Conception and design of the National Database of the Individual Dose of the Republic of Cuba

Transcription

1 Conception and design of the National Database of the Individual Dose of the Republic of Cuba Miguel Prendes Alonso *, Maryzury Valdés Ramos, Juan Tomás Zerquera, Daniel Molina Pérez, Gladys López Bejerano1, Ana Ilsa Lamadrid Center for Radiation Protection and Hygiene, City of Havana, Cuba Abstract. The individual radiological surveillance in the country covers all the workers occupationally exposed to radiation sources. Several techniques have been used and many laboratories have been in charge of guaranteeing the surveillance. Due to this situation the information of the dosimetric reports is not available in an only one format and it does not exist an unique database that allows its appropriate systematizing. The present work describes the conception that was used to create an automated system for management of the dosimetric information and the diverse requirements used for it. In the conception of the centralized dosimetric database were considered the requirements of the national competent authorities, not only those related to radiological field but also those of the legal and of the national statistical systems. The criteria of other stakeholders were taken into account, i.e. the users, the institutions that participate in the medical surveillance and organizations involving in to the radiological emergencies responses. KEYWORDS: Individual Radiological Surveillance, Dosimetric Database, Occupational radiation protection. 1. INTRODUCTION Individual radiological surveillance is an important tool to value the effectiveness of the radiological safety program that is undertaken in the practices with ionizing radiation exposures. Statistical analysis of the surveillance results decisively contribute to optimization actions of the practices to be developed by the regulatory body and by the institutions using nuclear techniques [1]. Similarly, their results have a legal character, so they may be available for regulatory institutions, techniques officers and personnel occupationally exposed. Individual radiological surveillance in Cuba covers 100% of the personnel occupationally exposed [2]. Diverse measurement techniques are used to estimate the received dose either by external exposure or by radionuclide intake. Exceptionally, biological methods are used to carry out retrospective assessments of doses potentially received by persons involved in abnormal exposures. Users of the surveillance services periodically receive the report of doses corresponding to the exposure period. The regulatory authority has an annual summary of the results. However, there is no a centralized Registry that manages the individual dosimetric information that would permit useful assessments for users and regulatory officers. 2. INDIVIDUAL MONITORING TECHNIQUES THAT HAVE BEEN PERFORMED IN CUBA. Cuba has had individual radiological surveillance coverage for almost 20 years. Many laboratories have provided these services and the techniques used have been diverse. In the table below there is a summary of the used techniques and the way in which they were or are still carried out the services of individual radiological surveillance. * Presenting author, prendes@cphr.edu.cu 1

2 NRO INDIVIDUAL MONITORING TECHNIQUE (SERVICE) 1. EXTERNAL DOSIMETRY, Whole Body, 2. EXTERNAL DOSIMETRY, Whole Body, CHARACTERISTICS o Film dosimeters. o Presently it is not used. It was used for almost ten years during the 90 s. o Approximately 3000 occupationally exposed workers controlled. o Magnitude that assess: personal equivalent dose (Hp(10)) o Thermoluminescent dosimeters. o Monthly monitoring o It is presently provided to more than 8500 occupationally exposed workers. o Magnitude that assess: personal equivalent dose (Hp(10)) 3. EXTREMITY DOSIMETRY 4. INTERNAL DOSIMETRY, Whole body counter o Thermoluminescent dosimeters. (Metallic ring). o Monthly monitoring frequencies o It is presently provided to 430 occupationally exposed workers. o Magnitude that assess: Equivalent dose o Direct measurements of gamma emitters. o Monitoring frequencies is in dependence of the practice category (monthly, quarterly, biannual) o It is presently provided to occupationally exposed workers working in open radiation sources. 5. INTERNAL DOSIMETRY, THYROID CONTROL o Direct measurements of Iodine in Thyroid o Monitoring frequencies is depending on the practice category (monthly, quarterly, biannual) o It is presently provided to occupationally exposed workers working with unsealed radiation sources. 2

