keyword
MENU ▼
Read by QxMD icon Read
search

Dosimetry

keyword
https://www.readbyqxmd.com/read/28102956/experimental-verification-of-4d-monte-carlo-simulations-of-dose-delivery-to-a-moving-anatomy
#1
Sara Gholampourkashi, Miro Vujicic, Jason Belec, Joanna E Cygler, Emily Heath
PURPOSE: To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom. METHODS: We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point-dose values at the center of the spherical tumor inside the insert...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102953/air-kerma-strength-determination-of-an-hdr-192-ir-source-including-a-geometric-sensitivity-study-of-the-seven-distance-method
#2
Blake R Smith, John A Micka, Manik Aima, Larry A DeWerd, Wesley S Culberson
PURPOSE: To perform an in-air air-kerma strength (SK) calibration of the Bebig model Ir2.A85-2 192Ir high-dose rate (HDR) brachytherapy source manufactured by Mallinckrodt Medical (Westerduinweg, Germany) with the NIST-traceable seven-distance technique established by the University of Wisconsin. A comparison was made between the reference air-kerma rate (RAKR) reported on a certificate from the Physikalisch-Technische Bundesanstalt (Berlin, Germany) (PTB) primary laboratory and the SK determined at the University of Wisconsin Madison Radiation Research Center (UWMRRC)...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102950/quantitative-impact-of-changes-in-marrow-cellularity-skeletal-size-and-bone-mineral-density-on-active-marrow-dosimetry-based-upon-a-reference-model
#3
Amy M Geyer, Bryan C Schwarz, Robert F Hobbs, George Sgouros, Wesley E Bolch
PURPOSE: The hematopoietically active tissues of skeletal bone marrow are a prime target for computational dosimetry given potential risks of leukemia and, at higher dose levels, acute marrow toxicity. The complex three-dimensional geometry of trabecular spongiosa, however, complicates schema for dose assessment in such a way that only a few reference skeletal models have been developed to date, and which are based upon microimaging of a limited number of cadaveric bone spongiosa cores...
January 2017: Medical Physics
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
#4
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
https://www.readbyqxmd.com/read/28102946/a-portal-dosimetry-dose-prediction-method-based-on-collapsed-cone-algorithm-using-the-clinical-beam-model
#5
J Martínez Ortega, N Gómez González, P Castro Tejero, M Pinto Monedero, N B Tolani, L Núñez Martín, R Sánchez Montero
PURPOSE: Amorphous silicon electronical portal imaging devices (EPIDs) are widely used for dosimetric measurements in Radiation Therapy. The purpose of this work was to determine if a portal dose prediction method can be utilized for dose map calculations based on the linear accelerator model within a commercial treatment planning system (Pinnacle(3) v8.0 m). METHODS: The method was developed for a 6 MV photon beam on the Varian Clinac 21-EX, at a nominal dose rate of 400 MU/min...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102836/preparation-characterization-and-in-vitro-dosimetry-of-dispersed-engineered-nanomaterials
#6
Glen M DeLoid, Joel M Cohen, Georgios Pyrgiotakis, Philip Demokritou
Evidence continues to grow of the importance of in vitro and in vivo dosimetry in the hazard assessment and ranking of engineered nanomaterials (ENMs). Accurate dose metrics are particularly important for in vitro cellular screening to assess the potential health risks or bioactivity of ENMs. To ensure meaningful and reproducible quantification of in vitro dose, with consistent measurement and reporting between laboratories, it is necessary to adopt standardized and integrated methodologies for (i) generation of stable ENM suspensions in cell culture media; (ii) colloidal characterization of suspended ENMs, particularly of properties that determine particle kinetics in an in vitro system (size distribution and formed agglomerate effective density); and (iii) robust numerical fate and transport modeling for accurate determination of the ENM dose delivered to cells over the course of the in vitro exposure...
