scholarly journals An Image Quality Comparison Study Between Homemade and Commercial Dental Cone-Beam CT Systems

2021 ◽  
Author(s):  
Trang Thi Ngoc Tran ◽  
David Shih-Chun Jin ◽  
Kun-Long Shih ◽  
Ming-Lun Hsu ◽  
Jyh-Cheng Chen
Keyword(s):  
Image Quality ◽  
Spatial Resolution ◽  
Image Distortion ◽  
Cone Beam ◽  
Prototype System ◽  
Micro Ct ◽  
Mineral Density ◽  
Image Intensity ◽  
System A ◽  
Noise Ratio

Abstract Purpose Cone-beam computed tomography (CBCT) has been widely applied in dental and maxillofacial imaging. Several dental CBCT systems have been recently developed in order to improve the performance. This study aimed to evaluate the image quality of our prototype (YMU-DENT-P001) and compare with a commercial POYE Expert 3DS dental CBCT system (system A). Methods The Micro-CT Contrast Scale, Micro-CT Water and Micro-CT HA phantoms were used to evaluate the two CBCT systems in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), uniformity (U), distortion, and linearity in the relationship between image intensity and calcium hydroxyapatite concentration. We also fabricated a proprietary thin-wire phantom to evaluate full width at half maximum (FWHM) spatial resolution. Both CBCT systems used the same exposure protocol, and data analysis was performed in accordance with ISO standards using a proprietary image analysis platform. Results The SNR of our prototype system was nearly five times higher than that of system A (prototype: 159.85 ± 3.88; A: 35.42 ± 0.61; p < 0.05) and the CNR was three times higher (prototype: 329.39 ± 5.55; A: 100.29 ± 2.31; p < 0.05). The spatial resolution of the prototype (0.2446 mm) greatly exceeded that of system A (0.5179 mm) and image distortion was lower (prototype: 0.03 mm; system A: 0.285 mm). Little difference was observed between the two systems in terms of the linear relationship between bone mineral density (BMD) and image intensity. Conclusions Within the scope of this study, our prototype YMU-DENT-P001 outperformed system A in terms of spatial resolution, SNR, CNR, and image distortion.

scholarly journals An Image Quality Comparison Study Between Homemade and Commercial Dental Cone-beam CT Systems

2021 ◽  
Author(s):  
Trang Thi Ngoc Tran ◽  
David Shih-Chun Jin ◽  
Kun-Long Shih ◽  
Ming-Lun Hsu ◽  
Jyh-Cheng Chen
Keyword(s):  
Image Quality ◽  
Spatial Resolution ◽  
Cone Beam Ct ◽  
Calcium Hydroxyapatite ◽  
Cone Beam ◽  
Micro Ct ◽  
Mineral Density ◽  
Image Intensity ◽  
System A ◽  
Noise Ratio

Abstract Purpose: Cone-beam computed tomography (CBCT) has been widely applied in dental and maxillofacial imaging. Several dental CBCT systems have been recently developed in order to improve the performance. This study aimed to evaluate the image quality of our prototype (YMU-DENT-P001) and compare with another commercial CBCT system made in Taipei, Taiwan (system A). Methods: The Micro-CT-Contrast Scale, Micro-CT Water and Micro-CT HA phantoms were utilized to evaluate the contrast to noise ratio (CNR), signal to noise ratio (SNR), uniformity, distortion, and the linear relation between image intensity and calcium hydroxyapatite concentrations. Another customized thin-wire phantom was used to evaluate the FWHM spatial resolution. These phantoms were scanned by the two CBCT systems using the same exposure protocol. Acquired data were evaluated using the image analysis platform designed by our lab, which followed ISO standard. Results: The SNR of our prototype YMU-DENT-P001 is nearly five times higher (prototype: 159.85 ± 3.88; A: 35.42 ± 0.61; p<0.05) while CNR is three times higher than system A (prototype: 329.39 ± 5.55; A: 100.29 ± 2.31; p < 0.05). The spatial resolutions recorded are 0.2446 mm in the prototype DENT and 0.5179 mm in the commercial system A. Image produced by the prototype is also better in terms of distortion level (0.03 mm in prototype, compared to 0.294 mm in A, p < 0.05). The linear relationship between bone mineral density (BMD) and image intensity of both systems were similarly performed.Conclusion: Within the limitation of this study, our prototype DENT-P001 has potential to produce better image quality than system A in terms of spatial resolution, SNR, CNR, uniformity, and distortion.

