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Radiation dose measurements

Sang Woo Park, Jaehoon Choi, Junhyung Kim, Woohhyeok Jeong, Jun Sik Kim, Bae Kwon Jeong, Sung Chul Shin, Jin Hee Kim
The aim of this study was to evaluate the protective effects of anthocyanins from the black soybean seed coat against radiation injury in dermal fibroblasts and mouse skin. Dermal fibroblasts treated with 50 and 100 µg/mL anthocyanins were irradiated with single doses of 20 Gy. Cell viability, intracellular reactive oxygen species (ROS) production, and mRNA expression were measured. A total of 60 mice were used for an in vivo study. A dose of 100 µg/mL anthocyanins was administered daily for 5 days before or after radiation therapy...
March 19, 2018: Archives of Dermatological Research
Ji-Bin Zhang, Li-Rong Zhao, Tian-Xiang Cui, Xie-Wan Chen, Qiao Yang, Yi-Bing Zhou, Zheng-Tang Chen, Shao-Xiang Zhang, Jian-Guo Sun
The aim of the present study was to investigate the optimal strategy and dosimetric measurement of thoracic radiotherapy based on three-dimensional (3D) modeling of mediastinal lymph nodes (MLNs). A 3D model of MLNs was constructed from a Chinese Visible Human female dataset. Image registration and fusion between reconstructed MLNs and original chest computed tomography (CT) images was conducted in the Eclipse™ treatment planning system (TPS). There were three plans, including 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), which were designed based on 10 cases of simulated lung lesions (SLLs) and MLNs...
April 2018: Oncology Letters
Tridip Phukan, Amar Nath Rai, Mayashree B Syiem
With the intention of getting an insight into the differential effect of UV-C radiation on the N2 -fixing heterocystous cyanobacterium Nostoc muscorum Meg1, various aspects of carbon and nitrogen metabolism was evaluated in the organism. Exposure to different doses of UV-C (6, 12, 18 and 24 mJ/cm2 ) showed that among various photo-absorbing pigments, phycobiliproteins were most sensitive. Oxygen evolving complex (OEC) activity measured as net oxygen evolution rate decreased by 63% upon 24 mJ/cm2 exposure...
July 15, 2018: Ecotoxicology and Environmental Safety
Katrine Munk Begtrup, Johanne Andersen Hojbjerg, Birgitte Vrou Offersen, Anne-Mette Hvas
Cancer is associated with increased risk of venous thromboembolic disease. Venous thromboembolic disease accounts for a substantial addition to morbidity and mortality rates in cancer patients and is the second leading cause of death in cancer patients, exceeded only by the underlying cancer. Only few previous studies have investigated the influence of radiotherapy on hemostasis and whether radiotherapy in itself causes an increased risk of venous thromboembolic disease. The aim was to investigate if adjuvant radiotherapy affects hemostasis after surgery and chemotherapy in patients with breast cancer...
March 19, 2018: Platelets
Karl A Hujsak, Eric W Roth, William Kellogg, Yue Li, Vinayak P Dravid
Technological advances in electron microscopy, particularly improved detectors and aberration correctors, have led to higher throughput and less invasive imaging of materials and biological structures by enhancing signal-to-noise ratios at lower electron exposures. Analytical methods, such as electron energy loss spectroscopy (EELS) and energy dispersive x-ray spectrometry (EDS), have also benefitted and offer a rich set of local elemental and bonding information with nano-or atomic resolution. However, spatially resolved spectrum imaging with EELS and EDS continue to be difficult to scale due to limited detector collection angles or high signal background, requiring hours or even days for full maps...
March 10, 2018: Micron: the International Research and Review Journal for Microscopy
Mel O'Leary, Daria Boscolo, Nicole Breslin, Jeremy M C Brown, Igor P Dolbnya, Chris Emerson, Catarina Figueira, Oliver J L Fox, David Robert Grimes, Vladimir Ivosev, Annette K Kleppe, Aaron McCulloch, Ian Pape, Chris Polin, Nathan Wardlow, Fred J Currell
Absolute measurements of the radiolytic yield of Fe3+ in a ferrous sulphate dosimeter formulation (6 mM Fe2+), with a 20 keV x-ray monoenergetic beam, are reported. Dose-rate suppression of the radiolytic yield was observed at dose rates lower than and different in nature to those previously reported with x-rays. We present evidence that this effect is most likely to be due to recombination of free radicals radiolytically produced from water. The method used to make these measurements is also new and it provides radiolytic yields which are directly traceable to the SI standards system...
March 16, 2018: Scientific Reports
Kurtis H Dekker, Rubin Hazarika, Matheus A Silveira, Kevin J Jordan
Optical cone beam computed tomography (CT) scanning of radiochromic gel dosimeters, using a CCD camera and a low stray light convergent source, provides fast, truly 3D radiation dosimetry with high accuracy. However, a key limiting factor in radiochromic gel dosimetry at large (⩾10 cm diameter) volumes is the initial attenuation of the dosimeters. It is not unusual to observe a 5-10×  difference in signal intensity through the dosimeter center versus through the surrounding medium in pre-irradiation images...
