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Radiation physics

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https://www.readbyqxmd.com/read/29165619/comparison-of-response-of-passive-dosimetry-systems-in-scanning-proton-radiotherapy-a-study-using-paediatric-anthropomorphic-phantoms
#1
Ž Kneževic, I Ambrozova, C Domingo, M De Saint-Hubert, M Majer, I Martínez-Rovira, S Miljanic, N Mojzeszek, P Porwol, O Ploc, M Romero-Expósito, L Stolarczyk, S Trinkl, R M Harrison, P Olko
Proton beam therapy has advantages in comparison to conventional photon radiotherapy due to the physical properties of proton beams (e.g. sharp distal fall off, adjustable range and modulation). In proton therapy, there is the possibility of sparing healthy tissue close to the target volume. This is especially important when tumours are located next to critical organs and while treating cancer in paediatric patients. On the other hand, the interactions of protons with matter result in the production of secondary radiation, mostly neutrons and gamma radiation, which deposit their energy at a distance from the target...
November 18, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29164929/psychosis-as-a-sequelae-of-paraneoplastic-syndrome-in-small-cell-lung-carcinoma-a-psycho-neuroendocrine-interface
#2
Christiana M Wilkins, Victoria L Johnson, Rachel E Fargason, Badari Birur
In 2013 more than 150,000 Americans died from all types of lung cancer. Small cell lung cancer (SCLC) represents about 13% of all lung cancers and is notoriously associated with paraneoplastic syndromes (PNS). Here we present an interesting case of psychosis associated with one such PNS-- ectopic Cushing syndrome of SCLC. A 56 year old African-American male with no prior psychiatric history who was diagnosed with SCLC two months prior, presented to the ER for treatment of a right arm laceration he sustained while fighting off attackers, with high concern these individuals may have been part of hallucinatory experiences and well-systematized persecutory delusions regarding his wife...
November 22, 2017: Clinical Schizophrenia & related Psychoses
https://www.readbyqxmd.com/read/29164895/interlayer-coupling-and-gate-tunable-excitons-in-transition-metal-dichalcogenide-heterostructures
#3
Shiyuan Gao, Li Yang, Catalin D Spataru
Bilayer van der Waals (vdW) heterostructures such as MoS2/WS2 and MoSe2/WSe2 have attracted much attention recently, particularly because of their type II band alignments and the formation of interlayer exciton as the lowest-energy excitonic state. In this work, we calculate the electronic and optical properties of such heterostructures with the first-principles GW+Bethe-Salpeter Equation (BSE) method and reveal the important role of interlayer coupling in deciding the excited-state properties, including the band alignment and excitonic properties...
November 22, 2017: Nano Letters
https://www.readbyqxmd.com/read/29163402/pharmacological-induction-of-heme-oxygenase-1-impairs-nuclear-accumulation-of-herpes-simplex-virus-capsids-upon-infection
#4
Francisco J Ibáñez, Mónica A Farías, Angello Retamal-Díaz, Janyra A Espinoza, Alexis M Kalergis, Pablo A González
Heme oxygenase-1 (HO-1) is an inducible enzyme that is expressed in response to physical and chemical stresses, such as ultraviolet radiation, hyperthermia, hypoxia, reactive oxygen species (ROS), as well as cytokines, among others. Its activity can be positively modulated by cobalt protoporphyrin (CoPP) and negatively by tin protoporphirin (SnPP). Once induced, HO-1 degrades iron-containing heme into ferrous iron (Fe(2+)), carbon monoxide (CO) and biliverdin. Importantly, numerous products of HO-1 are cytoprotective with anti-apoptotic, anti-oxidant, anti-inflammatory, and anti-cancer effects...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29160902/proportion-and-number-of-cancer-cases-and-deaths-attributable-to-potentially-modifiable-risk-factors-in-the-united-states
#5
Farhad Islami, Ann Goding Sauer, Kimberly D Miller, Rebecca L Siegel, Stacey A Fedewa, Eric J Jacobs, Marjorie L McCullough, Alpa V Patel, Jiemin Ma, Isabelle Soerjomataram, W Dana Flanders, Otis W Brawley, Susan M Gapstur, Ahmedin Jemal
Contemporary information on the fraction of cancers that potentially could be prevented is useful for priority setting in cancer prevention and control. Herein, the authors estimate the proportion and number of invasive cancer cases and deaths, overall (excluding nonmelanoma skin cancers) and for 26 cancer types, in adults aged 30 years and older in the United States in 2014, that were attributable to major, potentially modifiable exposures (cigarette smoking; secondhand smoke; excess body weight; alcohol intake; consumption of red and processed meat; low consumption of fruits/vegetables, dietary fiber, and dietary calcium; physical inactivity; ultraviolet radiation; and 6 cancer-associated infections)...
