We investigated two detector modules, each consisting of a 8 × 8 matrix of GaGG:Ce crystals with a crystal size of 3 × 3 × 20 mm3 and a 3.2 mm pitch. The light is collected by a 8 × 8 silicon ...photomultiplier array, with one silicon photomultiplier matching one crystal. The signals are read out and processed using the TOFPET2 ASIC. Performed laboratory tests of the detectors were performed using a 22Na source, where energy and coincidence time resolution with different optical coupling were examined between the crystals and silicon photomultipliers, as well as under various operating voltages. The mean energy resolution of 9.8±0.6% at 511 keV was observed and it was shown that the coincidence time resolution of 384±33 ps could be achieved. The results reassure that the GaGG scintillator is a very promising candidate for the development of imaging systems, in particular, ones utilizing Compton scattering where the energy resolution plays a critical role and a moderate timing performance is acceptable.
The Compton scattering of gamma rays is commonly detected using two detector layers, the first for detection of the recoil electron and the second for the scattered gamma. We have assembled detector ...modules consisting of scintillation pixels, which are able to detect and reconstruct the Compton scattering of gammas with only one readout layer. This substantially reduces the number of electronic channels and opens the possibility to construct cost-efficient Compton scattering detectors for various applications such as medical imaging, environment monitoring, or fundamental research. A module consists of a 4 × 4 matrix of lutetium fine silicate scintillators and is read out by a matching silicon photomultiplier array. Two modules have been tested with a 22 Na source in coincidence mode, and the performance in the detection of 511 keV gamma Compton scattering has been evaluated. The results show that Compton events can be clearly distinguished with a mean energy resolution of 12.2% ± 0.7% in a module and a coincidence time resolution of 0.56 ± 0.02 ns between the two modules.
An enormous increase in the application of wireless communication in recent decades has intensified research into consequent increase in human exposure to electromagnetic (EM) radiofrequency (RF) ...radiation fields and potential health effects, especially in school children and teenagers, and this paper gives a snap overview of current findings and recommendations of international expert bodies, with the emphasis on exposure from Wi-Fi technology indoor devices. Our analysis includes over 100
, animal, epidemiological, and exposure assessment studies (of which 37
and 30 covering Wi-Fi technologies). Only a small portion of published research papers refers to the “real” health impact of Wi-Fi technologies on children, because they are simply not available. Results from animal studies are rarely fully transferable to humans. As highly controlled laboratory exposure experiments do not reflect real physical interaction between RF radiation fields with biological tissue, dosimetry methods, protocols, and instrumentation need constant improvement. Several studies repeatedly confirmed thermal effect of RF field interaction with human tissue, but non-thermal effects remain dubious and unconfirmed.
Individual hand monitoring for workers who manipulate unsealed radioactive
sources in nuclear medicine is a necessity and the results can serve as the
base for optimization processes. We performed an ...analysis of individual hand
doses for medical staff preparing and applying radiopharmaceuticals (99mTc,
123I, 201Tl, 131I, or 125I) in three Croatian clinical hospitals, for a
period of one year since extremity monitoring became legally mandatory in
Croatia. The majority of annual hand doses for workers were below or slightly
above 150 mSv per year with only a few workers exceeding the annual dose
limit of 500 mSv. The analysis confirmed that the radiation protection
expert's role in an individual monitoring programme and personal dosimetry is
crucial in order to achieve the optimal radiation protection of workers.
nema
Measurement of gamma-ray polarization can provide valuable insight in different areas of physics research. One possible application is in Positron Emission Tomography, where the annihilation quanta ...with orthogonal polarizations are emitted. Since polarization can be measured via Compton scattering, the initial orthogonality of polarizations can be translated to correlation of azimuthal scattering angles, and this correlation may be exploited as an additional handle to identify the true coincidence events. In order to examine the concept of utilizing the polarization correlations in PET, we have used a system of two compact, position and energy-sensitive Compton scattering detectors in coincidence mode. Each consists of a single matrix of scintillation pixels, read-out by a matching array of Silicon photomultipliers on the back side. The Compton events in each module are clearly identified and the scattering angles are reconstructed from the energy deposition and event topology. We have extracted the polarimetric modulation factors from the measured azimuthal scattering angles of the two Compton-scattered gammas and studied their dependence on Compton scattering angles θ and on azimuthal resolution Δϕ. For scattering angles around θ1,2=82∘, where the maximum modulation is expected, the modulation factors from μ=0.15±0.01 to μ=0.27±0.02 have been measured, depending on the azimuthal resolution, which is governed by event topology in the detectors. Analogously, for scattering around θ1,2=70∘, modulation factors from μ=0.12±0.01 to μ=0.21±0.02 have been obtained. The results show that the measurement of the polarization correlations of annihilation quanta are feasible with compact single-layer, single-side read-out detectors, which may be used to build cost-efficient systems for various applications where gamma-ray polarization information is of interest.