February 2017: Nature Protocols
https://www.readbyqxmd.com/read/28102707/patient-dosimetry-audit-for-establishing-local-diagnostic-reference-levels-for-nuclear-medicine-ct
#7
Matthew Gardner, Ngonidzashe M Katsidzira, Erin Ross, Elizabeth A Larkin
OBJECTIVES: To establish a system for patient dosimetry audit and setting of Local Diagnostic Reference Levels (LDRLs) for Nuclear Medicine (NM) CT. METHODS: Computed Radiological Information System (CRIS) data were matched with NM paper records which provided the body region and dose mode for NMCT carried out at a large UK hospital. It was necessary to divide data in terms of the NM examination type, body region and dose mode. The mean and standard deviation Dose Length Products (DLPs) for common NMCT examinations were then calculated and compared to the proposed National DRLs (NDRLs)...
January 19, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28101733/3d-absorbed-dose-distribution-estimated-by-monte-carlo-simulation-in-radionuclide-therapy-with-a-monoclonal-antibody-targeting-synovial-sarcoma
#8
David Sarrut, Jean-Noël Badel, Adrien Halty, Gwenaelle Garin, David Perol, Philippe Cassier, Jean-Yves Blay, David Kryza, Anne-Laure Giraudet
BACKROUND: Radiolabeled OTSA101, a monoclonal antibody targeting synovial sarcoma (SS) developed by OncoTherapy Science, was used to treat relapsing SS metastases following a theranostic procedure: in case of significant (111)In-OTSA101 tumor uptake and favorable biodistribution, patient was randomly treated with 370/1110 MBq (90)Y-OTSA101. Monte Carlo-based 3D dosimetry integrating time-activity curves in VOI was performed on (111)In-OTSA101 repeated SPECT/CT. Estimated absorbed doses (AD) in normal tissues were compared to biological side effects and to the admitted maximal tolerated absorbed dose (MTD) in normal organs...
December 2017: EJNMMI Physics
https://www.readbyqxmd.com/read/28097640/priming-increases-the-anti-tumor-effect-and-therapeutic-window-of-177-lu-octreotate-in-nude-mice-bearing-human-small-intestine-neuroendocrine-tumor-got1
#9
Johanna Dalmo, Johan Spetz, Mikael Montelius, Britta Langen, Yvonne Arvidsson, Henrik Johansson, Toshima Z Parris, Khalil Helou, Bo Wängberg, Ola Nilsson, Maria Ljungberg, Eva Forssell-Aronsson
BACKGROUND: (177)Lu-[DOTA(0), Tyr(3)]-octreotate ((177)Lu-octreotate) is used for treatment of patients with somatostatin receptor (SSTR) expressing neuroendocrine tumors. However, complete tumor remission is rarely seen, and optimization of treatment protocols is needed. In vitro studies have shown that irradiation can up-regulate the expression of SSTR1, 2 and 5, and increase (177)Lu-octreotate uptake. The aim of the present study was to examine the anti-tumor effect of a (177)Lu-octreotate priming dose followed 24 h later by a second injection of (177)Lu-octreotate compared to a single administration of (177)Lu-octreotate, performed on the human small intestine neuroendocrine tumor cell line, GOT1, transplanted to nude mice...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28095550/the-diagnostic-role-of-optical-coherence-tomography-oct-in-measuring-the-depth-of-burn-and-traumatic-scars-for-more-accurate-laser-dosimetry-pilot-study
#10
Jill S Waibel, Ashley C Rudnick, Adam J Wulkan, Jon D Holmes
BACKGROUND: In recent decades, a number of optimal diagnostic technologies have emerged to assist in tissue visualization. Real-time monitoring of skin during laser therapies will help optimize laser parameters for more ef cient therapies. One of these technologies, optimal coherence tomography (OCT), may be used to help visualize burn and traumatic scars. When lasing severe scars, lasers have tunable pulse energies, which are made proportional to the scar thickness as estimated by palpation and the physician eye...