November 21, 2017: CA: a Cancer Journal for Clinicians
https://www.readbyqxmd.com/read/29159978/ahns-series-do-you-know-your-guidelines-guideline-recommendations-for-head-and-neck-cancer-of-unknown-primary-site
#6
Antoine Eskander, Tamer Ghanem, Amit Agrawal
This article reviews the clinical practice guidelines for head and neck oncology focusing on the management of head and neck cancers of unknown primary (CUP). The primary purpose of this series is to raise awareness of the current guidelines in head and neck oncology by reviewing the recommendations and the evidence supporting such recommendations, particularly those published by the National Comprehensive Cancer Network (NCCN). We review the importance of a thorough history and physical examination, the impact of the American Joint Committee on Cancer (AJCC) eighth edition changes and the importance of immunohistochemistry, the timing and type of imaging, the role of panendoscopy and tonsillectomy (palatine and lingual), and the role of surgery, radiation, and chemotherapy in the primary management of these tumors...
November 21, 2017: Head & Neck
https://www.readbyqxmd.com/read/29158835/theranostic-role-of-32-p-atp-as-radiopharmaceutical-for-the-induction-of-massive-cell-death-within-avascular-tumor-core
#7
Mirco Galiè, Federico Boschi, Ilaria Scambi, Flavia Merigo, Pasquina Marzola, Luisa Altabella, Umberto Lavagnolo, Andrea Sbarbati, Antonello E Spinelli
Drug inaccessibility to vast areas of the tumor parenchyma is amongst the major hurdles for conventional therapies. Treatment efficacy rapidly decreases with distance from vessels and most of the tumor cells survive therapy. Also, between subsequent cycles of treatment, spared cancer cells replace those killed near the vessels, improving their access to nutrients, boosting their proliferation rate, and thus enabling tumor repopulation. Because of their property of "acting at a distance," radioisotopes are believed to overcome the physical barrier of vascular inaccessibility...
2017: Theranostics
https://www.readbyqxmd.com/read/29158832/clinical-translation-and-first-in-human-use-of-44-sc-sc-psma-617-for-pet-imaging-of-metastasized-castrate-resistant-prostate-cancer
#8
Elisabeth Eppard, Ana de la Fuente, Martina Benešová, Ambreen Khawar, Ralph A Bundschuh, Florian C Gärtner, Barbara Kreppel, Klaus Kopka, Markus Essler, Frank Rösch
BACKGROUND: Various trivalent radiometals are well suited for labeling of DOTA-conjugated variants of Glu-ureido-based prostate-specific membrane antigen (PSMA) inhibitors. The DOTA-conjugate PSMA-617 has proven high potential in PSMA radioligand therapy (PSMA-RLT) of prostate cancer as well as PET imaging when labeled with lutetium-177 and gallium-68 respectively. Considering the relatively short physical half-life of gallium-68 this positron emitter precludes prolonged acquisition periods, as required for pre-therapeutic dosimetry or intraoperative applications...
2017: Theranostics
https://www.readbyqxmd.com/read/29157854/pet-and-single-photon-emission-computed-tomography-in-brain-concussion
#9
REVIEW
Cyrus A Raji, Theodore A Henderson
This article offers an overview of the application of PET and single photon emission computed tomography brain imaging to concussion, a type of mild traumatic brain injury and traumatic brain injury, in general. The article reviews the application of these neuronuclear imaging modalities in cross-sectional and longitudinal studies. Additionally, this article frames the current literature with an overview of the basic physics and radiation exposure risks of each modality.
