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https://www.readbyqxmd.com/read/28300367/4d-vmat-planning-and-verification-technique-for-dynamic-tracking-using-a-direct-aperture-deformation-dad-method
#1
Yongqian Zhang, Yong Yang, Weihua Fu, Xiang Li, Tianfang Li, Dwight E Heron, M Saiful Huq
We developed a four-dimensional volumetric modulated arc therapy (4D VMAT) planning technique for moving targets using a direct aperture deformation (DAD) method and investigated its feasibility for clinical use. A 3D VMAT plan was generated on a reference phase of a 4D CT dataset. The plan was composed of a set of control points including the beam angle, MLC apertures and weights. To generate the 4D VMAT plan, these control points were assigned to the closest respiratory phases using the temporal information of the gantry angle and respiratory curve...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297341/assessment-of-monte-carlo-algorithm-for-compliance-with-rtog-0915-dosimetric-criteria-in-peripheral-lung-cancer-patients-treated-with-stereotactic-body-radiotherapy
#2
Damodar Pokhrel, Sumit Sood, Rajeev Badkul, Hongyu Jiang, Christopher McClinton, Christopher Lominska, Parvesh Kumar, Fen Wang
The purpose of the study was to evaluate Monte Carlo-generated dose distributions with the X-ray Voxel Monte Carlo (XVMC) algorithm in the treatment of peripheral lung cancer patients using stereotactic body radiotherapy (SBRT) with non-protocol dose-volume normalization and to assess plan outcomes utilizing RTOG 0915 dosimetric compliance criteria. The Radiation Therapy Oncology Group (RTOG) protocols for non-small cell lung cancer (NSCLC) currently require radiation dose to be calculated using tissue density heterogeneity corrections...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297332/impact-of-incorporating-visual-biofeedback-in-4d-mri
#3
David T To, Joshua P Kim, Ryan G Price, Indrin J Chetty, Carri K Glide-Hurst
Precise radiation therapy (RT) for abdominal lesions is complicated by respiratory motion and suboptimal soft tissue contrast in 4D CT. 4D MRI offers improved contrast although long scan times and irregular breathing patterns can be limiting. To address this, visual biofeedback (VBF) was introduced into 4D MRI. Ten volunteers were consented to an IRB-approved protocol. Prospective respiratory-triggered, T2-weighted, coronal 4D MRIs were acquired on an open 1.0T MR-SIM. VBF was integrated using an MR-compatible interactive breath-hold control system...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297304/evaluation-of-kidney-motion-and-target-localization-in-abdominal-sbrt-patients
#4
Marcus Sonier, William Chu, Nafisha Lalani, Darby Erler, Patrick Cheung, Renee Korol
The purpose of this study was to evaluate bilateral kidney and target translational/rotational intrafraction motion during stereotactic body radiation therapy treatment delivery of primary renal cell carcinoma and oligometastatic adrenal lesions for patients immobilized in the Elekta BodyFIX system. Bilateral kidney motion was assessed at midplane for 30 patients immobilized in a full-body dual-vacuum-cushion system with two patients immobilized via abdominal compression. Intrafraction motion was assessed for 15 patients using kilovoltage cone-beam computed tomography (kV-CBCT) datasets (n=151) correlated to the planning CT...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28291941/influence-of-the-jaw-tracking-technique-on-the-dose-calculation-accuracy-of-small-field-vmat-plans
#5
REVIEW
Ans C C Swinnen, Michel C Öllers, Erik Roijen, Sebastiaan M Nijsten, Frank Verhaegen
PURPOSE: The aim of this study was to evaluate experimentally the accuracy of the dose calculation algorithm AcurosXB in small field highly modulated Volumetric Modulated Arc Therapy (VMAT). METHOD: The 1000SRS detector array inserted in the rotational Octavius 4D phantom (PTW) was used for 3D dose verification of VMAT treatments characterized by small to very small targets. Clinical treatment plans (n = 28) were recalculated on the phantom CT data set in the Eclipse TPS...
