Relevant bibliographies by topics / 4D-CT

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers
  5. Reports

Academic literature on the topic '4D-CT'

Author: Grafiati
Published: 4 June 2021
Last updated: 20 February 2023

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Journal articles on the topic "4D-CT"

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Hoang, Jenny K., Katherine Williams, Frank Gaillard, Andrew Dixon, and Julie A. Sosa. "Parathyroid 4D-CT." Otolaryngology–Head and Neck Surgery 155, no. 6 (July 22, 2016): 956–60. http://dx.doi.org/10.1177/0194599816655311.

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Pretet, Valentin, Marianela Rotania, Mehdi Helali, Mihaela Ignat, Michel Vix, and Alessio Imperiale. "18F-Fluorocholine PET and Multiphase CT Integrated in Dual Modality PET/4D-CT for Preoperative Evaluation of Primary Hyperparathyroidism." Journal of Clinical Medicine 9, no. 6 (June 26, 2020): 2005. http://dx.doi.org/10.3390/jcm9062005.

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The present retrospective study evaluates the diagnostic value of integrated 18F-Fluorocholine positron emission tomography/four-dimensional contrast-enhanced computed tomography (18F-FCH PET/4D-CT) as second-line imaging in preoperative work-up of primary hyperparathyroidism (pHPT), and compares 18F-FCH PET with 4D-CT. Patients with pHPT and negative/discordant first-line imaging addressed for integrated 18F-FCH PET/4D-CT were retrospectively selected. Sensitivity and detection rate (DR%) of 18F-FCH PET/CT, 4D-CT, and PET/4D-CT were calculated according to the per patient and per lesion analyses, and afterwards compared. Histology associated with a decrease more than 50% of perioperative parathyroid hormone (PTH) blood level was used as a gold standard. Persistent high serum PTH and calcium levels during a 6-month follow-up was considered as presence of pHPT in both operated and non-operated patients. 50 patients (55 glands) were included. 44/50 patients (88%) were surgically treated. On a per patient analysis, sensitivity was 93%, 80%, and 95%, and DR% was 82%, 68%, and 84%, respectively for PET/CT, 4D-CT, and PET/4D-CT. PET/CT was more sensitive than 4D-CT (p = 0.046). PET/4D-CT performed better than 4D-CT (p = 0.013) but was equivalent to PET/CT alone. On a per gland analysis, sensitivity PET/CT, 4D-CT, and PET/4D-CT was 88%, 66%, and 92%, and DR% was 79%, 57%, and 83%, respectively. PET/CT and PET/4D-CT were more sensitive than 4D-CT alone (p = 0.01, p < 0.001, respectively). However, PET/CT and PET/4D-CT performed similarly. In conclusion, 18F-FCH PET provides better identification of hyperfunctioning parathyroids than 4D-CT and the combination of both did not significantly improve diagnostic sensitivity. Further investigations involving larger populations are necessary to define the role of 18F-FCH PET/4D-CT as a “one-stop shop” second-line imaging in preoperative work-up of pHPT, especially considering the additional patient radiation exposure due to multi-phase CT.
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Latge, Adrien, Sophie Riehm, Michel Vix, Jacob Bani, Mihaela Ignat, Valentin Pretet, Mehdi Helali, Giorgio Treglia, and Alessio Imperiale. "18F-Fluorocholine PET and 4D-CT in Patients with Persistent and Recurrent Primary Hyperparathyroidism." Diagnostics 11, no. 12 (December 17, 2021): 2384. http://dx.doi.org/10.3390/diagnostics11122384.

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Patients with primary hyperparathyroidism (pHPT) can develop persistent (P-pHPT) or recurrent (R-pHPT) disease after parathyroidectomy. Before recommending reoperation, recurrence must be accurately identified because of the high risk of complications. Our study evaluates 18F-fluorocholine (18F-FCH) PET/CT and 4D-CT integrated in PET/4D-CT in patients with P-pHPT/R-pHPT. Patients with P-pHPT/R-pHPT investigated by 18F-FCH PET/4D-CT between May 2018 and March 2021 were retrospectively included. Forty-two patients were included, 37 of whom underwent 4D-CT. The sensitivity and detection rate (DR%) were 95% and 88% for 18F-FCH PET/CT and 70% and 63% for 4D-CT, respectively. PET/CT and 4D-CT were concordant in 18/24 glands and concordant and positive in 15/24 (63%) glands. Discordant results were obtained for 6/24 glands. The surgical success rate was 65%. PET/CT showed significantly higher sensitivity than 4D-CT. Dynamic CT allowed the identification of no additional glands missed by PET/CT, and the combination of the 2 techniques did not improve the sensitivity or DR%. 18F-FCH PET/CT appears to be a valuable technique to accurately detect hyperfunctioning parathyroid tissue in patients with P-pHPT/R-pHPT and is better than 4D-CT. Except for cases with doubtful locations of PET targets that may require 4D-CT for surgical guidance, standard nonenhanced 18F-FCH PET/CT can be effectively recommended in patients with P-pHPT/R-pHPT before reoperation.
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Yamamoto, Tokihiro, Sven Kabus, Cristian Lorenz, Eric Johnston, Peter G. Maxim, Maximilian Diehn, Neville Eclov, Cristian Barquero, Billy W. Loo, and Paul J. Keall. "4D CT lung ventilation images are affected by the 4D CT sorting method." Medical Physics 40, no. 10 (September 11, 2013): 101907. http://dx.doi.org/10.1118/1.4820538.

