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Cone beam CT

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https://www.readbyqxmd.com/read/28350523/comparison-of-micro-ct-and-cone-beam-ct-on-the-feasibility-of-assessing-mandibular-trabecular-structures-in-mandibular-condyle
#1
Xin Liang, Zuyan Zhang, Jianping Gu, Zhihui Wang, Bart Vandenberghe, Reinhilde Jacobs, Jie Yang, Guowu Ma, Haibin Ling, Xuchen Ma
OBJECTIVES: To evaluate the accuracy of Cone-beam CT (CBCT) in assessing trabecular structures Methods: Two human mandibles were scanned by micro-CT (Skyscan 1173 high energy spiral scan micro-CT, Skyscan NV, Kontich, Belgium) and CBCT(3D Accuitomo 170, Morita Japan). The CBCT images were reconstructed in 0.5mm and 1 mm thickness. The condylar images were selected for registration. A parallel algorithm for histogram computation was introduced to perform the registration. Mutual information (MI) value was used to evaluate the match between the images obtained from micro-CT and CBCT...
March 28, 2017: Dento Maxillo Facial Radiology
https://www.readbyqxmd.com/read/28343303/can-real-time-rgbd-enhance-intraoperative-cone-beam-ct
#2
Javad Fotouhi, Bernhard Fuerst, Wolfgang Wein, Nassir Navab
PURPOSE: Cone-Beam Computed Tomography (CBCT) is an important 3D imaging technology for orthopedic, trauma, radiotherapy guidance, angiography, and dental applications. The major limitation of CBCT is the poor image quality due to scattered radiation, truncation, and patient movement. In this work, we propose to incorporate information from a co-registered Red-Green-Blue-Depth (RGBD) sensor attached near the detector plane of the C-arm to improve the reconstruction quality, as well as correcting for undesired rigid patient movement...
March 25, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28341575/the-use-of-a-colapinto-tips-needle-under-cone-beam-computed-tomography-guidance-for-true-lumen-re-entry-in-subintimal-recanalization-of-chronic-iliac-artery-occlusion
#3
Huei-Lung Liang, Ming-Feng Li, Chia-Ling Chiang, Matt Chiung-Yu Chen, Chieh-Jen Wu, Huay-Ben Pan
BACKGROUND: To report the technique and clinical outcome of subintimal re-entry in chronic iliac artery occlusion by using a Colapinto transjugular intrahepatic portosystemic shunt (TIPS) needle under rotational angiography (cone-beam computed tomography; CT) imaging guidance. METHODS: Patients with chronic iliac artery occlusion with earlier failed attempts at conventional percutaneous recanalization during the past 5 years were enrolled in our study. In these patients, an ipsilateral femoral access route was routinely utilized in a retrograde fashion...
March 21, 2017: Journal of the Chinese Medical Association: JCMA
https://www.readbyqxmd.com/read/28332142/flat-detector-cone-beam-ct-guided-nephrostomy-using-virtual-navigation-in-patients-with-iatrogenic-ureteral-injury
#4
Dechao Jiao, Zongming Li, Zhiguo Li, Shaofeng Shui, Xin-Wei Han
PURPOSE: To evaluate the feasibility of flat detector cone beam computed tomography (CBCT)-guided nephrostomy using virtual navigation in patients with iatrogenic ureteral injury. MATERIALS AND METHODS: A retrospective review of percutaneous nephrostomy (PN) revealed the use of CBCT with 3D virtual navigation guidance in 42 procedures (40 patients) for patients with iatrogenic ureteral injury. All procedures were shown as second-line interventions after failed ultrasound-guided nephrostomy...
March 22, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28327698/accuracy-and-reliability-of-different-cone-beam-computed-tomography-cbct-devices-for-structural-analysis-of-alveolar-bone-in-comparison-with-multislice-ct-and-micro-ct
#5
Jeroen Van Dessel, Laura Ferreira Pinheiro Nicolielo, Yan Huang, Walter Coudyzer, Benjamin Salmon, Ivo Lambrichts, Reinhilde Jacobs
OBJECTIVE: The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). MATERIALS AND METHODS: Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution)...
