Characterization of optically-stimulated luminescence properties by NaCl: Eu2+ crystal and the thermal response

Radioprotection

Published On 2016

[en] Landauer optically stimulated luminescence (OSL) technology nanoDot dosimeters (OSLDs) are characterized for use in mammography screening at various tube voltages, mAs values and target/filter combinations. The average glandular dose (AGD) for a 50-mm breast, based on the representative compressed breast thickness of a 45-mm polymethyl methacrylate (PMMA) phantom, is assessed using OSLDs with different beam conditions. Further, the linearity of the OSLD response is measured and angular dependence tests are performed for various tube potentials, mAs and target/filter combinations. The breast-absorbed doses are measured at various depths for a 32-kVp X-ray beam at 100 mAs, with a Mo/Rh target/filter combination. The measured incident air kerma values at different lateral positions exhibit a maximum deviation of 6%, and the average relative response of the OSLDs at the reference point (center) with respect to various lateral positions is found to be 1.001±0.09%. The calculated AGD values are in the 1.3±0.1-3.5±0.2 mGy range, depending on the tube potential, tube loading and target/filter combinations. An exposure setup featuring the auto-exposure control (AEC) mode, 28 kVp, 73.8 mAs, and a Mo/Rh target/filter combination may be preferred for mammography screening for a compressed breast thickness of 45 mm.(authors)

Journal

Radioprotection

Published On

2016

Volume

51

Issue

1

Page

51-58

Authors

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Position

H-Index(all)

44

H-Index(since 2020)

19

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

Odor sensor

Dosimeter

Thin films

University Profile Page

Go Okada

Go Okada

Kanazawa Institute of Technology

Position

H-Index(all)

33

H-Index(since 2020)

28

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

Optoelectronics

Dosimetry

X-ray Imaging

Phosphor

University Profile Page

Mune-aki Sakamoto

Mune-aki Sakamoto

Kanazawa Institute of Technology

Position

H-Index(all)

9

H-Index(since 2020)

5

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

University Profile Page

Other Articles from authors

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Alloys and Compounds

Radiophotoluminescence properties of Bi-doped NaCaBO3

Bi-doped NaCaBO3 exhibits radiophotoluminescence (RPL) properties, where the Bi2+ centre is formed through X-ray irradiation. As a result of RPL, a broad emission band appears around 800 nm in the photoluminescence (PL) spectrum, attributed to X-ray irradiation. The intensity of the PL signal is proportional to the irradiation dose, making it useful for measuring accumulated radiation dose. The sensitivity depends on the doping concentration of Bi, and the optimal concentration to maximize sensitivity is approximately 0.005%. With a laboratory-constructed reader system, the optimal sample enables measurement of X-ray dose as low as 25 mGy. Following irradiation, the Bi2+ signal slightly increases by about 13%, but it is significantly reduced to around 7% of the initial value after heat treatment at 500°C for 100 s. The formation and annihilation of the Bi2+ centre can be reproduced multiple times. Therefore …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Sensors and Materials

Radio-photoluminescence Properties of Eu-doped CaBPO5

Eu-doped CaBPO5 was synthesized by the solid-state reaction route, and then its radiophotoluminescence properties were studied. On the basis of steady-state and time-resolved photoluminescence (PL) studies, it was confirmed that Eu2+ is formed by X-ray irradiation due to the valence change of the Eu ion (Eu3+→ Eu2+). In addition, for dosimetric applications, it was demonstrated that the PL intensity of Eu2+ is proportional to the accumulated radiation dose, is stable after irradiation, and can be reversed by heat treatment at 500℃ for 100 s.

Go Okada

Go Okada

Kanazawa Institute of Technology

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Photoluminescence, scintillation, and TSL properties of Dy-doped BaCaBO3F

We fabricated BaCaBO3F (BCBF) with various Dy concentrations (0.1 %, 1 %, and 5 %), and evaluated the luminescence properties for radiation dosimetry. Sharp scintillation peaks originating from the 4f → 4f transition of Dy3+ were observed. Furthermore, thermally stimulated luminescence (TSL) glow curves were recorded, and a TSL glow peak at approximately 120 °C was observed. The 0.1 % Dy-doped BCBF exhibited the highest TSL intensity, and dose response curves of the 0.1–1 % Dy-doped BCBF were obtained in the 0.1–10000 mGy range. Moreover, at least seven activation energy levels related to TSL were confirmed by the TSL isothermal decay analysis.

