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Inverse Planning

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https://www.readbyqxmd.com/read/28930092/a-monte-carlo-study-to-assess-the-effect-of-1-5t-magnetic-fields-on-the-overall-robustness-of-pencil-beam-scanning-proton-radiotherapy-plans-for-prostate-cancer
#1
Christopher Kurz, Guillaume Landry, Andreas Franz Resch, Georgios 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...
September 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28921538/a-fast-inverse-treatment-planning-strategy-facilitating-optimized-catheter-selection-in-image-guided-high-dose-rate-interstitial-gynecologic-brachytherapy
#2
Christian V Guthier, Antonio L Damato, Juergen W Hesser, Akila N Viswanathan, Robert A Cormack
PURPOSE: Interstitial high-dose-rate (HDR) brachytherapy is an important therapeutic strategy for the treatment of locally advanced gynecologic (GYN) cancers. The outcome of this therapy is determined by the quality of dose distribution achieved. This paper focuses on a novel yet simple heuristic for catheter selection for GYN HDR brachytherapy and their comparison against state of the art optimization strategies. The proposed technique is intended to act as a decision-supporting tool to select a favorable needle configuration...
September 18, 2017: Medical Physics
https://www.readbyqxmd.com/read/28902082/contrast-enhanced-3-dimensional-fluid-attenuated-inversion-recovery-sequences-have-greater-sensitivity-for-detection-of-leptomeningeal-metastases-in-pediatric-brain-tumors-compared-with-conventional-spoiled-gradient-echo-sequences
#3
Michael J Utz, Mandeep S Tamber, Gary E Mason, Ian F Pollack, Ashok Panigrahy, Giulio Zuccoli
Postcontrast 3-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequences have reduced vascular and flow-related artifacts and high sensitivity to low gadolinium concentrations. We compared the performance of postcontrast spoiled gradient echo images to 3D-FLAIR in the detection of leptomeningeal metastases in 47 pediatric patients with brain tumors. We found 10 cases with more leptomeningeal signal abnormalities on 3D-FLAIR. Overall there were significantly more lesions on 3D-FLAIR than spoiled gradient echo sequences...
September 8, 2017: Journal of Pediatric Hematology/oncology
https://www.readbyqxmd.com/read/28886980/-dose-constraints-to-organs-at-risk-for-conformational-and-stereotactic-radiotherapy-small-bowel-and-duodenum
#4
F Goupy, E Chajon, J Castelli, É Le Prisé, L Duvergé, N Jaksic, G Vogin, É Monpetit, V Klein, L de Bosschère, P Maingon
Radiotherapy of abdominopelvic primary or secondary lesions in conformational or stereotactic techniques is in full development. The small bowel is highly sensitive to irradiation and is the main organ at risk limiting prescription doses. This literature review aims to define the dose constraints to the small bowel and the duodenum in conformational and stereotactic body radiotherapy. The small bowel including the duodenum, jejunum and ileum is delineated on the simulation scanner. The radio-induced intestinal toxicities are acute related to the cellular depopulation of the intestinal mucosa, and late of more complex pathophysiology associating depletion in stem cells, microangiopathy, chronic inflammation and fibrosis...
September 5, 2017: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28871981/inversed-planned-respiratory-phase-gating-in%C3%A2-lung-conformal-radiation-therapy
#5
Arezoo Modiri, Pouya Sabouri, Xuejun Gu, Robert Timmerman, Amit Sawant
PURPOSE: To assess whether the optimal gating window for each beam during lung radiation therapy with respiratory gating will be dependent on a variety of patient-specific factors, such as tumor size and location and the extent of relative tumor and organ motion. METHODS AND MATERIALS: To create optimal gating treatment plans, we started from an optimized clinical plan, created a plan per respiratory phase using the same beam arrangements, and used an inverse planning optimization approach to determine the optimal gating window for each beam and optimal beam weights (ie, monitor units)...
