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https://www.readbyqxmd.com/read/28070864/factors-that-affect-the-content-of-cadmium-nickel-copper-and-zinc-in-tissues-of-the-knee-joint
#1
Wojciech Roczniak, Barbara Brodziak-Dopierała, Elżbieta Cipora, Agata Jakóbik-Kolon, Joanna Kluczka, Magdalena Babuśka-Roczniak
Osteoarthritis causes the degradation of the articular cartilage and periarticular bones. Trace elements influence the growth, development and condition of the bone tissue. Changes to the mineral composition of the bone tissue can cause degenerative changes and fractures. The aim of the research was to determine the content of cadmium (Cd), nickel (Ni), copper (Cu) and zinc (Zn) in the tibia, the femur and the meniscus in men and women who underwent a knee replacement surgery. Samples were collected from 50 patients, including 36 women and 14 men...
January 9, 2017: Biological Trace Element Research
https://www.readbyqxmd.com/read/28060314/analysis-of-simian-immunodeficiency-virus-specific-cd8-t-cells-in-rhesus-macaques-by-peptide-mhc-i-tetramer-staining
#2
Lucas Gonzalez-Nieto, Aline Domingues, Michael Ricciardi, Martin J Gutman, Helen S Maxwell, Nuria Pedreño-Lopez, Varian Bailey, Diogo M Magnani, Mauricio A Martins
Peptide-major histocompatibility complex class I (pMHC-I) tetramers have been an invaluable tool to study CD8(+) T-cell responses. Because these reagents directly bind to T-cell receptors on the surface of CD8(+) T-lymphocytes, fluorochrome-labeled pMHC-I tetramers enable the accurate detection of antigen (Ag)-specific CD8(+) T-cells without the need for in vitro re-stimulation. Moreover, when combined with multi-color flow cytometry, pMHC-I tetramer staining can reveal key aspects of Ag-specific CD8(+) T-cells, including differentiation stage, memory phenotype, and activation status...
December 23, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28048921/su-f-j-127-multi-institutional-evaluation-of-setup-organ-deformation-precision-dosimetry-in-total-marrow-irradiation
#3
D Zuro, S Hui
PURPOSE: Totals Marrow Irradiation (TMI) is a highly focused radiation delivery to the human skeleton structure therefore requiring a high amount of precision and accuracy for a quality treatment. Not much is known on how the patient position varies across multiple treatment fractions and how that positioning impacts the dose delivery. Currently TMI is studied as an international collaboration with multiple centers around the world; however, many of these centers used different pretreatment techniques...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048909/su-f-p-36-automation-of-linear-accelerator-star-shot-measurement-with-advanced-xml-scripting-and-electronic-portal-imaging-device
#4
N Nguyen, N Knutson, M Schmidt, M Price
PURPOSE: To verify a method used to automatically acquire jaw, MLC, collimator and couch star shots for a Varian TrueBeam linear accelerator utilizing Developer Mode and an Electronic Portal Imaging Device (EPID). METHODS: An XML script was written to automate motion of the jaws, MLC, collimator and couch in TrueBeam Developer Mode (TBDM) to acquire star shot measurements. The XML script also dictates MV imaging parameters to facilitate automatic acquisition and recording of integrated EPID images...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048903/su-f-e-17-a-dedicated-teaching-and-research-linac-as-a-stepping-stone-to-introduce-medical-physics-to-students
#5
L Beaulieu, L Gingras, M Bergeron, L Archambault
PURPOSE: This work describes how a non-clinical, research and teaching Linac is used as an extremely motivating and exciting way to introduce students to medical physics. METHODS: The dedicated facility was inaugurated in 2014. The facility is composed of a fully equipped and functional state-of-the-art Varian TrueBeam Linac and a complete set of physics instruments and QA phantoms for the Linac and onboard imaging. The Linac bunker and treatment console are oversized such that a class of 12-15 can comfortably fit, seated if needed for longer sessions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048898/mo-fg-brc-03-design-and-construction-of-a-dielectiric-wall-accelerator
#6
D Westerly
Experimental research in medical physics has expanded the limits of our knowledge and provided novel imaging and therapy technologies for patients around the world. However, experimental efforts are challenging due to constraints in funding, space, time and other forms of institutional support. In this joint ESTRO-AAPM symposium, four exciting experimental projects from four different countries are highlighted. Each project is focused on a different aspect of radiation therapy. From the USA, we will hear about a new linear accelerator concept for more compact and efficient therapy devices...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048888/su-g-tep4-08-automating-the-verification-of-patient-treatment-parameters