Go Okada

Go Okada

Kanazawa Institute of Technology

Optik

Effect of Al-doping on dosimetric properties of CaF2

In this study, the effect of Al-doping on dosimetric properties of CaF2 was investigated. Al-doped CaF2 showed a radiophotoluminescence (RPL) peak at 750 nm after X-ray irradiation. The RPL intensity decreased with the increase of Al concentration and was less than that of undoped CaF2. The minimum detectable dose as the RPL dosimeter of 0.01% Al-doped CaF2 was 42 mGy. Al-doped CaF2 also indicated thermally stimulated luminescence (TSL) glow peaks at 225, 285, 387, and 436 °C. The wavelengths of TSL were 390 and 500 nm. The minimum detectable dose as the TSL dosimeter of 1% Al-doped CaF2 turned out to be 0.43 μGy which is comparable to commercial dosimeters.

Go Okada

Go Okada

Kanazawa Institute of Technology

Journal of Luminescence

Investigation of radio-photoluminescence properties in Sm-doped Al4SiO8 single crystals

We report radio-photoluminescence (RPL) properties of Sm-doped Al4SiO8 single crystals as a new RPL material. The Sm-doped Al4SiO8 single crystals were synthesized by the floating zone method. In PL emission spectra, the emission peaks due to the 4f-4f transitions of Sm3+ ions and 2EJ–4A2 transitions of Cr3+ ions were observed before X-ray irradiation, and the ones due to the 4f-4f transitions of Sm2+ appeared as well as Sm3+ after X-ray irradiation. The RPL dose response functions showed linear response from 1 mGy to 10 Gy for the 2.0% Sm-doped sample and from 10 mGy to 10 Gy for the others. Sm2+ ions of the new emission center completely disappeared by heat treatment at 500 °C for 10 min.

Go Okada

Go Okada

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

Thermoluminescence response of a BeO ceramic dosimeter in therapeutic proton beam

BeO ceramics (Thermalox® 995, Materion Corp.) can function as thermoluminescent dosimeters (TLDs) with a tissue-equivalent effective atomic number and sufficient high solidity which can be used as postal dosimeters. To evaluate the feasibility of employing BeO ceramic in proton dosimetry, we investigated the dose–response and the linear energy transfer (LET) dependence of a BeO ceramic TLD. As the BeO ceramic TLDs exhibit two glow peaks, the dose–responses of the integral thermoluminescence (TL) signals for the low-temperature (GL) and high-temperature (GH) glow peaks, as well as those for entire TL signal (GT), were all investigated in this study. The irradiation doses were 0.5, 1.0, 2.0, and 5.0 Gy, and the LET dependence of the TL efficiency was investigated between 0.53 and 7.42 keVµm−1. All experiments were performed using a 160 MeV proton beam at NIRS-HIMAC in Japan. The TL …

Go Okada

Go Okada

Kanazawa Institute of Technology

Materials Research Bulletin

X-ray induced reduction of Sm3+ into Sm2+ in Li2CaSiO4 and its potential for radiation measurement applications

In Sm3+-doped Li2CaSiO4, the Sm3+ ion is reduced to the Sm2+ state by X-ray irradiation. The valence change was confirmed by the difference in their photoluminescence spectra, measured before and after irradiation. Only luminescence peaks due to the 4f-4f transitions of Sm3+ are observed before the irradiation while an additional luminescence band is observed at 900 nm due to the 5d-4f transition of Sm2+. The reaction is that a fraction of X-ray generated electrons is captured by Sm3+ ions, which convert to the Sm2+ state. The generated Sm2+ state is fairly stable while it is effectively reversed back to the Sm3+ state by a heat treatment at an elevated temperature. A numerical approximation revealed the activation energy to be 0.40 and 0.52 eV. Even after the heat-treatment, the reduction of Sm3+ to Sm2+ is reproducible multiple times, which shows good potential for using radiation measurement applications.

