Individual monitoring services for external radiation were tested in the Czech Republic. The results of the tests show that they are dosimetry systems authorized and regularly tested in the Czech Republic having outliers for low energy region and angle of 50 degree and greater. With the highest probability, it can be stated that the processing equipment does not determine the angle of exposure reliably. These cases may have caused overestimations of Hp(10) in the special conditions occurring e.g. in interventional radiology and cardiology procedures.

BACKGROUND:The information on the results of the survey of collective effective dose SE to children in the Czech Republic (CR) due to nuclear medicine examinations performed during the one-year period July 1995-June 1996.METHODS:The estimate of SE was based on the annual frequency of nuclear medicine procedures and the type and amount of administered radiopharmaceuticals provided by the General Health Insurance Company covering 75% of the CR population.RESULTS:In the period considered, 15,281 examinations of children younger than 18 years were performed, which represented 7.5% of total nuclear medicine examinations in the CR. The annual SE 43.8 man Sv formed 5.1% of the collective effective dose to all patients examined by nuclear medicine procedures in the CR. The contributions of procedures in various body systems of children to the annual SE: urinary tract 32.8%, bone 30.4%, brain 12.8 %, cardiovascular 6.4%, GIT 6.0%, thyroid 4.4%, lungs 3.0%, other 4.2%. In comparison with a similar survey performed in the CR in 1987 (based on a questionnaire) there was an increase in SE to children younger than 15 years by a factor of 2.8, mainly due to the expansion of kidney and bone investigations.CONCLUSIONS:The mean effective dose per exam to children younger than 15 years was 60% of that for adults, which was in agreement with the requirement that the radiation burden of children should not exceed that of adults. The use of data from the Insurance Company for regular conducting of such surveys appeared to be not as cumbersome and time-consuming as questionnaire surveys.

Consistent with the worldwide development of nuclear medicine, in the Czech Republic in 1987 to 1996 partly the spectrum of used radiopharmaceutical preparations and their ratio changed. In the majority of radiopharmaceutical preparations the mean administered activity increased by 20 to 80% and the range of activities administered in different departments diminished somewhat. Adherence to principles of radiation protection of patients is assisted by guidelines of administered activities of radiopharmaceutical preparations laid down in new regulations on radiation protection valid in the CR from the middle of 1997. The radiation burden associated with the majority of examinations in nuclear medicine expressed as the effective dose is comparable with the radiation burden of radiodiagnostic examinations, only after administration of preparations with 131I, 201Tl, 67Ga and 111In it is markedly higher. Based on knowledge of the effective dose it may be concluded that the lifetime extra risk of a fatal tumour due to administration of radiopharmaceutical preparations is by two to three orders lower than the lifetime risk of spontaneous development of fatal tumours. A special feature of radiation risk is its hypothetical character--it is frequently projected into the distant future of human life, contrary to immediate non-radiation risks of some medical procedures and risks in the living environment which frequently are higher. Any examination using ionising radiation can be made only if the expected health benefit for the patient is significantly greater than the radiation risk. Excessive fear of radiation risk should not lead to refusal of justified examinations with possible subsequent serious health damage for the patient.

This paper describes recent situation in the Czech Republic concerning the registration and evaluation of occupational and medical radiation exposures. Since 1993 the creation of the Central (national) Registries of Occupational (CROE) and Medical Exposure (CRME) has been started. One of the main functions of these registries will be to provide statistics to guide policy making on a national basis. Authors give more detailed information on the structure of creating programs and discuss some actual arising problems.

The recent situation in the Czech Republic (CZ) concerning the evaluation and recording of occupational radiation exposures is described. The individual monitoring is based on the interpretation of the personal dosemeters responses and the evaluation of the other special dosimetric methods (measurement of excreta, whole body counting, etc.), The evaluation of occupational radiation exposures is carried out by five approved dosimetric services, which control about 20,000 workers. Record keeping of overexposures is based on two systems, which principles are explained. Based on long time analysis of occupational radiation exposures in CZ it can be present that the average values and trends of individual and collective effective dose equivalents are comparable with those in developed countries. The distributions of the radiation exposures for the important occupational groups of workers are presented.