#7
D DiCostanzo, A Ayan, J Woollard, N Gupta
PURPOSE: To automate the daily verification of each patient's treatment by utilizing the trajectory log files (TLs) written by the Varian TrueBeam linear accelerator while reducing the number of false positives including jaw and gantry positioning errors, that are displayed in the Treatment History tab of Varian's Chart QA module. METHODS: Small deviations in treatment parameters are difficult to detect in weekly chart checks, but may be significant in reducing delivery errors, and would be critical if detected daily...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048885/mo-d-brb-03-quality-assurance-of-sbrt
#8
J Roper
: Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048879/su-f-t-656-monte-carlo-study-on-air-activation-around-a-medical-electron-linac
#9
F Horst, G Fehrenbacher, K Zink
PURPOSE: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048864/su-f-j-41-experimental-validation-of-a-cascaded-linear-system-model-for-mvcbct-with-a-multi-layer-epid
#10
Y Hu, R Fueglistaller, J Rottmann, M Myronakis, A Wang, D Shedlock, D Morf, J Star-Lack, R Berbeco
PURPOSE: The purpose of this study was to validate the use of a cascaded linear system model for MV cone-beam CT (CBCT) using a multi-layer (MLI) electronic portal imaging device (EPID) and provide experimental insight into image formation. A validated 3D model provides insight into salient factors affecting reconstructed image quality, allowing potential for optimizing detector design for CBCT applications. METHODS: A cascaded linear system model was developed to investigate the potential improvement in reconstructed image quality for MV CBCT using an MLI EPID...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048860/su-f-p-54-guidelines-to-check-image-registration-qa-of-a-clinical-deformation-registration-software-a-single-institution-preliminary-study
#11
G Gill, S Souri, A Rea, Y Chen, J Antone, X Qian, A Riegel, P Taylor, M Marrero, F Diaz, Y Cao, A Jamshidi, S Barley, V Sorell, G Karangelis, T Button, E Klein
PURPOSE: The objective of this study is to verify and analyze the accuracy of a clinical deformable image registration (DIR) software. METHODS: To test clinical DIR software qualitatively and quantitatively, we focused on lung radiotherapy and analyzed a single (Lung) patient CT scan. Artificial anatomical changes were applied to account for daily variations during the course of treatment including the planning target volume (PTV) and organs at risk (OAR). The primary CT (pCT) and the structure set (pST) was deformed with commercial tool (ImSimQA-Oncology Systems Limited) and after artificial deformation (dCT and dST) sent to another commercial tool (VelocityAI-Varian Medical Systems)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048855/th-d-brb-01-scripting-fundamentals-killing-cancer-with-code
#12
R Popple
: Scripting capabilities and application programming interfaces (APIs) are becoming commonly available in modern treatment planning systems. These links to the treatment planning system (TPS) allow users to read data from the TPS, and in some cases use TPS functionality and write data back to the TPS. Such tools are powerful extensions, allowing automation of routine clinical tasks and supporting research, particularly research involving repetitive tasks on large patient populations. The data and functionality exposed by scripting/API capabilities is vendor dependent, as are the languages used by script/API engines, such as the Microsoft ...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048834/th-ef-bra-03-assessment-of-data-driven-respiratory-motion-compensation-methods-for-4d-cbct-image-registration-and-reconstruction-using-clinical-datasets
#13
M J Riblett, E Weiss, G E Christensen, G D Hugo
PURPOSE: To evaluate the performance of a 4D-CBCT registration and reconstruction method that corrects for respiratory motion and enhances image quality under clinically relevant conditions. METHODS: Building on previous work, which tested feasibility of a motion-compensation workflow using image datasets superior to clinical acquisitions, this study assesses workflow performance under clinical conditions in terms of image quality improvement. Evaluated workflows utilized a combination of groupwise deformable image registration (DIR) and image reconstruction...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048825/su-f-t-50-evaluation-of-monte-carlo-simulations-performance-for-pediatric-brachytherapy-dosimetry
#14
C Chatzipapas, P Papadimitroulas, G Loudos, N Papanikolaou, G Kagadis
