Read by QxMD icon Read

Radiation Protection Dosimetry

Yong In Cho, Ja Mee Kim, Jung Hoon Kim
The dose distribution in the ocular organs of nuclear medicine workers during the handling of diagnostic radionuclides was assessed via simulation in virtual space. The cornea and lenses received the highest dose, and the dose distribution tended to be proportional to the gamma-ray energy emitted from the radiation source being handled. Moreover, calculations on the dose-reduction effects of eyewear protectors for the eyes of the workers showed that the effects were inversely proportional to the emitted gamma-ray energy, with the dose-reduction effect decreasing in the order of (201)Tl, (123)I, (99m)Tc, (67)Ga, (111)In and (18)F...
October 20, 2016: Radiation Protection Dosimetry
Kihong Son, Jin Sung Kim, Hoyeon Lee, Seungryong Cho
This study investigates dose distribution due to kV cone-beam computed tomography (CBCT) for the patients undergoing CBCT-based image-guided radiation therapy (IGRT). The kV-CBCT provides an efficient image-guidance tool for acquiring the latest volumetric image of a patient's anatomy, and has been being routinely used in clinics for an accurate treatment setup. Imaging radiation doses resulting from six different acquisition protocols of the on-board imager (OBI) were calculated using a Geant4 Application for Tomographic Emission (GATE) Monte Carlo simulation toolkit, and the absorbed doses by various organs were analyzed for the adult and pediatric numerical XCAT phantoms in this study...
October 20, 2016: Radiation Protection Dosimetry
B Behnke, O Hupe, R Behrens
Conversion coefficients (CCs) are an essential vehicle in radiation protection for the determination of the dose (rate) of a given radiation field. According to the current draft of the revision of international standard ISO 4037, an X-ray field is a reference field if the CCs of the field match the tabulated ISO values within 2%. Deviations of the high-voltage (HV) tube-potential from its nominal value influence the resulting spectra and change the corresponding CCs. This work investigates the maximum allowable deviation of the HV from its nominal value such that the requirements of ISO 4037 remain fulfilled...
October 20, 2016: Radiation Protection Dosimetry
Satish C Uniyal, Vineet Chaturvedi, Sunil D Sharma, Anurag Rawat
Cardiac interventions often result in high radiation dose to patient's skin, so a reliable indicator in terms of a commonly used dose descriptor is required to monitor skin exposures. In the present study, Gafchromic XR-RV3 film was used to measure the peak skin dose (PSD) during 40 coronary angiography (CA) and 50 percutaneous transluminal coronary angioplasty (PTCA) procedures. Corresponding values of kerma-area product (PKA), fluoroscopy time (FT) and reference air-kerma (Ka,r) were recorded and correlated with PSD...
October 15, 2016: Radiation Protection Dosimetry
Ian Litchfield, Martie van Tongeren, Tom Sorahan
Little is known about personal exposure to radiofrequency (RF) fields amongst employees in the telecommunications industry responsible for installing and maintaining transmitters. IARC classified RF exposure as a possible carcinogen, although evidence from occupational studies was judged to be inadequate. Hence, there is a need for improved evidence of any potentially adverse health effects amongst the workforce occupationally exposed to RF radiation. In this study, results are presented from an exposure survey using data from personal monitors used by employees in the broadcasting and telecommunication industries of the UK...
October 13, 2016: Radiation Protection Dosimetry
Renata Havránková, Zuzana Freitinger Skalická, Jiří Havránek, Dana Novotná, Friedo Zölzer
Results are presented of a survey of almost 1000 dosimetric records of employees at the former uranium processing plant MAPE Mydlovary. Located ~20 km to the north-west of České Budějovice in South Bohemia, it was the place where most of the uranium ore mined in Czechoslovakia in the years from 1962 to 1991 was processed. The records refer to incorporation of short-lived radon progeny and long-lived radionuclides as well as external gamma exposure. The average annual doses calculated from the recorded data were 2...
October 7, 2016: Radiation Protection Dosimetry
Sandipan Dawn, A K Bakshi, Deepa Sathian, T Palani Selvam
Neutron scatter contributions as a function of distance along the transverse axis of (241)Am-Be source were estimated by three different methods such as shadow cone, semi-empirical and Monte Carlo. The Monte Carlo-based FLUKA code was used to simulate the existing room used for the calibration of CR-39 detector as well as LB6411 doseratemeter for selected distances from (241)Am-Be source. The modified (241)Am-Be spectra at different irradiation geometries such as at different source detector distances, behind the shadow cone, at the surface of the water phantom were also evaluated using Monte Carlo calculations...
