Occupational exposure to ionising radiation in the region of anatolia, turkey for the period...

7/28/2019 Occupational exposure to ionising radiation in the region of anatolia, turkey for the period 19951999

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OCCUPATIONAL EXPOSURE TO IONISING RADIATIONIN THE REGION OF ANATOLIA, TURKEYFOR THE PERIOD 1995EEEE1999H. Gu ndu z, C. T. Zeyrek, L. Aksu and S. IsakTurkish Atomic Energy Agency, Ankara Nuclear Research and Training Centre, Department ofDosimetry, 06100, Bes evler, Ankara, Turkey

Received July 7 2003 in nal revised form December 22 2003, accepted December 31 2003

For this study, the individual annual doseinformation on classied workers who are occupationally exposed to extendedradiationsources in Turkey, was assessed and analysed by the Ankara Nuclear Research and Training Centre dosimetry service at theTurkish Atomic Energy Authority for the years 1995----1999. The radiation workers monitored are divided into three main worksectors: conventional industry (8.24%), medicine (90.20%) and research-education (1.56%). The average annual dose for allworkers in each particular sector was 0.14, 0.38 and 0.08 mSv, respectively, in 1995 ----1999. This paper contains the detailedanalysis of occupational exposure. The statistical analysis provided includes the mean annual dose, the collective dose,the distributions of the dose over the different sectors and the number of workers who have exceeded any of the established

dose levels.

INTRODUCTION

Radiation accidents over the last several years haveincreased the general awareness of the risks of expos-ure to ionising radiation. The International Com-mission on Radiological Protection (ICRP) andthe International Atomic Energy Agency (IAEA)are committed to the promotion of the principle ofoptimisations, effeciall through applications of theBasic Safety Standards (BSS-115) for radiation pro-

tection(1,2)

. In ICRP publication 60, the quantitiesrecommended for dose limitation are the effectivedose for whole-body exposure, the equivalent dosefor exposure of certain tissues or organs and thecommitted effective dose for intake of radionuclides.

All radiation protection workers in Turkey areregulated and supervised by the Turkish AtomicEnergy Authority (TAEA). The TAEA is respons-ible for monitoring workers in all radiation facil-ities(3). The TAEA has charged the two nationaldosimetry services to preside over the necessarymonitoring. One is the Ankara Nuclear Researchand Training Centre (ANAEM) dosimetry serviceand the other is the C ekmece Nuclear Research andTraining Centre (C NAEM) dosimetry service. TheANAEM dosimetry service has been in operationsince 1963. The ANAEM dosimetry service isresponsible for monitoring personnel working inthe large Anatolia region of Turkey. The C NAEMdosimetry service is responsible for monitoring

radiation in workers who work in Istanbul and ina part of the western region of Turkey.

Occupational exposure due to external radiationsources in Turkey arises from three different eldsof activity, namely: conventional industry (industrialradiography, industrial irradiation and others),medicine (diagnostic radiology, radiotherapy, nuclearmedicine, dental radiology and others) and research-education. There are no nuclear power plants in thecountry. However, there are two research reactors inIstanbul and the persons monitored have beenincluded in the C NAEM dosimetry service.

At present, individual monitoringfor externalradia-tion is performed at the ANAEM dosimetry serviceusing lm dosimetry. Approximately 10,000 radiationworkers in 1575 institutions throughout Turkey aremonitored. Over 70,000 whole-body dosimeters areprocessed per year. In addition, there are new auto-matic and manual thermoluminescence dosimetry(TLD) systems for whole-body and extremity moni-toring available since 2000. There will be a gradualtransfer from lm dosimetry to TLD in the near future.

This study presents initial statistics on personal

dose equivalent to ionising radiation of Turkishradiation workers in different occupations, evalu-ates the occupational doses for external radiationin workers for the period 1995----1999 and providesa source of data for epidemiological investigationand studies of dose trends(4).