Go Okada

Go Okada

Kanazawa Institute of Technology

Radiation Physics and Chemistry

Optically stimulated luminescence of K2SO4: Ce and its relationship with TL glow-curves

K2SO4:Ce was investigated with respect to its OSL and TL properties. Due to the doping with Ce3+ ions, the material shows strong emission in the range of 300–400 nm with a maximum of approx. 330 nm. The spectrum of OSL stimulation is wide and enables stimulation with visible light and infrared. When comparing the 550 nm and 900 nm stimulation, differences in the initial intensity, decay rate and total counts can be seen. The higher total counts are obtained for 550 nm green light, with the initial intensity being higher for 900 nm infrared. The OSL signal, for both stimulations, is sensitive to preheat, however, this relationship is different in both cases. The study of the mutual correlation of the TL and OSL signal showed that only a part of the peaks in the TL curve are bleached by optical stimulation. The result indicates that there are both optically active and non-optically active traps in the material. The OSL-TL …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Japanese Journal of Applied Physics

Radiophotoluminescence properties of Eu-doped Li2SrSiO4 for radiation detectors

To search for new radiophotoluminescence (RPL) materials, Eu-doped Li 2 SrSiO 4 was synthesized by the solid-state reaction and then studied its RPL properties for radiation detector applications. All the samples were identified to be Li 2 SrSiO 4 by X-ray diffraction. The as-prepared sample shows photoluminescence (PL) due to Eu 3+ while an additional PL band appears due to a formation of Eu 2+ after X-ray irradiation. This indicates that the Eu-doped Li 2 SrSiO 4 has RPL properties. The sensitivity of RPL (or PL intensity of Eu 2+) to X-ray dose is the highest when the Eu concentration is 0.1%, and the dynamic range is 5–10 000 mGy. In addition, the generated Eu 2+ is so stable that only 5% of the signal degrades over 20 min after irradiation. The RPL signal notably decreases to about 30% of the initial value by heating at 500 C for 100 s, and it is reproducible multiple times even after the heat treatment.

2023/12/20

Article Details
Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

ESR studies to elucidate the origin of the RPL emission of undoped-CaSO4

Recent research has shown that CaSO4, without any intentional addition of impurities, exhibits remarkable radiophotoluminescence (RPL) properties. However, the origin of the RPL in CaSO4 has yet to be fully understood. ESR measurements were carried out to identify the defect species responsible for RPL and elucidate the luminescence’s origin. ESR measurements on undoped-CaSO4 with different radiation sensitivities showed SO4−, SO2−+SO3−, PO42−, Si=O3 in P2O5–SiO2 (E’ center), Al2O3 hole center and Mn2+ defect species in CaSO4. This means that CaSO4 contains Al2O3, Mn2+, P, and Si as impurities, which are not intentionally added to CaSO4. As the results of this study, the different impurity states may influence the radiation sensitivity of the materials. It is suggested that the deliberate addition of P and Si elements, Al2O3 and Mn2+ could control the RPL properties.

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Materials Research Bulletin

X-ray induced reduction of Sm3+ into Sm2+ in Li2CaSiO4 and its potential for radiation measurement applications

In Sm3+-doped Li2CaSiO4, the Sm3+ ion is reduced to the Sm2+ state by X-ray irradiation. The valence change was confirmed by the difference in their photoluminescence spectra, measured before and after irradiation. Only luminescence peaks due to the 4f-4f transitions of Sm3+ are observed before the irradiation while an additional luminescence band is observed at 900 nm due to the 5d-4f transition of Sm2+. The reaction is that a fraction of X-ray generated electrons is captured by Sm3+ ions, which convert to the Sm2+ state. The generated Sm2+ state is fairly stable while it is effectively reversed back to the Sm3+ state by a heat treatment at an elevated temperature. A numerical approximation revealed the activation energy to be 0.40 and 0.52 eV. Even after the heat-treatment, the reduction of Sm3+ to Sm2+ is reproducible multiple times, which shows good potential for using radiation measurement applications.

