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Radiation Protection Dosimetry

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https://www.readbyqxmd.com/read/28453832/study-of-residual-tl-of-caso4-dy-based-thermoluminescence%C3%A2-dosemeter
#1
Manish K Sahai, S M Pradhan, A K Bakshi, D Datta
Thermoluminescence (TL) signal obtained during second readout of a TL dosemeter disc previously exposed to ionising radiation is termed as residual TL. The origin of residual TL has not been discussed in detail so far in the literature. In this work, experimentally obtained residual TL signal and its origin is studied for CaSO4:Dy-based TL dosemeter through numerical simulation and role of deeper traps has been discussed.
April 27, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28453660/effect-of-patient-size-anatomical-location-and-modulation-strength-on-dose-delivered-and-image-quality-on-ct-examination
#2
Joël Greffier, Ahmed Larbi, Francesco Macri, Jean-Paul Beregi, Fabricio Pereira
To study the effect of patient size, anatomical location and modulation strength (MS) on image-quality and delivered dose of CT scans acquired with automatic-exposure-control system (AEC). Four anthropomorphic phantoms (three paediatric and one thin adult) were studied, and normal and obese adults were simulated by placing bolus plates around the adult phantom. Thorax and abdomen-pelvis CT were performed using an AEC system equipped with five possible MS. Modulated tube current (mAsmod) was compared to Reference mAs and image-noise was assessed...
April 27, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28444374/measurement-of-neutron-ambient-dose-equivalent-in-proton-radiotherapy-with-line-scanning-and-wobbling-mode-treatment-system
#3
Sangmin Lee, Chaeyeong Lee, Eun Hyuk Shin, Sungkoo Cho, Dae-Hyun Kim, Youngyih Han, Doo Ho Choi, Sung-Joon Ye, Jin Sung Kim
The primary objective of this study was to measure secondary neutron dose during proton therapy using a detector that covers the entire neutron energy range produced in proton therapy. We analyzed and compared the neutron dose during proton treatment with passive scattering and line scanning. The neutron ambient dose equivalents were measured with a 190 MeV wobbling and line-scanning proton beam. The center of a plastic water phantom (30 × 30 × 60 cm3) was placed at the isocenter. A Wide-Energy Neutron Detection Instrument (WENDI-2) was located 1m from the isocenter at four different angles (0°, 45°, 90° and 135°)...
April 24, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28444292/excess-radiation-to-newborns-hospitalized-in-the-intensive-care-unit
#4
Cássio Vilela Komatsu, Cristiane Camargo Silva, Luis Ronan Marquez Ferreira de Souza, Luis Fernando Gonçalves
Newborns in intensive care units are generally subjected to a great number of X-rays procedures and to the risk of radiation-induced damage. This study evaluated a possible excess radiation by excess of radiographs, excess of dose per radiograph or under-collimation of the X-ray beam. The mean of X-rays per newborn was 12 (1-65) during a mean hospitalization of 29 d (1-226 d). The mean frequency was 0.8 X-ray exposures per newborn. About 13% of X-rays were performed without a well-defined clinical motivation...
April 24, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28444252/accurate-measurement-of-indoor-radon-concentration-using-a-low-effective-volume-radon-monitor
#5
Aya Tanaka, Nodoka Minami, Yumi Yasuoka, Takeshi Iimoto, Yasutaka Omori, Hiroyuki Nagahama, Jun Muto, Takahiro Mukai
AlphaGUARD is a low-effective volume detector and one of the most popular portable radon monitors which is currently available. This study investigated whether AlphaGUARD can accurately measure the variable indoor radon levels. The consistency of the radon-concentration data obtained by AlphaGUARD is evaluated against simultaneous measurements by two other monitors (each ~10 times more sensitive than AlphaGUARD). When accurately measuring radon concentration with AlphaGUARD, we found that the net counts of the AlphaGUARD were required of at least 500 counts, <25% of the relative percent difference...
April 24, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28444247/exposure-parameters-of-mammograms-with-and-without-mass-lesions-from-a-south-african-breast-care-centre
#6
Sussan N Acho, Willem P E Boonzaier, Ina F Nel
In South African breast care centres, full-field digital mammography units provide breast imaging services to symptomatic and asymptomatic women simultaneously. This study evaluated the technical exposure parameters of 800 mammograms of which 100 mammograms had obvious mass lesions in the fibroglandular tissue. The average breast compression force of mammograms with mass lesions in the fibroglandular tissue was 18.4% less than the average breast compression force of mammograms without mass lesions. The average mean glandular dose (MGD), tube potential (kVp) and compressed breast thickness (CBT) values were 2...
April 24, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28419374/patient-radiation-doses-in-therapeutic-endoscopic-retrograde-cholangiopancreatography-in-patras-and-the-key-role-of-the-operator
#7
Anastasia C Hadjiconstanti, Gerasimos A T Messaris, Konstantinos C Thomopoulos, George S Panayiotakis
The patient radiation doses, in conjunction with the operator experience, in therapeutic endoscopic retrograde cholangiopancreatography (ERCP) procedures, performed in our hospital, were obtained. Ninety-six patients participated in the study and were divided into 3 groups, based on the operator experience. The dosemetric indices, fluoroscopy time (FT), cumulative dose (Ka,r) and air kerma-area product (PKA), were collected. For the total and weight banding group the third quartile values of the distribution of FT, Ka,r and PKA were 2...