November 1, 2016: Journal of Drugs in Dermatology: JDD
https://www.readbyqxmd.com/read/28094856/percent-depth-doses-and-x-ray-beam-characterizations-of-a-fluoroscopic-system-incorporating-copper-filtration
#11
Kevin A Wunderle, Andrew R Godley, Zhilei Liu Shen, Joseph T Rakowski, Frank F Dong
PURPOSE: In this investigation, we sought to characterize X-ray beam qualities and quantify percent depth dose (PDD) curves for fluoroscopic X-ray beams incorporating added copper (Cu) filtration, such as those commonly used in fluoroscopically guided interventions (FGI). The intended application of this research is for dosimetry in soft tissue from FGI procedures using these data. METHODS: All measurements in this study were acquired on a Siemens (Erlangen, Germany) Artis zeego fluoroscope...
January 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28094853/high-dose-per-pulse-electron-beam-dosimetry-a-model-to-correct-for-the-ion-recombination-in-the-advanced-markus-ionization-chamber
#12
Kristoffer Petersson, Maud Jaccard, Jean-François Germond, Thierry Buchillier, François Bochud, Jean Bourhis, Marie-Catherine Vozenin, Claude Bailat
PURPOSE: The purpose of this work was to establish an empirical model of the ion recombination in the Advanced Markus ionization chamber for measurements in high dose rate/dose-per-pulse electron beams. In addition, we compared the observed ion recombination to calculations using the standard Boag two-voltage-analysis method, the more general theoretical Boag models, and the semi-empirical general equation presented by Burns and McEwen. METHODS: Two independent methods were used to investigate the ion recombination: 1) Varying the grid tension of the linear accelerator (linac) gun (controls the linac output) and measuring the relative effect the grid tension has on the chamber response at different source-to-surface distances (SSD)...
January 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28094138/new-normoxic-n-hydroxymethyl-acrylamide-based-polymer-gel-for-3d-dosimetry-in-radiation-therapy
#13
Khalid A Rabaeh, Ahmed A Basfar, Akram A Almousa, Slobodan Devic, Belal Moftah
A novel composition of normoxic polymer gel dosimeters based on radiation-induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) is introduced in this study for 3D dosimetry for Quality Assurance (QA) in radiation therapy. Dosimeters were irradiated by 6, 10 and 18MV photon beams of a medical linear accelerator at various dose rates to doses of up to 20Gy. The dose response of polymer gel dosimeters was studied using nuclear magnetic resonance (NMR) spin-spin relaxation rate (R2) of hydrogen protons within the water molecule...
January 13, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28092407/study-of-potential-health-effects-of-electromagnetic-fields-of-telephony-and-wi-fi-using-chicken-embryo-development-as-animal-model
#14
Henri Woelders, Agnes de Wit, Alexander Lourens, Norbert Stockhofe, Bas Engel, Ina Hulsegge, Dirkjan Schokker, Paula van Heijningen, Stefan Vossen, Dave Bekers, Peter Zwamborn
The objective of this study is to investigate possible biological effects of radiofrequency electromagnetic fields (RF-EMF) as used in modern wireless telecommunication in a well-controlled experimental environment using chicken embryo development as animal model. Chicken eggs were incubated under continuous experimental exposure to GSM (1.8 GHz), DECT (1.88 GHz), UMTS (2.1 GHz), and WLAN (5.6 GHz) radiation, with the appropriate modulation protocol, using a homogeneous field distribution at a field strength of approximately 3 V/m, representing the maximum field level in a normal living environment...
January 16, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/28089526/a-feasibility-study-of-2-mm-bolus-for-postmastectomy-radiation-therapy
#15
Lauren C Das, Daniel W Golden, Eugenia Perevalova, Anthony C Wong, Kimberly De Nardo, Christopher Stepaniak, Daniel S Joyce, Bradley P McCabe, Yasmin Hasan, Steven J Chmura, Anne McCall
PURPOSE: The purpose of this study was to prospectively evaluate the use of daily 2-mm bolus in patients undergoing postmastectomy radiation without reconstruction using optically stimulated luminescence dosimetry and weekly assessment of skin toxicity. METHODS AND MATERIALS: We prospectively collected data from the first 49 women treated with a daily 2-mm Superflab bolus during their postmastectomy radiation therapy from 2013 to 2016 at The University of Chicago Comprehensive Cancer Center at Silver Cross...