2017: European Journal of Oral Implantology
https://www.readbyqxmd.com/read/28327471/motion-compensation-in-extremity-cone-beam-ct-using-a-penalized-image-sharpness-criterion
#6
Alejandro Sisniega, Joseph Stayman, John Yorkston, Jeffrey Siewerdsen, Wojciech Zbijewski
Cone-beam CT (CBCT) for musculoskeletal imaging would benefit from a method to reduce the effects of involuntary patient motion. In particular, the continuing improvement in spatial resolution of CBCT may enable tasks such as quantitative assessment of bone microarchitecture (0.1 mm - 0.2 mm detail size), where even subtle, sub-mm motion blur might be detrimental. We propose a purely image based motion compensation method that requires no fiducials, tracking hardware or prior images. A statistical optimization algorithm (CMA-ES) is used to estimate a motion trajectory that optimizes an objective function consisting of an image sharpness criterion augmented by a regularization term that encourages smooth motion trajectories...
March 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28326738/-dental-implantation-in-a-patient-with-sj%C3%A3-gren-s-syndrome-a-case-report
#7
Luo Cuifen, Peng Guoguang, Feng Yuanhua, Huang Xingxiang
We reported one case of a patient with Sjögren's syndrome and dental implant. This patient was followed up for more than one year. The patient was diagnosed with Sjögren's syndrome for 5 years and treated with long-term corticosteroid. Four implant-tissue interface hydrophilic implants were placed on 15, 16, 44, and 46 of the mandibular and maxillary areas. After the surgery was completed, the patient was treated with oral antibiotic and "shenggu pills" to prevent infection and glucocorticoid to manage Sjögren's syndrome...
February 1, 2017: Hua Xi Kou Qiang Yi Xue za Zhi, Huaxi Kouqiang Yixue Zazhi, West China Journal of Stomatology
https://www.readbyqxmd.com/read/28323642/a-bayesian-approach-for-three-dimensional-markerless-tumor-tracking-using-kv-imaging-during-lung-radiotherapy
#8
Chun-Chien Shieh, Vincent Caillet, Michelle Dunbar, Paul J Keall, Jeremy T Booth, Nicholas Hardcastle, Carol Haddad, Thomas Eade, Ilana Feain
The ability to monitor tumor motion without implanted markers can potentially enable broad access to more accurate and precise lung radiotherapy. A major challenge is that kilovoltage (kV) imaging based methods are rarely able to continuously track the tumor due to the inferior tumor visibility on 2D kV images. Another challenge is the estimation of 3D tumor position based on only 2D imaging information. The aim of this work is to address both challenges by proposing a Bayesian approach for markerless tumor tracking for the first time...
April 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28302348/cone-beam-ct-guided-chemoembolization-of-probable-hepatocellular-carcinomas-smaller-than-1-cm-in-patients-at-high-risk-of-hepatocellular-carcinoma
#9
Jin Woo Choi, Hyo-Cheol Kim, Jeong-Hoon Lee, Su Jong Yu, Eun Ju Cho, Min-Uk Kim, Saebeom Hur, Myungsu Lee, Hwan Jun Jae, Jin Wook Chung
PURPOSE: To evaluate the effectiveness and safety of cone-beam computed tomography (CT)-guided chemoembolization for probable hepatocellular carcinomas (HCCs) smaller than 1 cm in patients at high risk for HCC. MATERIALS AND METHODS: From December 2009 to May 2014, 57 patients (43 male and 14 female; mean age, 61.1 y) at high risk for HCC underwent cone-beam CT-guided conventional chemoembolization for 79 treatment-naive probable HCCs < 1 cm. Probable HCCs were diagnosed when hepatic nodules showed arterial enhancement and washout on dynamic CT or magnetic resonance images...