February 2018: Neuroimaging Clinics of North America
https://www.readbyqxmd.com/read/29157155/work-environment-and-occupational-risk-assessment-for-small-animal-portuguese-veterinary-activities
#10
Angela C Macedo, Vânia T Mota, João M Tavares, Osvaldo L Machado, Francisco X Malcata, Marinela P Cristo, Olga N Mayan
The professional work of small animal veterinary staff encompasses a wide diversity of demanding tasks. This has prompted a number of studies covering physical, chemical, biological, ergonomic or psychological hazards, as well as their health effects upon veterinary workers. However, such results were obtained from self-reported surveys (via paper or online). This study reports the identification of potential hazards and provides a risk assessment of 15 veterinary clinics based on data from walk-through surveys, interviews with workers, and quantification of indoor air quality parameters including concentration of volatile organic compounds (total, isoflurane and glutaraldehyde)...
November 20, 2017: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/29156218/use-of-luminescent-gunshot-residues-markers-in-forensic-context-part-ii
#11
A M Arouca, M A M Lucena, R J Rossiter, M Talhavini, I T Weber
Gunshot residues (GSR) are important physical evidence in firearm-related crimes. Recently developed non-toxic ammunition, however, requires a new methodology for its characterization. To overcome this drawback, the introduction of noncommercial luminescent markers in ammunition was proposed. These markers, synthesized and added to the gunpowder, presented as a versatile tool for GSR analysis, since they require UV radiation alone to visualize the luminescent GSR (LGSR). This has opened up new perspectives for understanding GSR behavior at a crime scene...
November 6, 2017: Forensic Science International
https://www.readbyqxmd.com/read/29155794/an-array-based-comparative-genomic-hybridization-platform-for-efficient-detection-of-copy-number-variations-in-fast-neutron-induced-medicago-truncatula-mutants
#12
Yuhui Chen, Xianfu Wang, Shunfei Lu, Hongcheng Wang, Shibo Li, Rujin Chen
Mutants are invaluable genetic resources for gene function studies. To generate mutant collections, three types of mutagens can be utilized, including biological such as T-DNA or transposon, chemical such as ethyl methanesulfonate (EMS), or physical such as ionization radiation. The type of mutation observed varies depending on the mutagen used. For ionization radiation induced mutants, mutations include deletion, duplication, or rearrangement. While T-DNA or transposon-based mutagenesis is limited to species that are susceptible to transformation, chemical or physical mutagenesis can be applied to a broad range of species...
November 8, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29150160/medical-physics-in-radiation-oncology-new-challenges-needs-and-roles
#13
EDITORIAL
Dietmar Georg, David Thwaites
No abstract text is available yet for this article.
November 14, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29150143/life-after-endometrial-cancer-a-systematic-review-of-patient-reported-outcomes
#14
Robert Shisler, Jennifer A Sinnott, Vivian Wang, Courtney Hebert, Ritu Salani, Ashley S Felix
BACKGROUND: Women with endometrial cancer (EC) are the second largest population of female cancer survivors in the United States. However, the outcomes of EC survivors, from the patient perspective, are not well-understood. Therefore, we conducted a systematic review of patient-reported outcomes (PROs) following an EC diagnosis. METHODS: We searched MEDLINE, EMBASE, Scopus, CINAHL, and reference lists to identify published observational studies that examined PROs among women with EC...