METHODOLOGY

Radiation workers have been monitored by theANAEM dosimetry service since 1963. DosemetersCorresponding author: [email protected]

Radiation Protection Dosimetry (2004), Vol. 108, No. 4, pp. 293EEEE301DOI: 10.1093/rpd/nch025

Radiation Protection Dosimetry Vol. 108 No. 4 Oxford University Press 2004; all rights reserved

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are issued monthly in the Ankara region andbi-monthly outside Ankara. The database of thedose records has been continuously renewed andupdated during recent years. The registry contains

dose information on 20,621 workers for the years1995----1999.

The personal dosemeter is based on the AGFA-Geavart personal monitoring lms and used by aholder of the PTW type (see Figure 1). Each badgecontains two lms in a single lm pocket, one hav-ing a high sensitivity, and the other low sensitivity.The lm badge has ve lters: open window andwindows with 0.05 mm Cu, 0.3 mm Cu, 1.2 mm Cuand 0.8 mm Pb lters. The dosemeter's constructionoffers the possibility of a detailed analysis using themultiple lters. Energy calibrations of lm dose-meters are performed at the Secondary StandardDosimetry Laboratory (SSDL) at C NAEM.Routine calibration of dosemeters is performed atthe ANAEM dosimetry laboratory.

The lm dosemeters are processed manually. Theoptical densities are measured manually and trans-ferred automatically to the computer program fordose calculation. Up to 1987, dose records were kepton hard copy. Since then, the dose records are kept onoppy and compact disks. The earlier system reliedheavily on manual labour for both lm processingand data transfer. The new system for keepingdose records is designed to make use of modernhardware and software technologies to provide avery reliable and efcient system. The C NAEM

dosimetry service (SSDL) participated in theintercomparison for individual monitoring of radio-logical measurement for monitoring proposes orga-nized by the IAEA in 1999

(5). The methods of doseevaluation in the ANAEM dosimetry service are thesame as those adopted by the C NAEM dosimetryservice.

The ANAEM dosimetry service has established athermoluminescence dosimetry laboratory in 2000.There are two new thermoluminescence dosimetryreaders, Panasonic automatic UD-716AGL and

Panasonic manual UD-513A readers. The thermo-luminescence personal dosemeters are based on thePanasonic UD-802 and UD-809 dosemeter card andholder which contains 7Li2

11B4O7:Cu,6Li2

10B4O7:Cu,n

Li2n

B4O7:Cu and CaSO4:Tm thermoluminescencephosphor elements. The TL dosemeter allows themeasurement of the operational quantities Hp(10)and Hp(0.07), the personal dose equivalent penetrat-ing measured at the depth of 10 mm in tissue and thepersonal dose equivalent supercial measured at thedepth of 0.07 mm, respectively.

RESULTS AND DISCUSSION

In this study, the mean value of the radiation work-ers is all monitored persons in Turkey. Exposedworkers are those radiation workers who may beexposed to doses exceeding 0.1 mSv. Minimumdetectable dose level (MDL) is 0.1 mSv for ourdosimetry service. The results consider workerswho have effective dose less than 0.1 mSv (MDL)as non-exposed. Therefore, account is taken ofdoses occurring below MDL and recorded as zero.

The occupational monitoring areas of ANAEMand C NAEM dosimetry services in Turkey arerepresented in Figure 2. A total of 20,621 radiationworkers were monitored between the years 1995 and1999. The radiation workers monitored are dividedinto three main work sectors: conventional industry

sector (8.25%) (industrial radiography 4.48%, indus-trial irradiation 0.66% and others 3.11%), medicalsector (90.84%) (diagnostic radiology 73.75%,radiotherapy 4.71%, nuclear medicine 9.86%, dentalradiology 2.04% and others 0.48%) and research-education sector (0.90%) as shown in Figure 3.

In Table 1, the number of workers monitored andthe percentage of exposed workers with those in thefollowing effective dose (E) ranges: MDL to `1 mSv, 1 to `20 mSv, 20 to 30 mSv and b30 mSv

during the period 1995----1999 are presented. Doses

Figure 1. PTW type lm dosemeter holder (T8621).