January 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28288528/4d-ct-angiography-with-arterial-and-venous-phase-anatomical-pre-surgical-approaches-in-cases-with-head-and-neck-neoplasms
#6
Hsiou-Chun Lin, Kou-Mou Huang, Yung-Cheng Wang
PURPOSE: The relationship between neoplasm and its surrounding vascular structure is essential to the following clinical treatment plan. In this study, 4D computed tomography angiography (4D-CTA) with a wide scan range and dynamic phases of arteriography and venography was used to describe detailed anatomical information for pre-surgical approaches. MATERIALS AND METHODS: From January 2011 to February 2012, we subjected 13 patients with head and neck neoplasms to 4D-CTA...
March 14, 2017: British Journal of Neurosurgery
https://www.readbyqxmd.com/read/28273920/white-matter-and-gray-matter-segmentation-in-4d-computed-tomography
#7
Rashindra Manniesing, Marcel T H Oei, Luuk J Oostveen, Jaime Melendez, Ewoud J Smit, Bram Platel, Clara I Sánchez, Frederick J A Meijer, Mathias Prokop, Bram van Ginneken
Modern Computed Tomography (CT) scanners are capable of acquiring contrast dynamics of the whole brain, adding functional to anatomical information. Soft tissue segmentation is important for subsequent applications such as tissue dependent perfusion analysis and automated detection and quantification of cerebral pathology. In this work a method is presented to automatically segment white matter (WM) and gray matter (GM) in contrast- enhanced 4D CT images of the brain. The method starts with intracranial segmentation via atlas registration, followed by a refinement using a geodesic active contour with dominating advection term steered by image gradient information, from a 3D temporal average image optimally weighted according to the exposures of the individual time points of the 4D CT acquisition...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28268560/4d-lung-tumor-segmentation-via-shape-prior-and-motion-cues
#8
Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini
Lung tumor segmentation is important for therapy in the radiation treatment of patients with thoracic malignancies. In this paper, we describe a 4D image segmentation method based on graph-cuts optimization, shape prior and optical flow. Due to small size, the location, and low contrast between the tumor and the surrounding tissue, tumor segmentation in 3D+t is challenging. We performed 4D lung tumor segmentation in 5 patients, and in each case compared the results with the expert-delineated lung nodules. In each case, 4D image segmentation took approximately ten minutes on a PC with AMD Phenom II and 32GB of memory for segmenting tumor in five phases of lung CT data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28260811/a-4dct-imaging-based-breathing-lung-model-with-relative-hysteresis
#9
Shinjiro Miyawaki, Sanghun Choi, Eric A Hoffman, Ching-Long Lin
To reproduce realistic airway motion and airflow, the authors developed a deforming lung computational fluid dynamics (CFD) model based on four-dimensional (4D, space and time) dynamic computed tomography (CT) images. A total of 13 time points within controlled tidal volume respiration were used to account for realistic and irregular lung motion in human volunteers. Because of the irregular motion of 4DCT-based airways, we identified an optimal interpolation method for airway surface deformation during respiration, and implemented a computational solid mechanics-based moving mesh algorithm to produce smooth deforming airway mesh...
