[en] Our hospital is developing a nuclear medicine quality assurance program in order to comply with medical exposure Directive 97/43 EURATOM and the legal requirements established in our legislation. This program includes the quality control of equipment and, in addition, the dose estimation in patients undergoing nuclear medicine examinations. This paper is focused in the second aspect, and presents a new computer program, developed in our Department, in order to estimate the absorbed dose in different organs and the effective dose to the patients, based upon the data from the ICRP publication 53 and its addendum. (Author) 16 refs

[en] The aim of this study is to investigate the influence on image contrast, tube load and effective dose in paediatric fluoroscopy using added filtration. A Philips Omnidiagnosti is used in Nino Jesus Hospital and was therefore chosen for radiation dose measurements. The phantom consisted of varying methacrylate thickness to represent different patients sizes. All measurements were performed in automatic mode. For each exposure and additional filtration added the following data was recorded: tube voltage, tube current, air kerma rate on phantom surface and brightness on the image monitor. An 2026 electrometer (Radical Corporation) in conjunction with a model 2025-60 ion chamber were used for entrance dose measurements and the luxometer IL-400A (International Light) was used for brightness measurements on the image monitor: Evaluation of image quality was performed using a Leeds TOR TVF test object. Finally, the program PCXMC 1.5 based on the Monte Carlo method was used for calculating organ doses and the effective dose in fluoroscopy examinations. By increasing the filtration of the x-ray tube 1st Entrance radiation exposure can be decreased 58%, organ dose up to 40%, and effective dose up to 44%. 2nd The tube load increased up to 33%. 3rd Significant dose reduction is achievable without compromising image quality. The use of additional filtration in paediatric fluoroscopy should be evaluated taking into account dose reduction, additional tube loading and the possibility of some deterioration in image quality. (Author)

[en] A female employee working in diagnostic radiology should take additional controls to protect the unborn child from ionizing radiations. The fetus is particularly sensitive to the effects of x-rays and, so, the determination of the equivalent dose to the unborn child is of interest for risk estimates from occupational exposures of the pregnant workers. The ian of this study is to develop a method for fetus dose estimate of a pregnant worker who participates in interventional radiology procedures. Factors for converting dosemeter readings to equivalent dose to the fetus have been measured using thermoluminescence dosimetry. Equivalent dose to the uterus is used to simulate the equivalent dose to the fetus during the first two months of pregnancy. Measurements at different depths are made to consider the variations in the position of the uterus between pregnant women. The normalized doses obtained are dependent on the beam quality. Accurate estimation of fetus doses due to occupational exposures can be made using the data provided in the current study. (Author)

[en] The risks for the embryo-foetus in the developing stages, associated to pregnant patients being exposed to X-rays for diagnostic procedures, implies that the fulfillment of the principles of justification and optimisation and the recommendations established by the different organisations related to radiological protection are carried out. In order to do so, it is necessary for the professional people involved to have the maximum information available on the biological effects of ionising radiation on the embryo-foetus that is developing. In this article this matter is updated: the estimated doses values on the embryo-foetus in radiodiagnosis and the risks associated, as well as a series of recommendations that can be of use to establish procedure protocols, on which the measurements taken to reduce the risks of exposition to ionising radiation on the embryo-foetus in the developing stages are recorded. (Author) 11 refs

[en] The aim of this study is to evaluate the efficiency of bismuth breast shield in CT chest paediatric examinations when automatic exposure control techniques are used. The influence in the radiation dose and the image quality has been evaluated with and without the breast shield in the scoutview. In addition the radiation dose in shielded and non-shielded areas has been compared. Measurements were made in a 16 cm diameter cylindrical PMMA phantom simulating a newborn, and older children were simulated controlling the maximum intensities allowed by the automatic exposure control system AutomA. The highest dose reduction (59%) was obtained with AutomA system and when the breast shield is not used in the scoutview. This reduction in the radiation dose does not mean a significant increase of noise level. The use of the breast shield in the scoutview yielded an increase in the radiation dose in non-shielded areas. The use of bismuth breast shield is recommended only after the scoutview in order to optimise the radiation dose in CT chest paediatric examination when using automatic exposure control AutomA. (Author)