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higher than 30 mSv were received by three operatorsof medical and two operators of industry in thisperiod. The number of exposed radiation workers is6578 (31.9%). The majority of occupational groupand occupationally exposed workers 6471 (about35%) have activities in medical uses of radiation. AsTable 1 shows, 2037 workers received exposuresbetween 1 and `20 mSv and 11 workers receivedeffective doses equal to or more than 20 mSv in

medical uses of radiation. In the conventionalindustry and research-education establishment, thenumber of exposed workers is 96 persons (5.6%) and11 persons (5.9%). In these sectors, 40 persons areexposed between 1 and `20 mSv and 6 personsare exposed E! 20 mSv. Only 17 persons exceededan effective dose of 20 mSv per year average over veconsecutive years (1995----1999).

The collective effective dose was determinedaccording to the expressions (Equation 1) mentionedin the UNSCEAR 2000 Report(4), ICRP Publication

60(1) and in the Safety Series No. 115(2) in eachworking eld and presented in Tables 2----4 for theyears 1995----1999. The collective effective dose, S isgiven by

SN

i 1

Ei 1

where Ei is the annual effective dose received by theith worker and N is the total number of workers.The average annual effective dose, "E is equal to S/N.

Diagnostic radiology applications involve thelargest number of persons monitored in the medicaleld. The annual total average effective dose inmedicine is shown to range from 0.04 to 0.80 mSv.The largest annual average effective dose was foundin nuclear medicine (0.80 mSv) in the year 1997 asshown in Table 2.

Figure 2. Occupational monitoring area of ANAEM (white area) and C NAEM (dark area) dosimetry services in Turkey.

RadiotheraphyDiagnostic radiology

Nuclearmedicine

Dental radiology

Medical others

Industrial radiography

Industrial irradiation

Industrial others

Research-education

Figure 3. Occupational distribution in percentage (%) of the monitored workers for 1995----1999.

OCCUPATIONAL EXPOSURE TO IONISING RADIATION

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Table 1. Trend in occupational exposures in Turkey from 1995 to 1999.

Occupationalgroup

Year Total numberof workers

No. andpercentage of

exposed workers (%)

No. of workers in effective dose intervals

MDL to`1 mSv

1 to`20 mSv

20 to30 mSv

b30 mSv

Medical uses ofradiation

1995 3466 1247 (36.0) 810 435 ------ 21996 2971 865 (29.1) 627 235 3 ------1997 3247 1226 (37.8) 824 400 2 ------1998 4112 1609 (39.1) 1167 441 1 ------1999 4938 1524 (30.9) 995 526 2 1Total 18,734 6471 (34.5) 4423 2037 8 3

Industrial uses ofradiation

1995 315 10 (3.2) 7 3 ------ ------1996 350 12 (3.4) 5 6 1 ------1997 310 31 (10.0) 17 12 1 11998 332 27 (8.1) 14 10 2 11999 394 16 (4.1) 12 4 ------ ------Total 1701 96 (5.6) 55 35 4 2

Research-educationestablishment

1995 41 8 (19.5) 4 4 ------ ------1996 35 ------ ------ ------ ------ ------

1997 27 ------ ------ ------ ------ ------1998 39 1 (2.6) 1 ------ ------ ------1999 44 2 (4.5) ------ 2 ------ ------Total 186 11 (5.9) 6 5 ------ ------

Total 20,621 6578 (31.9) 4483 2078 12 5

Table 2. Occupational exposure data from 1995 to 1999 for workers in medical applications.