October 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28869143/a-novel-urethral-sparing-technique-for-high-dose-rate-prostate-brachytherapy-after-transurethral-resection-of-the-prostate
#6
Hiroaki Kunogi, Jason Adam M Cunha, Albert J Chang, Adam J Gadzinski, Katsuto Shinohara, I-Chow Hsu
PURPOSE: The purpose of this study was to assess retrospectively the variability of the urethral dose optimized using a Foley catheter versus urethral contrast injected using a new modified triple-lumen catheter, in CT-based high-dose-rate (HDR) prostate brachytherapy of posttransurethral resection of prostate (TURP) patients. METHODS AND MATERIALS: At our institution, there were six post-TURP patients with prostate carcinoma between July 2014 and April 2016 who underwent transperineal interstitial HDR brachytherapy (16 needles)...
August 28, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28865431/uncommon-presentation-of-a-rare-tumour-incidental-finding-in-an-asymptomatic-patient-case-report-and-comprehensive-review-of-the-literature-on-intrapericardial-solitary-fibrous-tumours
#7
Csilla Czimbalmos, Ibolya Csecs, Miklos Polos, Elektra Bartha, Nikolette Szucs, Attila Toth, Pal Maurovich-Horvat, David Becker, Zoltan Sapi, Zoltan Szabolcs, Bela Merkely, Hajnalka Vago
BACKGROUND: A solitary fibrous tumour is a rare, mainly benign spindle cell mesenchymal tumour most commonly originating from the pleura. An intrapericardial location of a solitary fibrous tumour is extremely unusual. We present a case of an asymptomatic patient with a slow-growing massive benign cardiac solitary fibrous tumour. CASE PRESENTATION: A 37-year-old asymptomatic female patient was referred to our hospital with an enlarged cardiac silhouette found on her screening chest X-ray...
September 2, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28861861/gate-monte-carlo-simulation-of-dose-distribution-using-mapreduce-in-a-cloud-computing-environment
#8
Yangchuan Liu, Yuguo Tang, Xin Gao
The GATE Monte Carlo simulation platform has good application prospects of treatment planning and quality assurance. However, accurate dose calculation using GATE is time consuming. The purpose of this study is to implement a novel cloud computing method for accurate GATE Monte Carlo simulation of dose distribution using MapReduce. An Amazon Machine Image installed with Hadoop and GATE is created to set up Hadoop clusters on Amazon Elastic Compute Cloud (EC2). Macros, the input files for GATE, are split into a number of self-contained sub-macros...
August 31, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28856591/tsh-oscillations-in-young-patients-with-type-1-diabetes-may-be-due-to-glycemic-variability
#9
G Bellastella, M I Maiorino, L Scappaticcio, O Casciano, M Petrizzo, M Caputo, V A Paglionico, D Giugliano, K Esposito
PURPOSE: A relationship between thyroid dysfunction and diabetes mellitus has been described by several authors but the role of glycemic variability is still unclear. We planned the present study to evaluate the influence of glycemic variability on thyroid hormones and TSH concentrations in patients with type 1 diabetes mellitus (T1DM). METHODS: Seventy-seven young patients with T1DM were enrolled and evaluated for basal glucose concentrations, HbA1c, thyroid hormones and TSH concentrations...
August 30, 2017: Journal of Endocrinological Investigation
https://www.readbyqxmd.com/read/28854073/major-bleeding-risk-during-anticoagulation-with-warfarin-dabigatran-apixaban-or-rivaroxaban-in-patients-with-nonvalvular-atrial-fibrillation
#10
Gboyega Adeboyeje, Gosia Sylwestrzak, John J Barron, Jeff White, Alan Rosenberg, Jacob Abarca, Geoffrey Crawford, Rita Redberg
BACKGROUND: The use of non-vitamin K oral anticoagulants (NOACs) has increased steadily following marketing approval; however, their relative safety in nonvalvular atrial fibrillation (NVAF) patients in real-world clinical practice remains unclear. OBJECTIVE: To compare the risk of major bleeding during anticoagulation therapy between warfarin and NOACs. METHODS: This retrospective cohort study analyzed administrative claims data on new NVAF users of warfarin, dabigatran, apixaban, or rivaroxaban in routine clinical care from November 2010 to February 2015 in a commercially insured population in the United States...