scholarly journals Image quality comparison between a phase-contrast synchrotron radiation breast CT and a clinical breast CT: a phantom based study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luca Brombal ◽  
Fulvia Arfelli ◽  
Pasquale Delogu ◽  
Sandro Donato ◽  
Giovanni Mettivier ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Image Quality ◽  
Spatial Resolution ◽  
Phase Retrieval ◽  
Medical Center ◽  
Equivalent Material ◽  
Noise Power ◽  
Breast Ct ◽  
Noise Ratio

AbstractIn this study we compared the image quality of a synchrotron radiation (SR) breast computed tomography (BCT) system with a clinical BCT in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), noise power spectrum (NPS), spatial resolution and detail visibility. A breast phantom consisting of several slabs of breast-adipose equivalent material with different embedded targets (i.e., masses, fibers and calcifications) was used. Phantom images were acquired using a dedicated BCT system installed at the Radboud University Medical Center (Nijmegen, The Netherlands) and the SR BCT system at the SYRMEP beamline of Elettra SR facility (Trieste, Italy) based on a photon-counting detector. Images with the SR setup were acquired mimicking the clinical BCT conditions (i.e., energy of 30 keV and radiation dose of 6.5 mGy). Images were reconstructed with an isotropic cubic voxel of 273 µm for the clinical BCT, while for the SR setup two phase-retrieval (PhR) kernels (referred to as “smooth” and “sharp”) were alternatively applied to each projection before tomographic reconstruction, with voxel size of 57 × 57 × 50 µm3. The CNR for the clinical BCT system can be up to 2-times higher than SR system, while the SNR can be 3-times lower than SR system, when the smooth PhR is used. The peak frequency of the NPS for the SR BCT is 2 to 4-times higher (0.9 mm−1 and 1.4 mm−1 with smooth and sharp PhR, respectively) than the clinical BCT (0.4 mm−1). The spatial resolution (MTF10%) was estimated to be 1.3 lp/mm for the clinical BCT, and 5.0 lp/mm and 6.7 lp/mm for the SR BCT with the smooth and sharp PhR, respectively. The smallest fiber visible in the SR BCT has a diameter of 0.15 mm, while for the clinical BCT is 0.41 mm. Calcification clusters with diameter of 0.13 mm are visible in the SR BCT, while the smallest diameter for the clinical BCT is 0.29 mm. As expected, the image quality of the SR BCT outperforms the clinical BCT system, providing images with higher spatial resolution and SNR, and with finer granularity. Nevertheless, this study assesses the image quality gap quantitatively, giving indications on the benefits associated with SR BCT and providing a benchmarking basis for its clinical implementation. In addition, SR-based studies can provide a gold-standard in terms of achievable image quality, constituting an upper-limit to the potential clinical development of a given technique.