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

Radio-photoluminescence properties of Eu-doped SrAl2O4 ceramics and thermally assisted charge transfer process

Radio-photoluminescence (RPL) properties of Eu-doped SrAl2O4 are studied focusing on the generation of a luminescent center by ionizing radiation of X-ray and its extinction by a thermally assisted charge transfer. The single phases of SrAl2O4 doped with Eu at concentrations of 0.05–1.0% are synthesized via solid-state reactions, as confirmed by X-ray diffractions analyses. They show photoluminescence (PL) due to both Eu3+ and Eu2+, and the PL intensity due to Eu3+ decreases after X-ray irradiation while the one due to Eu2+ notably increases. This indicates that Eu2+ as a luminescence center is generated as RPL through reduction from Eu3+ to Eu2+ by ionizing radiation of X-ray. Particularly, the 0.1% Eu-doped sample shows the highest sensitivity to X-ray dose, and the lowest detection limit is estimated to be 0.3 Gy with the present reader system. The RPL signal is reasonably stable, and it depends on …

Go Okada

Go Okada

Kanazawa Institute of Technology

Journal of Alloys and Compounds

Ce concentration dependence on scintillation properties of SrHfO3 single crystals

Transparent and yellowish Ce-doped SrHfO3 (Ce:SHO) single crystals were grown by the xenon lamp equipped floating zone method. The synthesized crystals were in the single phase of SHO crystal structure, and no impurity phases such as HfO2 were evident by the X-ray diffraction analysis. The Ce:SHO shows blue luminescence peaking at 410 nm in both the PL and scintillation spectra, and the decay time constant was approximately 14 ns. The PL QY increases with the Ce concentration, which was confirmed up to 5%. The afterglow level is the lowest when the Ce concentration is 3%. The full energy peak can be demonstrated with all the Ce:SHO single crystals prepared in this study under 241Am alpha-ray irradiation, and the estimated light yield is 396 photons/MeV for the 3% Ce:SHO, which is the highest among the samples studied.

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Go Okada

Kanazawa Institute of Technology

Ceramics International

Optical and photostimulated luminescence properties of Eu: BaFBr translucent ceramics synthesized by SPS

Eu:BaFBr translucent ceramics were synthesized by the spark plasma sintering method, and then the crystal structure, optical and photostimulated luminescence (PSL) properties were investigated. The synthesized 0.05–0.5% Eu:BaFBr are translucent, and the optical transmittance is 30–50%. The photoluminescence and PSL spectra consist of an emission band peaking around 390 nm due to the presence of Eu2+ ion. The photoluminescence quantum yield and the sensitivity of PSL to X-rays are the highest when the doping concentration is 0.5%, and they are higher than those of the commercial Eu:BaFBr imaging plate (IP). In addition, the spatial resolution of an X-ray image obtained by using the 0.5% Eu:BaFBr translucent ceramic as an imaging plate is higher than the one obtained by using the commercial IP.

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Go Okada

Kanazawa Institute of Technology

Materials Research Bulletin

Scintillation and dosimeter properties of Pr2O3-doped Ga2O3–K2O–La2O3 glasses

Rare-earth-activated glasses have attracted research attention for radiation measurements for decades because of several practical merits, including their amenability towards mass production, large-volume fabrication, easing shaping, and their low cost. Various glass materials (e.g., borate and silicate glasses) have been characterized. In this study, photoluminescence, scintillation, and thermally stimulated luminescence (TSL) characteristics were observed for Pr3+-activated gallate glasses (69Ga2O3–20K2O–(11-x)La2O3–xPr2O3). Clear photoluminescence and scintillation peaks derived from the 4f-4f transitions of Pr3+ appeared in the range of 480–670 nm, where the photoluminescence and scintillation decay time constants attributable to the 4f-4f transitions of Pr3+ were on the order of microseconds. The thermoluminescence of these glasses was also investigated, where a broad TSL glow peak was …

Go Okada

Go Okada

Kanazawa Institute of Technology

Radiation Measurements

Optically stimulated luminescence characteristics and dosimetric properties of copper-doped potassium sulphate

Optically Stimulated Luminescence (OSL) properties of the sol-gel synthesized nano-powders of Beryllium Oxide (BeO) were investigated. Luminescence properties of BeO nanoparticles are dependent on the crystal structure, particle size, and morphology and therefore strongly dependent on the way of synthesis, thus the preparation was modified to enhance the OSL signal from the material. Structural, thermal and morphological properties of BeO in nanopowder and pellet forms were studied using X-Ray Diffraction (XRD), Fourier Transform Infrared Microscopy (FTIR), Simultaneous Thermal Analysis STA (Thermo Gravimetric Analysis (TGA)/Differential Scanning Calorimetry (DSC)) and Scanning Electronic Microscopy (SEM) techniques. XRD and STA analysis suggested an enhancement in crystallinity and thermal stability of the BeO with increasing sintering temperature.OSL dosimetric properties of the pellets …

