Quality Assessment of Mobile Cone-beam Computerized Tomography Scanner Made in Thailand: A Phantom Study

2021 ◽  
Vol 104 (12) ◽  
pp. 1937-1946
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Technology Development ◽  
Human Subjects ◽  
Cone Beam ◽  
Geometric Accuracy ◽  
Ct Scanner ◽  
Ct Number ◽  
Good Spatial Resolution ◽  
Noise Production

Background: In 2011, the National Science and Technology Development Agency had successfully developed the first local-made mobile conebeam computed tomography (CBCT) scanner, called MobiiScan. Before a computed tomography (CT) scanner can be used in clinical practice, it must pass a quality assurance process. Objective: To assess the performance of MobiiScan before it can be further evaluated in human subjects. Materials and Methods: Images from scanning of an imaging phantom by MobiiScan were compared to a commercial 64-slice (GE Discovery CT750 HD) and a mobile (Neurologica CereTom) CT scanner, which were used as controls. Spatial resolution, uniformity, noise, accuracy of CT number, and geometric accuracy were examined by three investigators. Results: According to the bone scanning protocol, spatial resolution of the images produced by MobiiScan was comparable to the mobile scanner, but it was less than the 64-slice scanner. In addition, the signal uniformity of MobiiScan was poorer compared to the controls. MobiiScan produced more noise than the mobile and the 64-slice scanners at the 120-kVp mode, but less noise than the 64-slice scanner at the 80-kVp mode. Using the brain protocol, the spatial resolution from the MobiiScan was higher than the mobile scanner, but comparable to the 64-slice scanner. Although the signal uniformity of the MobiiScan was superior compared to the controls, the noise production was more than the controls. At all settings, the MobiiScan gave underrated distances and inaccurate CT numbers. However, it delivered very low radiation doses. Conclusion: MobiiScan had a good spatial resolution and delivered low radiation dose, which suggested that it could be used for bone examination as intended by the creator. However, its noise production and inaccurate CT numbers suggest that MobiiScan should not be used to diagnose soft tissue problems. It is recommended that the hardware and software should be adjusted to provide a better signal uniformity, lower noise level, accurate CT number, and geometric accuracy. Keywords: X-ray computed tomography; Cone-beam computed tomography; Craniofacial abnormalities; Radiologic phantom; MobiiScan

scholarly journals Comparison of the Hounsfield Unit Values Obtained From Cone-Beam Computed Tomography (CBCT) and Multidetector Computed Tomography (MDCT) Images for Different Bone Densities

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Atefeh Khavid ◽  
Mojgan Sametzadeh ◽  
Mostafa Godiny ◽  
Mohammad Mehdi Moarrefpour
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Pearson Correlation ◽  
Hounsfield Unit ◽  
Cone Beam ◽  
Ct Scanner ◽  
Significance Level ◽  
Dental Practitioners ◽  
Significant Difference ◽  
The Mean

Background and objective: In recent years, cone-beam computed tomography (CBCT) has become a key diagnostic tool in dentistry. CBCT can provide 3D images of the maxillofacial area to help dental practitioners in diagnosis and treatment, especially implant placement and treatment of pathogenic lesions. This study aimed to compare the Hounsfield Unit (HU) values obtained from CBCT images for bones of different densities with the corresponding HU values from MDCT images. Materials and methods: cube-shaped bone blocks of identical size were cut from the middle section of the cow ribs and femur area such that they had a layer of cortical bone in their buccal, lingual, and top surfaces and trabecular bone in the middle. MDCT scans were performed using a Somatom Sensation Ct Scanner. After determining HU from the results of these scans, nine suitable specimens from different ranges of HU were chosen for comparison. HU of the CBCT images was computed by the dedicated software of the CBCT machine. Finally, HU values obtained from MDCT and CBCT were compared. Data analysis was performed using SPSS version 25 at the 0.05 significance level. Results: The results showed a statistically significant difference between the mean HU from MDCT images and the mean HU from CBCT images (P<0.05). For similar specimens, CBCT produced higher mean HU values than MDCT. The Pearson correlation test detected a significant direct relationship between the HU values of specimens in MDCT and CBCT (P<0.05). Conclusion: For the tools and software used in this study, there was no significant difference between the HU values obtained from MDCT and CBCT, but the mean HU obtained from CBCT was higher than that from MDCT.

scholarly journals Time-Enhancement Curve of Four-Dimensional Computed Tomography Predicts Aneurysm Enlargement with Type-II Endoleak after Endovascular Aneurysm Repair

Aorta ◽  
2020 ◽  
Vol 08 (02) ◽  
pp. 029-034
Author(s):  
Yunosuke Nishihara ◽  
Kota Mitsui ◽  
Shinya Azama ◽  
Daisuke Okamoto ◽  
Manabu Sato ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Equilibrium Phase ◽  
Endovascular Aneurysm Repair ◽  
Three Dimensional ◽  
Type Ii ◽  
Ct Scanner ◽  
Stable Group ◽  
Ct Number ◽  
4D Ct ◽  
Aneurysm Repair

