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Analysis of the tooth, part 1: the pulp canal
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Micro-CT Phantoms
Standard Resolution Performance Evaluation Micro-CT Phantom, Model: MCTP 610 … Resolution coil plate offers four spiral coils of alternating Mylar and aluminum …
Source: www.simutec.com
Date Published: 2/24/2022
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Micro CT Phantom Kit
This Micro CT phantom kit allows for the assessment of Micro CT systems and in Micro CT research. The kit is a standard size of 32mm, but can be scaled up …
Source: www.pureimagingphantoms.com
Date Published: 7/29/2022
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MicroCT set – Leeds Test Objects
MicroCT set · Bone Density (HA) phantom · Low Contrast phantom · Image Reconstruction Artefacts phantom · Water phantom for Uniformity and Noise · Point Spread …
Source: www.leedstestobjects.com
Date Published: 1/21/2022
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A quality assurance phantom for the performance evaluation …
As a result, micro-computed tomography (micro-CT) systems are becoming more common in research laboratories, due to their ability to achieve …
Source: pubmed.ncbi.nlm.nih.gov
Date Published: 6/24/2021
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The importance of routine quality control for reproducible …
In this work, we outline a routine QC protocol for in vivo micro-CT, based on commercial preclinical phantoms, that is able to monitor over …
Source: www.nature.com
Date Published: 5/11/2022
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주제와 관련된 이미지 micro ct phantom
주제와 관련된 더 많은 사진을 참조하십시오 Bruker microCT tutorial: Analysis of the tooth part 1: the pulp canal. 댓글에서 더 많은 관련 이미지를 보거나 필요한 경우 더 많은 관련 기사를 볼 수 있습니다.
주제에 대한 기사 평가 micro ct phantom
- Author: Phil Salmon
- Views: 조회수 6,631회
- Likes: 좋아요 25개
- Date Published: 2013. 4. 20.
- Video Url link: https://www.youtube.com/watch?v=ckpbjX19aho
Micro-CT Phantoms
Standard Resolution Performance Evaluation Micro-CT Phantom, Model: MCTP 610
Resolution coil plate offers four spiral coils of alternating Mylar and aluminum sheets with layer thicknesses of;150µm, 200µm, 300µm & 500µm. Using our proprietary automated software, seven image quality parameters are accurately evaluated and automatically analyzed with a single volumetric scan, assuring accuracy and saving valuable time..
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Leeds Test Objects
The Leeds MicroCT set is a set of test objects used to assess image quality of MicroCT systems. Each test object is 32mm diameter as standard, but can be made in other diameters on request. The set includes;
Bone Density (HA) phantom
Low Contrast phantom
Image Reconstruction Artefacts phantom
Water phantom for Uniformity and Noise
Point Spread Function (PSF) phantom
CT dose index phantom
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The importance of routine quality control for reproducible pulmonary measurements by in vivo micro-CT
Ad-hoc QC tests for micro-CT systems have been established, using three commercial imaging phantoms (QRM GmbH, Möhrendorf, Germany) (Table 1).
Table 1 QC phantom specifications as reported in the manufacturer’s datasheets (QRM GmbH, Möhrendorf, Germany) and corresponding QC parameters for which they are used. Full size table
Phantoms are acquired by micro-CT monthly25,26,27,28,31 and segmentation maps with fixed regions of interest (ROIs) are applied to the scans for the assessment of the image quality parameters (Fig. 1). These measurements are conducted in a grey levels scale, that corresponds to the original scale of CT scans after reconstruction.