Image distortion and spatial resolution of a commercially available cone-beam computed tomography machine

2008 ◽  
Vol 134 (4) ◽  
pp. 573-582 ◽  
Author(s):  
John W. Ballrick ◽  
J. Martin Palomo ◽  
Edward Ruch ◽  
B. Douglas Amberman ◽  
Mark G. Hans
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Cone Beam Computed Tomography ◽  
Image Distortion ◽  
Cone Beam

scholarly journals Cone Beam Micro-CT System for Small Animal Imaging and Performance Evaluation

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Shouping Zhu ◽  
Jie Tian ◽  
Guorui Yan ◽  
Chenghu Qin ◽  
Jinchao Feng
Keyword(s):  
Spatial Resolution ◽  
Small Animal Imaging ◽  
Small Animal ◽  
Whole Body ◽  
Cone Beam ◽  
Large Field ◽  
Micro Ct ◽  
X Ray ◽  
Animal Imaging ◽  
Ct System

A prototype cone-beam micro-CT system for small animal imaging has been developed by our group recently, which consists of a microfocus X-ray source, a three-dimensional programmable stage with object holder, and a flat-panel X-ray detector. It has a large field of view (FOV), which can acquire the whole body imaging of a normal-size mouse in a single scan which usually takes about several minutes or tens of minutes. FDK method is adopted for 3D reconstruction with Graphics Processing Unit (GPU) acceleration. In order to reconstruct images with high spatial resolution and low artifacts, raw data preprocessing and geometry calibration are implemented before reconstruction. A method which utilizes a wire phantom to estimate the residual horizontal offset of the detector is proposed, and 1D point spread function is used to assess the performance of geometric calibration quantitatively. System spatial resolution, image uniformity and noise, and low contrast resolution have been studied. Mouse images with and without contrast agent are illuminated in this paper. Experimental results show that the system is suitable for small animal imaging and is adequate to provide high-resolution anatomic information for bioluminescence tomography to build a dual modality system.

scholarly journals Signal and noise in helioseismic holography

2018 ◽  
Vol 620 ◽  
pp. A136 ◽  
Author(s):  
Laurent Gizon ◽  
Damien Fournier ◽  
Dan Yang ◽  
Aaron C. Birch ◽  
Hélène Barucq
Keyword(s):  
Spatial Resolution ◽  
Green's Function ◽  
Sound Speed ◽  
Signal To Noise Ratio ◽  
Solar Interior ◽  
Solar Oscillations ◽  
Signal To Noise ◽  
Holographic Image ◽  
Image Intensity ◽  
Noise Ratio

Context. Helioseismic holography is an imaging technique used to study heterogeneities and flows in the solar interior from observations of solar oscillations at the surface. Holographic images contain noise due to the stochastic nature of solar oscillations. Aims. We aim to provide a theoretical framework for modeling signal and noise in Porter–Bojarski helioseismic holography. Methods. The wave equation may be recast into a Helmholtz-like equation, so as to connect with the acoustics literature and define the holography Green’s function in a meaningful way. Sources of wave excitation are assumed to be stationary, horizontally homogeneous, and spatially uncorrelated. Using the first Born approximation we calculated holographic images in the presence of perturbations in sound-speed, density, flows, and source covariance, as well as the noise level as a function of position. This work is a direct extension of the methods used in time-distance helioseismology to model signal and noise. Results. To illustrate the theory, we compute the holographic image intensity numerically for a buried sound-speed perturbation at different depths in the solar interior. The reference Green’s function is obtained for a spherically-symmetric solar model using a finite-element solver in the frequency domain. Below the pupil area on the surface, we find that the spatial resolution of the holographic image intensity is very close to half the local wavelength. For a sound-speed perturbation of size comparable to the local spatial resolution, the signal-to-noise ratio is approximately constant with depth. Averaging the image intensity over a number N of frequencies above 3 mHz increases the signal-to-noise ratio by a factor nearly equal to the square root of N. This may not be the case at lower frequencies, where large variations in the holographic signal are due to the contributions from the long-lived modes of oscillation.

scholarly journals The Effects Of High Dose and Low Dose Protocols In Thorax’s CT Scan Image Quality

2021 ◽  
Vol 11 (2) ◽  
pp. 189
Author(s):  
Ni Larasati Kartika Sari ◽  
Deni Tiko Bahagia ◽  
Puji Hartoyo ◽  
Dewi Muliyati
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Ct Scan ◽  
Spatial Resolution ◽  
Low Dose ◽  
High Dose ◽  
Ct Number ◽  
Noise Ratio ◽  
Computed Tomography Dose Index ◽  
Dose Index