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Maric, Slavica, Petar Janjic, Borut Bosancic, Milan Mijailovic, and Snezana Lukic. "Importance of four-dimensional computed tomography simulation in locally advanced lung cancer radiotherapy: Impact on reducing planning target volume." Vojnosanitetski pregled, no. 00 (2021): 96. http://dx.doi.org/10.2298/vsp210520096m.

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Background/Aim. Four dimensional (4DCT) simulation is a useful tool for motion assessment in lung cancer radiotherapy. Conventional Three dimensional (3D) - Free Breathing simulation is static, with limited motion information. The aim of this study was to compare clinically significant differences between the target volumes defined on 3D CT vs. 4D CT simulation and potential impact on the planning target volume (PTV). In addition, to quantify movements of primary tumour (GTV) during 4D CT simulation on three axis -Z-supero inferior (SI), X-mediolateral (ML), and Y-anteroposterior (AP). Methods. This retrospective study evaluated 20 lung cancer patients who underwent CT simulation for radical radiotherapy treatment. Free Breathing 3D CT and 4D CT simulation were acquired for each patient in accordance with our institutional protocol. Volumetric comparison radiation volumes defined on 3D CT vs. 4D CT simulation was done-Gross tumour volume GTV 3D vs. internal GTV- (iGTV 4D) and PTV 3D vs. iPTV 4D. Volumetric values expressed in cm3 and equivalent spherical diameter (ESD) expressed in cm were assessed. Comparison of GTV movement in the phase FB-GTV FB, phase 0-GTV0, phase 50-GTV 50, and phase Maximum intensity projection (MIP) -GTV MIP was made with GTV FB as the basic value. The evaluation was made in three axis. Results. Comparison volumetric values between GTV 3D vs. iGTV 4D was 63.15 vs.85.51 (p<0.001) respectively. iGTV 4D was significantly larger than GTV 3D (p<0.001). The mean value (ESD) PTV 3D vs.iPTV 4D was 8.44 vs. 7.82 (p<0.001) respectively, and mean value volume PTV 3D vs. iPTV 4D was 352.70 vs. 272.78 (p<0.001) respectively. PTV 3D was significantly larger than iPTV 4D (p<0.001). Statistically significant difference (p<0.05) was identified in the deviation related to Z axis between the upper and lower lobe. Conclusion. 4D CT simulation based delineation can reduce planning target volume compared to 3D simulation based radiation therapy and therefore, it is a prerequisite for high-quality and precise radiation therapy treatment.
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Galvin, Leo, Jorge D. Oldan, Manisha Bahl, James D. Eastwood, Julie A. Sosa, and Jenny K. Hoang. "Parathyroid 4D CT and Scintigraphy." Otolaryngology–Head and Neck Surgery 154, no. 5 (March 2016): 847–53. http://dx.doi.org/10.1177/0194599816630711.

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Reinartz, Gabriele, Uwe Haverkamp, Ramona Wullenkord, Philipp Lehrich, Jan Kriz, Florian Büther, Klaus Schäfers, Michael Schäfers, and Hans Theodor Eich. "4D-Listmode-PET-CT and 4D-CT for optimizing PTV margins in gastric lymphoma." Strahlentherapie und Onkologie 192, no. 5 (February 22, 2016): 322–32. http://dx.doi.org/10.1007/s00066-016-0949-0.

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Gill, Gurman, and Reinhard R. Beichel. "Lung Segmentation in 4D CT Volumes Based on Robust Active Shape Model Matching." International Journal of Biomedical Imaging 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/125648.

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Dynamic and longitudinal lung CT imaging produce 4D lung image data sets, enabling applications like radiation treatment planning or assessment of response to treatment of lung diseases. In this paper, we present a 4D lung segmentation method that mutually utilizes all individual CT volumes to derive segmentations for each CT data set. Our approach is based on a 3D robust active shape model and extends it to fully utilize 4D lung image data sets. This yields an initial segmentation for the 4D volume, which is then refined by using a 4D optimal surface finding algorithm. The approach was evaluated on a diverse set of 152 CT scans of normal and diseased lungs, consisting of total lung capacity and functional residual capacity scan pairs. In addition, a comparison to a 3D segmentation method and a registration based 4D lung segmentation approach was performed. The proposed 4D method obtained an average Dice coefficient of0.9773±0.0254, which was statistically significantly better (pvalue≪0.001) than the 3D method (0.9659±0.0517). Compared to the registration based 4D method, our method obtained better or similar performance, but was 58.6% faster. Also, the method can be easily expanded to process 4D CT data sets consisting of several volumes.
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Ehrhardt, J., T. Frenzel, D. Säring, W. Lu, D. Low, H. Handels, and R. Werner. "Motion Artifact Reducing Reconstruction of 4D CT Image Data for the Analysis of Respiratory Dynamics." Methods of Information in Medicine 46, no. 03 (2007): 254–60. http://dx.doi.org/10.1160/me9040.