December 1, 2016: Journal of Computational Physics
https://www.readbyqxmd.com/read/28240218/an-anthropomorphic-breathing-phantom-of-the-thorax-for-testing-new-motion-mitigation-techniques-for-pencil-beam-scanning-proton-therapy
#10
R L Perrin, M Zakova, M Peroni, K Bernatowicz, C Bikis, A K Knopf, S Safai, P Fernandez-Carmona, N Tscharner, D C Weber, T C Parkel, A J Lomax
Motion-induced range changes and incorrectly placed dose spots strongly affect the quality of pencil-beam-scanned (PBS) proton therapy, especially in thoracic tumour sites, where density changes are large. Thus motion-mitigation techniques are necessary, which must be validated in a realistic patient-like geometry. We report on the development and characterisation of a dynamic, anthropomorphic, thorax phantom that can realistically mimic thoracic motions and anatomical features for verifications of proton and photon 4D treatments...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28226737/4d-lung-tumor-segmentation-via-shape-prior-and-motion-cues
#11
Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini, Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini, Jung Won Cha, Amir Amini, Neal Dunlap, Mohammad M Farhangi
Lung tumor segmentation is important for therapy in the radiation treatment of patients with thoracic malignancies. In this paper, we describe a 4D image segmentation method based on graph-cuts optimization, shape prior and optical flow. Due to small size, the location, and low contrast between the tumor and the surrounding tissue, tumor segmentation in 3D+t is challenging. We performed 4D lung tumor segmentation in 5 patients, and in each case compared the results with the expert-delineated lung nodules. In each case, 4D image segmentation took approximately ten minutes on a PC with AMD Phenom II and 32GB of memory for segmenting tumor in five phases of lung CT data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28211367/high-quality-four-dimensional-cone-beam-ct-reconstruction-using-motion-compensated-total-variation-regularization
#12
Hua Zhang, Jianhua Ma, Zhaoying Bian, Dong Zeng, Qianjin Feng, Wufan Chen
Four dimensional cone-beam computed tomography (4D-CBCT) has great potential clinical value because its ability to describe tumor and organ motion. But the challenge in 4D-CBCT reconstruction is the limited number of projections at each phase, which resulting in the reconstruction full of noise and streak artifacts with the conventional analytical algorithms. To address this problem, in this paper, we propose a motion compensated total variation regularization approach which tries to maximum explore the temporal coherence of the spatial structures among 4D-CBCT phases...
February 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28203490/pulsatile-tinnitus-differential-diagnosis-and-radiological-work-up
#13
REVIEW
Sjoert A H Pegge, Stefan C A Steens, Henricus P M Kunst, Frederick J A Meijer
PURPOSE OF REVIEW: Identification of the underlying cause of pulsatile tinnitus is important for treatment decision making and for prognosis estimation. For this, an adequate diagnostic imaging strategy is crucial. RECENT FINDINGS: Both CT and MRI can be useful, and in general, these modalities provide complementary diagnostic information. The scanning protocol can be optimized based on the estimated a priori chance for finding specific pathology, or the need to rule out more rare but clinical significant disease...
2017: Current Radiology Reports
https://www.readbyqxmd.com/read/28191858/impact-of-the-pde4d-gene-polymorphism-and-additional-snp-snp-and-gene-smoking-interaction-on-ischemic-stroke-risk-in-chinese-han-population
#14
Xianxiang Wang, Zhongwu Sun, Yiquan Zhang, Xuefeng Tian, Qingxin Li, Jing Luo
AIMS: To investigate the association between phosphodiesterase 4D gene (PDE4D) gene single nucleotide polymorphisms (SNPs) and ischemic stroke (IS) risk, and impact of additional SNP- SNP and gene- smoking interaction on IS risk in Chinese population. METHODS: A total of 1228 subjects (666 males, 562 females) were selected, including 610 IS patients and 618 control subjects. Logistic regression model was used to examine the association between SNPs in PDE4D gene and IS risk...
February 13, 2017: Neurological Research
https://www.readbyqxmd.com/read/28140361/directional-sinogram-interpolation-for-motion-weighted-4d-cone-beam-ct-reconstruction
#15
Hua Zhang, Matthijs Kruis, Jan-Jakob Sonke
The image quality of respiratory sorted four-dimensional (4D) cone-beam (CB) computed tomography (CT) is often limited by streak artifacts due to insufficient projections. A motion weighted reconstruction (MWR) method is proposed to decrease streak artifacts and improve image quality. Firstly, respiratory correlated CBCT projections were interpolated by directional sinogram interpolation (DSI) to generate additional CB projections for each phase and subsequently reconstructed. Secondly, local motion was estimated by deformable image registration of the interpolated 4D CBCT...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28133755/evaluation-of-motion-mitigation-using-abdominal-compression-in-the-clinical-implementation-of-pencil-beam-scanning-proton-therapy-of-liver-tumors
#16
Liyong Lin, Kevin Souris, Minglei Kang, Adam Glick, Haibo Lin, Sheng Huang, Kristin Stützer, Guillaume Janssens, Edmond Sterpin, John A Lee, Timothy D Solberg, James E McDonough, Charles B Simone, Edgar Ben-Josef
PURPOSE: To determine whether individual liver tumor patients can be safely treated with pencil beam scanning proton therapy. This study reports a planning preparation workflow that can be used for beam angle selection and the evaluation of the efficacy of abdominal compression (AC) to mitigate motion. METHODS: Four-dimensional computed tomography scans (4DCT) with and without AC were available from 10 liver tumor patients with fluoroscopy-proven motion reduction by AC, previously treated using photons...