March 16, 2018: Physics in Medicine and Biology
Margarita Braunagel, Florian Ortner, Ulf Schönermarck, Antje Habicht, Andreas Schindler, Manfred Stangl, Frederik F Strobl, Maximilian Reiser, Dirk A Clevert, Christoph Trumm, Andreas Helck
RATIONALE AND OBJECTIVE: The objective of this study was to assess an optimized renal multiphase computed tomography angiography (MP-CTA) protocol regarding reduction of contrast volume. MATERIALS AND METHODS: Thirty patients underwent MP-CTA (12 phases, every 3.5 seconds, 80 kV/120 mAs) using 30 mL of contrast medium. The quality of MP-CTA was assessed quantitatively measuring vessel attenuation, image noise, and contrast-to-noise ratio. MP-CTA was evaluated qualitatively regarding depiction of vessels, cortex differentiation, and motion artifacts (grades 1-4, 1 = best)...
March 12, 2018: Academic Radiology
Melissa L Kirkwood, Gary M Arbique, Jeffrey B Guild, Katie Zeng, Yin Xi, John Rectenwald, Jon A Anderson, Carlos Timaran
OBJECTIVE: Radiation to the interventionalist's brain during fluoroscopically guided interventions (FGIs) may increase the incidence of cerebral neoplasms. Lead equivalent surgical caps claim to reduce radiation brain doses by 50% to 95%. We sought to determine the efficacy of the RADPAD (Worldwide Innovations & Technologies, Lenexa, Kan) No Brainer surgical cap (0.06 mm lead equivalent at 90 kVp) in reducing radiation dose to the surgeon's and trainee's head during FGIs and to a phantom to determine relative brain dose reductions...
March 12, 2018: Journal of Vascular Surgery
James A Crowhurst, Gregory M Scalia, Mark Whitby, Dale Murdoch, Brendan J Robinson, Arianwen Turner, Liesie Johnston, Swaroop Margale, Sarvesh Natani, Andrew Clarke, Darryl J Burstow, Owen C Raffel, Darren L Walters
BACKGROUND: Transesophageal echocardiography operators (TEEOP) provide critical imaging support for percutaneous structural cardiac intervention procedures. They stand close to the patient and the associated scattered radiation. OBJECTIVES: This study sought to investigate TEEOP radiation dose during percutaneous structural cardiac intervention. METHODS: Key personnel (TEEOP, anesthetist, primary operator [OP1], and secondary operator) wore instantly downloadable personal dosimeters during procedures requiring TEE support...
March 20, 2018: Journal of the American College of Cardiology
Wen-Zhao Sun, Dan-Dan Zhang, Ying-Lin Peng, Li Chen, De-Hua Kang, Bin Wang, Xiao-Wu Deng
BACKGROUND: Conventional phantom-based planar dosimetry (2D-PBD) quality assurance (QA) using gamma pass rate (GP (%)) is inadequate to reflect clinically relevant dose error in intensity-modulated radiation therapy (IMRT), owing to a lack of information regarding patient anatomy and volumetric dose distribution. This study aimed to evaluate the dose distribution accuracy of IMRT delivery for nasopharyngeal carcinoma (NPC), which passed the 2D-PBD verification, using a measurement-guided 3D dose reconstruction (3D-MGR) method...
March 15, 2018: Radiation Oncology
Jeff M Michalski, Jennifer Moughan, James Purdy, Walter Bosch, Deborah W Bruner, Jean-Paul Bahary, Harold Lau, Marie Duclos, Matthew Parliament, Gerard Morton, Daniel Hamstra, Michael Seider, Michael I Lock, Malti Patel, Hiram Gay, Eric Vigneault, Kathryn Winter, Howard Sandler
Importance: Optimizing radiation therapy techniques for localized prostate cancer can affect patient outcomes. Dose escalation improves biochemical control, but no prior trials were powered to detect overall survival (OS) differences. Objective: To determine whether radiation dose escalation to 79.2 Gy compared with 70.2 Gy would improve OS and other outcomes in prostate cancer. Design, Setting, and Participants: The NRG Oncology/RTOG 0126 randomized clinical trial randomized 1532 patients from 104 North American Radiation Therapy Oncology Group institutions March 2002 through August 2008...
March 15, 2018: JAMA Oncology
Ajay Kumar, Sumit Sharma, Rohit Mehra, Saurabh Narang, Rosaline Mishra
Background The inhalation doses resulting from the exposure to radon, thoron, and their progeny are important quantities in estimating the radiation risk for epidemiological studies as the average global annual effective dose due to radon and its progeny is 1.3 mSv as compared to that of 2.4 mSv due to all other natural sources of ionizing radiation. Objectives The annual inhalation dose has been assessed with an aim of investigating the health risk to the inhabitants of the studied region. Methods Time integrated deposition based222 Rn/220 Rn sensors have been used to measure concentrations in 146 dwellings of Udhampur district, Jammu and Kashmir...
