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Spectral CT

Jiahui Lin, Hao Zhang, Jing Huang, Zhaoying Bian, Shanli Zhang, Yongbo Wang, Yuting Liao, Sui Li, Hua Zhang, Dong Zeng, Jianhua Ma
Dual energy computed tomography (DECT) can improve the capability of differentiating different materials compared with conventional CT. However, due to non-negligible radiation exposure to patients, dose reduction has recently become a critical concern in CT imaging field. In this work, to reduce noise at the same time maintain DECT images quality, we present an iterative reconstruction algorithm for low-dose DECT images where in the objective function of the algorithm consists of a data-fidelity term and a regularization term...
March 15, 2018: Journal of X-ray Science and Technology
Katsuyuki Taguchi, Karl Stierstorfer, Christoph Polster, Okkyun Lee, Steffen Kappler
PURPOSE: The inter-pixel cross-talk of energy-sensitive photon counting x-ray detectors (PCDs) has been studied and an analytical model (version 2.1) has been developed for double-counting between neighboring pixels due to charge sharing and K-shell fluorescence x-ray emission followed by its re-absorption [Taguchi K, et al., Medical Physics 2016;43(12):6386-6404]. While the model version 2.1 simulated the spectral degradation well, it had the following problems that has been found to be significant recently: (1) The spectrum is inaccurate with smaller pixel sizes; (2) the charge cloud size must be smaller than the pixel size; (3) the model underestimates the spectrum/counts for 10-40 keV; and (4) the model version 2...
March 14, 2018: Medical Physics
Daniel González-Mancebo, Ana I Becerro, T Cristina Rojas, Andrés Olivencia, Ariadna Corral, Marcin Balcerzyk, Eugenio Cantelar, Fernando Cussó, Manuel Ocaña
The singular properties of lanthanide-based inorganic nanoparticles (NPs) has raised the attention of the scientific community in biotechnological applications. In particular, those systems with two or more functionalities are especially interesting. In this work, an effective and commercially attractive procedure has been developed that renders uniform, water-dispersible Ln3+ :CeF3 (Ln = Tb, Nd) NPs with different shapes and size. The method consists of the homogeneous precipitation, in a mixture of polyol and water, of cations and anions using precursors that allow the controlled release of the latter...
March 5, 2018: Journal of Colloid and Interface Science
Sinan Şen, Ralf Erber, Kevin Kunzmann, Stefanie Kirschner, Vanessa Weyer, Lothar Schilling, Marc A Brockmann, Stefan Rues, Gül Orhan, Christopher J Lux, Sebastian Zingler
OBJECTIVE: Optical coherence tomography (OCT) is a clinical standard in ophthalmology. Currently, its application in dentistry is gaining increasing interest. In this study, we tested the possibility to use a modified commercially available spectral domain OCT (SD-OCT) to assess the layer thickness of orthodontic surface sealants. MATERIALS AND METHODS: Reference samples of surface sealants for calibration and repeatability testing were measured using a micrometer screw...
March 9, 2018: Clinical Oral Investigations
Buxin Chen, Zheng Zhang, Dan Xia, Emil Y Sidky, Xiaochuan Pan
PURPOSE: We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for non-linear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data...
March 8, 2018: Medical Physics
Robbert W van Hamersvelt, Nienke G Eijsvoogel, Casper Mihl, Pim A de Jong, Arnold M R Schilham, Nico Buls, Marco Das, Tim Leiner, Martin J Willemink
We investigated the feasibility and extent to which iodine concentration can be reduced in computed tomography angiography imaging of the aorta and coronary arteries using low tube voltage and virtual monochromatic imaging of 3 major dual-energy CT (DECT) vendors. A circulation phantom was imaged with dual source CT (DSCT), gemstone spectral imaging (GSI) and dual-layer spectral detector CT (SDCT). For each scanner, a reference scan was acquired at 120 kVp using routine iodine concentration (300 mg I/ml). Subsequently, scans were acquired at lowest possible tube potential (70, 80, 80 kVp, respectively), and DECT-mode (80/150Sn, 80/140 and 120 kVp, respectively) in arterial phase after administration of iodine (300, 240, 180, 120, 60, 30 mg I/ml)...
March 8, 2018: International Journal of Cardiovascular Imaging
Yunhe Xie, Christopher Ainsley, Lingshu Yin, Wei Zou, James McDonough, Timothy D Solberg, Alexander Lin, Boon-Keng Kevin Teo
A major source of uncertainty in proton therapy is the conversion of Hounsfield unit (HU) to proton stopping power ratio relative to water (SPR). In this study, we measured and quantified the accuracy of a stoichiometric dual energy CT (DECT) SPR calibration. We applied a stoichiometric DECT calibration method to derive the SPR using CT images acquired sequentially at [Formula: see text] and [Formula: see text]. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the effective atomic number (Zeff ), relative electron density ([Formula: see text]), and SPRs of phantom and biological materials...
