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Radiation physics

Gregory Peter Horne, Thomas Ashley Donoclift, Howard Sims, Robin Orr, Simon M Pimblott
A multi-scale modelling approach has been developed for the extended timescale long-term radiolysis of aqueous systems. The approach uses a combination of stochastic track structure and track chemistry as well as deterministic homogeneous chemistry techniques and involves four key stages; radiation track structure simulation, the subsequent physicochemical processes, nonhomogeneous diffusion-reaction kinetic evolution, and homogeneous bulk chemistry modelling. The first three components model the physical and chemical evolution of an isolated radiation chemical track and provide radiolysis yields, within the extremely low dose isolated track paradigm, as the input parameters for a bulk deterministic chemistry model...
October 25, 2016: Journal of Physical Chemistry. B
Imran Ullah, Krishnendu Bhattacharyya, Sharidan Shafie, Ilyas Khan
Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method...
2016: PloS One
Jasmin Nurković, Ivan Zaletel, Selmina Nurković, Šefćet Hajrović, Fahrudin Mustafić, Jovan Isma, Aleksandra Jurišić Škevin, Vesna Grbović, Milica Kovačević Filipović, Zana Dolićanin
In recent years, electromagnetic field (EMF) and low-level laser (LLL) have been found to affect various biological processes, the growth and proliferation of cells, and especially that of stem cells. The aim of this study was to investigate the effects of EMF and LLL on proliferation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and thus to examine the impact of these therapeutic physical modalities on stem cell engraftment. hAT-MSCs were isolated from subcutaneous adipose tissue of six persons ranging in age from 21 to 56 years...
October 21, 2016: Lasers in Medical Science
Antonella Conforti, Nadia Starc, Simone Biagini, Luigi Tomao, Angela Pitisci, Mattia Algeri, Pietro Sirleto, Antonio Novelli, Giulia Grisendi, Olivia Candini, Cintia Carella, Massimo Dominici, Franco Locatelli, Maria Ester Bernardo
The risk of malignant transformation of ex-vivo expanded human mesenchymal stromal cells (huMSCs) has been debated in the last years; however, the biosafety of these cells after exposure to supramaximal physical and chemical stress has never been systematically investigated.We established an experimental in vitro model to induce supramaximal physical (ionizing radiation, IR) and chemical (starvation) stress on ex-vivo expanded bone marrow (BM)-derived huMSCs and investigated their propensity to undergo malignant transformation...
October 15, 2016: Oncotarget
Uday B Maachani, Uma Shankavaram, Tamalee Kramp, Philip J Tofilon, Kevin Camphausen, Anita T Tandle
Glioblastoma multiforme (GBM) continues to be the most frequently diagnosed and lethal primary brain tumor. Adjuvant chemo-radiotherapy remains the standard of care following surgical resection. In this study, using reverse phase protein arrays (RPPAs), we assessed the biological effects of radiation on signaling pathways to identify potential radiosensitizing molecular targets. We identified subsets of proteins with clearly concordant/discordant behavior between irradiated and non-irradiated GBM cells in vitro and in vivo...
October 14, 2016: Oncotarget
C Grassberger, H Paganetti
The variety of treatment options for cancer patients has increased significantly in recent years. Not only do we combine radiation with surgery and chemotherapy, new therapeutic approaches such as immunotherapy and targeted therapies are starting to play a bigger role. Physics has made significant contributions to radiation therapy treatment planning and delivery. In particular, treatment plan optimization using inverse planning techniques has improved dose conformity considerably. Furthermore, medical physics is often the driving force behind tumor control and normal tissue complication modeling...
October 19, 2016: Physics in Medicine and Biology
Wei Yu, Wei Hu, Yongjie Shui, Xiaoyang Zhu, Chao Li, Xiaoqiu Ren, Xueli Bai, Risheng Yu, Li Shen, Tingbo Liang, Lei Zheng, Qichun Wei
OBJECTIVES: To explore the areas at highest risk for postoperative pancreatic cancer local recurrence according to the spatial location of local failures, with the aim to provide a precise target volume for pancreatic cancer adjuvant radiotherapy. METHODS: Patients with pancreatic cancer who had undergone surgery for the primary tumor in pancreas at our institution from January 2010 to August 2015 were retrospectively analyzed. All local recurrences were plotted on the computed tomography (CT) image of a representative patient according to their relative coordinates to superior mesenteric artery (SMA) or celiac axis (CA)...