April 17, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28419332/new-model-for-mines-and-transportation-tunnels-external-dose-calculation-using-monte-carlo-simulation
#8
Kh A Allam
In this work, a new methodology is developed based on Monte Carlo simulation for tunnels and mines external dose calculation. Tunnels external dose evaluation model of a cylindrical shape of finite thickness with an entrance and with or without exit. A photon transportation model was applied for exposure dose calculations. A new software based on Monte Carlo solution was designed and programmed using Delphi programming language. The variation of external dose due to radioactive nuclei in a mine tunnel and the corresponding experimental data lies in the range 7...
April 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28419323/monte-carlo-simulation-used-to-calculate-energy-correction-factor-for-thermoluminescent-dosimeters-used-by-occupational-workers-on-pediatric-exams
#9
G Hoff, D Filipov, S Paschuk, H R Schelin, V Denyak
The main objective of this work is to simulate the X-ray scattered spectra by different pediatric phantoms (simulation of children subjected to barium meal procedures) to calculate an energy correction factor (ECF) to the reading of thermoluminescent dosimeters (TLDs). To perform this evaluation, the TLDs were positioned over three areas in two occupational workers: eyes, thyroid and hands. The Geant4 toolkit was used to define the spectra collected by TLDs, making possible to calculate the ECF. This work was developed in two stages: (1) evaluation of scattered spectra by different standard phantoms (newborn, 1, 5 and 10 years old); (2) definition of the ECF to the absorbed energy by each TLD...
April 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28419322/dosimetric-evaluation-of-laser-driven-x-ray-and-neutron-sources-utilizing-xg-iii-ps-laser-with-peak-power-of-300-terawatt
#10
Bo Yang, Rui Qiu, Jinlong Jiao, Wei Lu, Zhimeng Zhang, Weimin Zhou, Chi Ma, Hui Zhang, Junli Li
Current short-pulse high-intensity lasers can accelerate electrons and proton/ions to energies of giga-electron volts. For certain advanced applications, laser-accelerated electrons and protons are optimised for high-energy X-ray and neutron generation at the XG-III picosecond (ps) laser beamline. These energetic X-ray and neutron beams can significantly affect radiation safety at the facility; therefore, proper evaluation of the radiological hazards induced by laser-driven X-ray and neutron sources is required...
April 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28419318/double-exponential-fitting-function-for-evaluation-of-cosmic-ray-induced-neutron-fluence-rate-in-arbitrary-locations
#11
Huailiang Li, Yigang Yang, Qibiao Wang, Xianguo Tuo, Mark Julian Henderson, Jérémie Courtois
The fluence rate of cosmic-ray-induced neutrons (CRINs) varies with many environmental factors. While many current simulation and experimental studies have focused mainly on the altitude variation, the specific rule that the CRINs vary with geomagnetic cutoff rigidity (which is related to latitude and longitude) was not well considered. In this article, a double-exponential fitting function F=(A1e-A2CR+A3)eB1Al, is proposed to evaluate the CRINs' fluence rate varying with geomagnetic cutoff rigidity and altitude...
April 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28407114/establishment-of-detailed-eye-model-of-adult-chinese-male-and-dose-conversion-coefficients-calculation-under-neutron-exposure
#12
Hongyu Zhu, Rui Qiu, Zhen Wu, Li Ren, Chunyan Li, Hui Zhang, Junli Li
The human eye lens is sensitive to radiation. ICRP-118 publication recommended a reduction of the occupational annual equivalent dose limit from 150 to 20 mSv, averaged over defined periods of 5 y. Therefore, it is very important to build a detailed eye model for the accurate dose assessment and radiation risk evaluation of eye lens. In this work, a detailed eye model was build based on the characteristic anatomic parameters of the Chinese adult male. This eye model includes seven main structures, which are scleral, choroid, lens, iris, cornea, vitreous body and aqueous humor...
April 12, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28407092/letter-to-the-editor
#13
Victor A Leach, Steven Weller, Mary Redmayne
No abstract text is available yet for this article.
April 12, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28402564/three-decades-of-occupational-individual-monitoring-at-the-university-of-s%C3%A3-o-paulo
#14
E Okuno, N K Umisedo, F S Cancio, M A Aldred, E M Yoshimura
As the ionizing radiation to which workers are exposed is related to possible harmful biological effect, its dose evaluation gains relevance. Although the effects of low doses are still controversial, the radiation protection authorities assume that any dose of ionizing radiation is potentially harmful to the human health and adopt the linear non-threshold model for the dose-effect relation. The Dosimetry Laboratory of the Institute of Physics of the University of São Paulo performs the external individual monitoring of workers exposed to X- and gamma-rays since 1981, with the technique of thermoluminescence...
