scholarly journals Out‐of‐field dose assessment for a 1.5 T MR‐Linac with optically stimulated luminescence dosimeters

2021 ◽  
Author(s):  
Yan Zhang ◽  
Shaojie Yan ◽  
Zhen Cui ◽  
Yungang Wang ◽  
Zhenjiang Li ◽  
...  
Keyword(s):  
Optically Stimulated Luminescence ◽  
Dose Assessment

scholarly journals Some novel features of post-500°C heating blue stimulated OSL emission of fired natural quartz

2017 ◽  
Vol 44 (1) ◽  
pp. 287-298
Author(s):  
Dileep K Koul ◽  
Anuj Soni ◽  
Debabrata Datta
Keyword(s):  
Radiation Dose ◽  
Dose Range ◽  
Optically Stimulated Luminescence ◽  
Dose Assessment ◽  
High Radiation ◽  
Dose Limit ◽  
Natural Quartz ◽  
Reliable Assessment ◽  
Order Of Magnitude ◽  
High Dynamic

Abstract In this study, some novel features of the post 500°C blue stimulated optically stimulated luminescence (OSL) of fired geological quartz are reported. Different observations (i) pulse annealing and (ii) impact of bleaching on high temperature TL glow peak suggested 510°C (heating rate of 2°C/s) TL peak trap to be responsible for the observed emission. The dosimetric properties of this emission were seen to make its applicability for dose assessment till kGy range. The signal was seen to be easily bleachable, reaching background value within 100 s with blue light at 125°C. The signal qualified all the tests (i) reproducibility, (ii) negligible recuperation and (iii) accuracy of dose recovery needed for reliable assessment of the radiation dose with modified Single aliquot regenerative (SAR) protocol. Considering the bleachability and high dynamic dose range of this signal, it has the potential to stretch the upper dose limit of dating by one order of magnitude than possible with conventional OSL, corresponding to 325°C TL trap. So, combining all the results, the signal reported here could be very useful for dosimetric applications involving measurement of high radiation dose, like dating.

Uncertainty evaluation for organ dose assessment with optically stimulated luminescence measurements on mobile phone resistors after a radiological incident

2021 ◽  
Vol 141 ◽  
pp. 106520
Author(s):  
Olivier Van Hoey ◽  
Demi Römkens ◽  
Jonathan Eakins ◽  
Eftychia Kouroukla ◽  
Michael Discher ◽  
...  
Keyword(s):  
Mobile Phone ◽  
Organ Dose ◽  
Optically Stimulated Luminescence ◽  
Dose Assessment ◽  
Uncertainty Evaluation ◽  
Radiological Incident

scholarly journals Radiation Dose Assessment of the Fog Lead Acrylic Shields during Coronary Angiography: A Phantom Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10743
Author(s):  
Hsin-Hon Lin ◽  
Lu-Han Lai ◽  
Kuo-Ting Tang ◽  
Chien-Yi Ting ◽  
Cheng-Shih Lai
Keyword(s):  
Radiation Dose ◽  
Coronary Angiography ◽  
Image Intensifier ◽  
Optically Stimulated Luminescence ◽  
Dose Assessment ◽  
Conventional Coronary Angiography ◽  
Average Dose ◽  
Lead Glass ◽  
Post Surgery ◽  
Thyroid Glands

This study aimed to evaluate the effects of fogging on the effectiveness of a lead glass shield in protecting an operator from radiation exposure during conventional coronary angiography (CAG). Optically stimulated luminescence dosimeters (OSLDs) were used to measure the effects of fogged lead glass shields (FLSs) and clear lead glass shields (CLSs) on the radiation doses of a cardiac catheterization surgeon. We simulated the scatter radiation incident on the operator with five angiographic projections with 10-s exposures. Experiments were conducted with a field of view of 25 cm, maximum of 100 cm between the X-ray tube and image intensifier, and 80 cm between the image intensifier and operator. Lead glass fogging had no significant effect at any angiographic projection. The average dose at the lens of the eye, thyroid glands, and gonads did not differ significantly between FLS and CLS. Although most surgeons view ceiling-suspended shields as hindrances during surgical procedures, the radiation dose at the operator’s eyes and thyroid glands increased by 13 and 10 times without the shield. The fogging of the shield is probably caused by post-surgery UV decontamination or detergents. An operator has no cause for concern regarding the radiation protection afforded by an FLS during CAG procedures.

