keyword
MENU ▼
Read by QxMD icon Read
search

4D CT

keyword
https://www.readbyqxmd.com/read/28629434/reduction-of-breathing-irregularity-related-motion-artifacts-in-low-pitch-spiral-4d-ct-by-optimized-projection-binning
#1
René Werner, Christian Hofmann, Eike Mücke, Tobias Gauer
BACKGROUND: Respiration-correlated CT (4D CT) is the basis of radiotherapy treatment planning of thoracic and abdominal tumors. Current clinical 4D CT images suffer, however, from artifacts due to unfulfilled assumptions concerning breathing pattern regularity. We propose and evaluate modifications to existing low-pitch spiral 4D CT reconstruction protocols to counteract respective artifacts. METHODS: The proposed advanced reconstruction (AR) approach consists of two steps that build on each other: (1) statistical analysis of the breathing signal recorded during CT data acquisition and extraction of a patient-specific reference breathing cycle for projection binning; (2) incorporation of an artifact measure into the reconstruction...
June 19, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28622338/multi-phase-simultaneous-segmentation-of-tumor-in-lung-4d-ct-data-with-context-information
#2
Zhengwen Shen, Huafeng Wang, Weiwen Xi, Xiaogang Deng, Jin Chen, Yu Zhang
Lung 4D computed tomography (4D-CT) plays an important role in high-precision radiotherapy because it characterizes respiratory motion, which is crucial for accurate target definition. However, the manual segmentation of a lung tumor is a heavy workload for doctors because of the large number of lung 4D-CT data slices. Meanwhile, tumor segmentation is still a notoriously challenging problem in computer-aided diagnosis. In this paper, we propose a new method based on an improved graph cut algorithm with context information constraint to find a convenient and robust approach of lung 4D-CT tumor segmentation...
2017: PloS One
https://www.readbyqxmd.com/read/28617686/imaging-adult-patients-with-coarctation-of-the-aorta
#3
Akanksha N Thakkar, Ponraj Chinnadurai, C Huie Lin
PURPOSE OF REVIEW: To provide an overview of current recommendations and techniques used to image coarctations of the aorta. RECENT FINDINGS: Imaging of coarctation of the aorta in adults is moving away from conventional techniques such as echocardiography and invasive angiography. Echocardiography may assist in making the diagnosis but is limited in its ability to quantify the severity of coarctations. Current guidelines recommend that every patient with a coarctation must undergo a computed tomography (CT) or MRI scan for accurate delineation of morphology...
June 15, 2017: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/28595774/feasibility-of-using-single-photon-counting-x-ray-for-lung-tumor-position-estimation-based-on-4d-ct
#4
Katharina P Aschenbrenner, Christian V Guthier, Yulia Lyatskaya, Judit Boda-Heggemann, Frederik Wenz, Jürgen W Hesser
PURPOSE: In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i...
June 5, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28587761/itv-mid-ventilation-gating-or-couch-tracking-a-comparison-of-respiratory-motion-management-techniques-based-on-4d-dose-calculations
#5
Stefanie Ehrbar, Alexander Jöhl, Adrianna Tartas, Luisa Sabrina Stark, Oliver Riesterer, Stephan Klöck, Matthias Guckenberger, Stephanie Tanadini-Lang
PURPOSE: Respiratory motion-management techniques (MMT) aim to ensure tumor dose coverage while sparing lung tissue. Dynamic treatment-couch tracking of the moving tumor is a promising new MMT and was compared to the internal-target-volume (ITV) concept, the mid-ventilation (MidV) principle and the gating approach in a planning study based on 4D dose calculations. METHODS: For twenty patients with lung lesions, planning target volumes (PTV) were adapted to the MMT and stereotactic body radiotherapy treatments were prepared with the 65%-isodose enclosing the PTV...