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Summary Objectives: Respiratory motion represents a major problem in radiotherapy of thoracic and abdominal tumors. Methods for compensation require comprehensive knowledge of underlying dynamics. Therefore, 4D (= 3D + t) CT data can be helpful. But modern CT scanners cannot scan a large region of interest simultaneously. So patients have to be scanned in segments. Commonly used approaches for reconstructing the data segments into 4D CT images cause motion artifacts. In orderto reduce the artifacts, a new method for 4D CT reconstruction is presented. The resulting data sets are used to analyze respiratory motion. Methods: Spatiotemporal CT image sequences of lung cancer patients were acquired using a multi-slice CT in cine mode during free breathing. 4D CT reconstruction was done by optical flow based temporal interpolation. The resulting 4D image data were compared with data generated bythe commonly used nearest neighbor reconstruction. Subsequent motion analysis is mainly concerned with tumor mobility. Results: The presented optical flow-based method enables the reconstruction of 3D CT images at arbitrarily chosen points of the patient’s breathing cycle. A considerable reduction of motion artifacts has been proven in eight patient data sets. Motion analysis showed that tumor mobility differs strongly between the patients. Conclusions: Due to the proved reduction of motion artifacts, the optical flow-based 4D CT reconstruction offers the possibility of high-quality motion analysis. Because the method is based on an interpolation scheme, it additionally has the potential to enable the reconstruction of 4D CT data from a lesser number of scans.
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Lantz, Jonas, Vikas Gupta, Lilian Henriksson, Matts Karlsson, Anders Persson, Carl-Johan Carlhäll, and Tino Ebbers. "Intracardiac Flow at 4D CT: Comparison with 4D Flow MRI." Radiology 289, no. 1 (October 2018): 51–58. http://dx.doi.org/10.1148/radiol.2018173017.

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Dissertations / Theses on the topic "4D-CT"

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Richter, Christian. "Der Einfluss der Atembewegung auf die PET/CT-Schwächungskorrektur." Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-19591.

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Die Kombination von Positronen-Emissions-Tomographie (PET) und Röntgen-Computertomographie (CT) in Form moderner PET/CT-Geräte ermöglicht die Nutzung der CT-Information zur Korrektur der Photonenschwächung in der PET. Allerdings können Bewegungen, die zum Beispiel durch die Atmung hervorgerufen werden können, zu einer fehlerhaften Schwächungskorrektur führen. Die Einführung von zeitlich aufgelöster Bildgebung für beide Modalitäten (4D-PET/4D-CT) ermöglicht nicht nur die Auflösung von periodischen Bewegungen, sondern auch die Reduktion dieser Fehler in der Schwächungskorrektur. Dazu werden die einzelnen Datensätze des 4D-PET, die jeweils einer bestimmten Bewegungsphase entsprechen, mit dem entsprechenden CT-Datensatz dieser Atemphase schwächungskorrigiert. In der vorliegenden Arbeit wurde diese phasenkorrelierte Schwächungskorrektur des 4D-PET mit dem 4D-CT am Universitästsklinikum Dresden installierten PET/CT ermöglicht und anhand von Phantomexperimenten mit anderen Schwächungskorrekturmethoden für 4D-PET verglichen. Dazu musste zunächst die Aufnahme von 4D-CT an dem verwendeten PET/CT ermöglicht und dessen Synchronität mit dem 4D-PET hergestellt werden. Außerdem wurde ein vorhandenes Atemphantom so modifiziert, dass es typische Bewegungen von Bronchialkarzinomen in zwei Dimensionen und mit zwei möglichen Atemmustern simuliert. Die phasenkorrelierte Schwächungskorrektur führte zu einer quantitativ korrekten Wiederherstellung des Aktivitätsvolumens, der darin enthaltenen Aktivität sowie der Bewegungsamplitude und stellt somit die beste der hier verglichenen 4D-PET-Schwächungskorrekturmethoden dar. Diese Ergebnisse lassen vermuten, dass die phasenkorrelierte Schwächungskorrektur auch bei klinischer Anwendung eine signifikante Verbesserung in oben genannten Punkten darstellt. Dies sollte in Zukunft an Patientendaten überprüft werden
The combination of Positron Emission Tomography (PET) and Computed Tomography (CT) in one device allows the use of CT-information for attenuation correction in PET. Though motion, for example induced by respiration, can cause inaccurate attenuation correction. The implementation of time-resolved imaging methods for both modalities (4D-PET/4D-CT) enables not only the resolution of motion but also the reduction of artifacts caused by attenuation correction. Therefore, the single datasets of the 4D-PET that are related to a individual respiratory phase, are attenuation corrected with the corresponding dataset of the 4D-CT. This phase correlated attenuation correction of the 4D-PET with the 4D-CT was implemented at the PET/CT installed at the Universitätsklinikum Dresden. For that purpose the acquisition of 4D-CT was implemented at the PET/CT and its synchronisation with the 4D-PET was verified. Furthermore the new attenuation correction method was compared with other attenuation correction methods by performing phantom experiments. Therefore an exisisting respiratory phantom had to be modified to perform typical lung tumor motion in two dimensions with two possible patterns of respiration. The phase correlated attenuation correction leads to a quantitatively correct restauration of the activity volume, its total activity and its motion amplitude. Compared with other correction methods, the phase correlated attenuation correction shows the best results in all examined criteria. This findings suggest that the clinical application of the phase correlated attenuation correction will also lead to a significant improvement in all mentioned points. This has to be verified by analyzing patient data
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Richter, Christian. "Der Einfluss der Atembewegung auf die PET/CT-Schwächungskorrektur." Master's thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A25045.