scholarly journals Dose assessment in dental cone beam computed tomography: comparison of optically stimulated luminescence dosimetry with the Monte Carlo method

2019 ◽  
Author(s):  
Chena Lee ◽  
Jeongmin Yoon ◽  
Sang-Sun Han ◽  
Ji Yeon Na ◽  
Jeong-Hee Lee ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Effective Dose ◽  
Organ Dose ◽  
Optically Stimulated Luminescence ◽  
Dose Assessment ◽  
High Dose ◽  
Organ Doses ◽  
Dose Evaluation ◽  
Luminescence Dosimetry ◽  
Mc Simulation

AbstractThe usage and the model variety of CBCT machine has been rapidly increasing, the dose evaluation of individual devices became an important issue. Patient dose from CBCT was assessed with two different methods, optically stimulated luminescence dosimeter (OSLD) measured and monte carlo (MC) simulation, in four different examination modes. Through the measurement process and obtained value, more practical and efficient method in acquiring CBCT effective dose would be suggested. Twenty-five OSLD were calibrated and equipped in human phantom of head and neck organs. This was exposed on 2 CBCT units, CS9300 (Carestream Dental LLC, Atlanta, Georgia) and RAYSCAN α+ (Ray Co. Ltd, Hwaseong-si, Korea) with 2 different examination modes. Dose recorded in dosimetry was obtained and organ dose as well as an effective dose were obtained in each units of examination modes. Those values were also calculated using MC software, PCXMC (STUK, Helsinki, Finland). The organ doses and effective doses from both methods were compared by each examination mode of individual unit. OSLD measured effective dose value was higher than that obtained with MC method in each examination mode, except dual jaw mode of CS9300. The percent difference of effective dose between the two methods were ranged from 4.0 to 14.3 %. The dose difference between the methods was decreased as the examination FOV decreased. Organ dose values were varied according to the method, while overall trend was similar in both methods. The organs showing high dose were mostly consistent in both methods. In this study, the effective dose obtained by OSLD measurement and MC simulation were compared and both methods were described in detail. Consequently, as relatively efficient and easy-handling method, we carefully suggest MC simulation for further dose evaluation.

Neutron dose evaluation of Elekta Linac at two energies (10 & 18 MV) by MCNP code and comparison with experimental measurements

2014 ◽  
Vol 6 (1) ◽  
pp. 1006-1015
Author(s):  
Negin Shagholi ◽  
Hassan Ali ◽  
Mahdi Sadeghi ◽  
Arjang Shahvar ◽  
Hoda Darestani ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Measurement Data ◽  
Calculated Data ◽  
High Energy ◽  
Neutron Dose ◽  
Dose Assessment ◽  
Photon Flux ◽  
Dose Equivalent ◽  
Monte Carlo Techniques ◽  
Neutron Dose Equivalent

Medical linear accelerators, besides the clinically high energy electron and photon beams, produce other secondary particles such as neutrons which escalate the delivered dose. In this study the neutron dose at 10 and 18MV Elekta linac was obtained by using TLD600 and TLD700 as well as Monte Carlo simulation. For neutron dose assessment in 2020 cm2 field, TLDs were calibrated at first. Gamma calibration was performed with 10 and 18 MV linac and neutron calibration was done with 241Am-Be neutron source. For simulation, MCNPX code was used then calculated neutron dose equivalent was compared with measurement data. Neutron dose equivalent at 18 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 3.3, 4, 5 and 6 cm. Neutron dose at depths of less than 3.3cm was zero and maximized at the depth of 4 cm (44.39 mSvGy-1), whereas calculation resulted  in the maximum of 2.32 mSvGy-1 at the same depth. Neutron dose at 10 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 2.5, 3.3, 4 and 5 cm. No photoneutron dose was observed at depths of less than 3.3cm and the maximum was at 4cm equal to 5.44mSvGy-1, however, the calculated data showed the maximum of 0.077mSvGy-1 at the same depth. The comparison between measured photo neutron dose and calculated data along the beam axis in different depths, shows that the measurement data were much more than the calculated data, so it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry in linac central axis due to high photon flux, whereas MCNPX Monte Carlo techniques still remain a valuable tool for photonuclear dose studies.