Figure 1 Axial views of micro-CT phantoms and segmentation maps used for the corresponding QC tests. (A) Water phantom with the ROI used to perform noise test and water value evaluation, within five contiguous slices. (B) Bar Pattern phantom filled with air with the ROI used to monitor air value, within five contiguous slices. (C) Water phantom with the ROIs used for the uniformity test, within five contiguous slices: one central (ROI_a) and four peripheral ROIs (ROI_b, ROI_c, ROI_d, ROI_e). (D) Low Contrast V2 phantom: the cylindric inserts with different low contrast levels (− 9, − 6 and − 3%) are identified by means of proportional ROIs, orange for 3 mm diameter, green for 2 mm diameter and blue for 1 mm diameter. The central yellow ROI is used to detect the background value. (E) The 5 × 5 mm2 chip of the Bar Pattern phantom: the patterns used for the spatial resolution test are indicated in blue (10 lp/mm), red (5 lp/mm) and green (3.3 lp/mm) and (F) the corresponding line widths are reported. Full size image
The data reported in this study were collected on specific control charts and compared to baseline (BL) values, each defined by upper and lower tolerance limits, as suggested by literature25,31. BL values were initially established for our Quantum GX micro-CT (PerkinElmer, Inc. Waltham, MA), acquiring five consecutive scans of the QC phantoms31,32. For each monitored parameter, the BL and tolerance width were calculated, respectively:
$$ BL = Average\left( {\left( {x_{j} } \right)_{j = 1, \ldots ,5} } \right), $$
$$ Tolerance\,width = 2 \times SD\left( {\left( {x_{j} } \right)_{j = 1, \ldots ,5} } \right), $$
in which \(x\) represents an image quality parameter, \(j\) is the index of weekly acquisition and SD is the standard deviation of the baseline measures. All measures obtained by the QC tests were then compared to the corresponding tolerance range (Table 2):
$$ Tolerance\,range = BL \pm Tolerance\,width. $$
Table 2 Tolerance ranges calculated for all the monitored QC parameters for the Quantum GX micro-CT (PerkinElmer, Inc. Waltham, MA). Full size table
In this study, the dosimetry of the Quantum GX scanner33 and its impact on lung imaging were not objects of investigation, since they have been already evaluated in preclinical applications34,35,36, with findings suggesting that animal welfare was protected in this respect and that longitudinal CT data were not affected by multiple X-ray expositions.
Micro-CT phantoms and corresponding QC tests
Water, Low Contrast and Bar Pattern phantoms (QRM GmbH, Möhrendorf, Germany) were used for quality control tests, as detailed below.
Water phantom
A cylindric device with a diameter of 32 mm and filled with milli-Q water, was employed to evaluate noise, to extract the absolute grey value for water and measure uniformity (micro-CT water phantom, QRM GmbH, Möhrendorf, Germany).
Noise test
The noise value was extracted applying a circular ROI (ROI Noise ) to five spatially contiguous reconstructed slices, along the longitudinal z-axis (Fig. 1A). The ROI area (80.4 mm2) was chosen to be 10% of the cylinder base area (16 mm × 16 mm × π = 804 mm2), according to IPEM and IEC indications37,38. The noise was defined as the SD of the water grey level (i.e. SDwater) within the ROI (i.e. meanwater ± SDwater). In order to obtain the monthly noise value, namely \({Noise}\), we calculated the average of the five SDwater:
$$ Noise = \mathop \sum \limits_{i = 1}^{5} \frac{{\left( {SD_{i}^{water} } \right)}}{5}\quad {\text{i }} = {\text{ slice}}\,{\text{index}}{.} $$
Water evaluation
Water grey level was monitored applying the same ROI employed for the noise test (Fig. 1A). In this case, we evaluated the mean water grey level value (mean water ), averaging the values of the five contiguous cross sections that compose the ROIs:
$$ Water = \mathop \sum \limits_{i = 1}^{5} \frac{{\left( {mean \,value_{i}^{water} } \right)}}{5}\quad {\text{i }} = {\text{ slice}}\,{\text{index}}{.} $$
Uniformity test
Five circular ROIs were positioned in the centre and in peripheral locations of the image and propagated for five contiguous slices along z-axis, as shown in Fig. 1B. The image quality parameter for the uniformity test, i.e. \(Uniformity\), was calculated as the difference between the meanwater value of the central ROI a and the average of the four meanwater values of the peripheral ROIs (ROI b , ROI c , ROI d , ROI e ):
$$ Uniformity = mean\,value_{{ROI_{a} }} – \mathop \sum \limits_{h = b}^{e} \frac{{\left( {mean\,value_{{ROI_{h} }} } \right)}}{5}\quad {\text{h }} = {\text{ ROI}}\,{\text{index}}{.} $$
Each \({mean value}_{ROI}\) was calculated by averaging the mean of water grey values obtained from the five contiguous slices, as in the ‘Water evaluation’ method.