<p class="AbstractHeading">ABSTRACT</p><p class="AbstractText">The aim of this research was to evaluate the effects of two different dose protocols’ usage on image quality. This research was performed on three different CT Scanners using high dose and low dose protocols of thorax scan. Different exposure parameters were used, depending on each scanner’s setting. GE QA CT Scan phantom was used for image quality assessment.  Image quality measured were CT number accuracy, uniformity and linearity, noise uniformity, spatial resolution and Contrast To Noise Ratio (CNR). CT Scan’s dose index, CTDIvol (Volumetric Computed Tomography Dose Index), was also measured to evaluate how these two protocols work in reducing radiation dose. The result showed that the usage of low dose protocols reduce the CTDIvol value at 85-91% compared to the high dose protocols, meanwhile most of the image quality parameters obtained from both protocols were still considered good. The CT number accuracy, uniformity, linearity and noise uniformity for all CT Scans were all still inside BAPETEN’s (Indonesia National Regulator Agency) threshold. There were 20-23% difference on the spatial resolution value measured from both protocols. The most significant difference came from CNR. The CNR obtained from high dose protocols were 65-93% higher than the one from low dose protocols.   </p><p class="AbstractText">Keywords: contrast to noise ratio, CTDIvol, CT number, spatial resolution</p><p class="AbstractHeading">ABSTRAK</p><p>Penelitian ini mengevaluasi pengaruh penggunanaan protokol dosis tinggi dan protokol dosis rendah terhadap kualitias citra dan dosis khususnya pada pemeriksaan CT Scan thorax. Penelitian ini dilakukan pada 3 sampel CT Scan yang berbeda. Faktor eksposi yang digunakan berbeda untuk tiap scanner, bergantung pada setting yang terdapat pada scanner. Fantom yagdigunakan untuk menilai kualitas citra adalah fantom GE QA CT Scan. Adapun kualitas citra yang diukur adalah keseragaman, akurasi, dan linearitas CT number, keseragaman noise, resolusi spasial, serta <em>Contrast to Noise Ratio</em> (CNR). Sementara dosis radiasi yang diamati adalah CTDIvol (Volumetrik <em>Computed Tomography Dose Index</em>) yang tampil pada konsol. Hasil penelitian ini menunjukkan bahwa penggunaan protokol dosis rendah mampu mengurangi nilai CTDIvol sebesar 85-91% dibanding dengan protokol dosis tinggi, sementara sebagian besar parameter kualitas citra yang diukur masih dinilai baik. Nilai akurasi, keseragaman, dan linearitas CT number  serta keseragaman noise pada protokol dosis tinggi dan dosis rendah, keseluruhannya masih dalam batas ambang BAPETEN. Terdapat perbedaan sebesar 20-23% pada nilai resolusi spasial yang terukur dari  kedua protokol. Nilai CNR pada protokol dosis tinggi lebih baik dari pada protokol dosis rendah, dengan perbedaan yang cukup signifikan, yaitu 65-93%.</p><p class="AbstractText">Kata kunci: <em>contrast to noise ratio</em>, CTDIvol, <em>CT number</em>, resolusi spasial</p>

Cone-beam volumetric CT imagers: simulations for rapid prototype system design and prediciton of image quality

2001 ◽  
Author(s):  
Deborah J. Walter ◽  
Baorui Ren ◽  
Armin H. Pfoh ◽  
Peter M. Edic ◽  
Xiaoye Wu ◽  
...  
Keyword(s):  
Image Quality ◽  
System Design ◽  
Rapid Prototype ◽  
Cone Beam ◽  
Prototype System ◽  
Volumetric Ct ◽  
Rapid Prototype System
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