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https://www.readbyqxmd.com/read/28441289/radiological-nuclear-human-monitoring-tabletop-exercise-recommendations-and-lessons-identified
#1
Vinita Chauhan, Devin Duncan, Ruth C Wilkins
Health Canada is the lead department for coordinating the federal response to a Canadian nuclear emergency event. The framework to manage a radiological consequence is outlined in the Federal Nuclear Emergency Plan (FNEP). In 2014, a full scale exercise (FSX) was held to test the capacity of the federal government to handle a nuclear facility emergency disaster in Canada. The FSX provided a means to demonstrate the integration of various departments and agencies in response to such an event, and although a number of task teams within FNEP were tested, the capacity to monitor humans for exposure post-event was not played out fully...
June 2017: Health Physics
https://www.readbyqxmd.com/read/28441288/investigation-of-optically-stimulated-luminescence-and-signal-fading-properties-of-several-materials
#2
W Geoffrey West, Kimberlee J Kearfott, Chun Yong Seow
Optically stimulated luminescence (OSL) dosimetry involves the illumination of an irradiated sample on an appropriate material to produce a stimulated emission of light, whose intensity is indicative of the radiation dose. This technique is currently used for personnel dosimetry, environmental dosimetry, and geological dating applications. While a great deal of published research focusing on α-Al2O3:C and natural materials used for geological dating exist, relatively little is known about the OSL properties of thermoluminescent (TL) materials...
June 2017: Health Physics
https://www.readbyqxmd.com/read/28441286/behavior-of-americium-in-simulated-wounds-in-nonhuman-primates
#3
Deepesh Poudel, Raymond A Guilmette, Luiz Bertelli, John A Klumpp, Richard R Brey
An americium solution injected intramuscularly into several nonhuman primates (NHPs) was found to behave differently than predicted by the wound models described in the NCRP Report 156. This was because the injection was made along with a citrate solution, which is known to be more soluble than chlorides, oxides, or nitrates on which the NCRP Report was based. A multi-exponential wound model specific to the injected americium solution was developed based on the retention in the intramuscular sites. The model was coupled with the americium systemic model to interpret the urinary excretion data and assess the intake, and it was determined that the models were adequate to predict early urinary excretion in most cases but unable to predict late urinary excretion...
June 2017: Health Physics
https://www.readbyqxmd.com/read/28440238/thermal-ablation-of-pancreatic-cyst-with-a-prototype-endoscopic-ultrasound-capable-radiofrequency-needle-device-a-pilot-feasibility-study
#4
Maria Moris, Mustafa Atar, Abdurrahman Kadayifci, Murli Krishna, Ariston Librero, Eugene Richie, William Brugge, Michael B Wallace
BACKGROUND AND OBJECTIVES: Pancreatic cysts are evaluated by endoscopic ultrasound and fine needle aspiration (EUS). The only accepted treatment is pancreatectomy, which is associated with morbidity and mortality. This study evaluated the optimal thermal dosimetry of a novel radiofrequency ablation device using a standard electrosurgical unit in ex vivo cyst models. METHODS: A modified EUS 22-gauge monopolar needle prototype with a tip electrode connected to a standard electrosurgical unit (Erbe USA, Marietta, GA, USA) was used to induce a subboiling point temperature...
March 2017: Endoscopic Ultrasound
https://www.readbyqxmd.com/read/28438431/phantom-to-clinic-development-of-hypofractionated-stereotactic-body-radiotherapy-for-early-stage-glottic-laryngeal-cancer
#5
Chuxiong Ding, Stephen G Chun, Baran D Sumer, Lucien A Nedzi, Ramzi E Abdulrahman, John S Yordy, Pam Lee, Brian Hrycushko, Timothy D Solberg, Chul Ahn, Robert D Timmerman, David L Schwartz
The purpose of this study was to commission and clinically test a robotic stereotactic delivery system (CyberKnife, Sunnyvale, CA) to treat early-stage glottic laryngeal cancer. We enrolled 15 patients with cTis-T2N0M0 carcinoma of the glottic larynx onto an institutional review board (IRB)-approved clinical trial. Stereotactic body radiotherapy (SBRT) plans prescribed 45 Gy/10 fractions to the involved hemilarynx. SBRT dosimetry was compared with (1) standard carotid-sparing laryngeal intensity-modulated radiation therapy (IMRT) and (2) selective hemilaryngeal IMRT...
April 21, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28438215/predicting-liver-sbrt-eligibility-and-plan-quality-for-vmat-and-4%C3%AF-plans
#6
Angelia Tran, Kaley Woods, Dan Nguyen, Victoria Y Yu, Tianye Niu, Minsong Cao, Percy Lee, Ke Sheng
BACKGROUND: It is useful to predict planned dosimetry and determine the eligibility of a liver cancer patient for SBRT treatment using knowledge based planning (KBP). We compare the predictive accuracy using the overlap volume histogram (OVH) and statistical voxel dose learning (SVDL) KBP prediction models for coplanar VMAT to non-coplanar 4π radiotherapy plans. METHODS: In this study, 21 liver SBRT cases were selected, which were initially treated using coplanar VMAT plans...