March 7, 2018: Physics in Medicine and Biology
Thangavel Thirunavukkarasu, Hazel A Sparkes, C Balachandran, S Awale, Karuppannan Natarajan, V G Gnanasoundari
A novel one-dimensional coordination polymer containing Cu(I)Cu(II) core with chloro bridge on Cu(I) and ligand bridge on Cu(II) ions (1) and a mononuclear Cu(II) complex (2) have been synthesized from the reactions of 3- and 4-methoxy-3-quinolin-3-ylimino-methyl-2-phenol with [CuCl2 (PPh3 )2 ]. The ligands and the complexes have been characterized by spectral and analytical methods. In addition, the structures of both the ligands and the copper complexes were confirmed by single crystal X-ray diffraction studies...
February 13, 2018: Journal of Photochemistry and Photobiology. B, Biology
Kuddusi Teberik, Murat Kaya
Objective: To evaluate macular choroidal thickness (CT) and retinal thickness in Turkish patients with high myopia without maculopathy and in normal subjects and to examine the association with age, axial length (AL), best corrected visual acuity (BCVA), cycloplegic refraction, and spherical equivalent (SE). Methods: This prospective study was performed between January 2015 and June 2016 in the Department of Ophthalmology, Duzce University Medical Faculty. It had 65 individuals (30 patients with high myopia, 35 healthy subjects)...
November 2017: Pakistan Journal of Medical Sciences Quarterly
Pingding Kuang, Xinfa Ding, Jingjing Xu, Qijing Zhou, Minming Zhang
OBJECTIVE: To assess the diagnostic value of dual energy CT for lymph node metastasis in patients with non-small cell lung cancer (NSCLC). METHODS: Forty NSCLC patients, including 15 cases of squamous cell carcinoma and 25 cases of adenocarcinoma, underwent dual energy CT examination in pre-contrast and venous phase contrast scans, then the CT attenuation value of the lung cancer lesions and 85 mediastinal enlarged lymph nodes (the short diameter ≥ 5 mm, 53 metastatic and 32 non-metastatic) were measured at different energy levels (40-190 keV, spacing 10 keV) in venous phase contrast...
May 25, 2017: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
Xinhui Duan, Gary Arbique, Jeffrey Guild, Yin Xi, Jon Anderson
PURPOSE: To evaluate the quantitative accuracy of spectral images from a detector-based spectral CT scanner using a phantom with iodine loaded inserts. METHODS: A 40 cm long body phantom with seven iodine inserts (2-20 mg/ml of iodine) was used in the study. The inserts could be placed at 5.5 or 10.5 cm from the phantom axis. The phantom was scanned five times for each insert configuration using 120 kVp tube voltage. A set of iodine, virtual non-contrast, effective atomic number, and virtual mono-energetic spectral CT images were generated and measurements were made for all the iodine rods...
February 26, 2018: Medical Physics
Md Fazle Alam, Supriya Varshney, Masood Alam Khan, Amaj Ahmed Laskar, Hina Younus
The study of drug-DNA interactions is of great importance, as it paves the way towards the design of better therapeutic agents. Here, the interaction of DNA with a therapeutic and prophylactic drug citral has been studied. We have attempted to ascertain the mode of binding of citral with calf thymus DNA (Ct-DNA) through various biophysical techniques. Analysis of the UV-visible absorbance spectra and fluorescence spectra indicated the formation of a complex between citral and Ct-DNA. Competitive binding assays with ethidium bromide (EB), acridine orange (AO) and Hoechst 33258 reflected that citral possibly intercalates within the Ct-DNA...
February 22, 2018: International Journal of Biological Macromolecules
Christoph Schabel, Bhavik Patel, Scott Harring, Petar Duvnjak, Juan Carlos Ramírez-Giraldo, Konstantin Nikolaou, Rendon C Nelson, Alfredo E Farjat, Daniele Marin
Purpose To investigate the relationship between energy level of virtual monoenergetic (VM) imaging and sensitivity in the detection of minimally enhancing renal lesions. Materials and Methods Phantoms simulating unenhanced and contrast material-enhanced renal parenchyma were equipped with inserts containing different concentrations of iodine (range, 0-1.15 mg iodine per milliliter). A total of 180 patients (117 men; mean age, 65.2 years ± 13.0 [standard deviation]) with 194 (62 solid, 132 cystic) renal lesions larger than 10 mm in diameter underwent unenhanced single-energy CT and contrast-enhanced dual-energy CT...
