION:
TLD, RPL, in-situ gamma spectrometry

38. East Asian Workshop,
Mito, Japan, 2006

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EMEM
•their application to environmental dosimetry requires
performance under laboratory and field conditions
•performance testing and procedural specifications may be
found in national and international standards
International Electrotechnical Committee
(IEC). TLD Systems for Personal and
Environmental Monitoring. International
Standard - IEC 1066 (1991)

39. East Asian Workshop,
Mito, Japan, 2006

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Test methods for EM EM
•Batch homogenity:
•Detection threshold:
•Linearity:
•Energy dependence: 80-100 keV,
137
Cs
E: evaluated value
C: conventional true value
i: number of group
l
i
: half-width of confidence interval
3.0
E
EE
min
minmax


3.1
C
lE
7.0
i
i



1.1
C
lE
9.0
i
i
i



RPL
0.96-1.04
0.1
1.52μGy
1.1

40. East Asian Workshop,
Mito, Japan, 2006

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EMEM IIntercomparisonntercomparison
To reach international standards there is a
need for INTERCOMPARISONS (large scale)
•US DOE, EML 12 1972-2002
•EC 1984-1994
•NRPB 1985
•COMECOMA 1989
•EURADOS 1999-2002
•to improve environmental monitoring methods
•to serve as periodic quality control
AIM:

41. East Asian Workshop,
Mito, Japan, 2006

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IIntercomparison of ntercomparison of EMEM
Field irradiation
Lab irradiation

42. East Asian Workshop,
Mito, Japan, 2006

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PProtocolrotocol ofof EMEM
IIntercomparisonntercomparison
3 sets of RPL/TLD
field
fading (pre-irradiated)
transport
calibration + control
dosimeters - in the shield
HR shield
H
D1
D2
H1
H2
HR1HR2
shield shield
D

43. East Asian Workshop,
Mito, Japan, 2006

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IIntercomparison in ntercomparison in EMEM
•The suitability of RPL and new high
sensitivity TL detectors for EM
•shorter monitoring period
•influence of climatic conditions on fading and
dose according to the season or the location
Expected answers

44. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 44
Perspectives in EMEM
•to support a suitable infrastructure
for the characterisation and
intercomparison of EM systems
RPL system in RBI,
Zagreb

45. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 45
PERSPECTIVESPERSPECTIVES
The important thing is not to stop questioning.
Albert Einstein
US (German-born) physicist (1879 - 1955)

46. East Asian Workshop,
Mito, Japan, 2006

IRB CRPA 46
PERSPECTIVESPERSPECTIVES
HVALA
有難うございました
The author is grateful to Chiyoda Technol Corporation,
Japan for the support of participation