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Inverse Planning

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https://www.readbyqxmd.com/read/29160775/anatomical-robust-optimization-to-account-for-nasal-cavity-filling-variation-during-intensity-modulated-proton-therapy-a-comparison-with-conventional-and-adaptive-planning-strategies
#1
Steven van de Water, Francesca Albertini, Damien Charles Weber, Ben J M Heijmen, Mischa S Hoogeman, Antony John Lomax
The aim of this study is to develop an anatomical robust optimization method for intensity-modulated proton therapy (IMPT) that accounts for interfraction variations in nasal cavity filling, and to compare it with conventional single-field uniform dose (SFUD) optimization and online plan adaptation. We included CT data of five patients with tumors in the sinonasal region. Using the planning CT, we generated for each patient 25 'synthetic' CTs with varying nasal cavity filling. The robust optimization method available in our treatment planning system 'Erasmus-iCycle' was extended to also account for anatomical uncertainties by including (synthetic) CTs with varying patient anatomy as error scenarios in the inverse optimization...
November 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29159915/performance-of-a-hybrid-monte-carlo-pencil-beam-dose-algorithm-for-proton-therapy-inverse-planning
#2
Ana María Barragán Montero, Kevin Souris, Daniel Sánchez Parcerisa, Edmond Sterpin, John Aldo Lee
PURPOSE: Analytical algorithms have a limited accuracy when modelling very heterogeneous tumor sites. This work addresses the performance of a hybrid dose optimizer that combines both Monte Carlo (MC) and pencil beam (PB) dose engines to get the best trade-off between speed and accuracy for proton therapy plans. METHODS: The hybrid algorithm calculates the optimal spot weights (w) by means of an iterative optimization process where the dose at each iteration is computed by using a precomputed dose influence matrix based on the conventional PB plus a correction term c obtained from a MC simulation...
November 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/29159885/two-stage-ionoacoustic-range-verification-leveraging-monte-carlo-and-acoustic-simulations-to-stably-account-for-tissue-inhomogeneity-and-accelerator-specific-time-structure-a-simulation-study
#3
Sarah K Patch, Daniel E M Hoff, Tyler B Webb, Lee G Sobotka, Tianyu Zhao
PURPOSE: Range errors constrain treatment planning by limiting choice of ion beam angles and requiring large margins. Ionoacoustic range verification requires recovering the location of an acoustic source from low frequency signals. A priori information is applied to stably overcome resolution limits of inverse acoustic source imaging in this simulation study. In particular, the accuracy and robustness of ionoacoustic range verification for lateral and oblique delivery of high-energy protons to the prostate is examined...
November 20, 2017: Medical Physics
https://www.readbyqxmd.com/read/29158887/medical-imaging-lesion-detection-based-on-unified-gravitational-fuzzy-clustering
#4
Jean Marie Vianney Kinani, Alberto Jorge Rosales Silva, Francisco Gallegos Funes, Dante Mújica Vargas, Eduardo Ramos Díaz, Alfonso Arellano
We develop a swift, robust, and practical tool for detecting brain lesions with minimal user intervention to assist clinicians and researchers in the diagnosis process, radiosurgery planning, and assessment of the patient's response to the therapy. We propose a unified gravitational fuzzy clustering-based segmentation algorithm, which integrates the Newtonian concept of gravity into fuzzy clustering. We first perform fuzzy rule-based image enhancement on our database which is comprised of T1/T2 weighted magnetic resonance (MR) and fluid-attenuated inversion recovery (FLAIR) images to facilitate a smoother segmentation...
2017: Journal of Healthcare Engineering
https://www.readbyqxmd.com/read/29152846/on-the-geud-biological-optimization-objective-for-organs-at-risk-in-photon-optimizer-of-eclipse-treatment-planning-system
#5
Antonella Fogliata, Stephen Thompson, Antonella Stravato, Stefano Tomatis, Marta Scorsetti, Luca Cozzi
Inverse planning optimization using biologically based objectives is becoming part of the intensity modulated optimization process. The performances and efficacy of the biologically based gEUD (generalized Equivalent Uniform Dose) objective implemented in the Photon Optimizer (PO) of Varian Eclipse treatment planning system have been here analyzed. gEUD is associated with the parameter a that accounts for the seriality of a structure, being higher for more serial organs. The PO was used to optimize volumetric modulated arc therapy (VMAT) plans on a virtual homogeneous cylindrical phantom presenting a target and an organ at risk (OAR)...