Occupationalcategory


Annual totalcollective effective

dose (man Sv)

Annual averageeffective dose (mSv)

Diagnostic radiology 1995 2879 2.205 0.771996 2453 1.216 0.501997 2680 2.115 0.791998 3151 2.349 0.751999 4045 1.781 0.44

Radiotherapy 1995 133 0.035 0.261996 165 0.006 0.041997 150 0.022 0.151998 243 0.016 0.071999 281 0.017 0.06

Nuclear medicine 1995 371 0.227 0.611996 277 0.155 0.561997 329 0.262 0.801998 582 0.317 0.54

1999 475 0.203 0.43Dental radiology 1995 62 0.042 0.68

1996 58 0.015 0.261997 68 0.020 0.291998 111 0.015 0.141999 121 0.029 0.24

Other 1995 21 0.008 0.381996 18 0.002 0.111997 20 0.004 0.201998 25 0.006 0.241999 16 0.001 0.06

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Radiography involves the largest number of personsboth monitored and exposed in the industrial sector.All persons working in irradiation applications areexposed under MDL in the eld of industrial usesof radiation. Therefore, account is taken of dosesoccurring below MDL and recorded as zeros asshown in Table 3.

The research-education has the smallest number

of radiation workers as composed to the other sec-tors as shown in Table 4. The average effective doseshowed the largest value in 1995.

The results of the collective and average effectivedoses are schematically presented in Figure 4. In1995, the average effective dose has the largest valuein the medical sector. However, the collective effec-tive dose has the highest value in 1998. The averageeffective dose of industrial sector is the largest valuein 1997. In 1997 and 1999, the collective effective doseis the same largest value in the industrial sector. The

collective and average effective doses have the largestvalues in 1995 for research-education sector while thelowest value in 1996----1997.

Table 5 shows the collective dose (man Sv) fromworkers in effective dose intervals in 1995----1999.Table 6 shows the number of workers in effectivedose intervals in 1995----1999. It can be seenthat most annual doses are less than MDL in

14,043 persons and in the MDL----0.99 mSv rangein 4483 persons. The total collective dose is 3.062man Sv in this dose interval. But, total collectivedose of 1726 persons is 5.062 man Sv between 1.0and 4.99 mSv.

In conclusion, a statistical analysis was carriedout in order to better understand the occupationalradiation doses in Turkey. In the future, there is aplan to carry out an epidemiological study in orderto evaluate radiation effects on radiation workersbased on radiation dose data.

Table 3. Occupational exposure data from 1995 to 1999 for workers in industrial applications.




dose (man Sv)


Radiography 1995 160 0.002 0.01

1996 206 0.086 0.421997 173 0.065 0.381998 192 0.113 0.591999 192 0.015 0.08

Irradiation 1995 37 0.000 0.001996 37 0.000 0.001997 22 0.000 0.001998 14 0.000 0.001999 26 0.000 0.00

Other 1995 118 0.006 0.051996 107 0.001 0.011997 115 0.049 0.431998 126 0.006 0.051999 176 0.002 0.01

Table 4. Occupational exposure data from 1995 to 1999 for workers in research-education applications.




dose (man Sv)


Research-education 1995 41 0.014 0.341996 35 0.000 0.001997 27 0.000 0.001998 39 0.001 0.03

1999 44 0.002 0.05


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1994 1995 1996 1997 1998 1999 2000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Medical

collective effective dose

average effective dose

Year

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Collectivee

ffectived

os

e(

manSv)

Average

effectivedose(mSv)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

Industrial

Year

Collectivee

ffectived

ose(

manSv)

0.0

0.2

0.4

0.6

0.8

Averageeffectivedose(mSv)

1994 1995 1996 1997 1998 1999 2000

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

Research-education

collective effective doseaverage effective dose

Year

Collectivee

ffectived

ose(

manSv)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Averageeffectivedose(mSv)

1994 1995 1996 1997 1998 1999 2000

collective effective dose

average effective dose

Figure 4. Collective effective dose (~) and average effective dose (*) versus years.

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Table 5. Exposures of workers from all occupational categories during 1995----1999.