October 24, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28089106/-edge-on-moskin-detector-for-stereotactic-beam-measurement-and-verification
#16
Wei Loong Jong, Ngie Min Ung, Ath Vannyat, Zulaikha Jamalludin, Anatoly Rosenfeld, Jeannie Hsiu Ding Wong
Dosimetry in small radiation field is challenging and complicated because of dose volume averaging and beam perturbations in a detector. We evaluated the suitability of the "Edge-on" MOSkin (MOSFET) detector in small radiation field measurement. We also tested the feasibility for dosimetric verification in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). "Edge-on" MOSkin detector was calibrated and the reproducibility and linearity were determined. Lateral dose profiles and output factors were measured using the "Edge-on" MOSkin detector, ionization chamber, SRS diode and EBT2 film...
January 6, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28074017/the-mayak-worker-dosimetry-system-2013-treatment-of-organ-masses-in-the-calculation-of-organ-doses
#17
A Birchall, A B Sokolova
Previous Mayak worker epidemiological studies designed to quantify the risk of cancer following exposure to airborne plutonium have calculated organ doses by dividing the organ-absorbed energy by the individual's estimated organ mass. For living workers, this was done by using a relationship between organ mass and total mass and height. For autopsy cases, this was measured directly. In the Mayak Worker Dosimetry System-2013 study, organ doses are calculated by dividing this energy by a population average organ mass...
January 10, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28074015/electron-absorbed-fractions-in-an-image-based-microscopic-skeletal-dosimetry-model-of-chinese-adult-male
#18
Shenshen Gao, Li Ren, Rui Qiu, Zhen Wu, Chunyan Li, Junli Li
Based on the Chinese reference adult male voxel model, a set of microscopic skeletal models of Chinese adult male is constructed through the processes of computed tomography (CT) imaging, bone coring, micro-CT imaging, image segmentation, merging into macroscopic bone model and implementation in Geant4. At the step of image segmentation, a new bone endosteum (BE) segmentation method is realized by sampling. The set of model contains 32 spongiosa samples with voxel size of 19 μm cubes. The microscopic spongiosa bone data for Chinese adult male are provided...
January 10, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28072578/mathematical-modelling-of-scanner-specific-bowtie-filters-for-monte-carlo-ct-dosimetry
#19
R Kramer, V F Cassola, M E A Andrade, M W C de Araújo, D J Brenner, H J Khoury
The purpose of bowtie filters in CT scanners is to homogenize the x-ray intensity measured by the detectors in order to improve the image quality and at the same time to reduce the dose to the patient because of the preferential filtering near the periphery of the fan beam. For CT dosimetry, especially for Monte Carlo calculations of organ and tissue absorbed doses to patients, it is important to take the effect of bowtie filters into account. However, material composition and dimensions of these filters are proprietary...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28072461/adverse-and-beneficial-effects-in-chinese-hamster-lung-fibroblast-cells-following-radiofrequency-exposure
#20
Anna Sannino, Olga Zeni, Stefania Romeo, Rita Massa, Maria Rosaria Scarfi
In this study, the effect of radiofrequency (RF) exposure to 1950 MHz, Universal Mobile Telecommunication System signal, was investigated in Chinese hamster lung fibroblast cell line (V79). Genotoxic and cytotoxic effects of 20-h exposure at specific absorption rate (SAR) values from 0.15 W/kg to 1.25 W/kg were measured by means of cytokinesis-block micronucleus (MN) assay. Exposure was carried out blinded under strictly controlled conditions of dosimetry and temperature. The effect of RF exposure alone at four SAR values was tested, that is, 0...
January 10, 2017: Bioelectromagnetics
keyword
keyword
60683
1
2
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"