Micro-CT low contrast phantom
The low contrast phantom was chosen to measure the contrast resolution of the scanner. It provides three approximate contrast levels of − 9%, − 6% and − 3% compared to the background material, each level composed of three circular inserts with different diameters, i.e. 1, 2 and 3 mm, for a total of nine inserts (micro-CT Low Contrast Phantom V2, QRM GmbH, Möhrendorf).
Low contrast test
The low contrast detectability (LCD) is defined as the minimum visible dimension for low contrast objects, provided by the diameter of the smallest circular insert. The segmentation map for the LCD test consists of nine circular ROIs with dimensions proportional to the three different sizes of the inserts (Fig. 1D). After adjusting the position of the ROIs following the location of the inserts, the nine ROIs were propagated on 100 image slices to obtain a 3D evaluation. Two additional circular ROIs were also considered: one for resin background and one for air (outside the phantom). The image quality parameter for the LCD test, called \(Contrast\) and expressed in %, was calculated as follows:
$$ Contrast_{k} = \left[ {1 – \frac{{\left( {mean\,value_{k} – mean\,value_{air} } \right)}}{{\left( {mean\,value_{background} – mean\,value_{air} } \right)}}} \right] \times 100, $$
where k represents the insert index and ranges from one to nine (k = 1,…,9). Finally, for each contrast level (− 9%, − 6%, − 3%), the \(Contrast\) parameter was evaluated as the average value of the three inserts with the same low contrast level but different diameter sizes:
$${Contrast}^{c}=\frac{\left({Contrast}_{1mm}^{c}+{Contrast}_{2mm}^{c}+{Contrast}_{3mm}^{c}\right)}{3}$$
in which the index c can be − 9%, − 6% or − 3%. In this way, each month we obtained three values of \(Contrast\), one for each nominal level.
Micro-CT bar pattern phantom
The spatial resolution test, as well as the evaluation of the absolute grey value for air, were carried out with the bar pattern phantom filled with air, and with a diameter of 20 mm. Two chips placed inside the phantom contain bar patterns with different widths and points with different diameters allowed evaluation of the spatial resolution in the centre as well as in the periphery of the image in a single measurement (micro-CT Bar Pattern Phantom, QRM GmbH, Möhrendorf).
Spatial resolution test
The in-plane spatial resolution for micro-CT images was tested. Based on visual inspection of the line pairs in the phantom scan (Fig. 1E), the spatial resolution was in a range between 10 and 3.3 line pairs per mm (l p/mm), corresponding to 50–150 µm line width (Fig. 1F), which represents the range in which the bars can be resolved26. The Modulation Transfer Function (MTF) of a system is used to describe the resolution performance of the scanner, providing a quantitative measure of the relationship between the original object and its radiological reconstruction39. MTF was calculated monthly for the three different bar patterns (3.3 lp/mm, 5 lp/mm and 10 lp/mm) using the ‘line profile’ tool of Analyze software (Analyze 12.0; Copyright 1986–2017, Biomedical Imaging Resource, Mayo Clinic, Rochester, MN), https://www.analyzedirect.com. The value averaged over three measures for ‘background’ and ‘bars’ was recorded and MTF calculated as follow:
$$ MTF_{{}}^{c} = \left[ {\frac{{\left( {mean\,value_{background} – mean\,value_{bars} } \right)}}{{\left( {mean\,value_{background} + mean \,value_{bars} } \right)}}} \right] \times 100, $$
where the index c can be 3.3 lp/mm, 5 lp/mm or 10 lp/mm. Since axial resolution is the same as transversal resolution, only the latter data are reported.
Air evaluation
The monitoring of grey levels of air was performed using a circular ROI positioned inside the bar pattern phantom (in air), with an area of 31.4 mm2, thus covering 10% of the phantom section area (10 mm × 10 mm × π = 314 mm2). The ROI was propagated for five contiguous cross sections and the mean grey level of air (mean air ) was calculated as the average of the five values extracted, as following:
$$ Air = \mathop \sum \limits_{i = 1}^{5} \frac{{\left( {mean\,value_{i}^{air} } \right)}}{5}\quad {\text{i }} = {\text{ slice}}\,{\text{index}}{.} $$
Experimental control animals
A cohort of 22 control mice were used for a retrospective evaluation of the impact of routine QC tests on lung scans post-processing.