October 19, 2016: Radiation Oncology
Ryan M Bright, Wiley Bogren, Pierre Bernier, Rasmus Astrup
Surface albedo is an important physical property by which the land surface regulates climate. A wide and growing body of literature suggests that failing to account for surface albedo can result in suboptimal or even counterproductive climate-motivated policies of the land-based sectors. As such, albedo changes are increasingly included in climate impact assessments of forestry and other land sector projects through conversion of radiative forcings into carbon or carbon dioxide equivalents. However, the prevailing methodology does not sufficiently accommodate dynamic albedo changes on land or CO2 in the atmosphere...
September 2016: Ecological Applications: a Publication of the Ecological Society of America
Irina N Vasilyeva, Valery N Zinkin, Vladimir G Bespalov
Exposure to either to low-frequency noise or ionizing radiation causes an increase in the number of chromosomal aberrations in the bone marrow cells and the level of low-molecular-weight DNA in the blood plasma of experimental animals. The dynamics of the content of low-molecular-weight DNA increasing after exposure to low-frequency noise and ionizing radiation differs significantly. Both exposures are able to provide a direct damaging effect on DNA.
2016: Advances in Experimental Medicine and Biology
Yukihisa Sanada, Tadashi Orita, Tatsuo Torii
Aerial radiological survey using an unmanned aerial vehicle (UAV) was applied to measurement surface contamination around the Fukushima Daiichi nuclear power station (FDNPS). An unmanned helicopter monitoring system (UHMS) was developed to survey the environmental effect of radioactive cesium scattered as a result of the FDNPS accident. The UHMS was used to monitor the area surrounding the FDNPS six times from 2012 to 2015. Quantitative changes in the radioactivity distribution trend were revealed from the results of these monitoring runs...
October 3, 2016: Applied Radiation and Isotopes
O Rapalino, E M Ratai
Magnetic resonance spectroscopy (MRS) is a magnetic resonance-based imaging modality that allows noninvasive sampling of metabolic changes in normal and abnormal brain parenchyma. MRS is particularly useful in the differentiation of developmental or non-neoplastic disorders from neoplastic processes. MRS is also useful during routine imaging follow-up after radiation treatment or during antiangiogenic treatment and for predicting outcomes and treatment response. The objective of this article is to provide a concise but thorough review of the basic physical principles, important applications of MRS in brain tumor imaging, and future directions...
November 2016: Magnetic Resonance Imaging Clinics of North America
A H Lopez Gonzales, J C Santos, L Mariano, A Tomal, P R Costa
Ambient dose equivalent H (*)(10) is an operational quantity recommended by the IAEA to establish dose constraints in area monitoring for external radiation. The direct measurement of H (*)(10) is not common due to the complexity in the calibration procedures of radiation monitors involving the use of expanded and aligned radiation fields. Therefore, conversion coefficients are used to assess H (*)(10) from the physical quantity air-kerma. Conversion coefficients published by international commissions, ICRU and ICRP, present a correlation with the radiation beam quality...
October 14, 2016: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
Balraj Singh, Jennifer M Treece, Ghulam Murtaza, Samit Bhatheja, Steven J Lavine, Timir K Paul
A young otherwise healthy 27-year-old male who has been using anabolic steroids for a long time developed Type I aortic dissection associated with heavy weightlifting. The patient did not have a recent history of trauma to the chest, no history of hypertension, and no illicit drug use. He presented with severe chest pain radiating to back and syncopal event with exertion. Initial vitals were significant for blood pressure of 80/50 mmHg, pulse of 80 beats per minute, respirations of 24 per minute, and oxygen saturation of 92% on room air...
2016: Case Reports in Cardiology
James Rafferty, Lance Farr, Tim James, David Chase, John Heinrich, Michael Brady
We present a novel, high-resolution magnetic resonance technique, fine structure analysis (FSA) for the quantification and analysis of amorphous and quasi-amorphous biological structures. The one-dimensional technique is introduced mathematically and then applied to one simulated phantom, two physical phantoms and a set of ex vivo biological samples, scanned with interpoint spacings of 0.0038-0.195 mm and cross-sectional sizes of 3 × 3 or 5 × 5 mm. The simulated phantom and one of the physical phantoms consists of randomly arranged beads of known size in two and three dimensions, respectively...