November 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29139208/a-knowledge-based-approach-to-automated-planning-for-hepatocellular-carcinoma
#6
Yujie Zhang, Tingting Li, Han Xiao, Weixing Ji, Ming Guo, Zhaochong Zeng, Jianying Zhang
PURPOSE: To build a knowledge-based model of liver cancer for Auto-Planning, a function in Pinnacle, which is used as an automated inverse intensity modulated radiation therapy (IMRT) planning system. METHODS AND MATERIALS: Fifty Tomotherapy patients were enrolled to extract the dose-volume histograms (DVHs) information and construct the protocol for Auto-Planning model. Twenty more patients were chosen additionally to test the model. Manual planning and automatic planning were performed blindly for all twenty test patients with the same machine and treatment planning system...
November 15, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29129125/clinical-efficacy-and-safety-of-a-highly-conformal-supine-hybrid-forward-and-inverse-planned-intensity-modulated-radiation-therapy-technique-for-craniospinal-irradiation
#7
Safia K Ahmed, Jon J Kruse, Thomas B Bradley, Chris J Beltran, Nadia N Issa Laack
PURPOSE: To demonstrate the clinical efficacy and safety of a highly conformal, supine, hybrid forward and inverse planned intensity modulated radiation therapy (IMRT) technique for photon craniospinal irradiation (CSI). METHODS: Patients who received supine, hybrid IMRT CSI from 2009 to 2014 were included in this retrospective review. Clinical target volume (CTV) was defined as intracranial contents and thecal sac, including nerve roots. Dose was prescribed such that >99% of CTV received >99% of prescription and >95% of the planning target volume received >95% of prescription, with no attempt to include vertebral bodies...
November 12, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29128385/the-effectiveness-of-shingles-vaccine-among-albertans-aged-50%C3%A2-years-or-older-a-retrospective-cohort-study
#8
Bruce M McDonald, Douglas C Dover, Kimberley A Simmonds, Christopher A Bell, Lawrence W Svenson, Margaret L Russell
PURPOSE: We assessed the effectiveness of shingles vaccine in preventing incident shingles among Alberta residents aged 50 years or older over the period 2009 - 2015, using administrative health data. METHODS: The cohort comprised of Albertans from the Alberta Health Care Insurance Plan Registry (AHCIP) as of June 30, 2009 and aged 50 years or older. Those who received shingles vaccine were identified from the provincial pharmaceutical information network. The occurrence of incident shingles was identified through both inpatient and outpatients/community care data...
November 8, 2017: Vaccine
https://www.readbyqxmd.com/read/29115059/universal-field-matching-in-craniospinal-irradiation-by-a-background-dose-gradient-optimized-method
#9
Erik Traneus, Nicola Bizzocchi, Francesco Fellin, Barbara Rombi, Paolo Farace
PURPOSE: The gradient-optimized methods are overcoming the traditional feathering methods to plan field junctions in craniospinal irradiation. In this note, a new gradient-optimized technique, based on the use of a background dose, is described. METHODS: Treatment planning was performed by RayStation (RaySearch Laboratories, Stockholm, Sweden) on the CT scans of a pediatric patient. Both proton (by pencil beam scanning) and photon (by volumetric modulated arc therapy) treatments were planned with three isocenters...
November 7, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29090483/a-1-minute-full-brain-mr-exam-using-a-multicontrast-epi-sequence
#10
Stefan Skare, Tim Sprenger, Ola Norbeck, Henric Rydén, Lars Blomberg, Enrico Avventi, Mathias Engström
PURPOSE: A new multicontrast echo-planar imaging (EPI)-based sequence is proposed for brain MRI, which can directly generate six MR contrasts (T1 -FLAIR, T2 -w, diffusion-weighted (DWI), apparent diffusion coefficient (ADC), T2*-w, T2 -FLAIR) in 1 min with full brain coverage. This could enable clinical MR clinical screening in similar time as a conventional CT exam but with more soft-tissue information. METHODS: Eleven sequence modules were created as dynamic building blocks for the sequence...