Female inbred C57Bl/6 (7- to 8-weeks old) mice were purchased from Envigo, Italy (San Pietro al Natisone, Udine, Italy). Prior to use, animals were acclimatized for at least 5 days to the local vivarium conditions (room temperature: 20–24 °C; relative humidity: 40–70%; 12-h light–dark cycle), having free access to standard rodent chow and softened tap water.
All animal experiments described herein were authorized by the official competent authority and approved by the intramural animal-welfare body (AWB) of Chiesi Farmaceutici and authorized by the Italian Ministry of Health (protocol number: 809/2020-PR). All procedures were conducted in an AAALAC (Association for Assessment and Accreditation for Laboratory Animal Care) certified facility in compliance with the European Directive 2010/63 UE, Italian D.Lgs 26/2014, the revised “Guide for the Care and Use of Laboratory Animals”40 and with the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines41.
Animals were lightly anesthetized with 2.5% isoflurane delivered in a box and vehicle (50 μl saline [0.9%]) was administered via oropharyngeal aspiration (OA) using a micropipette42. Twenty-one days after saline administration, mice were anesthetized with 2% isoflurane and underwent micro-CT imaging10,14.
Micro-CT settings, images acquisition and processing
The Quantum GX Micro-CT (PerkinElmer, Inc. Waltham, MA) was used in this study. This scanner has a microfocus X-ray source with a Tungsten anode. A fixed filter of 0.5 mm aluminium (Al) and 0.06 mm copper (Cu) is placed in front of the exit port to remove low energy X-rays. QC phantoms were acquired with the following parameters: X-ray tube voltage 90 kV, X-ray tube current 88 μA, total scan time of 4 min. A sinogram-based ring reduction filter was used to minimize rings inherent in CT scans. After the ring reduction was applied to the sinograms, the resulting corrected sinograms were input to the GPU-based filtered back-projection algorithm with a Ram-Lak filter. The acquisition protocol allows acquisition of projections over a total angle of 360° resulting in 3D datasets with 50 μm isotropic reconstructed voxel size10,33. All the images were imported as 3D .vox files and analysed using Analyze software (Analyze 12.0; Copyright 1986–2017, Biomedical Imaging Resource, Mayo Clinic, Rochester, MN) https://www.analyzedirect.com.
All protocols for mouse lung acquisition and image post-processing were largely detailed by Mecozzi et al.10 applied to a bleomycin-induced fibrosis murine model. Lung density histograms were extracted from pulmonary scans and the area under curve (AUC), the skewness and kurtosis calculated.
Statistical analysis
Statistical analyses were performed using GraphPad Prism version 9.1.2 for Windows (GraphPad Software, La Jolla, CA, USA), https://www.graphpad.com. All data were presented as mean ± SD. The normality test was performed for the AUC, the skewness and kurtosis of the average lung histograms. A one-tailed unpaired t-test was performed to compare AUC parameters. Finally, an unpaired t-test and Mann–Whitney test were performed to compare the kurtosis and the skewness, respectively. The alpha level of all tests was set at 0.05.
키워드에 대한 정보 micro ct phantom
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이 기사는 인터넷의 다양한 출처에서 편집되었습니다. 이 기사가 유용했기를 바랍니다. 이 기사가 유용하다고 생각되면 공유하십시오. 매우 감사합니다!
사람들이 주제에 대해 자주 검색하는 키워드 Bruker microCT tutorial: Analysis of the tooth part 1: the pulp canal
- Bruker
- microCT
- micro-CT
- dental
- tooth
- image analysis
- image processing
- endodontics
- pulp canal
- root canal
Bruker #microCT #tutorial: #Analysis #of #the #tooth #part #1: #the #pulp #canal
YouTube에서 micro ct phantom 주제의 다른 동영상 보기
주제에 대한 기사를 시청해 주셔서 감사합니다 Bruker microCT tutorial: Analysis of the tooth part 1: the pulp canal | micro ct phantom, 이 기사가 유용하다고 생각되면 공유하십시오, 매우 감사합니다.
