Towards a National Dose Registry in Portugal

Transcription

1 Towards a National Dose Registry in Portugal M.B. Martins, J.G. Alves, A.R. Roda, J.N. Abrantes Instituto Tecnológico e Nuclear, Departamento de Protecção Radiológica e Segurança Nuclear, Estrada Nacional 10, Sacavém, Portugal bertatrm@itn.mces.pt Abstract. The aim of this paper is to present the capabilities of a home-developed Database created using MS- Access to gather the annual effective doses of the population monitored by the Individual Monitoring Service (IMS) of the Radiological Protection and Nuclear Safety Department (DPRSN) at the Nuclear and Technological Institute (ITN), in Portugal. Individual monitoring at DPRSN started in 1957 using film badges to ensure the monitoring of staff operating the nuclear research reactor of ITN. With time, the IMS was expanded and the service was provided to workers across Portugal. Technological developments allowed for the introduction of thermoluminescence dosimetry (TLD) in Today both methodologies are running simultaneously and almost 7 of the workers are monitored by TLD. In January 2004 ITN-DPRSN was still the main Institution in Portugal performing individual monitoring of external radiation to approximately 10,000 workers on a monthly or quarterly basis. This number represents nearly 85-9 of the workers professionally exposed to ionising radiation in the country. At present the database contains the annual effective dose data of the population that was monitored by ITN- DPRSN since the fifties, which corresponds to nearly 32,700 workers. The database also gathers information relative to the facilities that request monitoring and to the workers that are monitored. The facilities are grouped into four different fields of activity, namely health or medicine, conventional industry, research and mining. In each field of activity the most frequently found practices have also been identified. As there are no nuclear plants in the country the staff operating the research reactor of ITN were included in the research group. The recently published Decree-Law n. 165 of July 17 th, 2002 commits to ITN-DPRSN the task of keeping the records of the radiation doses received by workers in Portugal during their life time. The legislation also requires that the dose records should be kept for thirty five years. In the forthcoming future the effective doses of workers monitored by IMSs other than ITN-DPRSN and related information will be inserted. 1. Introduction In January 2004 the Individual Monitoring Service at ITN-DPRSN monitored approximately 9,500 professionally exposed workers from 970 facilities from all around the country. Two dosimetric systems were running at ITN-DPRSN, one based on film dosimetry and the other one on TLD. Approximately 3,000 and 6,500 workers were respectively monitored with film and TLD. Film monitoring was based on the Kodak type II film inserted in a homemade holder for the evaluation of H p (10) [1,2]. The TLD system is comprised of two 6600 Harshaw readers and on the Harshaw 8814 TLD card and holder containing two LiF:Mg,Ti (TLD-100) detectors for the evaluation of H p (10) and H p (0.07) [1-3]. Whole body doses were measured on a monthly or quarterly basis, for both systems. Until 1996 ITN-DPRSN was the sole institution in Portugal providing external dosimetry services. At that time ITN-DPRSN introduced TLDs in routine monitoring. From 1996 until 2004 at least three more companies started providing this type of service. For the previously mentioned reasons ITN s records could be considered the National Dose Registry until On the other hand, all the data produced at ITN and the records relative to the facilities and workers monitored since 1957 to date are presently available in database format. Portuguese law enforced by Decretos-Lei n. 165 and 167 of 2002 [4,5] commit to ITN-DPRSN the task of creating a National Dose Registry that is, collecting and keeping the records of the radiation doses received by workers during their life time. In the near future the dose data and related information produced by the other external dosimetry services should be inserted in the database. In this paper the database available at ITN and currently in use is presented. 2. Methodology Both film and TLD dosimetry services developed their own database in order to meet the needs of each monitoring method and to gather the information relative to the facilities that request individual monitoring, relative to the workers that are monitored and the regular storage of the evaluated dose 1