Occupational category Year Collective dose (man Sv) of workers in effective dose intervals (mSv)

MDL----0.99 1.0----4.99 5.0----9.99 10----14.9 15----19.9 20----29.9 b30

Diagnostic radiology 1995 0.495 1.078 0.422 0.045 0.064 ------ 0.101

1996 0.309 0.547 0.186 0.079 0.019 0.076 ------1997 0.547 0.852 0.377 0.225 0.063 0.051 ------1998 0.670 1.032 0.501 0.066 0.051 0.029 ------1999 0.644 0.842 0.174 0.013 0.015 0.048 0.045

Radiotheraphy 1995 0.005 0.030 ------ ------ ------ ------ ------1996 0.002 0.004 ------ ------ ------ ------ ------1997 0.002 0.008 ------ 0.012 ------ ------ ------1998 0.005 0.011 ------ ------ ------ ------ ------1999 0.005 0.002 0.010 ------ ------ ------ ------

Nuclear medicine 1995 0.049 0.115 0.027 0.036 ------ ------ ------1996 0.025 0.037 0.034 0.022 0.037 ------ ------1997 0.058 0.108 0.051 0.014 0.031 ------ ------1998 0.070 0.155 0.054 0.022 0.016 ------ ------1999 0.093 0.084 0.026 ------ ------ ------ ------

Dental radiology 1995 0.013 0.029 ------ ------ ------ ------ ------1996 0.005 0.010 ------ ------ ------ ------ ------1997 0.007 0.007 0.006 ------ ------ ------ ------1998 0.010 0.005 ------ ------ ------ ------ ------1999 0.007 0.022 ------ ------ ------ ------ ------

Other 1995 0.002 0.006 ------ ------ ------ ------ ------1996 0.002 ------ ------ ------ ------ ------ ------1997 0.004 ------ ------ ------ ------ ------ ------1998 0.003 0.003 ------ ------ ------ ------ ------1999 0.001 ------ ------ ------ ------ ------ ------

Radiography 1995 0.002 ------ ------ ------ ------ ------ ------1996 0.003 0.003 0.008 0.047 ------ 0.025 ------1997 0.006 0.029 0.005 ------ ------ 0.025 ------1998 0.005 0.012 0.006 0.010 ------ 0.050 0.030

1999 0.004 0.004 0.007 ------ ------ ------ ------

Irradiation 1995 ------ ------ ------ ------ ------ ------ ------1996 ------ ------ ------ ------ ------ ------ ------1997 ------ ------ ------ ------ ------ ------ ------1998 ------ ------ ------ ------ ------ ------ ------1999 ------ ------ ------ ------ ------ ------ ------

Other 1995 ------ 0.006 ------ ------ ------ ------ ------1996 0.001 ------ ------ ------ ------ ------ ------1997 0.003 0.001 0.006 ------ ------ ------ 0.0391998 0.001 0.005 ------ ------ ------ ------ ------1999 0.002 ------ ------ ------ ------ ------ ------

Research-education 1995 0.001 0.013 ------ ------ ------ ------ ------1996 ------ ------ ------ ------ ------ ------ ------1997 ------ ------ ------ ------ ------ ------ ------

1998 0.001 ------ ------ ------ ------ ------ ------1999 ------ 0.002 ------ ------ ------ ------ ------

Total for each year 1995 0.567 1.277 0.449 0.081 0.064 ------ 0.1011996 0.347 0.601 0.228 0.148 0.056 0.101 ------1997 0.627 1.005 0.445 0.251 0.094 0.076 0.0391998 0.765 1.223 0.561 0.098 0.067 0.079 0.0301999 0.756 0.956 0.217 0.013 0.015 0.048 0.045

Total 3.062 5.062 1.900 0.591 0.296 0.304 0.215


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Table 6. Dose distribution in occupational categories involved in Turkey from 1995 to 1999.


Year Number of workers in effective dose intervals (mSv)

bMDL MDL----0.99 1.0----4.99 5.0----9.99 10----14.9 15----19.9 20----29.9 b30

Diagnostic radiology 1995 1805 720 278 66 4 4 ------ 2

1996 1689 563 163 28 6 1 3 ------1997 1597 726 278 54 19 4 2 ------1998 1847 957 265 72 6 3 1 ------1999 2711 865 437 27 1 1 2 1

Radiotherapy 1995 112 8 13 ------ ------ ------ ------ ------1996 156 7 2 ------ ------ ------ ------ ------1997 139 6 4 ------ 1 ------ ------ ------1998 227 11 5 ------ ------ ------ ------ ------1999 267 11 1 2 ------ ------ ------ ------