October 31, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29079118/full-monte-carlo-based-biologic-treatment-plan-optimization-system-for-intensity-modulated-carbon-ion-therapy-on-graphics-processing-unit
#11
Nan Qin, Chenyang Shen, Min-Yu Tsai, Marco Pinto, Zhen Tian, Georgios Dedes, Arnold Pompos, Steve B Jiang, Katia Parodi, Xun Jia
PURPOSE: One of the major benefits of carbon ion therapy is enhanced biological effectiveness at the Bragg peak region. For intensity modulated carbon ion therapy (IMCT), it is desirable to use Monte Carlo (MC) methods to compute the properties of each pencil beam spot for treatment planning, because of their accuracy in modeling physics processes and estimating biological effects. We previously developed goCMC, a graphics processing unit (GPU)-oriented MC engine for carbon ion therapy...
September 12, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29077151/relationship-between-blood-remifentanil-concentration-and-stress-hormone-levels-during-pneumoperitoneum-in-patients-undergoing-laparoscopic-cholecystectomy
#12
P Aceto, C Dello Russo, C Lai, V Perilli, N Fucci, N De Giovanni, A Piras, P Navarra, L Sollazzi
OBJECTIVE: The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectomy...
October 2017: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/29065524/parents-perceived-barriers-to-accessing-sports-and-recreation-facilities-in-ontario-canada-exploring-the-relationships-between-income-neighbourhood-deprivation-and-community
#13
Daniel W Harrington, Jocelyn W Jarvis, Heather Manson
Sports and recreation facilities provide places where children can be physically active. Previous research has shown that availability is often worse in lower-socioeconomic status (SES) areas, yet others have found inverse relationships, no relationships, or mixed findings. Since children's health behaviours are influenced by their parents, it is important to understand parents' perceived barriers to accessing sports and recreation facilities. Data from computer assisted telephone interviews with parents living in Ontario, Canada were merged via postal codes with neighbourhood deprivation data...
October 23, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29063491/a-possible-correlation-between-the-basal-ganglia-motor-function-and-the-inverse-kinematics-calculation
#14
Armin Salimi-Badr, Mohammad Mehdi Ebadzadeh, Christian Darlot
The main hypothesis of this study, based on experimental data showing the relations between the BG activities and kinematic variables, is that BG are involved in computing inverse kinematics (IK) as a part of planning and decision-making. Indeed, it is assumed that based on the desired kinematic variables (such as velocity) of a limb in the workspace, angular kinematic variables in the joint configuration space are calculated. Therefore, in this paper, a system-level computational model of BG is proposed based on geometrical rules, which is able to compute IK...
December 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29061154/a-multi-centre-randomised-trial-to-compare-the-effectiveness-of-geriatrician-led-admission-avoidance-hospital-at-home-versus-inpatient-admission
#15
Sasha Shepperd, Andrea Cradduck-Bamford, Chris Butler, Graham Ellis, Mary Godfrey, Alastair Gray, Anthony Hemsley, Pradeep Khanna, Peter Langhorne, Patricia McCaffrey, Lubena Mirza, Maj Pushpangadan, Scott Ramsay, Rebekah Schiff, David Stott, John Young, Ly-Mee Yu
BACKGROUND: There is concern that existing models of acute hospital care will become unworkable as the health service admits an increasing number of frail older people with complex health needs, and that there is inadequate evidence to guide the planning of acute hospital level services. We aim to evaluate whether geriatrician-led admission avoidance to hospital at home is an effective alternative to hospital admission. METHODS/DESIGN: We are conducting a multi-site randomised open trial of geriatrician-led admission avoidance hospital at home, compared with admission to hospital...
October 23, 2017: Trials
https://www.readbyqxmd.com/read/29053446/simulation-of-constrained-musculoskeletal-systems-in-task-space
#16
Dimitar Stanev, Konstantinos Moustakas
OBJECTIVE: This work proposes an operational task space formalization of constrained musculoskeletal systems, motivated by its promising results in the field of robotics. METHODS: The change of representation requires different algorithms for solving the inverse and forward dynamics simulation in the task space domain. We propose an extension to the Direct Marker Control and an adaptation of the Computed Muscle Control algorithms for solving the inverse kinematics and muscle redundancy problems respectively...