March 14, 2017: Journal of Vascular and Interventional Radiology: JVIR
https://www.readbyqxmd.com/read/28298387/diagnosis-of-chronic-thromboembolic-pulmonary-hypertension
#10
REVIEW
Deepa Gopalan, Marion Delcroix, Matthias Held
Chronic thromboembolic pulmonary hypertension (CTEPH) is the only potentially curable form of pulmonary hypertension. Rapid and accurate diagnosis is pivotal for successful treatment. Clinical signs and symptoms can be nonspecific and risk factors such as history of venous thromboembolism may not always be present. Echocardiography is the recommended first diagnostic step. Cardiopulmonary exercise testing is a complementary tool that can help to identify patients with milder abnormalities and chronic thromboembolic disease, triggering the need for further investigation...
January 2017: European Respiratory Review: An Official Journal of the European Respiratory Society
https://www.readbyqxmd.com/read/28297422/a-methodology-for-on-board-cbct-imaging-dose-using-optically-stimulated-luminescence-detectors
#11
Noor Mail, Muhammad Yusuf, Nazeeh Alothmany, A Abdulrahman Kinsara, Fahad Abdulkhaliq, Suliman M Ghamdi, Abdelhamid Saoudi
Cone-beam computed tomography CBCT systems are used in radiation therapy for patient alignment and positioning. The CBCT imaging procedure for patient setup adds substantial radiation dose to patient's normal tissue. This study presents a complete procedure for the CBCT dosimetry using the InLight optically-stimulated-luminescence (OSL) nanoDots. We report five dose parameters: the mean slice dose (DMSD); the cone beam dose index (CBDIW); the mean volume dose (DMVD); point-dose profile, D(FOV); and the off-field Dose...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297352/improved-setup-and-positioning-accuracy-using-a-three-point-customized-cushion-mask-bite-block-immobilization-system-for-stereotactic-reirradiation-of-head-and-neck-cancer
#12
He Wang, Congjun Wang, Samuel Tung, Andrew Wilson Dimmitt, Pei Fong Wong, Mark A Edson, Adam S Garden, David I Rosenthal, Clifton D Fuller, Gary B Gunn, Vinita Takiar, Xin A Wang, Dershan Luo, James N Yang, Jennifer Wong, Jack Phan
The purpose of this study was to investigate the setup and positioning uncertainty of a custom cushion/mask/bite-block (CMB) immobilization system and determine PTV margin for image-guided head and neck stereotactic ablative radiotherapy (HN-SABR). We analyzed 105 treatment sessions among 21 patients treated with HN-SABR for recurrent head and neck cancers using a custom CMB immobilization system. Initial patient setup was performed using the ExacTrac infrared (IR) tracking system and initial setup errors were based on comparison of ExacTrac IR tracking system to corrected online ExacTrac X-rays images registered to treatment plans...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297337/one-year-analysis-of-elekta-cbct-image-quality-using-nps-and-mtf
#13
Satomi Nakahara, Masayuki Tachibana, Yoichi Watanabe
The image quality (IQ) of imaging systems must be sufficiently high for image-guided radiation therapy (IGRT). Hence, users should implement a quality assurance program to maintain IQ. In our routine IQ tests of the kV cone-beam CT system (Elekta XVI), image noise was quantified by noise standard deviation (NSD), which was the standard deviation of CT numbers measured in a small area in an image of an IQ test phantom (Catphan), and the high spatial resolution (HSR) was evaluated by the number of line-pairs (LPN) visually recognizable in the image...
