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https://www.readbyqxmd.com/read/28216931/predictors-of-radiation-exposure-to-providers-during-percutaneous-nephrolithotomy
#1
David L Wenzler, Joel E Abbott, Jeannie J Su, William Shi, Richard Slater, Daniel Miller, Michelle J Siemens, Roger L Sur
BACKGROUND: Limited studies have reported on radiation risks of increased ionizing radiation exposure to medical personnel in the urologic community. Fluoroscopy is readily used in many urologic surgical procedures. The aim of this study was to determine radiation exposure to all operating room personnel during percutaneous nephrolithotomy (PNL), commonly performed for large renal or complex stones. MATERIALS AND METHODS: We prospectively collected personnel exposure data for all PNL cases at two academic institutions...
January 2017: Urology Annals
https://www.readbyqxmd.com/read/28216528/the-measurement-of-x-ray-fluoroscopy-input-output-characteristics-in-angiography-system
#2
Yoshiaki Hagihara, Takayoshi Umehara, Kazuma Matsumoto, Tomoko Fujita, Youko Ikeuchi, Keita Fujikawa, Yoshiyuki Takahashi, Noriko Kotoura
PURPOSE: Determination of X-ray fluoroscopy radiation dose and contrast with angiographic system automatically depending on the objects, and to control setting manually, which is difficult for the measurement of characteristics. Therefore, we examined the method to adjust the conditions of fluoroscopy and measured the input-output characteristics. METHOD: To adjust and fix the condition of fluoroscopy, the exposure adjustment area at the center of the irradiation field was moved to the left side and attached the copper plates to regulate the exposure dose...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28206679/technical-note-determination-of-individual-thyroid-clearance-effective-half-life-with-a-common-handheld-electronic-dosimeter
#3
Markus Fürstner, Michael Hentschel, Petar-Marko Spanjol, George A Prenosil, Sabine Weidner, Thomas Krause, Bernd Klaeser
PURPOSE: To determine the thyroid clearance effective half-life (Ʈ) with a common handheld electronic dosimeter (ED) in patients undergoing radioiodine treatment for hyperthyroidism. METHODS: Dose rates from twelve inpatients were measured daily with an ED and with a clinical uptake counter. The ED was attached to the patient with two different setups, one using a cervical collar and another employing a neck strap. Estimation of Ʈ was performed by linear regression analysis of the log of both the ED and the uptake counter measurements versus time...
February 16, 2017: Medical Physics
https://www.readbyqxmd.com/read/28190371/occupational-radiation-exposure-of-anesthesia-providers
#4
Rachel R Wang, Amanda H Kumar, Pedro Tanaka, Alex Macario
Anesthesia providers are frequently exposed to radiation during routine patient care in the operating room and remote anesthetizing locations. Eighty-two percent of anesthesiology residents (n = 57 responders) at our institution had a "high" or "very high" concern about the level of ionizing radiation exposure, and 94% indicated interest in educational materials about radiation safety. This article highlights key learning points related to basic physical principles, effects of ionizing radiation, radiation exposure measurement, occupational dose limits, considerations during pregnancy, sources of exposure, factors affecting occupational exposure such as positioning and shielding, and monitoring...
February 1, 2017: Seminars in Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/28169334/operator-radiation-and-the-efficacy-of-ceiling-suspended-lead-screen-shielding-during-coronary-angiography-an-anthropomorphic-phantom-study-using-real-time-dosimeters
#5
Qianjun Jia, Ziman Chen, Xianxian Jiang, Zhenjun Zhao, Meiping Huang, Jiahua Li, Jian Zhuang, Xiaoqing Liu, Tianyu Hu, Wensheng Liang
Operator radiation and the radiation protection efficacy of a ceiling-suspended lead screen were assessed during coronary angiography (CA) in a catheterization laboratory. An anthropomorphic phantom was placed under the X-ray beam to simulate patient attenuation in eight CA projections. Using real-time dosimeters, radiation dose rates were measured on models mimicking a primary operator (PO) and an assistant. Subsequently, a ceiling-suspended lead screen was placed in three commonly used positions to compare the radiation protection efficacy...