June 3, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28585715/does-liver-resection-transplantation-affect-respiratory-induced-liver-motion-in-patients-with-hepatocellular-carcinoma
#6
Yong Hu, Yong-Kang Zhou, Yi-Xing Chen, Lu-Xi Ye, Zhao-Chong Zeng
The purpose of this study was to evaluate the changes in magnitude of three-dimensional (3D) liver motion after liver resection/transplantation in patients with hepatocellular carcinoma (HCC) using four-dimensional (4D)-computed tomography (CT) images. From January 2012 to April 2016, 74 HCC patients underwent 4D-CT scans under a free-breathing state to assess respiratory liver motion. Of the 74 patients, 40 did not have a liver resection/transplantation (Group A), 34 with liver resection/transplantation. 15 underwent major or minor resection in the right liver lobe (Group B), 14 underwent major or minor resection in the left liver lobe (Group C), and five underwent liver transplantation (Group D)...
June 6, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28585063/enabling-real-time-volume-rendering-of-functional-magnetic-resonance-imaging-on-an-ios-device
#7
Joseph Holub, Eliot Winer
Powerful non-invasive imaging technologies like computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI) are used daily by medical professionals to diagnose and treat patients. While 2D slice viewers have long been the standard, many tools allowing 3D representations of digital medical data are now available. The newest imaging advancement, functional MRI (fMRI) technology, has changed medical imaging from viewing static to dynamic physiology (4D) over time, particularly to study brain activity...
June 5, 2017: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
https://www.readbyqxmd.com/read/28580809/cardiovascular-imaging-environment-will-the-future-be-cloud-based
#8
Nadine Kawel-Boehm, David A Bluemke
In cardiovascular CT and MR imaging large datasets have to be stored, post-processed, analyzed and distributed. Beside basic assessment of volume and function in cardiac magnetic resonance imaging e.g., more sophisticated quantitative analysis is requested requiring specific software. Several institutions cannot afford various types of software and provide expertise to perform sophisticated analysis. Areas covered: Various cloud services exist related to data storage and analysis specifically for cardiovascular CT and MR imaging...
June 13, 2017: Expert Review of Medical Devices
https://www.readbyqxmd.com/read/28579281/interfractional-variability-of-respiration-induced-esophageal-tumor-motion-quantified-using-fiducial-markers-and-four-dimensional-cone-beam-computed-tomography
#9
Peng Jin, Maarten C C M Hulshof, Niek van Wieringen, Arjan Bel, Tanja Alderliesten
PURPOSE: To investigate the interfractional variability of respiration-induced esophageal tumor motion using fiducial markers and four-dimensional cone-beam computed tomography (4D-CBCT) and assess if a 4D-CT is sufficient for predicting the motion during the treatment. MATERIALS AND METHODS: Twenty-four patients with 63 markers visible in the retrospectively reconstructed 4D-CBCTs were included. For each marker, we calculated the amplitude and trajectory of the respiration-induced motion...
June 1, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28577254/the-value-of-whole-brain-ct-perfusion-imaging-and-ct-angiography-using-a-320-slice-ct-scanner-in-the-diagnosis-of-mci-and-ad-patients
#10
Bo Zhang, Guo-Jun Gu, Hong Jiang, Yi Guo, Xing Shen, Bo Li, Wei Zhang
OBJECTIVES: To validate the value of whole-brain computed tomography perfusion (CTP) and CT angiography (CTA) in the diagnosis of mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS: Whole-brain CTP and four-dimensional CT angiography (4D-CTA) images were acquired in 30 MCI, 35 mild AD patients, 35 moderate AD patients, 30 severe AD patients and 50 normal controls (NC). Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and correlation between CTP and 4D-CTA were analysed...