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Die Kombination von Positronen-Emissions-Tomographie (PET) und Röntgen-Computertomographie (CT) in Form moderner PET/CT-Geräte ermöglicht die Nutzung der CT-Information zur Korrektur der Photonenschwächung in der PET. Allerdings können Bewegungen, die zum Beispiel durch die Atmung hervorgerufen werden können, zu einer fehlerhaften Schwächungskorrektur führen. Die Einführung von zeitlich aufgelöster Bildgebung für beide Modalitäten (4D-PET/4D-CT) ermöglicht nicht nur die Auflösung von periodischen Bewegungen, sondern auch die Reduktion dieser Fehler in der Schwächungskorrektur. Dazu werden die einzelnen Datensätze des 4D-PET, die jeweils einer bestimmten Bewegungsphase entsprechen, mit dem entsprechenden CT-Datensatz dieser Atemphase schwächungskorrigiert. In der vorliegenden Arbeit wurde diese phasenkorrelierte Schwächungskorrektur des 4D-PET mit dem 4D-CT am Universitästsklinikum Dresden installierten PET/CT ermöglicht und anhand von Phantomexperimenten mit anderen Schwächungskorrekturmethoden für 4D-PET verglichen. Dazu musste zunächst die Aufnahme von 4D-CT an dem verwendeten PET/CT ermöglicht und dessen Synchronität mit dem 4D-PET hergestellt werden. Außerdem wurde ein vorhandenes Atemphantom so modifiziert, dass es typische Bewegungen von Bronchialkarzinomen in zwei Dimensionen und mit zwei möglichen Atemmustern simuliert. Die phasenkorrelierte Schwächungskorrektur führte zu einer quantitativ korrekten Wiederherstellung des Aktivitätsvolumens, der darin enthaltenen Aktivität sowie der Bewegungsamplitude und stellt somit die beste der hier verglichenen 4D-PET-Schwächungskorrekturmethoden dar. Diese Ergebnisse lassen vermuten, dass die phasenkorrelierte Schwächungskorrektur auch bei klinischer Anwendung eine signifikante Verbesserung in oben genannten Punkten darstellt. Dies sollte in Zukunft an Patientendaten überprüft werden.
The combination of Positron Emission Tomography (PET) and Computed Tomography (CT) in one device allows the use of CT-information for attenuation correction in PET. Though motion, for example induced by respiration, can cause inaccurate attenuation correction. The implementation of time-resolved imaging methods for both modalities (4D-PET/4D-CT) enables not only the resolution of motion but also the reduction of artifacts caused by attenuation correction. Therefore, the single datasets of the 4D-PET that are related to a individual respiratory phase, are attenuation corrected with the corresponding dataset of the 4D-CT. This phase correlated attenuation correction of the 4D-PET with the 4D-CT was implemented at the PET/CT installed at the Universitätsklinikum Dresden. For that purpose the acquisition of 4D-CT was implemented at the PET/CT and its synchronisation with the 4D-PET was verified. Furthermore the new attenuation correction method was compared with other attenuation correction methods by performing phantom experiments. Therefore an exisisting respiratory phantom had to be modified to perform typical lung tumor motion in two dimensions with two possible patterns of respiration. The phase correlated attenuation correction leads to a quantitatively correct restauration of the activity volume, its total activity and its motion amplitude. Compared with other correction methods, the phase correlated attenuation correction shows the best results in all examined criteria. This findings suggest that the clinical application of the phase correlated attenuation correction will also lead to a significant improvement in all mentioned points. This has to be verified by analyzing patient data.
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Andersson, Mats, and Hans Knutsson. "Adaptive Spatio-temporal Filtering of 4D CT-Heart." Linköpings universitet, Medicinsk informatik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-92725.

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The aim of this project is to keep the x-ray exposure of the patient as low as reasonably achievable while improving the diagnostic image quality for the radiologist. The means to achieve these goals is to develop and evaluate an ecient adaptive ltering (denoising/image enhancement) method that fully explores true 4D image acquisition modes. The proposed prototype system uses a novel lter set having directional lter responses being monomials. The monomial lter concept is used both for estimation of local structure and for the anisotropic adaptive ltering. Initial tests on clinical 4D CT-heart data with ECG-gated exposure has resulted in a signicant reduction of the noise level and an increased detail compared to 2D and 3D methods. Another promising feature is that the reconstruction induced streak artifacts which generally occur in low dose CT are remarkably reduced in 4D.
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Lindbäck, Elias. ""Imaging with CBCT and 4D-CT of objects moving with respiratory motions"." Thesis, Stockholms universitet, Medicinsk strålningsfysik (tills m KI), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89053.

