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Liver rotation

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https://www.readbyqxmd.com/read/28303395/movement-of-steel-jacketed-projectiles-in-biological-tissue-in-the-magnetic-field-of-a-3-t-magnetic-resonance-unit
#1
Stephan A Bolliger, Michael J Thali, Dominic Gascho, Sebastian A Poschmann, Sebastian Eggert
PURPOSE: The fact that ferromagnetic bullets can move in air or gelatine when subjected to magnetic resonance (MR) units is well known. A previous study showed that the movement of 7.5-mm GP 11 Suisse bullets also depends on their orientation toward the gantry. In order to compare the movement in gelatine to that in real tissue, we decided to measure the movement of these bullets, as well as 9-mm Luger bullets, in the brain and liver. METHODS: The GP 11 and 9-mm Luger bullets were inserted into the fresh calf brain or pig liver either vertically or horizontally in the x- or z-axis to the gantry...
March 16, 2017: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/28297461/clinical-experience-with-planning-quality-assurance-and-delivery-of-burst-mode-modulated-arc-therapy
#2
Kristofer Kainz, Douglas Prah, Ergun Ahunbay, X Allen Li
"Burst-mode" modulated arc therapy (hereafter referred to as "mARC") is a form of volumetric-modulated arc therapy characterized by variable gantry rotation speed, static MLCs while the radiation beam is on, and MLC repositioning while the beam is off. We present our clinical experience with the planning techniques and plan quality assurance measurements of mARC delivery. Clinical mARC plans for five representative cases (prostate, low-dose-rate brain, brain with partial-arc vertex fields, pancreas, and liver SBRT) were generated using a Monte Carlo-based treatment planning system...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28244421/dosimetric-implications-of-residual-tracking-errors-during-robotic-sbrt-of-liver-metastases
#3
Mark Chan, Melanie Grehn, Florian Cremers, Frank-Andre Siebert, Stefan Wurster, Stefan Huttenlocher, Jürgen Dunst, Guido Hildebrandt, Achim Schweikard, Dirk Rades, Floris Ernst, Oliver Blanck
PURPOSE: Although the metric precision of robotic stereotactic body radiation therapy in the presence of breathing motion is widely known, we investigated the dosimetric implications of breathing phase-related residual tracking errors. METHODS AND MATERIALS: In 24 patients (28 liver metastases) treated with the CyberKnife, we recorded the residual correlation, prediction, and rotational tracking errors from 90 fractions and binned them into 10 breathing phases. The average breathing phase errors were used to shift and rotate the clinical tumor volume (CTV) and planning target volume (PTV) for each phase to calculate a pseudo 4-dimensional error dose distribution for comparison with the original planned dose distribution...
March 15, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28216331/development-of-a-four-dimensional-monte-carlo-dose-calculation-system-for-real-time-tumor-tracking-irradiation-with-a-gimbaled-x-ray-head
#4
Yoshitomo Ishihara, Mitsuhiro Nakamura, Yuki Miyabe, Nobutaka Mukumoto, Yukinori Matsuo, Akira Sawada, Masaki Kokubo, Takashi Mizowaki, Masahiro Hiraoka
PURPOSE: To develop a four-dimensional (4D) dose calculation system for real-time tumor tracking (RTTT) irradiation by the Vero4DRT. METHODS: First, a 6-MV photon beam delivered by the Vero4DRT was simulated using EGSnrc. A moving phantom position was directly measured by a laser displacement gauge. The pan and tilt angles, monitor units, and the indexing time indicating the phantom position were also extracted from a log file. Next, phase space data at any angle were created from both the log file and particle data under the dynamic multileaf collimator...
February 16, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28177366/cobalt-supplementation-alone-or-in-combination-with-vitamin-b-and-selenium-effects-on-lamb-performance-and-mineral-status
#5
T W J Keady, J P Hanrahan, S P Fagan
The effects of supplementing lambs with Co, either alone or in combination with vitamin B and Se, were evaluated over the period from weaning to selection for slaughter. Two hundred and five recently weaned (at 14 wk [SD 0.44] of age), spring-born lambs of various crossbred genotypes were stratified, within genotype, by BW and gender and allocated to 3 groups, which were then allocated at random to one of the following treatments: no supplement (Control), a supplement containing Co only (Co-only), or a supplement containing Co, vitamin B, and Se (VitMin)...
