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https://www.readbyqxmd.com/read/28338894/establishment-of-radiation-doses-for-pediatric-x-ray-examinations-in-a-large-pediatric-hospital-in-turkey
#1
T Olgar, T Sahmaran
Pediatric patients are more sensitive to ionizing radiation when compared with adults. The aim of this study was to evaluate the radiation doses for some common pediatric x-ray examinations performed with various digital radiography systems. Quality control tests of the digital radiography systems were carried out according to international published protocols before the pediatric dose measurements. Radiation dose measurement was performed by using the x-ray tube outputs and thermoluminescent dosimeter dose measurement methods...
February 25, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28332995/three-dimensional-dosimetric-validation-of-a-magnetic-resonance-guided-intensity-modulated-radiation-therapy-system
#2
Leith J Rankine, Stewart Mein, Bin Cai, Austen Curcuru, Titania Juang, Devin Miles, Sasa Mutic, Yuhe Wang, Mark Oldham, H Harold Li
PURPOSE: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. METHODS AND MATERIALS: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data...
April 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28330794/radiation-exposure-and-vascular-access-in-acute-coronary-syndromes-the-radmatrix-trial
#3
Alessandro Sciahbasi, Enrico Frigoli, Alessandro Sarandrea, Martina Rothenbühler, Paolo Calabrò, Alessandro Lupi, Francesco Tomassini, Bernardo Cortese, Stefano Rigattieri, Enrico Cerrato, Dennis Zavalloni, Antonio Zingarelli, Paolo Calabria, Paolo Rubartelli, Gennaro Sardella, Matteo Tebaldi, Stephan Windecker, Peter Jüni, Dik Heg, Marco Valgimigli
BACKGROUND: It remains unclear whether radial increases the risk of operator or patient radiation exposure when performed by expert operators OBJECTIVES: To determine whether radial access increases radiation exposure METHODS: We randomly assigned 8404 patients, with or without ST-segment elevation acute coronary syndrome, to radial or femoral access for coronary angiography and percutaneous intervention, and collected fluoroscopy time and dose area product (DAP). In the radiation sub-study (RAD-MATRIX), we anticipated that 13 or more operators, each wearing a thorax (primary endpoint), wrist and head (secondary endpoints) lithium fluoride thermo luminescent dosimeter and randomizing at least 13 patients per access site were needed to establish non-inferiority of radial versus femoral access...
March 15, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28330408/using-and-explaining-individual-dosimetry-data
#4
Makoto Miyazaki
Measurement of individual radiation dose is crucial for planning protective measures after nuclear accidents. The purpose of this article is to explain the various initiatives taken after the TEPCO Fukushima Daiichi Nuclear Power Plant accident, including the D-shuttle project wherein residents from affected areas wore a personal dosimeter to measure their own external exposure. The experience in Fukushima revealed several issues such as gaining residents' trust and ensuring appropriate communication of the measured data...
March 2017: Asia-Pacific Journal of Public Health
https://www.readbyqxmd.com/read/28328223/an-organic-gelatin-free-nanocomposite-fricke-gel-dosimeter
#5
Takuya Maeyama, Nobuhisa Fukunishi, Kenichi L Ishikawa, Kazuaki Fukasaku, Shigekazu Fukuda
We report a nanocomposite Fricke gel (NC-FG) dosimeter prepared using only Fe(2+) and nano-clay in water, without any organic gelling agents. This dosimeter gels due to its thixotropic properties and exhibits linear energy transfer (LET)-independent radiological properties under carbon ion beam irradiation. The radiation sensitivity of this dosimeter was 1.8 [s(-1)kGy(-1)], which is three times higher than that reported previously (0.6 [s(-1)kGy(-1)]) for a similar dosimeter containing gelatin. The Fe(3+) yield was determined to be 0...
March 22, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28327469/total-body-irradiation-with-a-compensator-fabricated-using-a-3d-optical-scanner-and-a-3d-printer
#6
So-Yeon Park, Jung-In Kim, Yoon Ha Joo, Jung Chan Lee, Jong Min Park
We propose bilateral total body irradiation (TBI) utilizing a 3D printer and a 3D optical scanner. We acquired surface information of an anthropomorphic phantom with the 3D scanner and fabricated the 3D compensator with the 3D printer, which could continuously compensate for the lateral missing tissue of an entire body from the beam's eye view. To test the system's performance, we measured doses with optically stimulated luminescent dosimeters (OSLDs) as well as EBT3 films with the anthropomorphic phantom during TBI without a compensator, conventional bilateral TBI, and TBI with the 3D compensator (3D TBI)...
March 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28327296/local-diagnostic-reference-levels-for-intraoral-dental-radiography-in-the-public-hospitals-of-cyprus
#7
Stelios Christofides, Elina Pitri, Marios Lampaskis, Christos Papaefstathiou
PURPOSE: The purpose of this study was to determine local DRLs for children and adults undergoing intraoral dental examinations at the intraoral radiology units of the public hospitals in Cyprus. METHODS: Measurements were made on all the twenty intraoral X-ray units of the public hospitals in Cyprus with the intention to establish the local DRLs for all the possible intraoral X-ray examinations for children and adults. All units are film based. The measurements were made by a Dose Area Product (DAP) meter (GAMMEX RMI 841-RD) placed at the surface of the dental unit's X-ray shaping cone (FSD 20cm)...