February 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28168587/improving-the-quality-of-reconstructed-x-ray-ct-images-of-polymer-gel-dosimeters-zero-scan-coupled-with-adaptive-mean-filtering
#6
M B Kakakhel, A Jirasek, H Johnston, T Kairn, J V Trapp
This study evaluated the feasibility of combining the 'zero-scan' (ZS) X-ray computed tomography (CT) based polymer gel dosimeter (PGD) readout with adaptive mean (AM) filtering for improving the signal to noise ratio (SNR), and to compare these results with available average scan (AS) X-ray CT readout techniques. NIPAM PGD were manufactured, irradiated with 6 MV photons, CT imaged and processed in Matlab. AM filter for two iterations, with 3 × 3 and 5 × 5 pixels (kernel size), was used in two scenarios (a) the CT images were subjected to AM filtering (pre-processing) and these were further employed to generate AS and ZS gel images, and (b) the AS and ZS images were first reconstructed from the CT images and then AM filtering was carried out (post-processing)...
February 6, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28164865/the-correction-of-time-and-temperature-effects-in-mr-based-3d-fricke-xylenol-orange-dosimetry
#7
Mattea L Welch, David Jaffray
<b>Purpose:</b> MR-based three-dimensional (3D) Fricke-xylenol orange (FXG) dosimeters can provide end-to-end quality assurance and validation protocols for pre-clinical radiation platforms. FXG dosimeters quantify ionizing irradiation using pre- and post-irradiation MR imaging methods that detect changes in spin-lattice relaxation rates (R<sub>1</sub> = T<sub>1</sub><sup>-1</sup>) caused by irradiation induced oxidation of Fe<sup>2+</sup>. Chemical changes in MR-based FXG dosimeters that occur over time and with changes in temperature can decrease dosimetric accuracy if they are not properly characterized and corrected...
February 6, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28155883/first-on-site-true-gamma-ray-imaging-spectroscopy-of-contamination-near-fukushima-plant
#8
Dai Tomono, Tetsuya Mizumoto, Atsushi Takada, Shotaro Komura, Yoshihiro Matsuoka, Yoshitaka Mizumura, Makoto Oda, Toru Tanimori
We have developed an Electron Tracking Compton Camera (ETCC), which provides a well-defined Point Spread Function (PSF) by reconstructing a direction of each gamma as a point and realizes simultaneous measurement of brightness and spectrum of MeV gamma-rays for the first time. Here, we present the results of our on-site pilot gamma-imaging-spectroscopy with ETCC at three contaminated locations in the vicinity of the Fukushima Daiichi Nuclear Power Plants in Japan in 2014. The obtained distribution of brightness (or emissivity) with remote-sensing observations is unambiguously converted into the dose distribution...
February 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28155843/analysis-of-measurement-deviations-for-the-patient-specific-quality-assurance-using-intensity-modulated-spot-scanning-particle-beams
#9
Yongqiang Li, Wen Hsi
To analyze measurement deviations of patient-specific quality assurance (QA) using intensity-modulated spot-scanning particle beams, a commercial radiation dosimeter using 24 pin-point ionization chambers was utilized. Before clinical trial, the validations of radiation dosimeter as well as treatment planning system were executed. During clinical trial 165 measurements were performed on 36 patients enrolled. Two or three fields were used for each patient. Measurements were typically performed with the dosimeter placed at special regions of dose distribution along depth and lateral profiles...
February 3, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28144120/simplified-method-for-creating-a-density-absorbed-dose-calibration-curve-for-the-low-dose-range-from-gafchromic-ebt3-film
#10
Tatsuhiro Gotanda, Toshizo Katsuda, Rumi Gotanda, Tadao Kuwano, Takuya Akagawa, Nobuyoshi Tanki, Akihiko Tabuchi, Tetsunori Shimono, Yasuyuki Kawaji
Radiochromic film dosimeters have a disadvantage in comparison with an ionization chamber in that the dosimetry process is time-consuming for creating a density-absorbed dose calibration curve. The purpose of this study was the development of a simplified method of creating a density-absorbed dose calibration curve from radiochromic film within a short time. This simplified method was performed using Gafchromic EBT3 film with a low energy dependence and step-shaped Al filter. The simplified method was compared with the standard method...