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AB S TRACT purpose : To further investigate the effects of respiratory motions on CBCT imaging, as well as 4D-CT examinations, with a future goal of using obtained results to implement new methods for individual margins and daily matching procedures into routine clinical practice. background : Since the implementation of CBCT combined with modern accelerators, a higher degree of accuracy has been made possible in RT. However, due to the slow gantry speed of linear accelerators, the imaging procedure of CBCT is a slow process which is thereby degraded by internal motion such as respiration. material and methods : Attain patient specific respiratory motion patterns from CBCT projection data of previous examinations. Utilize this data to perform simulations for both CBCT and 4D-CT using a steering system which allows for arbitrary motion patterns in the longitudinal direction. results : Various imaging with CBCT showed that the resulting images during respiratory motion, can be described by the Probability Density Function of the motion for as long as it does not cause related distortions. This also meant that convolution could be implemented as a model to estimate the CBCT images during oscillation, knowing the object and motion pattern. The 4D-CT examinations using the steering system showed that irregular motion patterns were less accurately described than regular patterns, making the actual motion an important feature to combine together with the measured amplitude. conclusions : It was made clear that CBCT images can be described by the PDF, and thus can be seen as a Color Intensity Projection of the object position. Also it has been shown that the projection data of CBCT images contains valuable information about the respiratory motion of the patient. Another conclusion is that with the help of fiducials, the position of the target within the respiratory cycle can be determined relative to the 4D-CT examination, enabling further input data as to the daily matching procedure, proper applied margins as well as dose to the OAR.
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Stroian, Gabriela. "Optimized scanning procedures for 4D CT data acquisition in radiation therapy." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84077.

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The goal of conformal radiation techniques is to improve local tumor control through dose escalation to target volumes while at the same time sparing surrounding healthy tissue. Accurate target volume delineation is essential in achieving this goal to avoid inadequate tumor coverage and/or irradiation of an unnecessary volume of healthy tissue. Respiratory motion is known to be the largest intra-fractional organ motion and the most significant source of uncertainty in treatment planning for chest lesions. A method to minimize effects of respiratory motion is to use four-dimensional (4D) radiotherapy.
A novel scanning procedure for 4D CT data acquisition is described in this work. Three single-slice helical scans are acquired simultaneously with the real-time tracking of several markers placed on a moving phantom. At the end of the three scans. CT data is binned into different respiratory phases according to the externally recorded respiratory signal and the scanned volume is reconstructed for several respiratory phases. The 4D CT images obtained show an overall improvement when compared to conventional CT images of a moving phantom.
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Min, Yugang. "4D-CT Lung Registration and its Application for Lung Radiation Therapy." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5340.

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Radiation therapy has been successful in treating lung cancer patients, but its efficacy is limited by the inability to account for the respiratory motion during treatment planning and radiation dose delivery. Physics-based lung deformation models facilitate the motion computation of both tumor and local lung tissue during radiation therapy. In this dissertation, a novel method is discussed to accurately register 3D lungs across the respiratory phases from 4D-CT datasets, which facilitates the estimation of the volumetric lung deformation models. This method uses multi-level and multi-resolution optical flow registration coupled with thin plate splines (TPS), to address registration issue of inconsistent intensity across respiratory phases. It achieves higher accuracy as compared to multi-resolution optical flow registration and other commonly used registration methods. Results of validation show that the lung registration is computed with 3 mm Target Registration Error (TRE) and approximately 3 mm Inverse Consistency Error (ICE). This registration method is further implemented in GPU based real time dose delivery simulation to assist radiation therapy planning.
ID: 031001565; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Advisers: Sumanta N. Pattanaik, Anand P. Santhanam.; Title from PDF title page (viewed August 26, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 77-83).
Ph.D.
Doctorate
Computer Science
Engineering and Computer Science
Computer Science
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McNamara, Joanne. "Investigation of two respiratory monitoring systems used for 4D CT and respiratory gating." Faculty of Engineering, 2008. http://ro.uow.edu.au/theses/107.