October 18, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/29047455/a-monte-carlo-study-to-assess-the-effect-of-1-5-t-magnetic-fields-on-the-overall-robustness-of-pencil-beam-scanning-proton-radiotherapy-plans-for-prostate-cancer
#17
Christopher Kurz, Guillaume Landry, Andreas F Resch, George Dedes, Florian Kamp, Ute Ganswindt, Claus Belka, Bas W Raaymakers, Katia Parodi
Combining magnetic-resonance imaging (MRI) and proton therapy (PT) using pencil-beam scanning (PBS) may improve image-guided radiotherapy. We aimed at assessing the impact of a magnetic field on PBS-PT plan quality and robustness. Specifically, the robustness against anatomical changes and positioning errors in an MRI-guided scenario with a 30 cm radius 1.5 T magnetic field was studied for prostate PT. Five prostate cancer patients with three consecutive CT images (CT1-3) were considered. Single-field uniform dose PBS-PT plans were generated on the segmented CT1 with Monte-Carlo-based treatment planning software for inverse optimization...
October 19, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29041989/links-of-gut-microbiota-composition-with-alcohol-dependence-syndrome-and-alcoholic-liver-disease
#18
Veronika B Dubinkina, Alexander V Tyakht, Vera Y Odintsova, Konstantin S Yarygin, Boris A Kovarsky, Alexander V Pavlenko, Dmitry S Ischenko, Anna S Popenko, Dmitry G Alexeev, Anastasiya Y Taraskina, Regina F Nasyrova, Evgeny M Krupitsky, Nino V Shalikiani, Igor G Bakulin, Petr L Shcherbakov, Lyubov O Skorodumova, Andrei K Larin, Elena S Kostryukova, Rustam A Abdulkhakov, Sayar R Abdulkhakov, Sergey Y Malanin, Ruzilya K Ismagilova, Tatiana V Grigoryeva, Elena N Ilina, Vadim M Govorun
BACKGROUND: Alcohol abuse has deleterious effects on human health by disrupting the functions of many organs and systems. Gut microbiota has been implicated in the pathogenesis of alcohol-related liver diseases, with its composition manifesting expressed dysbiosis in patients suffering from alcoholic dependence. Due to its inherent plasticity, gut microbiota is an important target for prevention and treatment of these diseases. Identification of the impact of alcohol abuse with associated psychiatric symptoms on the gut community structure is confounded by the liver dysfunction...
October 17, 2017: Microbiome
https://www.readbyqxmd.com/read/29040510/genomic-fragmentation-and-extrachromosomal-telomeric-repeats-impact-assessment-of-telomere-length-in-human-spermatozoa-quantitative-experiments-and-systematic-review
#19
P Kurjanowicz, S Moskovtsev, C Librach
STUDY QUESTION: Can differences in DNA isolation alter assessment of sperm telomere length (spTL) and do they account for conflicting results in the literature on spTL and male fertility? SUMMARY ANSWER: DNA isolation methods preferentially include or exclude short, extrachromosomal (EC) telomere-specific sequences that alter spTL measurements, and are responsible for a proportion of the disparity observed between investigations. WHAT IS KNOWN ALREADY: The relationship between spTL and male fertility has become an active area of research...
November 1, 2017: Human Reproduction
https://www.readbyqxmd.com/read/29035270/quantifying-trace-element-and-isotope-fluxes-at-the-ocean-sediment-boundary-a-review
#20
William B Homoky, Thomas Weber, William M Berelson, Tim M Conway, Gideon M Henderson, Marco van Hulten, Catherine Jeandel, Silke Severmann, Alessandro Tagliabue
Quantifying fluxes of trace elements and their isotopes (TEIs) at the ocean's sediment-water boundary is a pre-eminent challenge to understand their role in the present, past and future ocean. There are multiple processes that drive the uptake and release of TEIs, and properties that determine their rates are unevenly distributed (e.g. sediment composition, redox conditions and (bio)physical dynamics). These factors complicate our efforts to find, measure and extrapolate TEI fluxes across ocean basins. GEOTRACES observations are unveiling the oceanic distributions of many TEIs for the first time...
November 28, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
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