October 2016: Journal of Medical Physics
https://www.readbyqxmd.com/read/28137364/nucleoplasmic-bridges-as-a-biomarker-of-dna-damage-exposed-to-radon
#11
C Meenakshi, K Sivasubramanian, B Venkatraman
Radon is a naturally occurring radionuclide in the environment, during decay it emits high linear energy transfer (LET) alpha particles. When radon exposure is accompanied by smoking it has been reported that lung cancer risk is higher. Blood samples were collected after prior consent, 25 smokers and 25 non smokers (only males) exposed in vitro to radon gas with doses ranging between 0.3-12.6mGy Ionizing radiation is a strong clastogenic agent and a potent inducer of MN. Cytokinesis-Blocked Micro Nucleus (CBMN) assay has proven to be a reliable, thoroughly validated and standardised technique in the field of radiation biology...
February 2017: Mutation Research
https://www.readbyqxmd.com/read/28134130/chemically-tuned-linear-energy-transfer-dependent-quenching-in-a-deformable-radiochromic-3d-dosimeter
#12
Ellen Marie Høye, Peter S Skyt, Peter Balling, Ludvig P Muren, Vicki T Taasti, Jan Swakoń, Gabriela Mierzwińska, Marzena Rydygier, Niels Bassler, Jørgen B B Petersen
Most solid-state detectors, including 3D dosimeters, show lower signal in the Bragg peak than expected, a process termed quenching. The purpose of this study was to investigate how variation in chemical composition of a recently developed radiochromic, silicone-based 3D dosimeter influences the observed quenching in proton beams. The dependency of dose response on linear energy transfer, as calculated through Monte Carlo simulations of the dosimeter, was investigated in 60 MeV proton beams. We found that the amount of quenching varied with the chemical composition: peak-to-plateau ratios (1 cm into the plateau) ranged from 2...
February 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28126487/single-pulse-per-second-setting-reduces-fluoroscopy-time-during-ureteroscopy
#13
Todd S Yecies, Anisleidy Fombona, Michelle J Semins
OBJECTIVE: To evaluate the effect of 1 pulse-per-second (pps) fluoroscopy on fluoroscopy time and surgeon radiation exposure during ureteroscopy. METHODS: A retrospective review of a single endourologist's operative records was performed over a 12 month period. Adult patients undergoing ureteroscopy were included. At the 6 month point, the switch from continuous "low-dose" to 1 pps "low-dose" fluoroscopy was made. Surgeon radiation exposure was measured using 1 dosimeter placed at the torso under the lead apron and 1 dosimeter overlying the chest outside the lead apron...
January 23, 2017: Urology
https://www.readbyqxmd.com/read/28121723/design-of-interrogation-protocols-for-radiation-dose-measurements-using-optically-stimulated-luminescent-dosimeters
#14
Sara A Abraham, Kimberlee J Kearfott, Ali H Jawad, Andrew J Boria, Tobias J Buth, Alexander S Dawson, Sheldon C Eng, Samuel J Frank, Crystal A Green, Mitchell L Jacobs, Kevin Liu, Joseph A Miklos, Hien Nguyen, Muhammad Rafique, Blake D Rucinski, Travis Smith, Yanliang Tan
Optically-stimulated luminescent dosimeters are capable of being interrogated multiple times post-irradiation. Each interrogation removes a fraction of the signal stored within the optically-stimulated luminescent dosimeter. This signal loss must be corrected to avoid systematic errors in estimating the average signal of a series of optically-stimulated luminescent dosimeter interrogations and requires a minimum number of consecutive readings to determine an average signal that is within a desired accuracy of the true signal with a desired statistical confidence...
March 2017: Health Physics
https://www.readbyqxmd.com/read/28119152/component-resolved-bleaching-study-in-natural-calcium-fluoride-using-cw-osl-lm-osl-and-residual-tl-glow-curves-after-bleaching
#15
Vasiliki Angeli, George S Polymeris, Ioanna K Sfampa, Nestor C Tsirliganis, George Kitis
Natural calcium fluoride has been commonly used as thermoluminescence (TL) dosimeter due to its high luminescence intensity. The aim of this work includes attempting a correlation between specific TL glow curves after bleaching and components of linearly modulated optically stimulated luminescence (LM-OSL) as well as continuous wave OSL (CW-OSL). A component resolved analysis was applied to both integrated intensity of the RTL glow curves and all OSL decay curves, by using a Computerized Glow-Curve De-convolution (CGCD) procedure...