January 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28149924/deformable-image-registration-for-tissues-with-large-displacements
#6
Xishi Huang, Jing Ren, Anwar Abdalbari, Mark Green
Image registration for internal organs and soft tissues is considered extremely challenging due to organ shifts and tissue deformation caused by patients' movements such as respiration and repositioning. In our previous work, we proposed a fast registration method for deformable tissues with small rotations. We extend our method to deformable registration of soft tissues with large displacements. We analyzed the deformation field of the liver by decomposing the deformation into shift, rotation, and pure deformation components and concluded that in many clinical cases, the liver deformation contains large rotations and small deformations...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28133947/serious-gaming-for-orthotopic-liver-transplant-anesthesiology-a-randomized-control-trial
#7
Daniel Katz, Jeron Zerillo, Sang Kim, Bryan Hill, Ryan Wang, Andrew Goldberg, Samuel DeMaria
Anesthetic management of orthotopic liver transplantation (OLT) is complex. Given the unequal distributions of liver transplant surgeries performed at different centers, anesthesiology providers receive relatively uneven OLT training and exposure. One well-suited modality for OLT training is the "serious game," an interactive application created for the purpose of imparting knowledge or skills, while leveraging the self-motivating elements of video games. We therefore developed a serious game designed to teach best practices for the anesthetic management of a standard OLT and determined if the game would improve resident performance in a simulated OLT...
April 2017: Liver Transplantation
https://www.readbyqxmd.com/read/28049368/a-wandering-folded-liver-displaced-by-the-distended-bowel-a-new-case-report-with-review-of-the-literature
#8
Mohamed A Rabie, Charles Godavitarne
INTRODUCTION: The wandering liver is an extremely rare condition in which the liver moves significantly or 'wander' with changes in patient's lie. This is believed to be an acquired condition perhaps precipitated by persistent congenital ventral mesogastrium which acts as an axis or a mesentery for the liver to rotate. The vast majority of reported cases were associated with other chronic abnormalities of the gastrointestinal tract, especially sigmoid volvulus. PATIENTS AND METHODS: We present a case report of an acquired isolated transposition of the liver with a review of the English-language literature of wandering liver in adults and paediatric age group...
January 3, 2017: Acta Chirurgica Belgica
https://www.readbyqxmd.com/read/28048932/th-b-204-03-tg-199-implanted-markers-for-radiation-treatment-verification
#9
Z Wang
Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048875/su-f-j-185-detection-of-low-contrast-objects-optimization-of-ct-simulation-reconstruction-protocol-parameters
#10
S Alani, A Schlocker, N Honig, B Corn
PURPOSE: CT simulation has become an integral component of modern RT planning and therefore must be continually optimized. We evaluated the detection of small and low-contrast regions in images obtained during CT simulation. METHODS: A CT phantom containing a contrast detail modulus for detection of low-contrast structures was used to optimize the CT reconstruction protocol for abdomen. The parameters (A) Pitch, (B) Reconstruction Filter, and (C) Rotation Time type were varied for assessment of image quality...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048866/su-f-i-47-optimizing-protocols-for-image-quality-and-dose-in-abdominal-ct-of-large-patients
#11
L Johnson, M Yester
PURPOSE: Newer CT scanners are able to use scout views to adjust mA throughout the scan in order to achieve a given noise level. However, given constraints of radiologist preferences for kVp and rotation time, it may not be possible to achieve an acceptable noise level for large patients. A study was initiated to determine for which patients kVp and/or rotation time should be changed in order to achieve acceptable image quality. METHODS: Patient scans were reviewed on two new Emergency Department scanners (Philips iCT) to identify patients over a large range of sizes...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048478/th-b-204-01-real-time-tracking-with-implanted-markers
#12
Q Xu
Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048155/th-ef-brb-04-4%C3%AF-dynamic-conformal-arc-therapy-dynamic-conformal-arc-therapy-dcat-for-sbrt
#13
T Chiu, T Long, A Modiri, Z Tian, A Sawant, Y Yan, S Jiang, X Gu
PURPOSE: To develop an efficient and effective trajectory optimization methodology for 4π dynamic conformal arc treatment (4π DCAT) with synchronized gantry and couch motion; and to investigate potential clinical benefits for stereotactic body radiation therapy (SBRT) to breast, lung, liver and spine tumors. METHODS: The entire optimization framework for 4π DCAT inverse planning consists of two parts: 1) integer programming algorithm and 2) particle swarm optimization (PSO) algorithm...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047824/th-b-204-02-application-of-implanted-markers-in-proton-therapy