[en] To compare from both dosimetry and image quality standpoints, a digital scanning system with a conventional screen film system, in the full spine radiological procedure. The standard patient is considered to be 12 years old, and a sample of forty patients referred for full spine radiological procedure has been studied. Gonad shielding has been used in all the patients, and its efficiency has been evaluated. Dosimetric study includes Kerma-area product, and thorax and gonad entrance surface dose. Kerma area product has been measured using a transmission camera, and for entrance surface dose estimation both thermoluminescent dosemeter LiF: Mg, Cu, P and LiF: Mg, Ti have been utilized. Three radiologists have evaluated the image quality according to the degree of fulfilment of the image quality criteria. (Author) 22 refs

[en] The absorbed dose outside of the direct fields of radiotherapy treatment (or peripheral dose, PD) is responsible for radiation exposure of the fetus in pregnant women. Because the radiological protection of the unborn child is of particular concern in the early period of the pregnancy, the aim of this study is to estimate the PD in order to assess the absorbed dose in the uterus in a pregnant patient irradiated for breast carcinoma therapy. The treatment was simulated on an Alderson-Rando anthropomorphic phantom, and the radiation dose to the fetus was measured using an ionisation chamber and thermoluminescence dosemeters. Two similar treatments plans with and without wedges were delivered, using a 6 MV photon beam with two isocentric opposite tangential fields with a total dose of 50 Gy, in accordance with common established procedures. Average field parameters for more than 300 patients were studied. Measurements showed the fetal dose to be slightly lower than 50 mGy, a level at which the risk to the fetus is uncertain, although several authors consider this value as the dose threshold for deterministic effects. The planning system underestimated PD values and no significant influence was found with the use of wedge filters. (author)

[en] The recommendations of ICRP-60 of 1990 provide the basis of the European Directive 96/26/Euratom in which new dose limits of radiation for workers have been established. These new dose limits assume important reductions compared to the previous limits, which are still in force in Spain, and might entail the reclassification of some of these workers. In the present work it is shown that the majority of the workers exposed to areas under our responsibility could be classified under Category B

[en] Since the middle of the century, when Spain entered the ''nuclear age'', legal provisions have been necessary both for the peaceful development of nuclear energy and for protection against risks arising from its use. Various levels of regulations have been established for this purpose: laws, degrees, ministerial orders, etc. Further progress in radiation protection and increasing knowledge have made it necessary to revise this legislation, which may become obsolete in a few years' time. Some of the present regulations are being modified and work is in progress on the drafting of new legal provisions. From the health point of view, radiation protection patients is extremely important, and although great benefits can be derived from the medical applications of ionizing radiation, unnecessary or dangerous exposures and the delivery of unjustified doses cannot be permitted. In the paper, the Spanish Ministry of Health and Food reviews the legal standards which have been developed in Spain for radiation protection, describes current legislation in this field and expresses its willingness to contribute to the development and implementation of this legislation with all the means at its disposal. (author). 1 fig

[en] The decrease in the limits of dose equivalent at the entry of the abdomen of occupationally exposed pregnant women, as recommended by ICRP-60, necessitates to evaluate with dosimeter the various professional positions in different services existing in a health care centre, to guarantee that such limits cannot be exceeded, and thus ensure the protection of the foetus. The results obtained in this work, related exclusively to external radiation dose, show that the radiation protection system currently in force is in compliance with the regulation in the majority of the professional positions evaluated, though stricter criteria for pregnant women workers must be established with the aim of obtaining a better dose optimization. The fact that pregnant operators are working in Nuclear Medicine requires an additional effort to ensure that doses in excess of the limits stated are prevented