June 2, 2017: European Radiology
https://www.readbyqxmd.com/read/28574192/feasibility-study-of-ultrasound-imaging-for-stereotactic-body-radiation-therapy-with-active-breathing-coordinator-in-pancreatic-cancer
#11
Lin Su, Iulian Iordachita, Yin Zhang, Junghoon Lee, Sook Kien Ng, Juan Jackson, Ted Hooker, John Wong, Joseph M Herman, H Tutkun Sen, Peter Kazanzides, Muyinatu A Lediju Bell, Chen Yang, Kai Ding
PURPOSE: Stereotactic body radiation therapy (SBRT) allows for high radiation doses to be delivered to the pancreatic tumors with limited toxicity. Nevertheless, the respiratory motion of the pancreas introduces major uncertainty during SBRT. Ultrasound imaging is a non-ionizing, non-invasive, and real-time technique for intrafraction monitoring. A configuration is not available to place the ultrasound probe during pancreas SBRT for monitoring. METHODS AND MATERIALS: An arm-bridge system was designed and built...
June 2, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28557310/larynx-motion-considerations-in-partial-larynx-volumetric-modulated-arc-therapy-for-early-glottic-cancer
#12
Houda Bahig, Phuc Félix Nguyen-Tan, Édith Filion, David Roberge, Pensavan Thanomsack, Jacques de Guise, Danis Blais, Robert Doucet, Laurent Létourneau-Guillon, Louise Lambert
INTRODUCTION: To assess laryngeal motion in early glottic cancer in order to determine safe margins for partial larynx volumetric modulated arc therapy (PL-VMAT), and to quantify dosimetric advantages of PL-VMAT. METHODS: This prospective study included T1-2N0 glottic cancers treated with whole larynx VMAT (WL-VMAT). Pre- and mid-treatment 4D-computed tomography (4D-CT) and dynamic magnetic resonance imaging (MRI) allowed for assessment of larynx swallowing and respiratory motion...
May 30, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/28553594/comparison-of-18f-fluorocholine-positron-emission-tomography-computed-tomography-and-four-dimensional-computed-tomography-in-the-preoperative-localization-of-parathyroid-adenomas-initial-results
#13
Sameer K Taywade, Nishikant A Damle, Abhishek Behera, K Devasenathipathy, Chandrasekhar Bal, Madhavi Tripathi, Shipra Agarwal, Nikhil Tandon, Sunil Chumber, V Seenu
OBJECTIVE: We aimed to compare the diagnostic accuracy of 18F-Fluorocholine (FCH)-positron emission tomography/computed tomography (PET/CT) and four-dimensional (4D)- CT in detection and localization of eutopic and ectopic parathyroid adenoma (PA) in patients with hyperparathyroidism. MATERIALS AND METHODS: Five patients with primary hyperparathyroidism underwent FCH-PET/CT after 60 min of 185 MBq of intravenous 18F-FCH administration. Images were acquired from head to mediastinum at 3 min per bed position...
May 2017: Indian Journal of Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28537761/correlation-analysis-of-18-f-fluorodeoxyglucose-and-18-f-fluoroazomycin-arabinoside-uptake-distributions-in-lung-tumours-during-radiation-therapy
#14
Dario Di Perri, John A Lee, Anne Bol, François-Xavier Hanin, Guillaume Janssens, Daniel Labar, Annie Robert, Edmond Sterpin, Xavier Geets
BACKGROUND: PET-guided dose painting (DP) aims to target radioresistant tumour regions in order to improve radiotherapy (RT) outcome. Besides the well-known [(18)F]fluorodeoxyglucose (FDG), the hypoxia positron emission tomography (PET) tracer [(18)F]fluoroazomycin arabinoside (FAZA) could provide further useful information to guide the radiation dose prescription. In this study, we compare the spatial distributions of FDG and FAZA PET uptakes in lung tumours. MATERIAL AND METHODS: Fourteen patients with unresectable lung cancer underwent FDG and FAZA 4D-PET/CT on consecutive days at three time-points: prior to RT (pre), and during the second (w2), and the third (w3) weeks of RT...