Nuclear medicine 1995 252 62 50 4 3 ------ ------ ------1996 209 38 21 5 2 2 ------ ------1997 224 71 23 8 1 2 ------ ------1998 338 159 74 8 2 1 ------ ------1999 328 98 45 4 ------ ------ ------ ------

Dental radiology 1995 37 15 10 ------ ------ ------ ------ ------1996 38 15 5 ------ ------ ------ ------ ------1997 46 16 5 1 ------ ------ ------ ------1998 78 30 3 ------ ------ ------ ------ ------1999 93 20 8 ------ ------ ------ ------ ------

Other 1995 13 5 3 ------ ------ ------ ------ ------1996 14 4 ------ ------ ------ ------ ------ ------1997 15 5 ------ ------ ------ ------ ------ ------1998 13 10 2 ------ ------ ------ ------ ------1999 15 1 ------ ------ ------ ------ ------ ------

Radiography 1995 153 7 ------ ------ ------ ------ ------ ------1996 195 4 1 1 4 ------ 1 ------1997 150 12 9 1 ------ ------ 1 ------1998 171 10 6 1 1 ------ 2 1

1999 179 9 3 1 ------ ------ ------ ------

Irradiation 1995 37 ------ ------ ------ ------ ------ ------ ------1996 37 ------ ------ ------ ------ ------ ------ ------1997 22 ------ ------ ------ ------ ------ ------ ------1998 14 ------ ------ ------ ------ ------ ------ ------1999 26 ------ ------ ------ ------ ------ ------ ------

Other 1995 115 ------ 3 ------ ------ ------ ------ ------1996 106 1 ------ ------ ------ ------ ------ ------1997 107 5 1 1 ------ ------ ------ 11998 120 4 2 ------ ------ ------ ------ ------1999 173 3 ------ ------ ------ ------ ------ ------

Research-education 1995 33 4 4 ------ ------ ------ ------ ------1996 35 ------ ------ ------ ------ ------ ------ ------1997 27 ------ ------ ------ ------ ------ ------ ------

1998 38 1 ------ ------ ------ ------ ------ ------1999 42 ------ 2 ------ ------ ------ ------ ------

Total for each year 1995 2557 821 361 70 7 4 ------ 21996 2479 632 192 34 12 3 4 ------1997 2327 841 320 65 21 6 3 11998 2846 1182 357 81 9 4 3 11999 3834 1007 496 34 1 1 2 1

Total 14,043 4483 1726 284 50 18 12 5

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ACKNOWLEDGEMENTS

In this study, all of the occupational dose database(1995----1999) are presented by permission of directo-rate of Ankara Nuclear Research and TrainingCentre (ANAEM), Turkish Atomic Energy Agency.The authors also wish to thank all personnel of

the ANAEM personnel dosimetry department fortheir contribution towards the development of theoccupational dose database.

REFERENCES

1. International Commission on Radiological Protection.1990 Recommendations of the International Commission

on Radiological Protection. ICRP Publication 60. Ann.ICRP 21(1----3) (Oxford: Pergamon Press) (1991).

2. International Basic Safety Standards for ProtectionAgainst Ionizing Radiation and for the Safety of Radia-tion Sources------Safety Series: 115, International AtomicEnergy Agency, IAEA (1996).

3. Law of Turkish Atomic Energy Agency (TAEA), Law

No. 2690, Turkish Government Ofcial GazetteNo. 17753, 13 July 1982.4. United Nations Scientic Committee on the Effects of

Atomic Radiation UNSCEAR 2000 Report to theGeneral Assembly. Sources and effects of ionizing radia-tion. UNSCEAR 2000 Report Vol 1.

5. Results of the 1999 Intercomparison for IndividualMonitoring of Radiological Measurement for MonitoringProposes, R. Cruz-Suarez, K. Mrabit, H. Stadtmann,International Atomic Energy Agency, IAEA (1999).


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