PURPOSE: Pediatric tumors are generally treated with multi-modal procedures. Brachytherapy can be used with pediatric tumors, especially given that in this patient population low toxicity on normal tissues is critical as is the suppression of the probability for late malignancies. Our goal is to validate the GATE toolkit on realistic brachytherapy applications, and evaluate brachytherapy plans on pediatrics for accurate dosimetry on sensitive and critical organs of interest. METHODS: The GATE Monte Carlo (MC) toolkit was used...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048822/su-f-j-163-in-vivo-quantification-of-sequence-parameter-effect-on-geometric-distortion-caused-by-implanted-titanium-brachytherapy-applicator
#15
T Sullivan, A Diak, M Surucu, J Yacoub, M Harkenrider, S Shea
PURPOSE: The use of MR to plan and evaluate brachytherapy treatment for cervical cancer is increasing given the availability of MR conditional or safe applicators and MRI's proven superiority to CT for characterizing soft tissue lesions. The titanium applicators, however, cause geometric distortions or imaging artifacts, which reduce the utility of MRI for dosimetry. We sought to quantify the observed volume of the same applicator on a previously optimized T2 sequence in comparison to the conventional T2 sequence and CT obtained for brachytherapy planning...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048809/mo-d-brc-01-memorial-lecture
#16
B Fraass
Treatment planning is a central part of radiation therapy, including delineation in tumor volumes and critical organs, setting treatment goals of prescription doses to the tumor targets and tolerance doses to the critical organs, and finally generation of treatment plans to meet the treatment goals. National groups like RTOG have led the effort to standardize treatment goals of the prescription doses to the tumor targets and tolerance doses to the critical organs based on accumulated knowledge from decades of abundant clinical trial experience...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048803/su-f-t-152-experimental-validation-and-calculation-benchmark-for-a-commercial-monte-carlo-pencil-beamscanning-proton-therapy-treatment-planning-system-in-heterogeneous-media
#17
L Lin, S Huang, M Kang, C Ainsley, C Simone, J McDonough, T Solberg
PURPOSE: Eclipse AcurosPT 13.7, the first commercial Monte Carlo pencil beam scanning (PBS) proton therapy treatment planning system (TPS), was experimentally validated for an IBA dedicated PBS nozzle in the CIRS 002LFC thoracic phantom. METHODS: A two-stage procedure involving the use of TOPAS 1.3 simulations was performed. First, Geant4-based TOPAS simulations in this phantom were experimentally validated for single and multi-spot profiles at several depths for 100, 115, 150, 180, 210 and 225 MeV proton beams, using the combination of a Lynx scintillation detector and a MatriXXPT ionization chamber array...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048791/su-f-j-48-effect-of-scan-length-on-magnitude-of-imaging-dose-in-kv-cbct
#18
S Deshpande, D Dhote, S Naidu, A Sutar, V Kannan
PURPOSE: To study effect of scan length on magnitude of imaging dose deposition in Varian kV CBCT for head & neck and pelvis CBCT. METHODS: To study effect of scan length we measured imaging dose at depth of 8 cm for head and neck Cone Beam Computed Tomography (CBCT) acquisition (X ray beam energy is used 100kV and 200 degree of gantry rotation) and at 16 cm depth for pelvis CBCT acquisition (X ray beam energy used is 125 kV and 360 degree of gantry rotation) in specially designed phantom...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048786/mo-d-brc-04-multiple-criteria-optimization-planning
#19
J Donaghue
Treatment planning is a central part of radiation therapy, including delineation in tumor volumes and critical organs, setting treatment goals of prescription doses to the tumor targets and tolerance doses to the critical organs, and finally generation of treatment plans to meet the treatment goals. National groups like RTOG have led the effort to standardize treatment goals of the prescription doses to the tumor targets and tolerance doses to the critical organs based on accumulated knowledge from decades of abundant clinical trial experience...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048778/su-f-t-101-insight-into-dosimetry-workload-and-planning-timelines-a-6-year-review-at-one-institution
#20
R Cardan, R Popple, H Smith, J Fiveash
PURPOSE: To elucidate realistic clinical treatment planning workload and timelines to improve understanding for patients, payers, and other institutions involved in radiotherapy processes. METHODS: A web based tool was developed using Oracle Express (Oracle Corp, Redwood City, CA) which allowed communication between the physicians and staff about the current state of the patient plan. For 6 years, all patient courses were logged and time-stamped in 22 discreet steps which detailed start and stop times for simulation, contouring, and treatment planning tasks...
June 2016: Medical Physics
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