Go Okada

Go Okada

Kanazawa Institute of Technology

Ceramics International

Radio-photoluminescence phenomenon in Cs2O-SrO-Al2O3-P2O5 glasses doped with different concentrations of Ag2O

In this study, Ag2O–Cs2O–SrO–Al2O3–P2O5 glasses with different Ag concentrations (0, 0.1, 0.3, 1.0, and 3.0 mol.%) were made by the melt-quenching method. In addition, the photoluminescence (PL) properties, the radio-photoluminescence (RPL) phenomenon, and spatial resolution on the X-ray imaging by the RPL were studied. The RPL was observed by irradiating with X-rays as an appearance of a new PL emission at around 590 nm. According to the shape of the PL spectrum and lifetime, the luminescence was confirmed to be due to Ag2+ with a lifetime constant of 14.7–45.5 ns. From the X-ray imaging resolution test, the 3.0% Ag-doped sample showed a spatial resolution of at least 10.0 LP/mm.

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Go Okada

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

Precise thermoluminescence glow curve analysis of BeO ceramic plates with slow heating rates

The glow curve components and thermoluminescence (TL) parameters of BeO ceramics plates with high bioequivalence were analyzed using extremely slow heating rates. Thermalox 995 was used as the BeO ceramic plates, which is a material with a BeO content of 99.5% or higher. The size of the plates was 10 × 10 × 0.7 mm3 with a density of 2.85 g/cm3, and an effective atomic number of 7.13. A linear accelerator was used for irradiation of the BeO plates at 5 Gy of 6 MV X-rays. After irradiation, the TL glow curve was measured using an in-house developed measurement instrument; the TL intensity was recorded from 50 to 400 °C with heating rates of 0.133, 0.05, and 0.005 °C/s used in three patterns. General-order kinetics were used for the theoretical analysis, which takes recapture into account. After irradiation, post-annealing was performed in the range of 50 to 350 °C at 50 °C intervals, and component …

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Go Okada

Kanazawa Institute of Technology

Phosphors for Radiation Detectors

radiophotoluminescence (RPL)

This chapter covers a wide range of radio‐photoluminescence (RPL) technologies, from fundamentals to applications. It presents the definition of the term of RPL and distinguishes it from thermally‐stimulated luminescence and optically‐stimulated luminescence as a different type of dosimetric technique using a phosphor medium. RPL is a very powerful tool when the measurement environment requires exposure to light or heat. The chapter introduces a list of RPL materials and their fundamental properties, as reported in the literature. The RPL center is typically very stable and the resulting luminescence is due to electronic transitions within the RPL center. The chapter also introduces the principal properties as well as applications of four selected RPL materials with many illustrative materials. These include: Ag‐doped sodium‐aluminophosphate glasses, Al …

Go Okada

Go Okada

Kanazawa Institute of Technology

Japanese journal of applied physics

Measurements of γ-rays and neutrons in BNCT irradiation field using thermoluminescent phosphor

Boron neutron capture therapy (BNCT) is an innovative cancer therapy that selectively destroys only cancer cells by utilizing the reaction between boron agents, which selectively accumulate in cancer cells, and neutron beams. However, the irradiation field in BNCT is a mixture of multiple radiation types, making accurate dose evaluation difficult. For dose evaluation in cancer tissue, which is particularly important, it is essential to discriminate between neutrons and γ-rays mixed in the BNCT irradiation field and to measure them correctly. In this paper, we introduce a new method for selective measurement of neutrons and γ-rays using a thermoluminescent phosphor, which is expected to be a promising method for improving the accuracy of dose evaluations.