3 6. INTERNAL DOSIMETRY, IN VITRO o Indirect measurements of Beta emitters in urine. o Measurements in urine samples of P- 32, C-14, S-35, H-3 using liquid scintillation techniques. o Monitoring frequencies is depending on the practice category (monthly, quarterly, biannual) o It is presently provided to occupationally exposed workers working with unsealed radiation sources 7. BIOLOGICAL DOSIMETRY o Cytogenetic Techniques o Estimation of doses by total irradiation for homogeneous exposures ; o Estimation of doses by partial irradiation for non- homogeneous exposures; o Estimation of the irradiated body fraction for non homogeneous exposures. o It is presently provided to persons involved in abnormal radiological situations in order to assess received doses. 3. PROCESSING OF THE INFORMATION OF THE RESULTS OF RADIOLOGICAL SURVEILLANCE. The state of the information available in individual radiological surveillance accomplished in the country is as follows: of the results from 1987 to 1992, the information of the doses report only exists in hard copy, there is no electronic version. From 1993 and up to 2000, the application DOSIS was used: DOSIS: Integrated system of data for the control of the dosimetric information of Workers Occupationally Exposed. It controlled the unified data of the radiological surveillance of Workers Occupationally Exposed, (External and Internal Dosimetry). This system had an interface tool (DFILM), for data reading and processing in a densitometry system, since it used a film dosimetry [3]. This tools were developed in FOXPRO and PASCAL, respectively. Data of the measures of that period are kept in DBF format files. A new version of the application DOSIS developed in Borland Delphis for Windows and Microsoft Access to control the information provided by the services of External dosimetry has been used since 2000 [4]. This system is composed of an interface tool (RADOS-DOSIS), for the acquisition and assessment of doses with TLD dosimeters provided by RADOS company [5]. Data of the measurements of this period are kept in MDB format files. Registers in EXCELL format have been used from 2000 on, to control dosimetric information of the services of Internal Dosimetry. Estimations of the doses used the dosimetric models recommended by ICRP. Data of the measurements of this period are kept in XLS format files. 3

4 DOSGEN, Integrated System of Data and Dose Estimation for information automatization of Cytogenetic Dosimetry Assays was developed for the information obtained from the services of Cytogenetic dosimetry. Data of the measurements of this service are kept in MDB format files. Consequently, the information is disperse and it is not completely in electronic format. This situation may affect the fulfillment of the established requirements in the BSS regarding the time the results of individual surveillance should be kept. Report of doses are limited to the surveillance subject, thus the results of all possible exposure routes controlled are not included in none of them. An individual dosimetric Registers with the sum of doses is not available, obviously this aspect is important for an non depreciable number of workers occupationally exposed. 4. CONCEPTION AND DESIGN OF THE NATIONAL BANK OF DOSIMETRIC DATA. The creation of a centralized national dosimetric Bank is a good practice promoted by the International Atomic Energy Agency (IAEA). In the conception of the national Bank the participation of four groups is foreseen. o Regulatory Authority: It will be in charged of the management of the dosimetric Bank and of proposing the statistical requirements. This aims at enhancing the usefulness of the information in optimizing the radiological protection in practices. Besides, it will ensure the information exchange with other regional or interregional projects in this field and will define the requirements of national legalization of the information and the interaction with other competent national organizations as well. o Service laboratories. They will provide the historic information that requires to be digitalized. In addition, they will provide their current informatics processing tools of essay reports in order to ensure that information updating will be performed automatically and reliable once the software was developed. o Users of the individual dosimetric surveillance programs. They will be secondary receptors of the bank management. They will promote the improvements of the software so as to ensure the visibility of doses report. The data bank is a backup of the individual dosimetric history. o Other interested organizations. Different national institutions use dosimetric information, for example those involved in medical surveillance of the personnel occupationally exposed or those participating in the national response plan for radiological emergencies. The software will be developed in a way that may facilitate the controlled access of the institutions representatives to the managed information. 4.1 Main components and interfaces of the National Dosimetric Bank. A group of interfaces (temporary and permanent) were developed to transfer the existing information and the currently generated by the different kind of services. o The dosimetric information of the first years is in written documents, so it was necessary to digitalized all the information and to develop a temporary interface tool to capture all the information and transfer to centralized format of the national dosimetric bank. o Information of the different services (external and internal contamination) of this first decade was also consolidated in FOXPRO database (*.dbf). The used structure, the different files and 4