Abstract Objective We investigated the hemodynamic features of Type-II endoleaks after endovascular aneurysm repair (EVAR) using four-dimensional (4D) computed tomography (CT) to identify patients with aneurysm enlargement. Methods During a 13-month period (January 2017–January 2018) at our institution, we performed 4D-CT examinations in 13 patients after EVAR because of suspected Type-II endoleaks. Three patients were excluded from the study because of other endoleaks or absence of detectable endoleaks. The ramaining 10 patients were divided into two groups: enlargement group (n = 4), in which the aneurysm volume increased, and stable group (n = 6), in which the aneurysm remained stable or shrank. A CT scanner and three-dimensional workstation were used. All images were obtained using a consistent protocol (22 phase scans using the test bolus tracking method). We analyzed the hemodynamics of the endoleak cavity (EC) relative to those of the aorta and evaluated the time-enhancement curves (TECs) using measurement protocols. The strengths of correlations between these factors in the two groups were analyzed statistically. Results TECs in the enlargement group showed a more gradual curve, and the upslope, the gradient of TEC in the ascending phase and the upslope index were significantly more gradual than those in the stable group (p = 0.0247, 0.0243). The EC washout and the EC washout index were also more gradual than in the stable group's (p = 0.019, 0.019). The enhancement duration was longer in the former than in the latter (80%, p = 0.0195; 70%, p = 0.0159; 60%, p = 0.0159). The CT number in the equilibrium phase was larger in the enlargement group than in the stable group (p = 0.019). Conclusion The 4D-CT is useful for predicting aneurysm enlargement with Type-II endoleaks after EVAR.

Positional dependence of the CT number with use of a cone-beam CT scanner for an electron density phantom in particle beam therapy

2012 ◽  
Vol 6 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Yohsuke Kusano ◽  
Saki Uesaka ◽  
Kaori Yajima ◽  
Motoki Kumagai ◽  
Hideyuki Mizuno ◽  
...  
Keyword(s):  
Electron Density ◽  
Cone Beam Ct ◽  
Particle Beam ◽  
Cone Beam ◽  
Ct Scanner ◽  
Ct Number ◽  
Particle Beam Therapy

scholarly journals Cone Beam Computed Tomography Application in Finding Ectopic Tooth: A Systemic Analysis and a Case Report

2019 ◽  
Vol 7 (24) ◽  
pp. 4333-4336
Author(s):  
Vo Truong Nhu Ngoc ◽  
Le Quynh Anh ◽  
Nguyen Minh Duc ◽  
Thien Chu Dinh ◽  
Toi Chu Dinh
Keyword(s):  
Computed Tomography ◽  
Case Report ◽  
Maxillary Sinus ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Ct Scanner ◽  
Systemic Analysis ◽  
Rare Phenomenon ◽  
Asymptomatic Patients ◽  
Ectopic Tooth

BACKGROUND: Nowadays, cone beam computed tomography (CBCT) are commonly used in dentistry with an advantage about significantly lower dose comparing with CT-Scanner. Utilizing CBCT images which are indicated in dentistry like orthodontics can help diagnose diseases beyond dentistry field. One rare phenomenon can be seen in maxillary sinus, which is often overlooked by dentists, is ectopic teeth. CASE REPORT: This article describes one orthodontic case found accidentally an ectopic tooth in maxillary sinus by inspecting CBCT images. CONCLUSION: Dentists and oral radiologists should carefully inspect non-dental structures, like maxillary sinus, even its distance from the dentoalveolar region, especially in asymptomatic patients.

scholarly journals Effect of Filtered Back-Projection Filters to Low-Contrast Object Imaging in Ultra-High-Resolution (UHR) Cone-Beam Computed Tomography (CBCT)

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6416
Author(s):  
Sunghoon Choi ◽  
Chang-Woo Seo ◽  
Bo Kyung Cha
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Spatial Frequency ◽  
Spatial Resolution ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Acquisition Time ◽  
Imaging Protocol ◽  
Low Contrast ◽  
Smoothing Window

In this study, the effect of filter schemes on several low-contrast materials was compared using standard and ultra-high-resolution (UHR) cone-beam computed tomography (CBCT) imaging. The performance of the UHR-CBCT was quantified by measuring the modulation transfer function (MTF) and the noise power spectrum (NPS). The MTF was measured at the radial location around the cylindrical phantom, whereas the NPS was measured in the eight different homogeneous regions of interest. Six different filter schemes were designed and implemented in the CT sinogram from each imaging configuration. The experimental results indicated that the filter with smaller smoothing window preserved the MTF up to the highest spatial frequency, but larger NPS. In addition, the UHR imaging protocol provided 1.77 times better spatial resolution than the standard acquisition by comparing the specific spatial frequency (f50) under the same conditions. The f50s with the flat-top window in UHR mode was 1.86, 0.94, 2.52, 2.05, and 1.86 lp/mm for Polyethylene (Material 1, M1), Polystyrene (M2), Nylon (M3), Acrylic (M4), and Polycarbonate (M5), respectively. The smoothing window in the UHR protocol showed a clearer performance in the MTF according to the low-contrast objects, showing agreement with the relative contrast of materials in order of M3, M4, M1, M5, and M2. In conclusion, although the UHR-CBCT showed the disadvantages of acquisition time and radiation dose, it could provide greater spatial resolution with smaller noise property compared to standard imaging; moreover, the optimal window function should be considered in advance for the best UHR performance.

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 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>

scholarly journals Location dependency of the spatial resolution of cone beam computed tomography for dental use

2013 ◽  
Vol 116 (5) ◽  
pp. 648-655 ◽  
Author(s):  
Yoshihiro Ozaki ◽  
Hiroshi Watanabe ◽  
Yoshikazu Nomura ◽  
Eiichi Honda ◽  
Yasunori Sumi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Cone Beam Computed Tomography ◽  
Cone Beam
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