2022/11/21

Article Details

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Zinat Mohebbi

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Tarbiat Modares University

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Article Details
Fatemeh Seif

Fatemeh Seif

Arak University of Medical Sciences

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Evaluation of the knowledge and observance of radiation protection for pregnant radiology technologists and pregnant patients in radiology and CT scan departments of Arak

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ahmadreza sayadi

ahmadreza sayadi

Rafsanjan University of Medical Sciences

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Radioprotection

Clinical capability of Iranian operating room nurses and surgeons regarding radiation protection protocols in radiation-exposed operating rooms

Background: Considering the daily increasing use of radiation in operating rooms and the existing problems in the field of radiation protection, the present study aimed to evaluate the clinical capability of operating room nurses and surgeons regarding radiation protection protocols in radiation-exposed operating rooms in Shiraz. Methods: This descriptive, cross-sectional study was carried out in 2019-2020 by conducting a census of radiation-exposed nurses and surgeons in the operating rooms of private and public hospitals in Shiraz. The study data were collected using a demographic and professional information form and a questionnaire on the radiation protection capability of operating room personnel. Then, the data were entered into the SPSS 25 software and were analyzed via descriptive and inferential statistics. Results: Totally, 200 questionnaires were completely filled out. The mean age of the …

Ademir Xavier da Silva

Ademir Xavier da Silva

Universidade Federal do Rio de Janeiro

Radioprotection

Potential increased radiological risk in cargo scanning activity

The image-based cargo inspection systems are generally intended to identify illegal practices. However, imaging processes from the scanning of motorized containers have been used for increasing industrial safety. This is made possible by the application of high-energy particle linear accelerators (linac). Measurements of both the environmental equivalent dose rate (delta H*(10), and the integrated environmental equivalent dose (H*(10) were performed. The estimation of delta H*(10) and H*(10) in the scanning channel, including the driver's cab of the truck transporting the container, is critical. The aim of this study is to check the radiological safety for occasional users (drivers) by comparing the levels of delta H*(10) and H*(10) with those adopted for public exposure. The study was experimentally conducted in a cargo and container inspection facility that uses a linac operating at the maximum energy of 4.5 MeV …

roya ershadpour

roya ershadpour

Shiraz University of Medical Sciences

Radioprotection

Clinical capability of Iranian operating room nurses and surgeons regarding radiation protection protocols in radiation-exposed operating rooms

Background: Considering the daily increasing use of radiation in operating rooms and the existing problems in the field of radiation protection, the present study aimed to evaluate the clinical capability of operating room nurses and surgeons regarding radiation protection protocols in radiation-exposed operating rooms in Shiraz. Methods: This descriptive, cross-sectional study was carried out in 2019-2020 by conducting a census of radiation-exposed nurses and surgeons in the operating rooms of private and public hospitals in Shiraz. The study data were collected using a demographic and professional information form and a questionnaire on the radiation protection capability of operating room personnel. Then, the data were entered into the SPSS 25 software and were analyzed via descriptive and inferential statistics. Results: Totally, 200 questionnaires were completely filled out. The mean age of the …

parinaz mehnati

parinaz mehnati

Tabriz University of Medical Sciences

Radioprotection

Evaluation of silicon and 10 bismuth shield with variable thickness compared with constant thickness on the dose reduction and image quality during chest CT examination

One of the best methods to reduce the breast radiation dose in chest CT scan exam is using the bismuth shield. Due to the fact that, in CT scan tests, the breast dose is higher in the central axis of body than other sides, so the bismuth shield with variable thickness (outer half 1 mm thick and inner half 2 mm thick) is designed in this study. The objective of this study is to investigate in effectiveness of silicon and 10 bismuth composite shied with variable thickness on reducing radiation dose and image quality parameters in chest CT scan test compare to 1 mm and 2 mm of fixed thickness shield. Physical chest phantom underwent chest CT scan without or with bismuth shields with thickness of 1 mm, 2 mm, and variable in 90, 120 and 140 kVp in inactive TCM mode. Dosimetry was performed by using TLD, and image quality was evaluated quantitatively (by drawing the ROI in the identical images like image j, calculation of noise, CT number, SNR and CNR) and qualitatively (by two expert radiologists). Designed bismuth shield with unsteady thickness in inner and outer side compare to 1 mm and 2 mm thickness shields is presented in 120 kVp, has a significant difference in the amount of breast dose reduction (19 reduction), as well as in 140 kVp, all these three bismuth shields resulted in a significant dose reduction almost in the same similarity. At 120 kVp, the bismuth shield with variable thickness lead to a significant change in CT numbers in the heart and lungs, but it does not have a remarkable effect on other image quality parameters. The bismuth shield with variable thickness can lead to a better effectiveness in reducing breast dose without any …