5 data fields were identified, and a temporary interface tool was developed to transfer this information to the centralized format of the national dosimetric bank. o The dosimetric information of Internal Dosimetry Services of the last decade is in format EXCELL (*.XLS). The used structure in the calculation sheets was identified and a permanent interface tool was developed in order to transfer this information to the centralized format of the national Dosimetric bank. o The dosimetric information of the external dosimetry services of the last decade is in format ACCESS (*.mdb). The used structure, the different files, data fields and relations were identified, and a permanent interface tool was developed to transfer this information to the centralized format of the national dosimetric bank. The National Dosimetric Bank is a database management system that stores, controls and correlates all the information generated by the different services of individual radiological surveillance which were accomplished or are currently accomplished in the country, with a WEB interface connected for visualized the main results by direct or indirect users of the bank. The main components and interfaces of the National Dosimetric Bank are representing in the figure No.1. Figure 1: Structure of the National Dosimetric Bank. The main information processes by the national dosimetric bank are: o National Register of Workers occupationally exposed (WOE) that had or have individual radiological surveillance in the country. This is the main Registry of the system to which the rest of the information of the system is related to. Using the identification card number of the WOE the information of the bank can be accessed with the different applications that manage 5

6 dosimetric data in the country and with the system RASSYN, automated tool of the national regulatory authority to control radiological safety and protection data nationwide. o National Register of user entities that includes the general characterization of the entities to where WOE belongs to. o Register of associated practices to which WOE are involved in. o Register of different dosimetric techniques used in the country and their characterization. o Register of the measurements accomplished. There is a strict control to access the national Dosimetric Bank considering the important information that is manager and it depends on the user accessing the system. There is an attractive and comprehensible environment which allows to work in net. Results may be presented in reports and correlations, printed or by screen, in text, graph and table formats. 5. CONCLUSIONS Individual radiological surveillance has been based on the application of several essay techniques and has been carried out in many specialized laboratories. Part of the monitoring results is not available in permanent digital format. There is no a unique registry of the individual doses able to consider all the exposure routes which are controlled presently. The conception of an unique national dosimetric bank, managed by the regulatory authority and with the participation of all interested parties will allow the satisfaction of the requirements and expectations on this matter. 6. REFERENCES [1] Diaz B., E. et al., Interrelation between the result of the individual dosimetric control and the regulatory control in Cuba. Contributed paper IAEA-CN-67/26. International Conference on Low Doses of Ionizing Radiation: Biological Effects and Regulatory Control. IAEA-TECDOC- 976, Vienna, Austria, (1997). [2] Diaz B., E. et al., Seven years of individual monitoring services in Cuba. Proceedings of 1996 International Congress on radiation Protection, IRPA 9, Volume 4, page , Vienna, Austria, April 14-19, (1996). [3] Valdes R., M. et al., DOSIS-DFLIM: A system to control dosimetric information from the occupational personnel exposed to radiation with an interface to read and process data in a computer-densitometer system. Proceedings of the III Regional Congress on Radiological and Nuclear Safety, Peru, Vol II, page , (1996). [4] Manzano J., M. et al., DOSIS: Management System of data in Personal Dosimetry. V Regional Congress on Radiation Protection and Safety. Regional IRPA Congress, April 29 may 04, Recife, Brazil. (2001) [5] Valdes R., M. et al., "RADOS-DOSIS: Interface Program for the acquisition and evaluation of the dose with TLD dosimeters of the RADOS firm". Paper book of VI Regional Congress on Radiological and Nuclear Safety.. Lima, Peru, November, 9-13, (2003). 6