November 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/28325434/radiation-exposure-and-the-orthopedic-surgeon-s-hand-measurement-of-the-equivalent-dose-over-13%C3%A2-months
#8
F Loisel, G Menu, E Boyer, I Pluvy, L Obert
Exposure to ionizing radiation in the operating room is governed by practical prevention and protection measures on the international, national and local levels. We evaluated the equivalent dose to the hand of an orthopedic surgeon over 13 months. An orthopedic surgeon wore a ring dosimeter on the ring finger of his right hand for all surgical procedures requiring intraoperative fluoroscopy between March 2014 and April 2015. Monthly doses were evaluated by the IRSN over the study period. The number and type of procedures were compiled as well as the type of fluoroscopy unit used...
April 2017: Hand Surgery and Rehabilitation
https://www.readbyqxmd.com/read/28317312/evaluation-of-dose-calculation-accuracy-of-treatment-planning-systems-at-hip-prosthesis-interfaces
#9
David Paulu, Parham Alaei
There are an increasing number of radiation therapy patients with hip prosthesis. The common method of minimizing treatment planning inaccuracies is to avoid radiation beams to transit through the prosthesis. However, the beams often exit through them, especially when the patient has a double-prosthesis. Modern treatment planning systems employ algorithms with improved dose calculation accuracies but even these algorithms may not predict the dose accurately at high atomic number interfaces. The current study evaluates the dose calculation accuracy of three common dose calculation algorithms employed in two commercial treatment planning systems...
March 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300387/real-time-ray-casting-based-scatter-dose-estimation-for-c-arm-x-ray-system
#10
Zaid Alnewaini, Eric Langer, Philipp Schaber, Matthias David, Dominik Kretz, Volker Steil, Jürgen Hesser
OBJECTIVES: Dosimetric control of staff exposure during interventional procedures under fluoroscopy is of high relevance. In this paper, a novel ray casting approximation of radiation transport is presented and the potential and limitation vs. a full Monte Carlo transport and dose measurements are discussed. METHOD: The x-ray source of a Siemens Axiom Artix C-arm is modeled by a virtual source model using single Gaussian-shaped source. A Geant4-based Monte Carlo simulation determines the radiation transport from the source to compute scatter from the patient, the table, the ceiling and the floor...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300371/energy-dependence-and-angular-dependence-of-an-optically-stimulated-luminescence-dosimeter-in-the-mammography-energy-range
#11
Ai Kawaguchi, Yuta Matsunaga, Shoichi Suzuki, Koichi Chida
This study aimed to investigate the energy dependence and the angular dependence of commercially available optically stimulated luminescence (OSL) point dosimeters in the mammography energy range. The energy dependence was evaluated to calculate calibration factors (CFs). The half-value layer range was 0.31-0.60 mmAl (Mo/Mo 22-28 kV, Mo/Rh 28-32 kV, and W/Rh 30-34 kV at 2-kV intervals). Mo/Rh 28 kV was the reference condition. Angular dependence was tested by rotating the X-ray tube from -90° to 90° in 30° increments, and signal counts from angled nanoDots were normalized to the 0° signal counts...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300368/reduction-in-stray-radiation-dose-using-a-body-shielding-device-during-external-radiation-therapy
#12
Shuxu Zhang, Shaohui Jiang, Quanbin Zhang, Shengqu Lin, Ruihao Wang, Xiang Zhou, Guoqian Zhang, Huaiyu Lei, Hui Yu
With the purpose of reducing stray radiation dose (SRD) in out-of-field region (OFR) during radiotherapy with 6 MV intensity-modulated radiation therapy (IMRT), a body-shielding device (BSD) was prepared according to the measurements obtained in experimental testing. In experimental testing, optimal shielding conditions, such as 1 mm lead, 2 mm lead, and 1 mm lead plus 10 mm bolus, were investigated along the medial axis of a phantom using thermoluminescent dosimeters (TLDs). The SRDs at distances from field edge were then measured and analyzed for a clinical IMRT treatment plan for nasopharyngeal carcinoma before and after shielding using the BSD...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300363/activation-of-hip-prostheses-in-high-energy-radiotherapy-and-resultant-dose-to-nearby-tissue
#13
Stephanie Keehan, Ryan L Smith, Jeremy Millar, Max Esser, Michael L Taylor, Peta Lonski, Tomas Kron, Rick D Franich
High energy radiotherapy can produce contaminant neutrons through the photonuclear effect. Patients receiving external beam radiation therapy to the pelvis may have high-density hip prostheses. Metallic materials such as those in hip prostheses, often have high cross-sections for neutron interaction. In this study, Thackray (UK) prosthetic hips have been irradiated by 18 MV radiotherapy beams to evaluate the additional dose to patients from the activation products. Hips were irradiated in- and out-of field at various distances from the beam isocenter to assess activation caused in-field by photo-activation, and neutron activation which occurs both in and out-of-field...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297463/technical-note-out-of-field-dose-measurement-at-near-surface-with-plastic-scintillator-detector