October 7, 2016: Radiation Protection Dosimetry
A A Dos Reis, L Bertelli, W O Sousa
Radiological or nuclear emergency situations could lead to incorporation of radionuclides by the population. Intakes of radionuclides can be evaluated through measurements of radionuclides present in organs and tissues, or in urinary and/or fecal excretion. In an emergency situation involving a large number of people, the decision to provide medical treatment to an individual will likely be based on a single measurement. For that purpose, the National Council on Radiation Protection and Measurements (NCRP) has presented the Clinical Decision Guide (CDG) quantity, which corresponds to an intake amount of a radionuclide by an individual for which treatment is recommended...
October 7, 2016: Radiation Protection Dosimetry
R B Rakesh, Munish Kumar, C Sneha, P Ratna, D Datta
The prevalent algorithm for the estimation of beta dose, which in turn is used for estimation of skin dose for exposures involving beta radiations was observed to significantly overestimate the dose in individual monitoring based on CaSO4:Dy TLD badge in India. A new algorithm has been developed by estimating the correction factor from the response of dosemeter to different beta sources at various angles of incidence. The correction factor was observed to vary linearly with the ratio of the responses of dosemeter element without filter (D3) and dosemeter element under Perspex filter (D2)...
October 7, 2016: Radiation Protection Dosimetry
Bonnie A B Blackwell, Danny M K Kim, B Brandon Curry, David A Grimley, Joel I B Blickstein, Anne R Skinner
During the Sangamon Episode, North America occasionally experienced warm climates. At Hopwood Farm, IL, a small kettle lake filled with sediment after the Illinois Episode glaciers retreated from southern Illinois. To date those deposits, 14 mollusc samples newly collected with associated sediment from three depths at Hopwood Farm were dated by standard electron spin resonance (ESR) dating. ESR can date molluscs from ~0.5 ka to >2 Ma in age with 5-10% precision, by comparing the accumulated radiation dose with the total radiation dose rate from the mollusc and its environment...
September 28, 2016: Radiation Protection Dosimetry
A Clouvas, F Leontaris, S Xanthos, D Alifragis
Radon concentration as function of the soil depth was measured during the years (2011-2015), in a location of the Aristotle University campus. Radium distribution in soil was found constant. On the contrary, as expected, radon concentration increases with soil depth. The experimental distribution was reproduced by solving the general transport equation (diffusion and advection). From the general radon migration (diffusion and advection) equation it was indirectly deduced, from the measured radon profile in the soil, the radon exhalation rate from the soil (26...
September 24, 2016: Radiation Protection Dosimetry
M G Florescu, O G Duliu, D Pantazi, C M Ticos, D Sporea, R Vasilache, V Ionescu, M Oane
Ultra-high intensity lasers in use are connected with ionizing radiation sources that raise a real concern in relation to installations, personnel, population and environment protection. The shielding of target areas in these facilities has to be evaluated from the conceptual stage of the building design. The sizing of the protective concrete walls was determined using computer codes such as Fluka. For the experiments to be carried out in the facility of the Center for Advanced Laser Technologies (CETAL), both proton beams with the energy of 100 MeV and electron beams with 300 MeV energy were considered to calculate the dimensions of structural shielding and to establish technical solutions fulfilling the radiation protection constraints imposed by the National Commission for Nuclear Activities Control...
September 24, 2016: Radiation Protection Dosimetry
Hirokazu Miyoshi, Mitsunori Hiroura, Kazunori Tsujimoto, Namiko Irikura, Tamaki Otani, Yasuo Shinohara
A new scintillation imaging material [scintillator-silica fine powder (FP)] was prepared using silica FPs and scintillator-encapsulating silica nanoparticles (NPs) (scintillator-silica NPs). The wt% values of scintillator-silica NPs on the scintillator-silica FPs were 38, 43, 36 and 44%. Scintillation images of (3)H, (63)Ni, (35)S, (33)P, (204)Tl, (89)Sr and (32)P dropped on the scintillator-silica FPs were obtained at about 37 kBq per 0.1-10 µl with a charge-coupled device (CCD) imager for a 5 min exposure...
