[en] An inexpensive and simple test device was developed and used in a field study to evaluate entrance dose, dose to an intra-oral film, filtration and field size under routine conditions in more than 150 dental practices. The test device consists of two films of different speed and a set of 5 thin copper filters for a filter analytical determination of the radiation quality. Dentists voluntarily participating in the study were asked to expose the test device like they usually do when examining a molar tooth. The main result was the evidence of a significant dose reduction compared to the findings of similar studies performed in 1970 and 1976. This reduction is due to a general shift to lower values and a complete disappearance of values above 45 mGy (5 R) which in 1970 were still more than 15%. In the same way the number of facilities showing insufficient filtration or collimation had decreased. Nevertheless, a large spread of dose values could still be observed, ranging from less than 0.45 mGy (50 mR) to more than 26 mGy (3 R), for the entrance dose. The most striking result, however, was that such an important parameter like the speed of the films used at the respective unit turned out to have no impact on the entrance dose. (orig./HP)

[en] An inexpensive and simple test device was developed and used in a field study to evaluate entrance dose, dose to an intra-oral film, filtration and field size under routine conditions in more than 200 dental practices. The test device consists of two films of different speeds and a set of five thin copper filters for a filter-analytical determination of the radiation quality. Dentists were asked to expose the test device when examining a molar tooth. Together with a short questionnaire, describing the respective conditions of film exposure and processing, the test device was returned for development and evaluation. The main result was the evidence of a significant dose reduction compared to the findings of similar studies performed in 1970 and 1975. This reduction is due to a general shift to lower values and a complete disappearance of values above 45 mGy (5R) which in 1970 were still more than 15%. In the same way the number of facilities showing insufficient filtration or collimation had decreased. Nevertheless, a large spread of dose values could still be observed, ranging from 2.5 mGy (290 mR) to more than 30 mGy (3.4R) for the entrance dose. The most striking result, however, was that such an important parameter as the speed of the films used at the respective unit had no impact on the entrance dose. (author)

[en] This field study has been carried out in order to collect information on the dose values (entrance dose, exit dose) and mean optical densities (blackening) generally obtained in routine mammography with the equipment available at a variety of hospitals. Another goal was to find out to what extent recent applications of new methods in this field have had an effect on those values. About 300 physicians of hospitals in Bavaria have been asked to participate in this study, of which 170 agreed to cooperate. (orig.)

[en] Dose reduction methods, like the use of high sensitivity film screen combinations, have become more common in Germany. To find out the influence of these measures on the dose to patients a survey was started in 1983 to collect dose values under routine conditions at mammographic facilities. Three hundred hospitals and small clinics were asked for cooperation and finally about 160 agreed to participate. The participants have to expose a simple phantom, sent to them by mail, together with the film or film-screen combination commonly used at the unit. The developed films and two sets of three CaSo₄ TL-dosemeters mounted on the entrance and exit surfaces of the phantom are returned to the Gesellschaft fuer Strahlen- und Umweltforschung (GSF) for evaluation of film density and surface dose. In addition the participants are asked to answer a short questionnaire on the conditions of film exposure. Preliminary results on about 130 participants do not indicate a clear separation of the three routinely applied techniques (non-screen film, screen-film, and screen-film with anti-scatter grid) as expected. This demonstrates that even a distinct increase in image detector sensitivity does not always correspond to a comparable decrease of dose to the patient. (author)

[en] 122 CT scanners were studied in order to determine close values free in air on the axis of rotation during the most common types of examination. In addition, other exposure parameters were collected, which may be important in relation to dose to patients. The results showed a surprising variation in the dose values of CT examinations. It is concluded that it is not possible to estimate patient exposure reliably by using the information on exposure parameters supplied by the operator. (orig.)

[en] This Europe-wide dosimetry study, covering 89 departments in 11 EC countries, measured entrance surface dose (ESD) using TLDs, and surveyed X ray equipment and radiographic techniques used for frequent paediatric X ray examinations of the chest, abdomen, pelvis, skull and spine. The survey was limited to infants (10 months, 4 months and prematures of ∼ 1 kg). Data analysis shows that radiographic techniques differed widely. This was one of the reasons for the large variations in ESD of an order of magnitude of 1:50. A substantial number of departments used either very old X ray generators and/or techniques which are poorly suited for paediatric radiology. A significant dose reduction was seen when recommended guidelines for good radiographic technique were followed. The results of this study emphasize the necessity for the adherence to easily followed guidelines for the improvement of training and equipment in paediatric radiology

[en] Highlights: • CO-RADS improves the risk classification by 65.8% in patients affected by COVID-19. • CO-RADS combined with RT-PCR presents an AUC of 0.98 for patients with COVID-19. • CO-RADS improves the risk classification by 82.1% in patients not affected by COVID-19.