April 24, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28436921/feasibility-study-of-entrance-and-exit-dose-measurements-at-the-contra-lateral-breast-with-alanine-electron-spin-resonance-dosimetry-in-volumetric-modulated-radiotherapy-of-breast-cancer
#7
Daniela M Wagner, Petra Huettenrauch, Mathias Anton, Philip von Voigts-Rhetz, Klemens Zink, Hendrik Wolff
PURPOSE: The Physikalisch-Technische Bundesanstalt (PTB) has established a secondary standard measurement system for the dose to water, DW, based on alanine/ ESR (Anton et. al. 2013). The aim of this study was to test the established measurements system for out of field measurements inpatient with breast cancer. METHOD AND MATERIALS: A set of five alanine pellets were affixed to each patients` skin at the contra lateral breast beginning at the sternum and extending over the mammilla to the distal surface...
April 24, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28429827/a-descriptive-and-broadly-applicable-model-of-therapeutic-and-stray-absorbed-dose-from-6-mv-to-25-mv-photon-beams
#8
Christopher W Schneider, Wayne D Newhauser, Lydia J Wilson, Uwe Schneider, Robert Kaderka, Saveta Miljanić, Željka Knežević, Liliana Stolarcyzk, Marco Durante, Roger M Harrison
PURPOSE: To develop a simple model of therapeutic and stray absorbed dose for a variety of treatment machines and techniques without relying on proprietary machine-specific parameters. METHODS: Dosimetry measurements conducted in this study and from the literature were used to develop an analytical model of absorbed dose from a variety of treatment machines and techniques in the 6 MV to 25 MV interval. A modified one-dimensional gamma-index analysis was performed to evaluate dosimetric accuracy of the model on an independent dataset consisting of measured dose profiles from seven treatment units spanning four manufacturers...
April 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/28428468/multicenter-investigation-of-the-effective-dose-for-whole-body-ct-scanning
#9
Toshimitsu Sato, Yukihiro Saito, Nobutoshi Saito, Makoto Ooba
OBJECTIVE: To study whether the actual radiation exposure is different between computed tomography (CT) scanners and medical centers when the same patient is scanned, we investigated the actual effective doses for a whole body (Chest-Pelvis) CT scan in a multicenter study. MATERIALS AND METHODS: Data from subjects were collected using 12 CT scanners at six medical centers in Yamagata city. Effective-dose data were acquired by scanning the same phantom (ATOM Dosimetry Phantoms Model702-B) using 120 kV tube voltage...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28427834/doped-silica-fibre-thermoluminescence-measurements-of-radiation-dose-in-the-use-of-223-ra
#10
Bradley, S F Abdul Sani, A S Siti Shafiqah, S M Collins, R P Hugtenburg, H A Abdul Rashid, Nurul Najua Zulkepely, M J Maah
Using tailor-made sub-mm dimension doped-silica fibres, thermoluminescent dosimetric studies have been performed for α-emitting sources of (223)RaCl2 (the basis of the Bayer Healthcare product Xofigo®). The use of (223)RaCl2 in the palliative treatment of bone metastases resulting from late-stage castration-resistant prostate cancer focuses on its favourable uptake in metabolically active bone metastases. Such treatment benefits from the high linear energy transfer (LET) and associated short path length (<100µm) of the α-particles emitted by (223)Ra and its decay progeny...
April 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28422381/comparison-of-multi-institutional-varian-probeam-pencil-beam-scanning-proton-beam-commissioning-data
#11
Ulrich W Langner, John G Eley, Lei Dong, Katja Langen
PURPOSE: Commissioning beam data for proton spot scanning beams are compared for the first two Varian ProBeam sites in the United States, at the Maryland Proton Treatment Center (MPTC) and Scripps Proton Therapy Center (SPTC). In addition, the extent to which beams can be matched between gantry rooms at MPTC is investigated. METHOD: Beam data for the two sites were acquired with independent dosimetry systems and compared. Integrated depth dose curves (IDDs) were acquired with Bragg peak ion chambers in a 3D water tank for pencil beams at both sites...
April 19, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28421342/selective-retina-therapy-with-automatic-real-time-feedback-controlled-dosimetry-for-chronic-central-serous-chorioretinopathy-in-korean-patients
#12
Young Gun Park, Seungbum Kang, Minhee Kim, Nari Yoo, Young Jung Roh
PURPOSE: To evaluate the safety and efficacy of selective retina therapy (SRT) with real-time feedback-controlled dosimetry (RFD) in the treatment of chronic central serous chorioretinopathy (CSC). METHODS: In this retrospective case series study, 50 eyes of 49 patients with chronic CSC demonstrating focal or diffuse foveal leakages on fundus fluorescein angiography (FFA) were included. Following evaluation of test spots at temporal arcades, SRT (wavelength 527 nm, pulse repetition rate 100 Hz, pulse energy ramp with maximal 15 pulses) with retinal spot diameter of 200 μm was applied to the areas of each leakage observed on fluorescein angiography...
