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In mammography clinical practice, various radiation fields are used, produced using different X-ray tube anode and filtration setups. It is important to calibrate diagnostic dosimeters in different radiation qualities as these dosimeters are used for quality control tests and most dosimeters have significant dependence of response on radiation spectra. TRS 457 Code of Practice [1] is an IAEA document which recommends calibration of diagnostic dosimeters in reference radiation fields established according to IEC 61267:2005 international standard [2], which considers the Mo/Mo anode-filter combination (abbreviated as the RQR-M series). Other, non-standard beam qualities are also used for calibration, such as the beams with W/Al anode-filter combination, used by Vinca Institute Secondary Standard Dosimetry Laboratory. Traceability is established to IAEA Dosimetry Laboratory, and radiation qualities are established by adding 0.5 mm Al additional filtration, following the IAEA procedure [3]. Mammography radiation qualities can be validated by determining the half-value layer (HVL) of the radiation beam. To determine HVL we measured incident air kerma at 1 m distance using a 1 cm3 plane parallel ionization chamber, by successively adding Al attenuators of different thickness. The Al attenuators have been placed at 0.5 m distance, equidistantly from the radiation source and the ionization chamber. HVL was obtained using a linear regression for the additional filtration values near the expected HVL value. Calculated HVL was 0.326 mm Al, 0.367 mm Al, 0.395 mm Al, 0.456 mm Al for tube voltages 25 kV, 28 kV, 30 kV and 35 kV, respectively. The results were compared with the values given by IAEA SSDL [3] (deviation for all qualities was less than 5%) and PTB Primary Standard Dosimetry Laboratory (PSDL) [4]. Radiation qualities established in this manner allow proper calibration and traceability of diagnostic dosimeters in W/Al radiation qualities to be used for routine QC tests

The regular participation of an accredited individual monitoring service (IMS) in the international and/or interlaboratory intercomparisons (IC) is required according to ISO/IEC 17025:2017 standard, General requirements for the competence of testing and calibration laboratories. By taking the part in an IC, IMS shows competence, reliability, and has an opportunity to learn further and improve its measurement method. The European Dosimetry Group (EURADOS) Working Group 2 (WG2) has acknowledged the value of the regular IC and also found that data and results from it are fundamental for the harmonization of the measurement process [1]. Thus, EURADOS started a self-sustained program of IC for IMS for external radiation on a biannual basis. The results of an accredited IMS at the Department of Radiation and Environmental Protection, “VINČA” Institute of Nuclear Sciences, Belgrade, Serbia (IMS VINS) in the EURADOS IC for the period 2010-2020 (excluding 2014) are presented. IMS VINS use thermoluminescent whole body dosemeters based on two TLD-100TM (Thermo Scientific™ Harshaw™, USA) detectors. The readouts are done on the Harshaw TLD™ Model 6600 Plus Automated Reader (Thermo Fisher Scientific, USA). The whole glow curve is used for dose estimation (all of 200 channels). The calibration of the dosimetric system is done twice a year in S-Cs (previously in S-Co) field at the secondary standard dosimetry laboratory (SSDL VINS), according to ISO 4037-3:2019. The IC had 40 different reference values of personal dose equivalent, Hp(10) in noted period ranging from 0.431 mSv to 501 mSv. There were 20, 16, 22, 22, 20 dosemeters irradiated in year 2010, 2012, 2016, 2018, 2020, respectively. The radiations were done in 12 different fields: N-60, S-Co, S-Cs, N-40, N-150, S-Cs+Sr90, S-Cs+N-40, W-110, S-Cs+W-250, W-60, S-Cs+W-80, and S-Cs+N-150. The relative response (R) range is from 0.23 to 2.26. Quantile values for R are: 0.23, 0.79, 0.90, 1.1, and 2.26, respectively for (0%, 25 %, 5

Due to constant development in radiodiagnostic and radiotherapy procedures with increasing complexity, a need for high-level coordination of the ionizing radiation metrology community was recognized to better respond to the needs of end users. In order to facilitate knowledge dissemination and improve communication between stakeholders involved in medical applications of ionizing radiation, a Joint Network Project was started in 2020. One of the specific objectives of Work Package 2 of the project 19NET04 MIRA, “Support for a European Metrology Network on the medical use of ionizing radiation” is to support the developing states, ensuring that the planned EMN is inclusive through improvements in the medical use of ionizing radiation [1]. Czech Republic, Romania and Serbia were defined as countries of interest to conduct the survey and collect relevant data from stakeholders in the category of medical staff and professionals, so that the potential for improvement for medical applications of ionizing radiation can be evaluated. For the purpose of data collection, an online questionnaire was prepared and distributed to the stakeholders. The questionnaire was structured in such a way to allow easier collection of information regarding availability of (1) calibration services; (2) documented technical protocols; (3) standard documentation in the establishments for different ionizing radiation applications. Implementation of a Quality assurance (QA) programme was investigated, as well as the consistency in realization of proficiency testing (PT) or audits. The stakeholders were asked if additional workshops or training programmes are needed in their area of expertise. The radiodiagnostic modalities included in the questionnaire were the general radiography, mammography, computed tomography and interventional procedures, while radiotherapy modalities included external beam radiotherapy (teletherapy) and brachytherapy. Although nuclear medicine (therapy and diagnostic) proc