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Respiratory gating enables breathing synchronised activation of CT image acquisition and linear accelerator radiation output. Two commercially available respiratory gating systems used for planning and treatment of thoracic and abdominal cancer are investigated. The strain gauged AZ-733V respiratory gating system (Anzai Medical Systems, Tokyo, Japan) was used concurrently with the infrared Real-time Position Management system (Varian Medical Systems, Palo Alto, CA) to measure the respiratory cycle of 15 volunteers. Correlation between systems was measured in six locations and the optimum position of the external surrogates determined based on signal amplitude, reproducibility of breathing waveforms and the coefficient of determination between Anzai and RPM signals. The mean value of R2 between the two systems was found to be 0.611, 0.788 and 0.925 when both markers were positioned at the xiphoid, midway between the xiphoid process and umbilicus, and at the umbilicus respectively. When positioned in separate locations results were varied, R2 values ranging from 0.345-0.965. Results highlighted the importance of external surrogate position to the respiratory signal obtained, and indicated that the external marker position on the chest wall needs to be reproducible between 4D CT scanning and treatment. Recommendations are made that external surrogates must always be positioned at the umbilicus for the most clinically useful scans. Image distortion and artifacts were studied using the Anzai AZ-733V respiratory gating system in combination with the Siemens Sensation Open CT scanner. A moving respiratory phantom was constructed and the volumetric accuracy of retrospectively reconstructed 4D CT images for three moving test objects, across five frequencies and four amplitudes of movement was compared. Volumetric accuracy was found to be within 10% for retrospectively reconstructed gated objects moving with a period of 4 s, amplitude 1 cm. Large deviations of 19.4-51.6% from the static volume of the objects were observed in gated images for periods of 3 s or less. Significant distortion and under sampling was observed in gated images of the objects moving with a period of 10 s. Artifacts were related to the partial projection effect and data sufficiency conditions outlined in literature (Keall 2004, Pan 2004, Dinkel 2007).
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Jakubíček, Roman. "Korekce pohybu v hrudních dynamických kontrastních CT datech." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220059.

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This thesis deals with a nonrigid image registration for movement correction in thoracic dynamic contrast CT data. The deformation field is initialized by the analysis of disparities based on nonlinear matched filter, which defines local movement deformation. The values of control points are optimized by the Nelder-Mead method. The transformation model is based on a 4D (3D + time) free-form B-spline deformation for feature of movement distortion. The first part of the thesis briefly discusses the theory of image registration. Knowledge of this theory is necessary for understanding the remaining chapters, which describe the proposed method and its realization. The large part of this thesis is devoted to the geometrical image transformations, that is very important for the image registration. The thesis also describes a simplex method for function minimization. Three publicated methods of registration of medical 4D CT data are given. In the following chapter are individual parts of the purposed nonrigid registration including possible problems and their solution described.
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Dhou, Salam. "IMAGE-BASED RESPIRATORY MOTION EXTRACTION AND RESPIRATION-CORRELATED CONE BEAM CT (4D-CBCT) RECONSTRUCTION." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/496.

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Accounting for respiration motion during imaging helps improve targeting precision in radiation therapy. Respiratory motion can be a major source of error in determining the position of thoracic and upper abdominal tumor targets during radiotherapy. Thus, extracting respiratory motion is a key task in radiation therapy planning. Respiration-correlated or four-dimensional CT (4DCT) imaging techniques have been recently integrated into imaging systems for verifying tumor position during treatment and managing respiration-induced tissue motion. The quality of the 4D reconstructed volumes is highly affected by the respiratory signal extracted and the phase sorting method used. This thesis is divided into two parts. In the first part, two image-based respiratory signal extraction methods are proposed and evaluated. Those methods are able to extract the respiratory signals from CBCT images without using external sources, implanted markers or even dependence on any structure in the images such as the diaphragm. The first method, called Local Intensity Feature Tracking (LIFT), extracts the respiratory signal depending on feature points extracted and tracked through the sequence of projections. The second method, called Intensity Flow Dimensionality Reduction (IFDR), detects the respiration signal by computing the optical flow motion of every pixel in each pair of adjacent projections. Then, the motion variance in the optical flow dataset is extracted using linear and non-linear dimensionality reduction techniques to represent a respiratory signal. Experiments conducted on clinical datasets showed that the respiratory signal was successfully extracted using both proposed methods and it correlates well with standard respiratory signals such as diaphragm position and the internal markers’ signal. In the second part of this thesis, 4D-CBCT reconstruction based on different phase sorting techniques is studied. The quality of the 4D reconstructed images is evaluated and compared for different phase sorting methods such as internal markers, external markers and image-based methods (LIFT and IFDR). Also, a method for generating additional projections to be used in 4D-CBCT reconstruction is proposed to reduce the artifacts that result when reconstructing from an insufficient number of projections. Experimental results showed that the feasibility of the proposed method in recovering the edges and reducing the streak artifacts.
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Ho, Andrew Kenneth. "A novel SPH method for investigating the role of saliva in swallowing using 4D CT images." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61288.