April 18, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28410679/dual-energy-imaging-method-to-improve-the-image-quality-and-the-accuracy-of-dose-calculation-for-cone-beam-computed-tomography
#13
Kuo Men, Jianrong Dai, Xinyuan Chen, Minghui Li, Ke Zhang, Peng Huang
PURPOSE: To improve the image quality and accuracy of dose calculation for cone-beam computed tomography (CT) images through implementation of a dual-energy cone-beam computed tomography method (DE-CBCT), and evaluate the improvement quantitatively. METHODS: Two sets of CBCT projections were acquired using the X-ray volumetric imaging (XVI) system on a Synergy (Elekta, Stockholm, Sweden) system with 120kV (high) and 70kV (low) X-rays, respectively. Then, the electron density relative to water (relative electron density (RED)) of each voxel was calculated using a projection-based dual-energy decomposition method...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28410678/novel-6mv-x-ray-photoneutron-detection-and-dosimetry-of-medical-accelerators
#14
Mehdi Sohrabi, Amir Hakimi
PURPOSE: Dosimetry of fast, epithermal and thermal photoneutrons in 6MV X-ray beams of two medical accelerators were studied by novel dosimetry methods. METHODS: A Siemens ONCOR and an Elekta COMPACT medical accelerators were used. Fast, epithermal and thermal photoneutron dose equivalents in 10cm×10cm 6MV X-rays fields were determined in air and on surface of a polyethylene phantom in X and Y directions. Polycarbonate dosimeters as bare or with enriched (10)B convertors (with or without cadmium covers) were used applying a 50Hz-HV electrochemical etching method...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28408529/targeted-alpha-therapy-of-mcrpc-with-225-actinium-psma-617-dosimetry-estimate-and-empirical-dose-finding
#15
Clemens Kratochwil, Frank Bruchertseifer, Hendrik Rathke, Marcus Bronzel, Christos Apostolidis, Wilko Weichert, Uwe Haberkorn, Frederick Lars Giesel, Alfred Morgenstern
To develop a treatment protocol for (225)Ac-PSMA-617 alpha-radiation therapy in advanced stage, metastatic castration-resistant prostate cancer patients with PSMA-positive tumor phenotype. Methods: A dosimetry estimate was calculated based on time-activity-curves derived from serially performed (177)Lu-PSMA-617 scans extrapolated to the physical half-life of (225)Ac, assuming instant decay of instable daughter nuclides. Salvage therapies empirically conducted with 50kBq/kg (n = 4), 100kBq/kg (n = 4), 150kBq/kg (n = 2), 200kBq/kg (n = 4) (225)Ac-PSMA-617 were evaluated retrospectively regarding toxicity and treatment response...
April 13, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28408153/refinement-of-the-oral-exposure-description-in-the-cyclic-siloxane-pbpk-model-for-rats-and-humans-implications-for-exposure-assessment
#16
Jerry L Campbell, Melvin E Andersen, Cynthia Van Landingham, Robinan Gentry, Elke Jensen, Jean Y Domoradzki, Harvey J Clewell
The multi-compound, and multi-dose (MC-MD) route physiologically based pharmacokinetic (PBPK) model for cyclic siloxanes reported by McMullin et al. (2016) brought together the series of models for octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in rat and human into a unified code structure that would allow simulation of both compounds following the inhalation and dermal routes of exposure. The refined MC-MD PBPK model presented here expands upon this effort to include representation of rat kinetic data in plasma, tissues and exhaled breath for the parent compounds after oral bolus administration...
April 10, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28405107/response-of-nanodot-optically-stimulated-luminescence-dosimeters-to-therapeutic-electron-beams
#17
Y Retna Ponmalar, Ravikumar Manickam, S Sathiyan, K M Ganesh, R Arun, Henry Finlay Godson
Response of Al2O3:C-based nanoDot optically stimulated luminescence (OSL) dosimeter was studied for the dosimetry of 6, 9, 12, 16, and 20 MeV therapeutic electron beams. With reference to ionization chamber, no change in the response was observed with the change in the energy of electron beams for the field size from 6 cm × 6 cm to 25 cm × 25 cm, dose rates from 100 MU/min to 600 MU/min, and the linearity in the response up to 300 cGy. The fading of the transient signal was higher for 20 MeV electron beam than that of 6 MeV electron beam by about 5% as compared to value at 20 min after irradiation...
January 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28405103/comparison-of-rapid-arc-and-intensity-modulated-radiotherapy-plans-using-unified-dosimetry-index-and-the-impact-of-conformity-index-on-unified-dosimetry-index-evaluation
#18
Jayapalan Krishnan, Jayarama Shetty, Suresh Rao, Sanath Hegde, C Shambhavi
The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning techniques namely intensity-modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans, UDI at conformity index one of all plan (UDIunit_CI) score was calculated by assuming conformity index is equal to one...
January 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28402564/three-decades-of-occupational-individual-monitoring-at-the-university-of-s%C3%A3-o-paulo
#19
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/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
#20
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
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