October 2016: Journal of the Royal Society, Interface
Amar U Kishan, Percy Lee
Non-small cell lung cancer (NSCLC) is the second most common solid malignancy in the United States of America, and the leading cause of cancer-related mortality. Nearly 15% of patients present with early-stage disease, for which the standard of care is lobectomy. However, the median age at diagnosis ranges from 65 to 74 years, and many patients have significant comorbidities that preclude surgical treatment. Previously, the standard of care for these patients was definitive radiotherapy (RT) with conventional fractionation (i...
October 2016: Seminars in Respiratory and Critical Care Medicine
Antony L Palmer, Michael Pearson, Paul Whittard, Katie E McHugh, David J Eaton
OBJECTIVES: To assess the status and practice of kilovoltage (kV) radiotherapy in the UK. METHODS: 96% of the radiotherapy centres in the UK responded to a comprehensive survey. An analysis of the installed equipment base, patient numbers, clinical treatment sites, quality control (QC) testing and radiation dosimetry processes were undertaken. RESULTS: 73% of UK centres have at least one kV treatment unit, with 58 units installed across the UK...
October 12, 2016: British Journal of Radiology
L Sim
The purpose of this study was to evaluate if MED610 3D printed material can be used as a surrogate for acrylic in the manufacturing of a replacement insert used in an eye plaque brachytherapy applicator. Measurement of the dose distributions from a standard acrylic insert were compared with dose obtained from MED610 3D printed replica using GafChromic(®) EBT3 films. The study used a 15 mm Radiation Oncology Physics and Engineering Services, Australia (ROPES) type eye plaque applicator loaded with I-125 (model 6711) seeds...
October 11, 2016: Australasian Physical & Engineering Sciences in Medicine
Minh Tam Truong, Qiang Zhang, David I Rosenthal, Marcie List, Rita Axelrod, Eric Sherman, Randal Weber, Phuc Felix Nguyen-Tân, Adel El-Naggar, André Konski, James Galvin, David Schwartz, Andy Trotti, Craig Silverman, Anurag Singh, Karen Godette, James A Bonner, Christopher U Jones, Adam S Garden, George Shenouda, Chance Matthiesen, Quynh-Thu Le, Deborah Bruner
PURPOSE: To analyze the quality of life (QOL) and performance status (PS) (secondary outcome) in patients with stage III to IV head and neck cancer (HNC) enrolled on a prospective randomized phase 3 trial comparing radiation-cisplatin without cetuximab (CIS) or with cetuximab (CET/CIS). The QOL hypothesis proposed a between-arm difference in Functional Assessment of Cancer Therapy-Head and Neck (FACT-HN) total score of ≥10% of the instrument range from baseline to 1 year. METHODS AND MATERIALS: Patients who gave consent to the QOL/PS study completed the FACT-HN, Performance Status Scale for HNC (PSS-HN), and EuroQol (EQ-5D) at baseline through to 5 years...
August 12, 2016: International Journal of Radiation Oncology, Biology, Physics
B Lembcke
Despite sophisticated physical examination and laboratory support, diagnosis of acute appendicitis remained challenging in clinical practice with a negative appendectomy rate of 15 - 30 %. As a remarkable clue and as early as 1986, ultrasonography (US) has been proven a reliable diagnostic method that is also explicitly helpful in difficult cases with atypical presentation and enables to rule out many differential diagnoses.Recent publications emphasized the role of multidetector computed tomography (CT) resulting in a significant reduction of false negative findings at operation...
October 2016: Zeitschrift Für Gastroenterologie
Xiao-Jing Song, Shu-You Wang, Yin-Long Li, Dong Zhang
The objective of this study was to investigate the spectra characteristics (SC) at wavelengths of 400~1000 nm and 2.5~15.5 μm of pure moxa stick (MS) during its 25-minute burning process using new spectral imaging techniques. Spectral images were collected for the burning pure MS at 5, 10, 15, 20, and 25 min using hyperspectral imaging (HSI) and Fourier transform infrared spectroscopy (FTIR) for the first time. The results showed that, at wavelengths of 400~1000 nm, the spectral range of the cross section of MS burning was 750~980 nm; the peak position was 860 nm...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
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