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
#14
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/28296331/treatment-accuracy-without-rotational-setup-corrections-in-intracranial-srt
#15
Eeva Boman, Mika Kapanen, Marko Laaksomaa, Hanna Mäenpää, Simo Hyödynmaa, Pirkko-Liisa Kellokumpu-Lehtinen
The aim of this study was to evaluate the impact of actual rotational setup errors on dose distributions in intracranial stereotactic radiotherapy (SRT) with different alternatives for treatment position selection. A total of 38 SRT fractions from 18 patients were retrospectively evaluated with rotational setup errors obtained from actual treatments. The planning computed tomography (CT) images were rotated according to online cone-beam CT (CBCT) images and the dose distribution was recalculated to the rotated CT images using three different patient positionings derived from: 1) an automatic 6D match neglecting rotation correction (Auto6D); 2) an automatic 3D match (Auto3D); and 3) a manual 3D match from actual treatment (Treat3D)...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296330/an-energy-minimization-method-for-the-correction-of-cupping-artifacts-in-cone-beam-ct
#16
Shipeng Xie, Wenqin Zhuang, Haibo Li
The purpose of this study was to reduce cupping artifacts and improve quantitative accuracy of the images in cone-beam CT (CBCT). An energy minimization method (EMM) is proposed to reduce cupping artifacts in reconstructed image of the CBCT. The cupping artifacts are iteratively optimized by using efficient matrix computations, which are verified to be numerically stable by matrix analysis. Moreover, the energy in our formulation is convex in each of its variables, which brings the robustness of the proposed energy minimization algorithm...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296323/dosimetric-accuracy-of-the-cone-beam-ct-based-treatment-planning-of-the-vero-system-a-phantom-study
#17
Indra Yohannes, Heru Prasetio, Karoline Kallis, Christoph Bert
We report an investigation on the accuracy of dose calculation based on the cone-beam computed tomography (CBCT) images of the nonbowtie filter kV imaging system of the Vero linear accelerator. Different sets of materials and tube voltages were employed to generate the Hounsfield unit lookup tables (HLUTs) for both CBCT and fan-beam CT (FBCT) systems. The HLUTs were then implemented for the dose calculation in a treatment planning system (TPS). Dosimetric evaluation was carried out on an in-house-developed cube phantom that consists of water-equivalent slabs and inhomogeneity inserts...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296306/a-novel-phantom-and-procedure-providing-submillimeter-accuracy-in-daily-qa-tests-of-accelerators-used-for-stereotactic-radiosurgery
#18
Ivan A Brezovich, Richard A Popple, Jun Duan, Sui Shen, Xingen Wu, Sidi Benhabib, Mi Huang, Rex A Cardan
Stereotactic radiosurgery (SRS) places great demands on spatial accuracy. Steel BBs used as markers in quality assurance (QA) phantoms are clearly visible in MV and planar kV images, but artifacts compromise cone-beam CT (CBCT) isocenter localization. The purpose of this work was to develop a QA phantom for measuring with sub-mm accuracy isocenter congruence of planar kV, MV, and CBCT imaging systems and to design a practical QA procedure that includes daily Winston-Lutz (WL) tests and does not require computer aid...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296304/low-dose-2-5-mv-cone-beam-computed-tomography-with-thick-csi-flat-panel-imager
#19
Grace Tang, Christopher Moussot, Daniel Morf, Edward Seppi, Howard Amols
Most of the treatment units, both new and old models, are equipped with a megavoltage portal imager but its use for volumetric imaging is limited. This is mainly due to the poor image quality produced by the high-energy treatment beam (>6 MV). A linac at our center is equipped with a prototype 2.5 MV imaging beam. This study evaluates the feasibility of low-dose megavoltage cone-beam imaging with the 2.5 MV beam and a thick cesium iodide detector, which is a high-efficiency imager. Basic imaging properties such as spatial resolution and modulation transfer function were assessed for the 2...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296300/experimental-validation-of-a-kv-source-model-and-dose-computation-method-for-cbct-imaging-in-an-anthropomorphic-phantom
#20
Yannick Poirier, Mauro Tambasco
We present an experimental validation of a kilovoltage (kV) X-ray source characterization model in an anthropomorphic phantom to estimate patient-specific absorbed dose from kV cone-beam computed tomography (CBCT) imaging procedures and compare these doses to nominal weighted CT-dose index (CTDIw) dose estimates. We simulated the default Varian on-board imager 1.4 (OBI) default CBCT imaging protocols (i.e., standard-dose head, low-dose thorax, pelvis, and pelvis spotlight) using our previously developed and easy to implement X-ray point-source model and source characterization approach...
July 2016: Journal of Applied Clinical Medical Physics
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