Personal Dosimetry in Sweden - Challenges and Developments

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1 Personal Dosimetry in Sweden - Challenges and Developments - Present status - Unresolved issues - Developments and trends

2 Swedish Facilities Nuclear facilities 10 operating and 3 closed reactors, fuel factory, waste management facilities (~10,000 persons each year) Industry Research > 1,000 licensees Dentists > 12, universities, ~ 200 licensees Hospitals 230 X-ray (> 5.5 millions / year) 33 Nucl. Med.(~100,000 / y, ~2,500 therapy) 18 Ext. Therapy (~20,000 / year)

3 Legislation Radiation Protection Act (SFS 1988:220) SSMFS 2008:51 The SSM s Regulations on Basic Requirements for the Protection of Workers and the Public in connection with Activities involving Ionising Radiation (96/29/Euratom EU BSS) Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation (EUR EN, 1994) SSMFS 2008:52 The SSM s Regulations on External Persons taking part in Activities involving Ionising Radiation (90/641/Euratom)

4 Exposed Personnel # of workers with dosimeter: 18-20,000 per year, decreasing number since years About 6,500 per year receive an effective dose above 0.1 msv in any monitoring period (one month) E.g. during period : Total recorded collective dose: (11.0 ± 1.0) mansv Highest estimated effective dose: (24.1 ± 1.4) msv Average individual dose: (1.7 ± 0.1) msv (Patient doses from diagnostic procedures: ~ 5,800 mansv)

5 National Dose Register Two parts Central Dose Register in Sweden - CDIS operated by the Nuclear Industry but with full access for SSM Computer register at the SSM where all dosimetry data from hospitals, research and other industry is registered SSM:s use: Tool for SSM s inspection and control activities Dose passports Data to international organisations (UNSCEAR etc.) Information requests from individuals and authorities

6 Calibration arrangement

7 Dosimetry Services Used Detectors 11 certified dosimetry services in Sweden. SSM formally approves services every 2 nd year TLD is used as legal dosimeter. One university uses electronic dosimeter (RADOS DIS-1) Data is reported to the National register within two weeks after evaluation from nuclear facilities Other dosimetry services report data within six weeks after dosimeter evaluation

8 # Persons in thousand's 1,4 Registered Occupational Radiation Doses in Sweden during ,2 1 0,8 0,6 0,4 0,2 0 0,1-0,3 0,4-1,0 1,1-2,5 2,6-5,0 5,1-10,0 10,1-15,0 15,1-20,0 20,1-25,0 msv Nuclear facilities Other industry, hospitals, research Effective dose intervals / msv

9 Average dose / msv Average individual radiation doses during ,00 7,00 6,00 Nuclear Facilities Other industry, Hospitals, Research 5,00 4,00 3,00 2,00 1,00 0,00 Radiation protection Mechanics Service personnel Scaffolding Insulation workers Operation Material testing Electricians Chemists Others Radiation treatment X-ray Nuclear Medecine Odonthology Instrument service R&D Radiography Veterinary act. Transport Others

10 Highest Individual Dose / msv Highest Individual Radiation Dose during 2006 Nuclear Facilities Other Industry, Hospitals, Research Radiation protection Mechanics Service personnel Scaffolding Insulation workers Operation Material testing Electricians Chemists Others Radiation treatment X-ray Nuclear Medecine Odonthology Instrument service R&D Radiography Veterinary act. Transport Others

11 msv Radiation Dose to Hands - Hospitals, Industry, Research ,0 12,0 9,0 6,0 3,0 0, Year Median Dose / msv 1,5 1,5 1,8 1,8 2,8 1,9 Mean Dose 9,6 8,4 8,5 9,4 11,8 9,6

12 Unresolved Issues - I 96/29/Euratom EU BSS (SSMFS 2008:51) Workers in category A - Individual dosimetry and annual health examinations Workers in category B - Area monitoring supplemented by calculations Regulations lead to incompatible decisions by the licensees while categorising workers Difficulties for the SSM to evaluate and compare radiation doses between comparable activities The SSM has issued recommendations

13 SSMFS 2008:51, Attachment 2, General Advice on practices, activities where affiliation to Category A should be considered

14 Unresolved Issues - II The national dose register needs renewal A tendering process was started 2007 Halted 2008 in connection with establishing SSM Planned to restart in autumn 2009 The computer system needs upgrading - overview of categories, data items Formal instructions to dosimetry services and licensees

15 Unresolved Issues - III Olsson et al Linköpings Universitet Radiation doses to lens of the eye and hands Is the used dosimetry adequate? Very few eye doses registered in the national dose register Reported events with high hand doses later revised on grounds of incongruity (not possible) Interventional radiology, radio chemistry Inappropriate hand / finger dosimetry?

16 ICRU 56, 1997 Unresolved Issues - IV Beta dosimetry SSM has initiated a review of existing β-sources protective equipment and β-dosimetry at the Swedish licensees Sources, PET, brachytherapy, nuclear facilities (fuel), laboratories

17 Developments and Trends New methods and new sources! PET is increasing More facilities Complex therapy Dynamic wedges, protons & ions Research facilities Neutron spallation source

18 Developments and Trends Electronic dosimeters One type certified in Sweden (Linköpings University) Private companies promotes new detectors Other dosimeters Neutrons (TLD, track etch technique CR-39) OSL, RPL limited knowledge in Sweden!?