In accordance with ISO/IC 17025:2017 testing laboratory shall have a procedure for monitoring the validity of results that includes regular participation in interlaboratory comparisons. Interlaboratory comparison RADON2021 was organized in the frame of the bilateral project between Serbia and Montenegro: “Measurement of the radon equilibrium factor in typical residential buildings in Serbia and Montenegro and harmonization of radon measurement techniques” in order to assess congruence of different measurement techniques, and then harmonize methods in case of inconsistencies. Harmonization is of particular importance to neighboring countries, in order to avoid inconsistencies in the classification of radon risk zones along border areas. Thus, six regional laboratories took part in the intercomparison – three from Belgrade and one from Novi Sad, Serbia; one from Podgorica, Montenegro; one from Banja Luka, Bosnia and Herzegovina. All laboratories participated in the indoor radon measurements, while 4 laboratories measured radon in the soil also. The measurement methods and detectors used by the laboratories were: • for air - EPA 402-R-92-004 – Indoor Radon and Radon Decay Product Measurement Devices Protocols, ch. 3.1. with RAD 7, RTM1688-2 and RadonEye; EPA 520/5-87-005 – 1987 EERF Standard Operating Procedures for Rn-222 Measurement Using Charcoal Canisters, ch. 3.4 using adsorption on charcoal canisters; ISO 11665- 4: Measurement of radioactivity in the environment – Air Radon 222: Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysis with Electretes, and • for soil gas - ISO 11665-11:2016 Measurement of radioactivity in the environment — Air: radon-222 — Part 11: Test method for soil gas with sampling at depth by using active devices RTM1688-2 and RAD 7. The measurements were performed in real conditions where the radon concentration varied following a typical daily variation. Indoor radon c

The results of the post-irradiation fading of whole body dosemeters based on two TLD-100TM (Thermo Scientific™ Harshaw™, USA) detectors are presented. The dosemeters are regularly used by accredited individual monitoring service (IMS) at Vinca Institute of Nuclear Science (VINS), Belgrade, Serbia. The testing of post-irradiation fading was carried out according to International Electrotechnical Commission (IEC) 62387:2020 standard. The irradiations are done in S-Cs137 field at secondary standard dosimetry laboratory (SSDL) at VINS, according to International Organization for Standardization document ISO 4037-3:2019. The chosen reference personal dose equivalent value was 3 mSv. The research was carried out in the period from October 2020 to February 2021, and it lasted 128 days. The frequency of irradiations was approximately 7 days, while 3 periods between irradiations were longer than 10 days, due to COVID-19 pandemic. The irradiations were performed at different dates; thus, all dose readouts were done on the same day to prevent influence of reader’s instabilities. The irradiated dosemeters were stored at the same room where the average temperature was nearly 20°C. There were 14 groups with 6 dosemeters for irradiation and 2 dosemeters for natural background radiation level correction. The reader was Harshaw TLD™ Model 6600 Plus Automated Reader (Thermo Fisher Scientific, USA). The whole glow curve was used for dose estimation (all of 200 channels). The time as influence quantity was considered to be of type F, thus the range of relative response was limiting factor in the analysis. The results showed that the maximum measurement time tmax is 72 days for deep dose (Hp(10)) detector, and 85 days for shallow dose (Hp(0.07)) detector. Thus, the standard’s requirement is satisfied, as it is required minimum of 30 days. The relative response range for all of the 14 groups was from 0.82 to 1.14 and from 0.83 to 1.17, for deep and shallow dose, respectively. The researc

Radon is the radioactive gas originating from the decay chain, mainly uranium and thorium series. The main source of population exposure to ionizing radiation (more than 80 %) is the natural radioactivity. Radon and its short lived progeny contribute with more than 50 % to the radiation dose received by the general population from all sources, and the World Health Organization has recognized radon as the second most important cause of lung cancer. The European Council has laid down a basic safety standards (BSS, Council Directive 2013/59/Euratom) for the protection against the dangers arising from exposure to ionizing radiation, obliging member states, among other, to investigate the exposure of members of the public and workers to indoor radon, to develop a radon action plan and to inform the public about radon levels they are exposed to. As a consequence, this has led to increased number of indoor radon measurements in recent years. There are numerous methods for indoor radon measurement which can be performed either by direct measurement of radon or indirectly by measuring radon progeny, with or without radon presence. The choice of method used depends on the purpose of the measurements, available instrumentation and time. In order to assess the reliability of indoor radon measurement methods available in “Vinca” Institute of Nuclear Sciences, comparative measurement were conducted. Indoor radon concentration was measured in four working rooms in Vinca Institute, two offices and two laboratory premises, in the period of October-November 2020. In all locations continuous radon measurements were performed with tree different active measurement devices: RTM1688-2 and Radon Scout from SARAD GmbH, and RadonEye from RadonFTLAB, while integrated radon measurements were conducted with charcoal canisters. In addition, Equilibrium Equivalent Radon Concentration EERC was measured with radon progeny monitor RPM2200 (SARAD GmbH). Measurement by all active devices was performe