Ali  Mehdipour

Ali Mehdipour

Rafsanjan University of Medical Sciences

Radioprotection

evaluation of silicon and 10% bismuth shield with variable thickness compared with constant thickness on the dose reduction and image quality during chest CT examination

One of the best methods to reduce the breast radiation dose in chest CT scan exam is using the bismuth shield. Due to the fact that, in CT scan tests, the breast dose is higher in the central axis of body than other sides, so the bismuth shield with variable thickness (outer half 1 mm thick and inner half 2 mm thick) is designed in this study. The objective of this study is to investigate in effectiveness of silicon and 10 bismuth composite shied with variable thickness on reducing radiation dose and image quality parameters in chest CT scan test compare to 1 mm and 2 mm of fixed thickness shield. Physical chest phantom underwent chest CT scan without or with bismuth shields with thickness of 1 mm, 2 mm, and variable in 90, 120 and 140 kVp in inactive TCM mode. Dosimetry was performed by using TLD, and image quality was evaluated quantitatively (by drawing the ROI in the identical images like image j, calculation of noise, CT number, SNR and CNR) and qualitatively (by two expert radiologists). Designed bismuth shield with unsteady thickness in inner and outer side compare to 1 mm and 2 mm thickness shields is presented in 120 kVp, has a significant difference in the amount of breast dose reduction (19 reduction), as well as in 140 kVp, all these three bismuth shields resulted in a significant dose reduction almost in the same similarity. At 120 kVp, the bismuth shield with variable thickness lead to a significant change in CT numbers in the heart and lungs, but it does not have a remarkable effect on other image quality parameters. The bismuth shield with variable thickness can lead to a better effectiveness in reducing breast dose without any …

Afsaneh Karami

Afsaneh Karami

Zanjan University of Medical Sciences

Radioprotection

Patient radiation dose and lifetime attributable risk of cancer due to ionizing radiation in cardiovascular interventional radiological procedures

The aim of this study is to calculate the patient radiation dose and Lifetime Attributable Risk (LAR) in Cardiovascular Interventional Radiological (CVIR) procedures. The patient population included 327 patients who underwent Coronary Angiography (CA) and Percutaneous Coronary Interventions (PCI). Exposure data were reported for every examination such as Kerma-Area Product (KAP), fluoroscopy time and number of exposures. Organ dose and effective dose were assessed by PCXMC software. LAR values were determined according to BEIR VII report. The mean effective dose per examination in CA is 12.6 mSv for males and 10.25 mSv for females. In PCI, the mean effective dose is 18.06 mSv for males and 22.73 mSv for females. Organs with highest dose are thymus, heart, breast, and lung. The mean of LAR value in CA is 62 and 60 for males and females, respectively. In PCI, the mean of LAR value is 89 …

Saad S. Al-Shehri

Saad S. Al-Shehri

Taif University

RADIOPROTECTION

Effects of high ambient temperature on the accuracy of thermoluminescent dosimeters for environmental monitoring

Thermoluminescence dosimeters (TLDs) are widely used for both personal and environmental dosimetry. TLDs should have high accuracy under different conditions. The TL signal can drop over time because of fading (loss of signal due to thermally induced recombination of trapped charriers), thus leading to underestimation of the irradiation dose. The Saudi climate is extremely hot for most of the year, which could significantly affect TLD measurements. Therefore, the effect of ambient temperature, storage time and irradiation dose were investigated both in laboratory controlled-temperature conditions and field experiments, for two commercial dosimeters: Harshaw (TLD-100H (TM)) and RADCARD (MCP-N (TM)), which are used for environmental monitoring. The irradiated TLDs were exposed to a range of ambient temperatures (25 degrees C-65 degrees C) then stored for 30, 60, and 90 days. A signal fading due …

Nasser Shubayr

Nasser Shubayr

Jazan University

Radioprotection

An analysis of trauma-related CT utilization and abnormal findings in emergency department: a one-year retrospective study