September 2017: Journal of Managed Care & Specialty Pharmacy
https://www.readbyqxmd.com/read/28844834/what-makes-new-ischemic-lesions-symptomatic-after-aortic-valve-replacement
#11
Ronen R Leker, Steven R Messé, Guray Erus, Michel Bilello, Molly Fanning, Michael Acker, Allie Massaro, Scott E Kasner, Thomas Floyd
BACKGROUND: Acute cerebral infarctions on diffusion-weighted magnetic resonance imaging (MRI) are common after cardiothoracic surgery. However, most are asymptomatic and we aimed to identify features associated with clinical stroke symptoms. METHODS: Patients over 65 years of age undergoing surgical aortic valve replacement (AVR) for calcific stenosis were prospectively recruited (N = 196). All patients underwent neurological evaluation preoperatively and on postoperative days 1, 3, and 7, and MRI on planned postoperative day 5...
August 24, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28840134/diagnostic-performance-and-safety-of-positron-emission-tomography-using-18-f-fluciclovine-in-patients-with-clinically-suspected-high-or-low-grade-gliomas-a-multicenter-phase-iib-trial
#12
Toshihiko Wakabayashi, Toshihiko Iuchi, Naohiro Tsuyuguchi, Ryo Nishikawa, Yoshiki Arakawa, Takashi Sasayama, Keisuke Miyake, Tadashi Nariai, Yoshitaka Narita, Naoya Hashimoto, Osamu Okuda, Hiroshi Matsuda, Kazuo Kubota, Kimiteru Ito, Yoichi Nakazato, Kan Kubomura
OBJECTIVES: The study objective was to assess the diagnostic performance of positron emission tomography (PET) for gliomas using the novel tracer (18)F-fluciclovine (anti-[(18)F]FACBC) and to evaluate the safety of this tracer in patients with clinically suspected gliomas. METHODS: Anti-[(18)F]FACBC was administered to 40 patients with clinically suspected high- or low-grade gliomas, followed by PET imaging. T1-weighted, contrast-enhanced T1-weighted, and fluid-attenuated inversion recovery (or T2-weighted) magnetic resonance imaging (MRI) scans were obtained to plan for the tissue collection...
2017: Asia Oceania Journal of Nuclear Medicine & Biology
https://www.readbyqxmd.com/read/28834556/deterministic-direct-aperture-optimization-using-multiphase-piecewise-constant-segmentation
#13
Dan Nguyen, Daniel O'Connor, Dan Ruan, Ke Sheng
PURPOSE: Direct Aperture Optimization (DAO) attempts to incorporate machine constraints in the inverse optimization to eliminate the post-processing steps in fluence map optimization (FMO) that degrade plan quality. Current commercial DAO methods utilize a stochastic or greedy approach to search a small aperture solution space. In this study, we propose a novel deterministic direct aperture optimization that integrates the segmentation of fluence map in the optimization problem using the multiphase piecewise constant Mumford-Shah formulation...
August 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28813840/a-novel-protocol-to-evaluate-ankle-movements-during-reaching-tasks-using-pedianklebot
#14
Francesca Martelli, Eduardo Palermo, Stefano Rossi
The aim of the study is to design a novel protocol to characterize the ankle movements during dorsal and plantar flexion reaching tasks using the pediAnklebot. Five healthy children were instructed to control a pointer and hit targets appearing on the monitor, by moving their ankle alternatively up and down. The protocol consisted of 60 targets, 30 up and 30 down, reachable via dorsiflexion and plantarflexion movements, respectively. Ankle angular displacements and torques were gathered by encoders and load cells embedded in the robot...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28811996/experimental-method-and-statistical-analysis-to-fit-tumor-growth-model-using-spect-ct-imaging-a-preclinical-study
#15
Ivan Hidrovo, Joyoni Dey, Megan E Chesal, Dmytro Shumilov, Narayan Bhusal, J Michael Mathis
BACKGROUND: Over the last decade, several theoretical tumor-models have been developed to describe tumor growth. Oncology imaging is performed using various modalities including computed tomography (CT), magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and fluorodeoxyglucose-positron emission tomography (FDG-PET). Our goal is to extract useful, otherwise hidden, quantitative biophysical parameters (such as growth-rate, tumor-necrotic-factor, etc.) from these serial images of tumors by fitting mathematical models to images...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28802913/salvage-high-dose-rate-brachytherapy-and-external-beam-radiotherapy-for-isolated-vaginal-recurrences-of-endometrial-cancer-with-no-prior-adjuvant-therapy
#16
Christopher H Chapman, Kaveh Maghsoudi, Ramey D Littell, Lee-May Chen, I-Chow Hsu
PURPOSE: To evaluate clinical outcomes for isolated vaginal recurrence of endometrial cancer without adjuvant therapy treated with salvage external beam radiation therapy (EBRT) and high-dose-rate CT-based inverse-planned brachytherapy. METHODS AND MATERIALS: Thirty women were included in this retrospective study. Median time to first recurrence was 16.7 months, and median age at recurrence was 73 years. Initial grade was 1 or 2 in 19 patients (63%), and 2009 FIGO stage IA in 19 patients...