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The thesis presents novel computer methods towards simulation of oropha- ryngeal swallowing. The anatomy and motion of the human upper airway was extracted from dynamic Computed Tomography (CT) data using a novel tool and workflow. A state-of-the-art SPH method is extended to accommo- date non-Newtonian materials in the extracted geometries. A preliminary numerical experiment of six human oropharyngeal swallows using Smoothed Particle Hydrodynamics (SPH) demonstrates that the methods are robust and useful for simulation of oropharyngeal swallowing. The presence of saliva is well known to be important for mastication, swallowing, and overall oral health. However, clinical studies of patients with hyposalivation are unable to isolate the effect of saliva from other con- founding factors. The simulation presented in this thesis examines fluid boluses under lubricated and non-lubricated boundary conditions. Upon comparison with medical image data, the experiments suggest that saliva does not provide a significant lubricative effect on the bolus transit times, but it may serve to reduce residue and therefore improve overall swallowing efficacy. Our findings, while preliminary, corroborate with existing clinical research that finds that groups with hyposalivation do not have significantly different transit times with control groups, but that residue may be increased in the hyposalivation group. Previous studies using computer simulation of fluid flow in the orophar- ynx typically make use of simplified geometries. Our work uses dynamic 320-row Area Detector Computed Tomography (ADCT) images as the ba- sis for the simulations, and therefore does not require simplifying geometric assumptions. Since the data are dynamic, motion trajectories are all sup- plied by the ADCT data, and extrapolation from 2D sources such as bi-plane videofluoroscopy is not required. Processing the image data required the de- velopment of a novel workflow based on a new tool, which we call BlendSeg. We utilize and extend Unified Semi-Analytic Wall (USAW) SPH methods so that orophrayngeal swallowing simulations may be performed. These extensions include the simulation of non-Newtonian boluses, and moving 3D boundaries. Partial validation of the extended USAW SPH method is performed using canonical flows.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Book chapters on the topic "4D-CT"

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Chen, George T. Y., and Eike R. M. Rietzel. "4D CT Simulation." In Image-Guided IMRT, 247–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-30356-1_20.

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Werner, René. "4D-CT-Bilddaten." In Strahlentherapie atmungsbewegter Tumoren, 15–32. Wiesbaden: Springer Fachmedien Wiesbaden, 2013. http://dx.doi.org/10.1007/978-3-658-01146-8_2.

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Pan, Tinsu. "Helical 4D CT and Comparison with Cine 4D CT." In 4D Modeling and Estimation of Respiratory Motion for Radiation Therapy, 25–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36441-9_2.

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Kabus, Sven, Tobias Klinder, Keelin Murphy, Bram van Ginneken, Cristian Lorenz, and Josien P. W. Pluim. "Evaluation of 4D-CT Lung Registration." In Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009, 747–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04268-3_92.

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Low, Daniel. "Acquiring 4D Thoracic CT Scans Using Ciné CT Acquisition." In 4D Modeling and Estimation of Respiratory Motion for Radiation Therapy, 43–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36441-9_3.

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Murray, Iain. "4D PET/CT Respiratory Gated Acquisition Techniques." In PET/CT in Radiotherapy Planning, 39–42. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54744-2_7.

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Sentker, Thilo, Frederic Madesta, and René Werner. "GDL-FIRE$$^\text {4D}$$: Deep Learning-Based Fast 4D CT Image Registration." In Medical Image Computing and Computer Assisted Intervention – MICCAI 2018, 765–73. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00928-1_86.

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Gao, Mingchen, Junzhou Huang, Shaoting Zhang, Zhen Qian, Szilard Voros, Dimitris Metaxas, and Leon Axel. "4D Cardiac Reconstruction Using High Resolution CT Images." In Functional Imaging and Modeling of the Heart, 153–60. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21028-0_19.

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Shu-Xu, Z. H. A. N. G., Z. H. O. U. Lin-hong, Yu Hu, Wang Shi-Qin, C. H. E. N. Guang-jie, L. I. N. Sheng-qu, and Z. H. A. N. G. Hai-nan. "4D-CT reconstruction based on body volume change." In IFMBE Proceedings, 569–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03474-9_160.

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Werner, René. "Patientenspezifische Bewegungsfeld-schätzung in thorakalen 4D-CT-Bilddaten." In Strahlentherapie atmungsbewegter Tumoren, 33–82. Wiesbaden: Springer Fachmedien Wiesbaden, 2013. http://dx.doi.org/10.1007/978-3-658-01146-8_3.

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Conference papers on the topic "4D-CT"

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Bruder, H., R. Raupach, T. Allmendinger, J. Sunnegårdh, K. Stierstorfer, and T. Flohr. "4D iterative reconstruction in cardiac CT." In SPIE Medical Imaging, edited by Norbert J. Pelc, Robert M. Nishikawa, and Bruce R. Whiting. SPIE, 2012. http://dx.doi.org/10.1117/12.910890.

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Kato, Mitsuaki, Kenji Hirohata, Akira Kano, Shinya Higashi, Akihiro Goryu, Takuya Hongo, Shigeo Kaminaga, and Yasuko Fujisawa. "Fast CT-FFR Analysis Method for the Coronary Artery Based on 4D-CT Image Analysis and Structural and Fluid Analysis." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51124.