November 14, 2017: Gynecologic Oncology
https://www.readbyqxmd.com/read/29149412/the-translationally-controlled-tumor-protein-and-the-cellular-response-to-ionizing-radiation-induced-dna-damage
#15
Jie Zhang, Grace Shim, Sonia M de Toledo, Edouard I Azzam
The absorption of ionizing radiation by living cells can directly disrupt atomic structures, producing chemical and biological changes. It can also act indirectly through radiolysis of water, thereby generating reactive chemical species that may damage nucleic acids, proteins, and lipids. Together, the direct and indirect effects of radiation initiate a series of biochemical and molecular signaling events that may repair the damage or culminate in permanent physiological changes or cell death. In efforts to gain insight into the mechanisms underlying these effects, we observed a prominent upregulation of the Translationally Controlled Tumor Protein (TCTP) in low dose/low dose rate (137)Cs γ-irradiated cells that was associated with adaptive responses that reduced chromosomal damage to a level lower than what occurs spontaneously...
2017: Results and Problems in Cell Differentiation
https://www.readbyqxmd.com/read/29149393/challenges-in-minor-tbi-and-indications-for-head-ct-in-pediatric-tbi-an-update
#16
Navneet Singh, Ash Singhal
INTRODUCTION: Pediatric head trauma is one of the commonest presentations to emergency departments. Over 90% of such head injuries are considered mild, but still present risk acute clinical deterioration and longer term morbidity. Identifying which children are at risk of clinically important brain injuries remains challenging and much of the data on minor head injuries is based on the adult population. CHALLENGES IN PEDIATRICS: Children, however, are different, both anatomically and in terms of mechanism of injury, to adults and, even within the pediatric group, there are differences with age and stage of development...
October 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
https://www.readbyqxmd.com/read/29148717/raman-spectroscopy-of-single-light-absorbing-carbonaceous-particles-levitated-in-air-using-an-annular-laser-beam
#17
Masaru Uraoka, Keisuke Maegawa, Shoji Ishizaka
A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a noncontact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve noncontact levitation of single light-absorbing particles in air...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29148554/modelling-direct-dna-damage-for-gold-nanoparticle-enhanced-proton-therapy
#18
Marios Sotiropoulos, Nicholas T Henthorn, John W Warmenhoven, Ranald I Mackay, Karen J Kirkby, Michael J Merchant
Gold nanoparticles have been proven as potential radiosensitizer when combined with protons. Initially the radiosensitization effect was attributed to the physical interactions of radiation with the gold and the production of secondary electrons that induce DNA damage. However, emerging data challenge this hypothesis, supporting the existence of alternative or supplementary radiosensitization mechanisms. In this work we incorporate a realistic cell model with detailed DNA geometry and a realistic gold nanoparticle biodistribution based on experimental data...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29146904/backward-cherenkov-radiation-emitted-by-polariton-solitons-in-a-microcavity-wire
#19
D V Skryabin, Y V Kartashov, O A Egorov, M Sich, J K Chana, L E Tapia Rodriguez, P M Walker, E Clarke, B Royall, M S Skolnick, D N Krizhanovskii
Exciton-polaritons in semiconductor microcavities form a highly nonlinear platform to study a variety of effects interfacing optical, condensed matter, quantum and statistical physics. We show that the complex polariton patterns generated by picosecond pulses in microcavity wire waveguides can be understood as the Cherenkov radiation emitted by bright polariton solitons, which is enabled by the unique microcavity polariton dispersion, which has momentum intervals with positive and negative group velocities...
November 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/29145033/is-chronic-postsurgical-pain-surgery-induced-a-study-of-persistent-postoperative-pain-following-breast-reconstruction
#20
Randy S Roth, Ji Qi, Jennifer B Hamill, Hyungjin M Kim, Tiffany N S Ballard, Andrea L Pusic, Edwin G Wilkins
BACKGROUND: Chronic postsurgical pain (CPSP) is a reported risk for women undergoing breast reconstruction, but it remains unclear that such persistent pain is induced by reconstructive surgery. To address this concern, this prospective cohort study examined the prevalence of and risk factors associated with CPSP among women undergoing breast reconstruction. MATERIALS AND METHODS: Women (n = 1996) recruited for the Mastectomy Reconstruction Outcomes Consortium (MROC) Study were assessed preoperatively and at two-years postoperatively for relevant medical/...
November 13, 2017: Breast: Official Journal of the European Society of Mastology
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