#14
Alexandra Bourgouin, Nicolas Varfalvy, Louis Archambault
Out-of-field dose depends on multiple factors, making peripheral dosimetry complex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements were performed with a parallel-plate ion chamber, a small volume ion chamber, and with a PSD. Lateral-dose measurements (LDM) at 0...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297458/translucent-poly-vinyl-alcohol-cryogel-dosimeters-for-simultaneous-dose-buildup-and-monitoring-during-chest-wall-radiation-therapy
#15
Molham M Eyadeh, Mark A Weston, Janos Juhasz, Kevin R Diamond
Chest wall radiation therapy treatment delivery was monitored using a 5 mm thick radiochromic poly(vinyl alcohol) cryogel that also provided buildup material. The cryogels were used to detect positioning errors and measure the impact of shifts for a chest wall treatment that was delivered to a RANDO phantom. The phantom was shifted by ±2,±3, and ±5 mm from the planned position in the anterior/posterior (A/P) direction; these shifts represent setup errors and the uncertainty associated with lung filling during breath-hold...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297433/secondary-cancer-incidence-risk-estimates-for-external-radiotherapy-and-high-dose-rate-brachytherapy-in-cervical-cancer-phantom-study
#16
Boram Lee, Sung Hwan Ahn, Hyeyoung Kim, Jaeman Son, Jiwon Sung, Youngyih Han, Seung Jae Huh, Jin Sung Kim, Dong Wook Kim, Myonggeun Yoon
This study was designed to estimate radiation-induced secondary cancer risks from high-dose-rate (HDR) brachytherapy and external radiotherapy for patients with cervical cancer based on measurements of doses absorbed by various organs. Organ doses from HDR brachytherapy and external radiotherapy were measured using glass rod dosimeters. Doses to out-of-field organs were measured at various locations inside an anthropomorphic phantom. Brachytherapy-associated organ doses were measured using a specialized phantom that enabled applicator insertion, with the pelvis portion of the existing anthropomorphic phantom replaced by this new phantom...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297336/effect-of-electron-contamination-on-in-vivo-dosimetry-for-lung-block-shielding-during-tbi
#17
Ganesh Narayanasamy, Wilbert Cruz, Daniel L Saenz, Sotirios Stathakis, Niko Papanikolaou, Neil Kirby
Our institution performs in vivo verification measurement for each of our total body irradiation (TBI) patients with optically stimulated luminescent dosimeters (OSLD). The lung block verification measurements were commonly higher than expected. The aim of this work is to understand this discrepancy and improve the accuracy of these lung block verification measurements. Initially, the thickness of the lung block was increased to provide adequate lung sparing. Further tests revealed the increase was due to electron contamination dose emanating from the lung block...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297327/small-field-detector-correction-factors-effects-of-the-flattening-filter-for-elekta-and-varian-linear-accelerators
#18
Madelaine K Tyler, Paul Z Y Liu, Christopher Lee, David R McKenzie, Natalka Suchowerska
Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization chambers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297294/real-time-in-vivo-dosimetry-for-sbrt-prostate-treatment-using-plastic-scintillating-dosimetry-embedded-in-a-rectal-balloon-a-case-study
#19
Justin L Cantley, Chee-Wai Cheng, Fredrick B Jesseph, Tarun K Podder, Valdir C Colussi, Bryan J Traughber, Lee E Ponsky, Rodney J Ellis
A novel FDA approved in vivo dosimetry device system using plastic scintillating detectors placed in an endorectal balloon to provide real-time in vivo dosimetry for prostatic rectal interface was tested for use with stereotactic body radiotherapy (SBRT). The system was used for the first time ever to measure dose during linear accelerator based SBRT. A single patient was treated with a total dose of 36.25 Gy given in 5 fractions. Delivered dose was measured for each treatment with the detectors placed against the anterior rectal wall near the prostate rectal interface...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297291/evaluation-of-dose-area-product-of-common-radiographic-examinations-towards-establishing-a-preliminary-diagnostic-reference-levels-pdrls-in-southwestern-nigeria
#20
Nnamdi N Jibiri, Christopher J Olowookere
In Nigeria, a large number of radiographic examinations are conducted yearly for various diagnostic purposes. However, most examinations carried out do not have records of doses received by the patients, and the employed exposure parameters used are not documented; therefore, adequate radiation dose management is hindered. The aim of the present study was to estimate the dose-area product (DAP) of patients examined in Nigeria, and to propose regional reference dose levels for nine common examinations (chest PA, abdomen AP, pelvis AP, lumbar AP, skull AP, leg AP, knee AP, hand AP, and thigh AP) undertaken in Nigeria...
November 2016: Journal of Applied Clinical Medical Physics
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