2 data [6,7]. The main aim of either database is to enable the user full access to the data related to the facilities, monitored workers and measured doses and at the same time to give an answer to all the administrative features necessary to keep the service running. Nearly 25,950 records of all the workers monitored by film are kept in one database and 6,750 records corresponding to the number of workers monitored by TLD are kept in another database. A third database was developed using MS-Access to gather the annual accumulated doses of all the workers monitored by ITN-DPRSN since it started operating as an external dosimetry service provider in The records of approximately 32,700 workers are presently available in electronic format allowing a fast access to the annual and total annual accumulated doses. Data relative to a new monitoring period or yearly doses are automatically updated. In order to preserve the confidentiality of personal records, the data presented in this paper as examples are fictitious. 3. Database description The database main menu is displayed in Figure1 and directs the user to the following functions: 1. Facilities Data; 2. Workers Data; 3. Search on Facilities and Workers; 4. Visualization of Individual Dose Records and Accumulated Doses; 5. Print out of Individual Dose Records; 6. Search on Individual Records. FIG 1. Main Menu 3.1 Data related to the facility In Option 1, the facility record is displayed. As shown in Figure 2, the facility record contains all the information found necessary to identify the facility that requests monitoring for their workers. Each facility is uniquely identified with a code, called the File_Code, given at the onset of the monitoring. All the information related to a facility can be divided into ordinary and activity data. Ordinary data is the sort of information necessary to identify the facility as a client, typed at the onset of the monitoring and changed when necessary. Examples of this data are the facility's designation, mailing and invoice addresses, fiscal number, telephone, fax, the identification of the person responsible for the facility and other minor information such as the start (and end) date and the number of monitored workers. Activity data are related to the field of work and practices performed at the facility. Considering the monitored population in Portugal, four fields of work are available, namely, health or medicine, industry, research and mining, which are respectively identified by the acronyms MED, IND, INV and MIN, selected by the user from a combo box. Choosing one of the acronyms allows the selection of the predefined practices linked to it. A list of all the predefined practices can be found in Table 1. 2

3 FIG 2. Facility record mentioning the field of work and the practice performed. 3.2 Data related to the monitored worker Option 2 directs the user to the record of a monitored worker. The record is uniquely identified using both the facility code (File_Code) and the worker s ID number. The record contains information related to the facility, the worker and the type of work performed, as shown in Figure 3. FIG 3. Worker record mentioning the selection of professions and practices performed. The facility information needed is the File_Code, the monitoring period and the activity code. The worker personal information required is the ID number, full name, birth date, nationality, monitoring start (and end) date. The information related to the type of work is available on the questionnaire provided by the facility or is given by the worker himself. The type of work is also linked to the facility activity code and it comprises the profession and practices performed by the worker, chosen 3

4 from a predefined selection. A list of all the predefined practices and professions can be found in Tables 1 and 2, respectively. Table I - List of practices performed by workers. MED INV 1,1 Radiologia, Convencional 1,1 Ensino 1,2 Radiologia, Angiografia 2,1 Inv. Médica: Diagnóstico in-vitro 1,3 Radiologia, Intervenção 2,2 Inv. Médica: Outros 1,4 Radiologia, TAC 3,1 Mét. Analíticos: RX Convencional 1,5 Radiologia, Mamografia 3,2 Mét. Analíticos: Difracção, Fluor. RX 1,6 Radiologia, Pediátrica 3,2 Mét. Analíticos: Outros 1,7 Radiologia, Dentária Convencional 1,8 Radiologia, Dentária Panorâmica IND 1,9 Radiologia, Todas as Aplicações 1,1 Radiografia Industrial em Câmara 2,1 Braquiterapia, Todas as Aplicações 1,2 Radiografia Industrial em Estaleiro 2,2 Braquiterapia, After-loading 1,3 Radioscopia Industrial 3,1 Radioterapia, Co-60 2,1 Gamagrafia Industrial em Câmara 3,2 Radioterapia, Acelerador 2,2 Gamagrafia Industrial em Estaleiro 3,3 Radioterapia, Todas as Aplicações 3,1 Controlo de Processos Industriais 4,1 Med. Nuclear, Terapia 3,2 Controlo Laboratorial 4,2 Med. Nuclear, Diagnóstico 3,3 Equip. Portátil para Controlo 4,3 Med. Nuclear, Todas as Aplicações 4,1 Assistência a Equip: Raios-X Médico 5,1 Física / Engª Hospitalar 4,2 Assistência a Equip: TAC 5,2 Protecção Radiológica 4,3 Assistência a Equip: Aceleradores 6,1 Radiologia, Medicina Veterinária 4,4 Assistência a Equip: Med. Nuclear 7,1 Outros 4,5 Assistência a Equip: Industrial 4,6 Assistência a Equip: Laboratorial 4,7 Assistência a Equip: Vários (Médico) MIN 4,8 Assistência a Equip: Outros 1,1 Extracção de Minério 5,1 Protecção Radiológica 1,2 Tratamento de Minério 6,1 Outros 2,1 Outros 7,1 Não Exposto Table II - List of predefined professions of monitored workers. MED INV ADM Administrativo(a) ADM Administrativo(a) ASS Assistente de Consultório BIOL Biólogo(a) AUX Auxiliar BIOQ Bioquímico(a) BIOL Biólogo(a) BOL Bolseiro BIOQ Bioquímico(a) ENG Engenheiro(a) ENF Enfermeiro(a) FARM Farmacêutico(a) ENG FIS Eng.(a) Físico(a) FIS Físico(a) FARM Farmacêutico(a) GEOL Geólogo(a) FIS Físico(a) O Outro MED Médico(a) PROF Professor(a) O Outro QUIM Químico(a) QUIM Químico(a) TEC AN Téc.(a) de Análises TEC AN Téc.(a) de Análises TEC LAB Téc.(a) de Laboratório TEC MN Téc.(a) de Medicina Nuclear TEC RD Téc.(a) de Radiologia IND TEC RT Téc.(a) de Radioterapia ADM Administrativo(a) ENG Engenheiro(a) MIN FIS Físico(a) ADM Administrativo(a) GEOL Geólogo(a) ENG Engenheiro(a) MOT Motorista GEOL Geólogo O Outro MIN Mineiro OP FAB Operário(a) fabril O Outro TEC LAB Téc.(a) de Laboratório TEC Técnico(a) TEC OP Téc.(a)-Operador(a) de Radiologia 4