February 2017: Medical Physics
https://www.readbyqxmd.com/read/28133752/respiratory-motion-resolved-self-gated-4d-mri-using-rotating-cartesian-k-space-rock
#17
Fei Han, Ziwu Zhou, Minsong Cao, Yingli Yang, Ke Sheng, Peng Hu
PURPOSE: To propose and validate a respiratory motion resolved, self-gated (SG) 4D-MRI technique to assess patient-specific breathing motion of abdominal organs for radiation treatment planning. METHODS: The proposed 4D-MRI technique was based on the balanced steady-state free-precession (bSSFP) technique and 3D k-space encoding. A novel ROtating Cartesian K-space (ROCK) reordering method was designed that incorporates repeatedly sampled k-space centerline as the SG motion surrogate and allows for retrospective k-space data binning into different respiratory positions based on the amplitude of the surrogate...
January 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28128544/high-resolution-4d-preclinical-single-photon-emission-computed-tomography-x-ray-computed-tomography-imaging-of-technetium-transport-within-a-heterogeneous-porous-media
#18
Mine Dogan, Stephen M J Moysey, Ruud M Ramakers, Timothy A DeVol, Frederik J Beekman, Harald C Groen, Brian A Powell
A dynamic (99m)Tc tracer experiment was performed to investigate the capabilities of combined preclinical single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) for investigating transport in a heterogeneous porous medium. The experiment was conducted by continuously injecting a (99m)Tc solution into a column packed with eight layers (i.e., soil, silica gel, and 0.2-4 mm glass beads). Within the imaging results it was possible to correlate observed features with objects as small as 2 mm for the SPECT and 0...
February 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28126751/application-of-time-resolved-3d-digital-subtraction-angiography-to-plan-cerebral-arteriovenous-malformation-radiosurgery
#19
K-K Chen, W-Y Guo, H-C Yang, C-J Lin, C-H F Wu, S Gehrisch, M Kowarschik, Y-T Wu, W-Y Chung
BACKGROUND AND PURPOSE: Time-resolved 3D-DSA (4D-DSA) enables viewing vasculature from any desired angle and time frame. We investigated whether these advantages may facilitate treatment planning and the feasibility of using 4D-DSA as a single imaging technique in AVM/dural arteriovenous fistula radiosurgery. MATERIALS AND METHODS: Twenty consecutive patients (8 dural arteriovenous fistulas and 12 AVMs; 13 men and 7 women; mean age, 45 years; range, 18-64 years) who were scheduled for gamma knife radiosurgery were recruited (November 2014 to October 2015)...
January 26, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28113545/radiolucent-4d-ultrasound-imaging-system-design-and-application-to-radiotherapy-guidance
#20
Jeffrey Schlosser, Dimitre Hristov
Four-dimensional (4D) ultrasound (US) is an attractive modality for image guidance due to its real-time, non-ionizing, volumetric imaging capability with high soft tissue contrast. However, existing 4D US imaging systems contain large volumes of metal which interfere with diagnostic and therapeutic ionizing radiation in procedures such as CT imaging and radiation therapy. This study aimed to design and characterize a novel 4D Radiolucent Remotely-Actuated UltraSound Scanning (RRUSS) device that overcomes this limitation...
April 27, 2016: IEEE Transactions on Medical Imaging
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