Mandatory eye lens monitoring for exposed workers who are liable to receive an equivalent dose to the lens of the eye higher than 15 mSv in one year, required by the new European Basic Safety ...Standard 2013/59 and the recommendation given by the International Commission on Radiological Protection to lower the annual dose limit for the lens of the eye to 20 mSv, have put dosimetry services using Panasonic dosemeters in a difficult position. There are no commercially available eye lens dosemeter holders to fit Panasonic TLD pellets. Therefore, we designed and 3D printed inexpensive, splash proof, reusable and comfortable holders to fit a Panasonic nLi2nB4O7:Cu pellet. The eye lens dosemeter consists of an acrylonitrile butadiene styrene (ABS) plastic holder with a slot for a TLD pellet. The slot with the TLD pellet is covered by a heat-shrink tube and shortly heated with hot air to shrink wrap. Results of combined energy/angular response measurements, for all photon radiation qualities used, relative to N-100 at 0° as the reference energy, were within IEC 62387:2012 limits. Additionally, electron spin resonance spectroscopy was used to test the effect of irradiation to the degradation properties of the plastic ABS holder. The dosemeter is to be worn fixed to a headband, close to the eye, on the left side of the head or in the middle of the forehead.
•An inexpensive and comfortable eye lens dosimeter holder can be 3D printed.•The 3D-printed holder fits a Panasonic TL single dosimeter element.•Holders with Li2B4O7 TLD are suitable for Hp(3) measurements in IR and IC.•Properties of the ABS plastic are not affected by radiation in low range.
The ERICA project (Environmental Risk from Ionising Contaminants: Assessment and Management) was co-funded by the European Union as part of the 6
Framework Programme (FP EURATOM). The project was ...carried out between 2004 and 2007 as the collective work of 15 organisations in seven European countries. Two significant outputs of the project are the ERICA Integrated Approach and the ERICA Tool. The ERICA Integrated Approach consists of three elements: assessment, risk characterisation and management. The ERICA Tool is a practical implementation of the assessment component of the ERICA Integrated Approach and has a three-tier structure. The aim of this review paper is to give a concise overview of ERICA project outputs and their structure, updates done since their first release in 2007, as well as to provide a context for their practical application in environmental radiation protection and radiological risk assessments for various engineering scenarios.
Airborne radioruthenium, as a result of an accidental release, presents a risk for occupational and public exposure. In fall 2017, a detection of 106Ru was reported by the European atmospheric ...radioactive contamination monitoring networks. We investigated the daily specific total beta activity of PM10 particle fractions samples. The presented method enables indirect determination of airborne 106Ru activity concentration from total beta activity, in case 106Ru was confirmed as single excess radiological pollutant. This allows for daily measurements and time-resolved 106Ru activity concentration data. We estimated the indicative committed effective dose due to 106Ru inhalation for the Croatian population during the exposure period. Although the estimated dose value of ~169.7 nSv, for ~6-d duration of ruthenium air pollution, was very low, it was ~40 times higher than the value for Hinh from inhalation of other radionuclides (90Sr + 137Cs + 40K + 7Be).
Wi-Fi i ljudsko zdravlje Prlić, Ivica; Šiško, Jerko; Varnai, Veda Marija ...
Arhiv za higijenu rada i toksikologiju,
06/2022, Letnik:
73, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Značajan porast uporabe bežične RF komunikacije u posljednjim desetljećima te s tim povezane izloženosti ljudi umjetno stvorenom neionizirajućem zračenju (RF polja), koje prije nije postojalo na ...Zemlji, tema su velikog broja istraživanja mogućih utjecaja tih zračenja na okoliš i zdravlje ljudi, osobito djece i mladih, kako bi se utvrdile činjenice o međudjelovanju RF polja s genskim materijalom živih bića. U ovom radu dan je pregled aktualnih istraživanja i preporuka međunarodnih stručnih tijela. Poseban naglasak dan je na mogući utjecaj radiofrekvencijskoga zračenja na mlade odnosno na školsku djecu koja su mu tijekom školovanja svakodnevno dodatno izložena tijekom e-škole korištenjem najmodernijih Wi-Fi tehnologijskih rješenja za komunikaciju u obrazovanju.
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