January 18, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28118149/assessment-of-the-occupational-eye-lens-dose-for-clinical-staff-in-interventional-radiology-cardiology-and-neuroradiology
#16
Artur Omar, Nils Kadesjö, Charlotta Palmgren, Maria Marteinsdottir, Tony Segerdahl, Annette Fransson
In accordance with recommendations by the International Commission on Radiological Protection, the current European Basic Safety Standards has adopted a reduced occupational eye lens dose limit of 20 mSv yr(-1). The radiation safety implications of this dose limit is of concern for clinical staff that work with relatively high dose x-ray angiography and interventional radiology. Presented in this work is a thorough assessment of the occupational eye lens dose based on clinical measurements with active personal dosimeters worn by staff during various types of procedures in interventional radiology, cardiology and neuroradiology...
January 24, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28115659/deep-shallow-and-eye-lens-doses-from-106ru-106rh-a-comparsion
#17
Munish Kumar, A K Bakshi, R B Rakesh, P Ratna, M S Kulkarni, D Datta
(106)Ru/(106)Rh is unique amongst other commonly used beta sources such as (147)Pm, (85)Kr, (204)Tl, (32)P, (nat)U and (90)Sr/(90)Y in the sense that it is capable of simultaneously delivering shallow/skin, eye lens and deep/whole body doses (WBDs) and they differ from each other substantially. In view of this, the investigation of various quantities defined for individual monitoring is possible and this makes (106)Ru/(106)Rh beta source, a classical example in radiation protection and dosimetry. This led us to estimate skin, eye lens and WBDs for (106)Ru/(106)Rh beta source...
January 23, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28110197/outdoor-dose-rate-mapping-in-kuwait
#18
Darwish Al-Azmi
As part of ongoing efforts to develop the data base required for the gamma dose rate baseline in Kuwait, a survey of ambient outdoor gamma-ray dose rates was carried out in 112 locations within the country. Measurements were performed, during the period from August 2013 to March 2016, in various undisturbed open areas in the desert using a NaI dosimeter/spectrometer. The dose rates were recorded along with the corresponding gamma-ray spectra for in-situ relative contribution of the primordial radionuclides and (137)Cs in the outdoor environment...
January 19, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28104641/measured-head-ct-cta-skin-dose-and-intensive-care-unit-patient-cumulative-exposure
#19
R D Nawfel, G S Young
BACKGROUND AND PURPOSE: Estimates of cumulative CT/CTA radiation dose based on volumetric CT dose index have raised concern that neurological intensive care unit patient exposures may reach thresholds for deterministic skin injury. Because the accuracy of volumetric CT dose index for this purpose in unknown, we set out to directly measure head CT and CTA peak skin dose, assess the relationship of volumetric CT dose index to measured peak skin dose, and determine whether multiple CT/CTA exposures in typical patients in the neurological intensive care unit produce cumulative doses approaching or exceeding single-dose deterministic thresholds for skin injury...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28102948/use-of-parallel-plate-ionization-chambers-in-reference-dosimetry-of-novac-and-liac-%C3%A2-mobile-electron-linear-accelerators-for-intraoperative-radiotherapy-a-multi-center-survey
#20
Paolo Scalchi, Alessia Ciccotelli, Giuseppe Felici, Assunta Petrucci, Raffaella Massafra, Valeria Piazzi, Paola D'Avenia, Francesca Cavagnetto, Federica Cattani, Raffaella Romagnoli, Antonella Soriani
PURPOSE: LIAC(®) and NOVAC are two mobile linear accelerators dedicated to intraoperative radiation therapy (IORT), generating electron beams in the energy range of 3-12 MeV. Due to high dose-per-pulse (up to 70 mGy per pulse), in 2003 the Italian National Institute of Health (ISS) stated that "for the measure of dose to water in reference conditions, ionization chambers cannot be employed and no published dosimetry protocol can be used". As a consequence, ferrous sulphate (or, alternatively alanine) dosimetry was recommended...
January 2017: Medical Physics
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