5 3.3 Visualization of dose records by monitoring period In Option 3, the effective dose values measured in one year and received by a worker are displayed, see Figure 4. It contains information relative to the facility and to the worker, along with the doses measured either monthly or quarterly in one year along with the respective annual accumulated dose. FIG 4. Quarterly measured doses and the respective annual accumulated dose. 3.4Visualization of yearly dose records and lifetime doses Option 4, allows for the visualization of the annual accumulated doses received by the worker as well as the total lifetime dose. The form is organized so that a quick view of the accumulated annual doses received since 1957 to date is obtained (Figure 5). FIG 5. Individual record of a worker showing the annual accumulated doses since 1957 to date. 5

6 3.5 Report on the annual accumulated doses and lifetime dose Option 5, allows the print out of a report containing the information mentioned in Option 4. An example of the report produced is shown in Figure 6. According to Portuguese legislation the responsible person for the facility is the responsible for the radiation doses received in the facility s premises [5,8]. The number of individual dose reports produced equals the number of facilities where the worker has worked from the beginning of his working life until presently, either simultaneously or not. The report can be divided into two different areas. In the top area, the worker and the facility are identified along with the monitoring starting and ending dates. In the main area the annual accumulated doses received in each working year are displayed along with the lifetime dose received in that particular facility. FIG 6. Report on the annual accumulated doses and the respective lifetime dose. 3.6 Search on individual records This option allows the user to select a particular worker or facility, using all the data fields in user friendly environment. 4. The database in figures Concerning the records of facilities and workers monitored with film since 1957 until 2002, approximately 1,800 facilities requested monitoring for nearly 26,000 workers, 33% of which were female workers, as shown in Table III. Table III - Distribution of the number of facilities and workers by field of activity and by gender. Data for film monitoring from 1957 until Field Facilities Workers Female Male number (%) number (%) number (%) Number (%) Health Industry Research Mining Total The relative distribution of the number of facilities and workers organized by field of activity are 6