March 15, 2018: International Journal of Occupational and Environmental Health
Nathan Cho, Panagiotis Tsiamas, Esteban Velarde, Erik Tryggestad, Robert Jacques, Ross Berbeco, Todd McNutt, Peter Kazanzides, John Wong
PURPOSE: The Small Animal Radiation Research Platform (SARRP) has been developed for conformal micro irradiation with on-board cone-beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS) for SARRP. This paper describes the validation of the SC method for the kilovoltage energy by comparing with EBT2 film measurements and Monte Carlo (MC) simulations...
March 15, 2018: Medical Physics
Nazmi Narin, Ozge Pamukcu, Aydin Tuncay, Ali Baykan, Suleyman Sunkak, Onur Tasci, Kazim Uzum, Levent Saltık
Untreated ventricular septal defect (VSD) is an important cause of congestive heart failure in early infancy. Growth is impaired in this population, and surgical closure is challenging because of congestion in the lungs, making infants prone to respiratory infection, and because of their poor nutritional status. The aim of this study is to share our experience with percutaneous VSD closure in patients under 1 year of age. Patients with hemodynamically significant left-to-right shunt, less than 1 year of age, and with VSD diameter ≤ 6 mm were retrospectively included in the study between December 2014 and January 2017...
March 15, 2018: Pediatric Cardiology
Yan Wu, Yaojun Jiang, Xueli Han, Mingyue Wang, Jianbo Gao
Background: To investigate the repeatability and accuracy of quantitative CT (QCT) measurement of bone mineral density (BMD) by low-mAs using iterative model reconstruction (IMR) technique based on phantom model. Methods: European spine phantom (ESP) was selected and measured on the Philips Brilliance iCT Elite FHD machine for 10 times. Data were transmitted to the QCT PRO workstation to measure BMD (mg/cm3 ) of the ESP (L1, L2, L3). Scanning method: the voltage of X-ray tube is 120 kV, the electric current of X-ray tube output in five respective groups A-E were: 20, 30, 40, 50 and 60 mAs...
February 2018: Quantitative Imaging in Medicine and Surgery
James R Kerns, David Followill, Jessica Lowenstein, Andrea Molineu, Paola Alvarez, Paige A Taylor, Stephen F Kry
PURPOSE: Reference dosimetry data can provide an independent second check of acquired values when commissioning or validating a treatment planning system (TPS). The Imaging and Radiation Oncology Core at Houston (IROC-Houston) has measured numerous linear accelerators throughout its existence. The results of those measurements are given here, comparing accelerators and the agreement of measurement versus institutional TPS calculations. METHODS: Data from IROC-Houston on-site reviews from 2000 through 2014 were analyzed for all Elekta accelerators, approximately 50...
March 14, 2018: Medical Physics
David M Edmunds, Lone Gothard, Komel Khabra, Anna Kirby, Poonam Madhale, Helen McNair, David Roberts, K K Tang, Richard Symonds-Tayler, Fatemeh Tahavori, Kevin Wells, Ellen Donovan
Voluntary inspiration breath hold (VIBH) for left breast cancer patients has been shown to be a safe and effective method of reducing radiation dose to the heart. Currently, VIBH protocol compliance is monitored visually. In this work, we establish whether it is possible to gate the delivery of radiation from an Elekta linac using the Microsoft Kinect version 2 (Kinect v2) depth sensor to measure a patient breathing signal. This would allow contactless monitoring during VMAT treatment, as an alternative to equipment-assisted methods such as active breathing control (ABC)...
March 13, 2018: Journal of Applied Clinical Medical Physics
Amir Pourmorteza, Noemie Keller, Richard Chen, Albert Lardo, Henry Halperin, Marcus Y Chen, Elliot McVeigh
Resting regional wall motion abnormality (RWMA) has significant prognostic value beyond the findings of computed tomography (CT) coronary angiography. Stretch quantification of endocardial engraved zones (SQUEEZ) has been proposed as a measure of regional cardiac function. The purpose of the work reported here was to determine the effect of lowering the radiation dose on the precision of automatic SQUEEZ assessments of RWMA. Chronic myocardial infarction was created by a 2-h occlusion of the left anterior descending coronary artery in 10 swine (heart rates 80-100, ejection fraction 25-57%)...
March 13, 2018: International Journal of Cardiovascular Imaging
Vladica Stevanović, Ljiljana Gulan, Biljana Milenković, Aleksandar Valjarević, Tijana Zeremski, Ivana Penjišević
Activity levels of natural and artificial radionuclides and content of ten heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and Hg) were investigated in 41 soil samples collected from Toplica region located in the south part of Serbia. Radioactivity was determined by gamma spectrometry using HPGe detector. The obtained mean activity concentrations ± standard deviations of radionuclides226 Ra,232 Th,40 K and137 Cs were 29.9 ± 9.4, 36.6 ± 11.5, 492 ± 181 and 13.4 ± 18.7 Bq kg-1 , respectively...
March 13, 2018: Environmental Geochemistry and Health
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