May 24, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28535915/virtual-patient-3d-dose-reconstruction-using-in-air-epid-measurements-and-a-back-projection-algorithm-for-imrt-and-vmat-treatments
#15
Igor Olaciregui-Ruiz, Roel Rozendaal, René F M van Oers, Ben Mijnheer, Anton Mans
PURPOSE: At our institute, a transit back-projection algorithm is used clinically to reconstruct in vivo patient and in phantom 3D dose distributions using EPID measurements behind a patient or a polystyrene slab phantom, respectively. In this study, an extension to this algorithm is presented whereby in air EPID measurements are used in combination with CT data to reconstruct 'virtual' 3D dose distributions. By combining virtual and in vivo patient verification data for the same treatment, patient-related errors can be separated from machine, planning and model errors...
May 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28493110/bem-based-simulation-of-lung-respiratory-deformation-for-ct-guided-biopsy
#16
Dong Chen, Weisheng Chen, Lipeng Huang, Xuegang Feng, Terry Peters, Lixu Gu
PURPOSE: Accurate and real-time prediction of the lung and lung tumor deformation during respiration are important considerations when performing a peripheral biopsy procedure. However, most existing work focused on offline whole lung simulation using 4D image data, which is not applicable in real-time image-guided biopsy with limited image resources. In this paper, we propose a patient-specific biomechanical model based on the boundary element method (BEM) computed from CT images to estimate the respiration motion of local target lesion region, vessel tree and lung surface for the real-time biopsy guidance...
May 10, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28477378/evaluating-the-accuracy-of-4d-ct-ventilation-imaging-first-comparison-with-technegas-spect-ventilation
#17
Fiona Hegi-Johnson, Paul Keall, Jeff Barber, Chuong Bui, John Kipritidis
INTRODUCTION: Computed tomography ventilation imaging (CTVI) is a highly accessible functional lung imaging modality that can unlock the potential for functional avoidance in lung cancer radiation therapy. Previous attempts to validate CTVI against clinical ventilation single-photon emission computed tomography (V-SPECT) have been hindered by radioaerosol clumping artifacts. This work builds on those studies by performing the first comparison of CTVI with (99m) Tc-carbon ('Technegas'), a clinical V-SPECT modality featuring smaller radioaerosol particles with less clumping...
May 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28469512/does-motion-assessment-with-4-dimensional-computed-tomographic-imaging-for-non-small-cell-lung-cancer-radiotherapy-improve-target-volume-coverage
#18
Naseer Ahmed, Sankar Venkataraman, Kate Johnson, Keith Sutherland, Shaun K Loewen
INTRODUCTION: Modern radiotherapy with 4-dimensional computed tomographic (4D-CT) image acquisition for non-small cell lung cancer (NSCLC) captures respiratory-mediated tumor motion to provide more accurate target delineation. This study compares conventional 3-dimensional (3D) conformal radiotherapy (3DCRT) plans generated with standard helical free-breathing CT (FBCT) with plans generated on 4D-CT contoured volumes to determine whether target volume coverage is affected. MATERIALS AND METHODS: Fifteen patients with stage I to IV NSCLC were enrolled in the study...
2017: Clinical Medicine Insights. Oncology
https://www.readbyqxmd.com/read/28467314/subpopulation-based-correspondence-modelling-for-improved-respiratory-motion-estimation-in-the-presence-of-inter-fraction-motion-variations
#19
Matthias Wilms, René Werner, Tokihiro Yamamoto, Heinz Handels, Jan Ehrhardt
Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients...
May 3, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28464747/cone-beam-ct-based-set-up-strategies-with-and-without-rotational-correction-for-stereotactic-body-radiation-therapy-in-the-liver
#20
Jenny Bertholet, Esben Worm, Morten Høyer, Per Poulsen
BACKGROUND: Accurate patient positioning is crucial in stereotactic body radiation therapy (SBRT) due to a high dose regimen. Cone-beam computed tomography (CBCT) is often used for patient positioning based on radio-opaque markers. We compared six CBCT-based set-up strategies with or without rotational correction. MATERIAL AND METHODS: Twenty-nine patients with three implanted markers received 3-6 fraction liver SBRT. The markers were delineated on the mid-ventilation phase of a 4D-planning-CT...
June 2017: Acta Oncologica
keyword
keyword
92855
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"