September 24, 2016: Radiation Protection Dosimetry
Anastasia C Hadjiconstanti, Gerasimos A T Messaris, Konstantinos C Thomopoulos, Aikaterini G Solomou, George S Panayiotakis
A phantom-based study is presented aiming to optimise patient dose and image quality (IQ) in endoscopic retrograde cholangiopancreatography procedures, utilising a fluoroscopy system equipped with a flat panel detector. The patient thickness was simulated with various polymethyl methacrylate slabs, whilst IQ was evaluated using the Leeds test object. The main factors evaluated were phantom thickness, distance between phantom and detector, field of view and pulse rate. For all these factors, the dosemetric indices, entrance surface air kerma (ESAK) rate and ESAK per pulse, as well as the IQ parameters, signal-to-noise ratio and high contrast spatial resolution, were measured...
September 24, 2016: Radiation Protection Dosimetry
Vadim Vostrotin, Alan Birchall, Alexey Zhdanov, Matthew Puncher, Alexander Efimov, Bruce Napier, Alexandra Sokolova, Scott Miller, Klara Suslova
The distribution of calculated internal doses has been determined for 8043 Mayak Production Associate (Mayak PA) workers. This is a subset of the entire cohort of 25 757 workers, for whom monitoring data are available. Statistical characteristics of point estimates of accumulated doses to 17 different tissues and organs and the uncertainty ranges were calculated. Under the MWDS-2013 dosimetry system, the mean accumulated lung dose was 185 ± 594 mGy (geometric mean = 28 mGy; geometric standard deviation = 9...
September 24, 2016: Radiation Protection Dosimetry
Alice Bonin, Aimé Tsilanizara
Radiation shielding assessments may underestimate the expected dose if some isotopes at trace level are not considered in the isotopes inventory of the shielded radioactive materials. Indeed, information about traces is not often available. Nevertheless, the activation of some minor isotopic traces may significantly contribute to the dose build-up. This paper presents a new method (Isotopes Inventory Reconstruction-IIR) estimating the concentration of the minor isotopes in the irradiated material at the beginning of the cooling period...
September 24, 2016: Radiation Protection Dosimetry
M C Alves, W S Santos, C Lee, W E Bolch, J G Hunt, A B Carvalho Júnior
The aim of this study was the calculation of conversion coefficients for absorbed doses per fluence (DT/Φ) using the sitting and standing male hybrid phantom (UFH/NCI) exposure to monoenergetic protons with energy ranging from 2 MeV to 10 GeV. Sex-averaged effective dose per fluence (E/Φ) using the results of DT/Φ for the male and female hybrid phantom in standing and sitting postures were also calculated. Results of E/Φ of UFH/NCI standing phantom were also compared with tabulated effective dose conversion coefficients provided in ICRP publication 116...
September 24, 2016: Radiation Protection Dosimetry
Dennis Rottke, Jonas Andersson, Ken-Ichiro Ejima, Kunihiko Sawada, Dirk Schulze
The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO(®) phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500(®), ProMax(®) 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron...
September 24, 2016: Radiation Protection Dosimetry
A Birchall, M Puncher
Two important aspects in which the MWDS-2013 output (absorbed dose to organs calculated in each calendar year) differs from previous data bases (MWDS-2008 and DOSES-2005) are that they have been designed to (a) deal explicitly with uncertainties in model parameters, and (b) differentiate parameters that are considered to be shared (unknown, but having the same value for all workers) and unshared (unknown, but having different values between workers). A multiple-realisation approach is used to preserve information on the effects of shared and unshared parameters both for internal and external doses...
September 21, 2016: Radiation Protection Dosimetry
Tran Xuan Hoi, Huynh Truc Phuong, Nguyen Van Hung
Besides the most common methods of internal dose assessment from inhaled (131)I, that are thyroid monitoring and urine analysis, air sampling is a possible way but rarely used for dose estimate. This study aimed to focus on the utilisation of portable air sampler to estimate the internal dose for workers working at (131)I production facility. In addition, internal dose estimated from urine analysis at the same time was carried out for comparison. Based on this research, it was found that air monitoring can be done efficiently as urine monitoring if the following conditions are met: (1) the indoor areas are not large, (2) sampling sites need to be placed as near breathing zone as possible and (3) the time-micro-environment patterns of monitored workers are collected carefully...
September 21, 2016: Radiation Protection Dosimetry
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"