February 22, 2018: Radiology
Reshma Munbodh, Jonathan P S Knisely, David A Jaffray, Douglas J Moseley
PURPOSE: We present and evaluate a fully automated 2D-3D intensity-based registration framework using a single limited field-of-view (FOV) 2D kV radiograph and a 3D kV CBCT for 3D estimation of patient setup errors during brain radiotherapy. METHODS: We evaluated two similarity measures, the Pearson correlation coefficient on image intensity values (ICC) and maximum likelihood measure with Gaussian noise (MLG), derived from the statistics of transmission images...
February 22, 2018: Medical Physics
André Euler, Markus M Obmann, Zsolt Szucs-Farkas, Achille Mileto, Caroline Zaehringer, Anna L Falkowski, David J Winkel, Daniele Marin, Bram Stieltjes, Bernhard Krauss, Sebastian T Schindera
OBJECTIVES: To compare image quality and radiation dose of abdominal split-filter dual-energy CT (SF-DECT) combined with monoenergetic imaging to single-energy CT (SECT) with automatic tube voltage selection (ATVS). METHODS: Two-hundred single-source abdominal CT scans were performed as SECT with ATVS (n = 100) and SF-DECT (n = 100). SF-DECT scans were reconstructed and subdivided into composed images (SF-CI) and monoenergetic images at 55 keV (SF-MI). Objective and subjective image quality were compared among single-energy images (SEI), SF-CI and SF-MI...
February 19, 2018: European Radiology
Julia Dangelmaier, Daniel Bar-Ness, Heiner Daerr, Daniela Muenzel, Salim Si-Mohamed, Sebastian Ehn, Alexander A Fingerle, Melanie A Kimm, Felix K Kopp, Loic Boussel, Ewald Roessl, Franz Pfeiffer, Ernst J Rummeny, Roland Proksa, Philippe Douek, Peter B Noël
OBJECTIVES: After endovascular aortic repair (EVAR), discrimination of endoleaks and intra-aneurysmatic calcifications within the aneurysm often requires multiphase computed tomography (CT). Spectral photon-counting CT (SPCCT) in combination with a two-contrast agent injection protocol may provide reliable detection of endoleaks with a single CT acquisition. METHODS: To evaluate the feasibility of SPCCT, the stent-lined compartment of an abdominal aortic aneurysm phantom was filled with a mixture of iodine and gadolinium mimicking enhanced blood...
February 19, 2018: European Radiology
Mariadoss Asha Jhonsi, Devanesan Arul Ananth, Gayathri Nambirajan, Thilagar Sivasudha, Rekha Yamini, Soumen Bera, Arunkumar Kathiravan
In recent years, quantum dots (QDs) are one of the most promising nanomaterials in life sciences community due to their unexploited potential in biomedical applications; particularly in bio-labeling and sensing. In the advanced nanomaterials, carbon dots (CDs) have shown promise in next generation bioimaging and drug delivery studies. Therefore the knowledge of the exact nature of interaction with biomolecules is of great interest to designing better biosensors. In this study, the interaction between CDs derived from tamarind and calf thymus DNA (ct-DNA) has been studied by vital spectroscopic techniques, which revealed that the CDs could interact with DNA via intercalation...
February 8, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Kyungsoo Bae, Kyung Nyeo Jeon, Soo Buem Cho, Sung Eun Park, Jin Il Moon, Hye Jin Baek, Bo Hwa Choi
OBJECTIVE: The objective of our study was to evaluate the quality of virtual monoenergetic imaging (VMI) from dual-layer detector spectral CT and the effect of virtual monoenergetic images obtained at low energies on the detection of pulmonary embolism (PE) in patients with a suboptimally enhanced pulmonary artery on chest CT. MATERIALS AND METHODS: Of 1552 consecutive chest CT examinations performed with dual-layer detector spectral CT using a routine protocol with a tube voltage of 120 kVp, 79 examinations with suboptimal enhancement of the pulmonary artery (i...
February 15, 2018: AJR. American Journal of Roentgenology
Jessica L Nute, Megan C Jacobsen, Wolfgang Stefan, Wei Wei, Dianna D Cody
PURPOSE: A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV-switching dual-energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual-energy quality control (DEQC). METHODS: A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging...
February 15, 2018: Medical Physics
Charmainne Cruje, Joy Dunmore-Buyze, Jarret P MacDonald, David W Holdsworth, Maria Drangova, Elizabeth R Gillies
Despite recent technological advancements in microcomputed tomography (micro-CT) and contrast agent development, pre-clinical contrast agents are still predominantly iodine-based. Higher contrast can be achieved when using elements with higher atomic numbers, such as lanthanides; lanthanides also have x-ray attenuation properties that are ideal for spectral CT. However, the formulation of lanthanide-based contrast agents at the high concentrations required for vascular imaging presents a significant challenge...
February 13, 2018: Biomacromolecules
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