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Non invasive fractional flow reserve derived from CT coronary angiography (CT-FFR) has to date been typically performed using the principles of computational fluid analysis in which a lumped parameter coronary vascular bed model is assigned to represent the impedance of the downstream coronary vascular networks absent in the computational domain for each coronary outlet. This approach may have a number of limitations. It may not account for the impact of the myocardial contraction and relaxation during the cardiac cycle, patient-specific boundary conditions for coronary artery outlets and vessel stiffness. We have developed a novel approach based on 4D-CT image tracking (registration) and structural and fluid analysis based on one dimensional mechanical model, to address these issues. In our approach, we analyzed the deformation variation of vessels and the volume variation of vessels to better define boundary conditions and stiffness of vessels. We focused on the blood flow and vessel deformation of coronary arteries and aorta near coronary arteries in the diastolic cardiac phase from 70% to 100 %. The blood flow variation of coronary arteries relates to the deformation of vessels, such as expansion and contraction of the cross-sectional area, during this period where resistance is stable, pressure loss is approximately proportional to flow. We used a statistical estimation method based on a hierarchical Bayes model to integrate 4D-CT measurements and structural and fluid analysis data. Under these analysis conditions, we performed structural and fluid analysis to determine pressure, flow rate and CT-FFR. Furthermore, the reduced-order model based on fluid analysis was studied in order to shorten the computational time for 4D-CT-FFR analysis. The consistency of this method has been verified by a comparison of 4D-CT-FFR analysis results derived from five clinical 4D-CT datasets with invasive measurements of FFR. Additionally, phantom experiments of flexible tubes with and without stenosis using pulsating pumps, flow sensors and pressure sensors were performed. Our results show that the proposed 4D-CT-FFR analysis method has the potential to accurately estimate the effect of coronary artery stenosis on blood flow.
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Sothmann, Thilo, René Werner, and Tobias Gauer. "Influence of 4D CT motion artifacts on correspondence model-based 4D dose accumulation." In Image-Guided Procedures, Robotic Interventions, and Modeling, edited by Robert J. Webster and Baowei Fei. SPIE, 2018. http://dx.doi.org/10.1117/12.2291481.

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Bhavsar, Arnav, Guorong Wu, and Dinggang Shen. "Motion-guided resolution enhancement for Lung 4D-CT." In 2014 13th International Conference on Control Automation Robotics & Vision (ICARCV). IEEE, 2014. http://dx.doi.org/10.1109/icarcv.2014.7064328.

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Miranda, Dayton, Parya Jafari, Sergio Dempsey, and Abbas Samani. "4D-CT Hyper-Elastography Using a Biomechanical Model." In 2020 42nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) in conjunction with the 43rd Annual Conference of the Canadian Medical and Biological Engineering Society. IEEE, 2020. http://dx.doi.org/10.1109/embc44109.2020.9176432.

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Dhou, Salam, Geoffrey D. Hugo, and Alen Docef. "Motion-based projection generation for 4D-CT reconstruction." In 2014 IEEE International Conference on Image Processing (ICIP). IEEE, 2014. http://dx.doi.org/10.1109/icip.2014.7025340.

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Rasheed, Zahid, and Derek Magee. "Modeling of airway in 4D lung CT images." In 2012 International Conference on Robotics and Artificial Intelligence (ICRAI). IEEE, 2012. http://dx.doi.org/10.1109/icrai.2012.6413397.

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Saito, Yasuo, Hiroshi Aradate, Hiroaki Miyazaki, Kenji Igarashi, and Hideki Ide. "Large-area two-dimensional detector for real-time three-dimensional CT (4D CT)." In Medical Imaging 2001, edited by Larry E. Antonuk and Martin J. Yaffe. SPIE, 2001. http://dx.doi.org/10.1117/12.430896.

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Endo, Masahiro, Schin'ichiro Mori, Takanori Tsunoo, Kanae Nishizawa, and Takahiko Aoyama. "Dose profile measurement of a four-dimensional CT (4D-CT) including scattered radiation." In Medical Imaging 2004, edited by Martin J. Yaffe and Michael J. Flynn. SPIE, 2004. http://dx.doi.org/10.1117/12.535207.

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Saito, Yasuo, Hiroshi Aradate, Hiroaki Miyazaki, Yoji Kudo, Kazuhiko Tsujita, Nobuhisa Shimadu, and Yuji Sawanaga. "Development and evaluation of a real-time three-dimensional CT (4D-CT) scanner." In Medical Imaging 2002, edited by Larry E. Antonuk and Martin J. Yaffe. SPIE, 2002. http://dx.doi.org/10.1117/12.465631.

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Reports on the topic "4D-CT"

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Maxim, Peter G., and Billy W. Loo. Improving the Diagnostic Specificity of CT for Early Detection of Lung Cancer: 4D CT-Based Pulmonary Nodule Elastometry. Fort Belvoir, VA: Defense Technical Information Center, August 2014. http://dx.doi.org/10.21236/ada610834.

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Loo, Jr, Maxim Billy W., and Peter G. Improving the Diagnostic Specificity of CT for Early Detection of Lung Cancer: 4D CT-Based Pulmonary Nodule Elastometry. Fort Belvoir, VA: Defense Technical Information Center, August 2013. http://dx.doi.org/10.21236/ada596026.

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Loo, Billy W., and Peter G. Maxim. Improving the Diagnostic Specificity of CT for Early Detection of Lung Cancer: 4D CT-Based Pulmonary Nodule Elastometry. Fort Belvoir, VA: Defense Technical Information Center, August 2014. http://dx.doi.org/10.21236/ada617240.

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