#14
S Park
Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047598/su-f-j-158-respiratory-motion-resolved-self-gated-4d-mri-using-rotating-cartesian-k-space-sampling
#15
F Han, Z Zhou, Y Yang, K Sheng, P Hu
PURPOSE: Dynamic MRI has been used to quantify respiratory motion of abdominal organs in radiation treatment planning. Many existing 4D-MRI methods based on 2D acquisitions suffer from limited slice resolution and additional stitching artifacts when evaluated in 3D(1) . To address these issues, we developed a 4D-MRI (3D dynamic) technique with true 3D k-space encoding and respiratory motion self-gating. METHODS: The 3D k-space was acquired using a Rotating Cartesian K-space (ROCK) pattern, where the Cartesian grid was reordered in a quasi-spiral fashion with each spiral arm rotated using golden angle(2) ...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047290/tu-h-brc-02-biological-dose-escalation-for-liver-sbrt-through-spatiotemporal-fractionation
#16
J Unkelbach, Z Perko, J Wolfgang, T Hong
PURPOSE: Stereotactic body radiotherapy (SBRT) has become an established treatment option for liver cancer. For patients with large tumors, the prescription dose is often limited by constraints on the mean liver dose, leading to tumor recurrence. In this work, we demonstrate that spatiotemporal fractionation schemes, ie delivering distinct dose distributions in different fractions, may allow for a 10% increase in biologically effective dose (BED) in the tumor compared to current practice where each fraction delivers the same dose distribution...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046767/su-g-bra-08-diaphragm-motion-tracking-based-on-kv-cbct-projections-with-a-constrained-linear-regression-optimization
#17
J Wei, M Chao
PURPOSE: To develop a novel strategy to extract the respiratory motion of the thoracic diaphragm from kilovoltage cone beam computed tomography (CBCT) projections by a constrained linear regression optimization technique. METHODS: A parabolic function was identified as the geometric model and was employed to fit the shape of the diaphragm on the CBCT projections. The search was initialized by five manually placed seeds on a pre-selected projection image. Temporal redundancies, the enabling phenomenology in video compression and encoding techniques, inherent in the dynamic properties of the diaphragm motion together with the geometrical shape of the diaphragm boundary and the associated algebraic constraint that significantly reduced the searching space of viable parabolic parameters was integrated, which can be effectively optimized by a constrained linear regression approach on the subsequent projections...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046411/th-b-204-00-implanted-markers-for-radiation-therapy-and-tg-199-update
#18
Zhiheng Wang
Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28038482/microsomal-metabolism-of-prochiral-polychlorinated-biphenyls-results-in-the-enantioselective-formation-of-chiral-metabolites
#19
Eric Uwimana, Anna Maiers, Xueshu Li, Hans-Joachim Lehmler
Polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substituents and their metabolites exist as stable rotational isomers, or atropisomers, that are nonsuperimposable mirror images of each other. Additionally, the oxidation of certain axially prochiral PCBs, such as 2,2',4,6'-tetrachlorobiphenyl (PCB 51) and 2,2',4,5,6'-pentachlorobiphenyl (PCB 102), in the meta position of the symmetrically substituted phenyl ring is expected to form axially chiral hydroxylated metabolites (OH-PCBs); however, the formation of chiral OH-PCBs from prochiral PCBs has not been demonstrated experimentally...
February 7, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28024148/solution-structure-of-discoidal-high-density-lipoprotein-particles-with-a-shortened-apolipoprotein-a-i
#20
Stefan Bibow, Yevhen Polyhach, Cédric Eichmann, Celestine N Chi, Julia Kowal, Stefan Albiez, Robert A McLeod, Henning Stahlberg, Gunnar Jeschke, Peter Güntert, Roland Riek
High-density lipoprotein (HDL) particles are cholesterol and lipid transport containers. Mature HDL particles destined for the liver develop through the formation of intermediate discoidal HDL particles, which are the primary acceptors for cholesterol. Here we present the three-dimensional structure of reconstituted discoidal HDL (rdHDL) particles, using a shortened construct of human apolipoprotein A-I, determined from a combination of nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and transmission electron microscopy (TEM) data...
December 26, 2016: Nature Structural & Molecular Biology
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