August 9, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28801191/household-survey-of-hiv-incidence-in-rwanda-a-national-observational-cohort-study
#17
Sabin Nsanzimana, Eric Remera, Steve Kanters, Augustin Mulindabigwi, Amitabh B Suthar, Jean Paul Uwizihiwe, Mutagoma Mwumvaneza, Edward J Mills, Heiner C Bucher
BACKGROUND: In Rwanda, HIV prevalence among adults aged 15-49 years has been stable at 3% since 2005. The aim of this study was to characterise HIV incidence across Rwanda. METHODS: We did a nationally representative, prospective HIV incidence survey for the period of 2013-14, which used two-stage sampling. We randomly selected 492 villages in the first sampling stage and 14 households per village in the second stage. Participants completed a questionnaire and 14 140 people were tested for HIV...
August 8, 2017: Lancet HIV
https://www.readbyqxmd.com/read/28793118/quality-of-life-of-elderly-people-with-chronic-kidney-disease-in-conservative-treatment
#18
Roberta Maria de Pina Pereira, Marcelo Aparecido Batista, Aline de Sousa Meira, Marília Pilotto de Oliveira, Luciana Kusumota
Objective: To describe the quality of life (QOL) of elderly people with Chronic Kidney Disease (CKD) in conservative treatment, correlating it with sociodemographic and health-related aspects. Method: This is a quantitative, cross-sectional, and descriptive study that used: a previously validated instrument for data collection; the WHOQOL-BREF and WHOQOL-OLD QOL scales; and the Mini-Mental State Examination. Results: Thirty-five elderly people (54...
July 2017: Revista Brasileira de Enfermagem
https://www.readbyqxmd.com/read/28777112/the-relationship-between-professional-quality-of-life-and-caring-ability-in-critical-care-nurses
#19
Marzieh Mohammadi, Hamid Peyrovi, Mahmood Mahmoodi
BACKGROUND: Critical care nursing has some features that may affect the ability of critical care nurses to provide care. Professionals as critical care nurses who deal with peoples' health and life often experience some levels of stress that affects their quality of life. OBJECTIVE: This study examined the relationship between professional quality of life and caring ability of critical care nurses. METHOD: In this descriptive correlational study, 253 critical care nurses working in the medical and surgical intensive care units of Tehran University of Medical Sciences were recruited by convenience sampling method...
September 2017: Dimensions of Critical Care Nursing: DCCN
https://www.readbyqxmd.com/read/28777059/modality-specific-changes-in-motor-cortex-excitability-after-visuo-proprioceptive-realignment
#20
Felipe Munoz-Rubke, Jasmine L Mirdamadi, Anna K Lynch, Hannah J Block
Spatial realignment of visual and proprioceptive estimates of hand position is necessary both to keep the estimates in register over time and to compensate for sensory perturbations. Such realignment affects perceived hand position, which the brain must use to plan hand movements. We would therefore expect visuo-proprioceptive realignment to affect the motor system at some level, but the physiological basis of this interaction is unknown. Here, we asked whether activity in primary motor cortex (M1), a well-known substrate of motor control, shows evidence of change after visuo-proprioceptive realignment...
August 4, 2017: Journal of Cognitive Neuroscience
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