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PURPOSE X-ray cabinets are replacing 137 Cs/60 Co sources in radiation biology research due to advantages in size, handling, and radiation protection. However, because of their different physical properties, X-ray cabinets are more susceptible to experimental influences than conventional sources. The aim of this study was to examine the variations related to the experimental setups typically used to investigate biological radiation effects with X-ray cabinets. MATERIALS AND METHODS A combined approach of physical dose measurements by thermoluminescence dosimetry and detection of biological effects by quantification of γH2AX and 53BP1 foci was used to analyze field inhomogeneity and evaluate the influence of the components of the experimental setup. RESULTS Irradiation was performed using an X-ray tube (195 kV, 10 mA, 0.5-mm-thick copper filter, dose rate of 0.59 Gy/min). Thermoluminescence dosimetry revealed inhomogeneity and a dose decrease of up to 42.3% within the beam area (diameter 31.1 cm) compared to the dose at the center. This dose decrease was consistent with the observed decline in the number of radiation-induced foci by up to 55.9 %. Uniform dose distribution was measured after reducing the size of the radiation field (diameter 12.5 cm). However, when using 15-ml test tubes placed at different positions within this field, the dose decreased by up to 17% in comparison to the central position. Analysis of foci number revealed significant differences between the tubes for γH2AX (1 h) and 53BP1 (4 h) at different time points after irradiation. Neither removal of some tubes nor of the caps improved the dose decrease significantly. By contrast, when using 1.5-ml tubes, dose differences were less than 4%, and no significant differences in foci number were detected. CONCLUSION X-ray cabinets are user-friendly irradiation units for investigating biological radiation effects. However, field inhomogeneities and experimental setup components considerably affect the delivered irradiation doses. For this reason, strict dosimetric monitoring of experimental irradiation setups is mandatory for reliable studies.

The use of patient contact-shielding has become a topic of intensive scientific debate. While it has been common practice during the last decades, some studies have questioned the efficiency of using such shielding while others have highlighted the inconsistencies in its application. The objective of this work is to review current recommendations and legislative documents on the use of out-of-field shielding in X-ray imaging, including those from national authorities and from international and national organisations and professional bodies. The review, performed within the framework of the activities of EURADOS Working Group 12, covers available recommendations on use of contact shielding in adult, pregnant and paediatric patients in general radiography, fluoroscopy, computed tomography, mammography and dental radiology. It includes a comprehensive search of 83 documents from 32 countries and 6 international organisations over the last 39 years. In general, using shielding is recommended only under two conditions: if it does not compromise the diagnostic task and the performance of the procedure and/or if it reassures the patient and comforters that they are appropriately protected against potentially harmful effects of radiation. There are very few specific regulatory requirements to use shielding in a particular imaging modality, although they may consider use of shielding either as part of good radiological practice or as requirements for availability of protective or ancillary tools, without further specification of their use. There is a wide variety of positions among documents that recommend out-of-field shielding, those that do not recommend it and those that are not specific. Therefore, evidence-based consensus is still needed to ensure best and consistent practice.

The purpose of this paper is to investigate the impact of a commercial lead apron on patient skin dose delivered during maxillofacial CBCT in five critical regions by means of solid-state-dosimetry. Five anatomical regions (thyroid gland, left and right breast, gonads, back of the phantom torso) in an adult female anthropomorphic phantom were selected for dose measurement by means of the highly sensitive solid-state dosimeter QUART didoSVM. Ten repeated single exposures were assessed for each patient body region for a total of five commercial CBCT devices with and without a lead apron present. Shielded and non-shielded exposures were compared under the paired Wilcoxon test, with absolute and relative differences computed. Reproducibility was expressed as the coefficient of variation (CV) between the 10 repeated assessments. The highest doses observed at skin level were found at the thyroid (mean shielded ± SD: 450.5 ± 346.7 μGy; non-shielded: 339.2 ± 348.8 μGy, p = 0.4922). Shielding resulted in a highly significant (p < 0.001) 93% dose reduction in skin dose in the female breast region with a mean non-shielded dose of approximately 35 μGy. Dose reduction was also significantly lower for the back-region (mean: -65%, p < 0.0001) as well as for the gonad-region (mean: -98%, p < 0.0001) in the shielded situation. Reproducibility was inversely correlated to skin dose (Rspearman = -0.748, p < 0.0001) with a mean CV of 10.45% (SD: 24.53 %). Skin dose in the thyroid region of the simulated patient was relatively high and not influenced by the lead apron, which did not shield this region. Dose reduction by means of a commercial lead apron was significant in all other regions, particularly in the region of the female breast.

Purpose The protocol for quality control of CBCT devices was produced as consensus among active MPEs of EFOMP, ESTRO and IAEA. It is available on-line since September 2017. In the beginning of 2018 we published an update including an appendix on patient dosimetry by EURADOS, comments by the German institute of standards (DIN) and remarks by users from countries that were not involved in the first edition, such as Austria, Costa Rica and Australia. This contribution gives a general overview of the guideline including insights about this recent update. Methods The guideline focuses on the measurement of objective image quality parameters and radiation output from any kind of CBCT device, including applications in dental radiology, C-arms and guidance systems in radiotherapy. Indications to use commercial or non-commercial phantoms and software are given, as well as to use ionization chambers or solid state dosemeters. The new EURADOS appendix includes an extensive review of patient dose data from recent research papers, organized by application and dose indicators: CTDI, DAP, effective dose, entrance surface dose, CTDIw, absorbed dose, D1-D2 and air kerma. The DIN has reviewed the details of the standards 6868–161 and 6868–15 for acceptance and constancy tests in dental CBCT. Individual comments have helped to clarify the measurements of radiation output and the methods to measure the modulation transfer function. Some colleagues have stressed the informative value of the appendices. Results The comments received were reviewed by the authors of the corresponding sections and discussed by the group in virtual meetings before being published as an update. The mentioned additions are meant to keep the document alive. They respond to questions raised by physicists that are starting to use the protocol inside and outside Europe. Conclusions The first presentation in the ECMP in Athens was followed by international presentations at ESTRO, ECR, IOMP and IRPA and national presentations in Italy, Spain, UK, Germany and other countries. Thanks to these voluntary efforts, physicists around the world are using and improving the document together. We also welcome your participation in this session and your feedback.

Any kind of technology needs some kind of quality assurance program. As an example, a bicycle needs to be checked regularly, and sometimes, one must have it thoroughly checked by professionals. Otherwise, a sudden failure of some part may lead to serious consequences for the rider or for anyone close by.

Purpose: This paper presents the features of a new laboratory x-ray platform for 3D breast imaging at FDA and initial projection images and tomosynthesis reconstructions.