April 11, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28402502/evaluation-of-human-body-irradiation-caused-by-radionuclides-deposited-in-the-filtration-unit-of-gas-mask
#15
R Cerny, K Johnova, P Otahal, L Thinova, J Kluson
Radioactive aerosol particles represent a serious risk for people facing the consequences of nuclear accident of any kind. The first responders to emergency situation need to be protected by personal protective equipment which includes radiation protection suit supplemented with gas mask. The purpose of this work is to estimate the dose to the organs of responder's body as a result of radionuclide deposition in the filtration unit of the gas mask. The problem was analyzed using Monte Carlo simulations. The dose absorbed by different organs for five representative radionuclides and the dose distribution over the responder's body are presented in this paper...
April 11, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28402484/location-of-disease-on-imaging-may-predict-radiation-exposure-during-endoscopic-retrograde-cholangiopancreatography
#16
Moon Hyung Choi, Seung Eun Jung, Seung Bae Yoon, In Seok Lee, Jae Young Byun
Endoscopic retrograde cholangiopancreatography (ERCP) is performed for various diseases. The aim of this study is to evaluate the difference of dose-area product (DAP) during the ERCP procedures according to location of the lesion. We performed a retrospective study of consecutive 217 therapeutic ERCP examinations performed between November 2014 and April 2015 at a tertiary care center. ERCP procedures divided into two groups according to location of the lesion identified on imaging: lesions in the common hepatic duct (CHD) or the common bile duct (CBD) and lesions in the hepatic hilum or the intrahepatic duct (IHD)...
April 11, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28402513/intercomparison-on-the-measurement-of-the-quantity-personal-dose-equivalent-hp-10-in-photon-fields-linearity-dependence-lower-limit-of-detection-and-uncertainty-in-measurement-of-dosimetry-systems-of-individual-monitoring-services-in-gabon-and-ghana
#17
P Ondo Meye, C Schandorf, J K Amoako, P O Manteaw, E A Amoatey, D N Adjei
An inter-comparison study was conducted to assess the capability of dosimetry systems of individual monitoring services (IMSs) in Gabon and Ghana to measure personal dose equivalent Hp(10) in photon fields. The performance indicators assessed were the lower limit of detection, linearity and uncertainty in measurement. Monthly and quarterly recording levels were proposed with corresponding values of 0.08 and 0.025 mSv, and 0.05 and 0.15 mSv for the TLD and OSL systems, respectively. The linearity dependence of the dosimetry systems was performed following the requirement given in the Standard IEC 62387 of the International Electrotechnical Commission (IEC)...
April 10, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28398558/studying-the-structural-optical-chemical-and-electrochemical-etching-changes-of-cr-39-for-dosemetric-applications
#18
M F Zaki, Y H Elshaer, Doaa H Taha
The present work shows the induced modification of the structural, optical, chemical etching and electrochemical etching parameters of CR-39 irradiated with alpha-particles. CR-39 polymer track detectors were irradiated with different fluences (1.62 × 106, 2.72 × 106, 3.82 × 106 and 5.21 × 106 particles/cm2) of alpha-particles using 241Am source. The structural and optical properties were measured by FT-IR spectroscopy, X-ray diffraction and UV/Vis spectroscopy, respectively. The FT-IR spectra reveal that no major changes in the typical functional groups of irradiated polymer detectors...
April 7, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28398501/a-comparative-study-of-the-dosimetric-features-of-%C3%AE-al2o3-c-mg-and-%C3%AE-al2o3-c
#19
J M Kalita, M L Chithambo
A comparative study of the dosimetric features of α-Al2O3:C,Mg and α-Al2O3:C relevant to thermoluminescence dosimetry is reported. A glow curve of α-Al2O3:C,Mg measured at 1°C/s after beta irradiation to 1 Gy shows two subsidiary peaks at 42°C (labelled as I) and 72°C (II) and the main peak at 161°C (III) whereas a glow curve of α-Al2O3:C measured under the same conditions shows the main peak at 178°C (II') and a lower intensity peak at 48°C (I'). Apart from these ones, there are several other peaks at temperatures beyond that of the main peak in both α-Al2O3:C,Mg and α-Al2O3:C...
April 7, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28383681/effective-doses-radiation-to-the-patients-in-examinations-performed-in-three-ct-scanners-in-brazil%C3%A2
#20
Mônica Silva Costa Janson Ney, Alair Augusto Sarmet Moreira Damas Dos Santos, GIuliana Vasconcelos De Souza Fonseca, Caio Silva Lodi
This work aimed to analyze the effective doses radiation, estimated from the dose-length product, in 4821 examinations carried out in three CT scanners (named as A, B and C) during the period of December 1st 2013 to 30th November 2014 and compare them, with 95% confidence interval, with typical values for the CT practice described in the American Association of Physicists in Medicine (AAPM) Report # 96 (2008). The mean values of effective doses found in the A, B and C equipments were, respectively, 1.55, 2...
April 5, 2017: Radiation Protection Dosimetry
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