scholarly journals Internal dose assessment of 148Gd using isotope ratios of gamma-emitting 146Gd or 153Gd in accidently released spallation target particles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. Rääf ◽  
V. Barkauskas ◽  
K. Eriksson Stenström ◽  
C. Bernhardsson ◽  
H. B. L. Pettersson
Keyword(s):  
Operation Time ◽  
Isotope Ratios ◽  
Dose Assessment ◽  
Sensitive Indicator ◽  
Whole Body ◽  
Internal Dose ◽  
Tungsten Target ◽  
Alpha Emitter ◽  
Spallation Source ◽  
Effective Doses

AbstractThe pure alpha emitter 148Gd may have a significant radiological impact in terms of internal dose to exposed humans in case of accidental releases from a spallation source using a tungsten target, such as the one to be used in the European Spallation Source (ESS). In this work we aim to present an approach to indirectly estimate the whole-body burden of 148Gd and the associated committed effective dose in exposed humans, by means of high-resolution gamma spectrometry of the gamma-emitting radiogadolinium isotopes 146Gd and 153Gd that are accompanied by 148Gd generated from the operation of the tungsten target. Theoretical minimum detectable whole-body activity (MDA) and associated internal doses from 148Gd are calculated using a combination of existing biokinetic models and recent computer simulation studies on the generated isotope ratios of 146Gd/148Gd and 153Gd/148Gd in the ESS target. Of the two gamma-emitting gadolinium isotopes, 146Gd is initially the most sensitive indicator of the presence of 148Gd if whole-body counting is performed within a month after the release, using the twin photo peaks of 146Gd centered at 115.4 keV (MDA < 1 Bq for ingested 148Gd, and < 25 Bq for inhaled 148Gd). The corresponding minimum detectable committed effective doses will be less than 1 µSv for ingested 148Gd, but substantially higher for inhaled 148Gd (up to 0.3 mSv), depending on operation time of the target prior to the release. However, a few months after an atmospheric release, 153Gd becomes a much more sensitive indicator of body burdens of 148Gd, with a minimum detectable committed effective doses ranging from 18 to 77 µSv for chronic ingestion and between 0.65 to 2.7 mSv for acute inhalation in connection to the release. The main issue with this indirect method for 148Gd internal dose estimation, is whether the primary photon peaks from 146 and 153Gd can be detected undisturbed. Preliminary simulations show that nuclides such as 182Ta may potentially create perturbations that could impair this evaluation method, and which impact needs to be further studied in future safety assessments of accidental target releases.

scholarly journals Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective

2021 ◽  
Vol 18 (3) ◽  
pp. 920
Author(s):  
Eka Djatnika Nugraha ◽  
Masahiro Hosoda ◽  
June Mellawati ◽  
Untara Untara ◽  
Ilsa Rosianna ◽  
...  
Keyword(s):  
Public Health ◽  
Effective Dose ◽  
Radiation Protection ◽  
Water Samples ◽  
Hot Springs ◽  
Hot Spring ◽  
Annual Effective Dose ◽  
Spring Water ◽  
Dose Assessment ◽  
West Java

The world community has long used natural hot springs for tourist and medicinal purposes. In Indonesia, the province of West Java, which is naturally surrounded by volcanoes, is the main destination for hot spring tourism. This paper is the first report on radon measurements in tourism natural hot spring water in Indonesia as part of radiation protection for public health. The purpose of this paper is to study the contribution of radon doses from natural hot spring water and thereby facilitate radiation protection for public health. A total of 18 water samples were measured with an electrostatic collection type radon monitor (RAD7, Durridge Co., USA). The concentration of radon in natural hot spring water samples in the West Java region, Indonesia ranges from 0.26 to 31 Bq L−1. An estimate of the annual effective dose in the natural hot spring water area ranges from 0.51 to 0.71 mSv with a mean of 0.60 mSv for workers. Meanwhile, the annual effective dose for the public ranges from 0.10 to 0.14 mSv with an average of 0.12 mSv. This value is within the range of the average committed effective dose from inhalation and terrestrial radiation for the general public, 1.7 mSv annually.

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