7 represented in Figure 7. The large majority of the monitored population worked in the medical field, followed by industry, research and mining. Over this time period the mining industry related mainly to the extraction and chemical treatment of uranium ore represented nearly a half of the persons dedicated to conventional industry. 100, 90, Workers Facilities 80, 70, 60, 65,7% 63,7% 50, 40, 30, 22,7% 20, 10, 14,9% 11,9% 7,8% 7,5% 5,7% 0, Health Industry Research Mining FIG 7. Percentage of facilities and workers organized by field of activity, for film monitoring since 1957 until In Figure 8 the relative number of workers organized by field of activity and by gender are shown. The data presented in Table III and Figure 8 shows there is a similar proportion of male and female workers in both the medical and research fields of activity, standing aproximately 4 to 6, respectively. In the other two fields of activity the number of female workers is very small, and almost negligible in the case of mining (1.3%) ,7% 98,7% 9 Female Male ,1% 6 59,3% 56,9% Workers ,7% 43,1% 32,9% ,3% Health Industry Research Mining Total 1,3% FIG 8. Distribution of workers by field of activity and gender, for film monitoring since 1957 until The relative distribution of the effective dose measured in the period 1998 to 2002 organized by fields of activity and by dose intervals is presented in Figure 9. The figure shows that the overall majority of the monitored workers received an effective dose well below the annual dose limit established for the members of the public [9]. In the five-year period a little number of workers received dose values higher than 50 msv, but these data will be analyzed in detail in ref

8 % 98% 89% Number of Workers % 2 1 3% D<0,5 0,5<=D<1 17% 2% 2% 14% 2% 3% 2% 1% 3% 1% 1% 1% 2% 1% 1% 1% 1% 7% 1% 1% 7% 3% 1<=D<2 2<=D<5 5<=D<10 10<=D<20 20<=D<50 50<=D<100 D>=100 Industry Research Mining Total Health FIG 9. Relative distribution of the effective dose measured in the period Conclusions The main features of a home developed database for the storage of the annual accumulated dose values evaluated at ITN-DPRSN was presented. This database represents the embryo of the National Dose Registry, a task enforced by law to ITN-DPRSN. The same law requires ITN-DPRSN to produce annual reports on the effective doses due to occupational exposure in Portugal. This database allows a statistical evaluation of the inserted data enabling ITN-DPRSN to answer the requests of ESOREX and UNSCEAR in an easier way, as suggested by the results presented in the last figure and in more detail in ref. 10. A large amount of work still remains to be done, namely, the collection and insertion of all the data related to facilities, workers and effective dose evaluated and stored by other companies operating in Portugal. References 1. Alves, J.G., Martins, M.B, Amaral, E.M. Occupational Radiation Doses in Portugal from 1994 to Proceedings of the IRPA-10, the 10 th International Congress of the International Radiological Protection Association, Hiroshima, Japan, May 2000, P-3b-174, 1-9 (2000). 2. Alves, J.G., Martins, M.B, Amaral, E.M. Occupational Exposure in Portugal in Radiat. Prot. Dosim. 96, 1-3, (2001). 3. Carreiro, J.V., Alves, J.G. A Dosimetria por Termoluminescência na Avaliação de Doses dos Trabalhadores Profissionalmente Expostos às Radiações Ionizantes em Portugal. Proceedings of the III Congresso Nacional de Radiologia CNR 96, Coimbra, Portugal, May 1996, DGA- DPSR nº34/96 (1996). 4. Decreto-Lei nº 165/2002, 17 th of July, Diário da República, Imprensa Nacional Casa da Moeda (2002). 5. Decreto-Lei nº 167/2002, 18 th of July, Diário da República, Imprensa Nacional Casa da Moeda (2002). 6. Alves, J.G., Batel, V.I. A Base de Dados da Dosimetria Individual por Termoluminescência: Manual de Instruções para Actualizações Periódicas, DPRSN Draft to be published. 7. Alves, J.G., Martins, M.B., Abrantes, J. Databases in use at the Individual Monitoring Service of ITN-DPRSN. 1 st International Meeting on Applied Physics (APHYS-2003), October 2003, 8

9 Badajoz, Spain (2003). 8. Decreto-Lei nº 9/1990, 19 th of April, Diário da República, Imprensa Nacional Casa da Moeda (1990). 9. European Commission. Council Directive 96/29 EURATOM of 13 th May 1996 laying down the Basic Safety Standards for the Protection of the Health of Workers and the General Public Against the Dangers Arising from Ionizing Radiation. Official Journal of the European Communities L 159, vol. 39 (29 June 1996). 10. Alves, J.G., Martins, M.B., Roda, A.R., Abrantes, J.N. Occupational Exposure in Portugal in in 5-year periods. Poster presented at the 11 th International Congress of the International Radiological Protection Association, Madrid, Spain, May 2004 (2004). 9