Trauma is one of the major indications for admission to the emergency department (ED) and Computed Tomography (CT) scan requests. Understanding of CT utilization is important to reduce unnecessary imaging and radiation exposure. This study aimed to examine the utilization pattern of CT scans for trauma patients in the ED and how often traumatic abnormalities occurred. A retrospective study was conducted over a one-year period. Data for patients who were admitted to the ED and underwent CT scans for trauma indications, type of CT procedure performed, findings, and prior radiography were collected from the picture archiving and communication system. A total of 881 trauma patients underwent a CT scan as part of their investigation. Abnormalities were identified in 527 (59.9%) of cases and proportional with prior radiography [828 (94%)]. Different types of CT procedures were performed, as requested …

Ademir Xavier da Silva

Ademir Xavier da Silva

Universidade Federal do Rio de Janeiro

Radioprotection

Evaluation of the radiological risk in cargo scanning by comparison with known biological consequences

This study proposes a quick, easy, and low-cost method that can be used to assess the radiological safety of an irradiation line used for cargo and container inspection facilities. The radiation-emitting equipment used was a Smiths Heimam particle accelerator model HCVP4029 operating at 4.5 MeV. The radiation dose measurements were performed using a personal radiation monitor Ultra Radac mod MRAD 111 (Geiger-Muller). The ambient equivalent dose H*(10) was estimated for two facilities: A (real) (1.12E-03 mSv per scan) and B (fictitious) (3.25E-03 mSv per scan). The dimensionless factor R, which represents a ratio between two specific scanning (Ss) quantities regarding the facilities A and B, is introduced as a reference for assessing the level of radiological safety. This study compares facilities A and B by using a simple alternative safety assessment based on the R factor. The dimensionless R-value …

Nasser Shubayr

Nasser Shubayr

Jazan University

RADIOPROTECTION

Effects of high ambient temperature on the accuracy of thermoluminescent dosimeters for environmental monitoring

Thermoluminescence dosimeters (TLDs) are widely used for both personal and environmental dosimetry. TLDs should have high accuracy under different conditions. The TL signal can drop over time because of fading (loss of signal due to thermally induced recombination of trapped charriers), thus leading to underestimation of the irradiation dose. The Saudi climate is extremely hot for most of the year, which could significantly affect TLD measurements. Therefore, the effect of ambient temperature, storage time and irradiation dose were investigated both in laboratory controlled-temperature conditions and field experiments, for two commercial dosimeters: Harshaw (TLD-100H (TM)) and RADCARD (MCP-N (TM)), which are used for environmental monitoring. The irradiated TLDs were exposed to a range of ambient temperatures (25 degrees C-65 degrees C) then stored for 30, 60, and 90 days. A signal fading due …

Yoshito Tsushima

Yoshito Tsushima

Gunma University

Radioprotection

A lightweight 0.25 mm lead equivalence protective apron for shielding radiological technologists from radiation exposure during single-photon emission computed tomography in …

< jats: p> Radiological technologists in nuclear medicine departments (NMRTs) are exposed to higher radiation doses than other nuclear medicine staff. Consequently, the Australian Radiation Protection and Nuclear Safety Agency recommends using a 0.5-mm lead equivalence protective apron (PA) for staff with radiation exposure> 800 MBq of< jats: sup> 99m Tc. However, 0.5 mm PA is heavy and cumbersome to use. We evaluated the effectiveness of a 0.25 mm lead equivalence lightweight protective apron (L-PA) for NMRT radiation exposure during daily nuclear medicine procedures. The work was performed both with a phantom and in a real situation in our study. The phantom study was conducted with five radioisotopes (RI) placed 0.5 m from the human phantom with and without L-PA. In the clinical study, NMRT recorded the radiation dose for 20 days inside and outside the L-PA using clinical agents (140 examinations). In the phantom study, L-PA decreased the measured doses by 63% with< jats: sup> 201 Tl, 41% with< jats: sup> 99m Tc, 27% with< jats: sup> 67 Ga, 33% with< jats: sup> 123 I, and 10% with< jats: sup> 131 I. In the clinical study, L-PA reduced the average dose per day by 43%. Therefore, L-PA could have sufficient shielding ability for daily work, mainly using< jats: sup> 99m Tc, and could be recommended by considering PA weight.