Journal articles: 'Image tube'

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Mai, Hang-Nga, and Du-Hyeong Lee. "Effects of Exposure Parameters and Voxel Size for Cone-Beam Computed Tomography on the Image Matching Accuracy with an Optical Dental Scan Image: An In Vitro Study." BioMed Research International 2021 (June 10, 2021): 1–6. http://dx.doi.org/10.1155/2021/6971828.

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This study is aimed at assessing the effects of exposure parameters and voxel size for cone-beam computed tomography (CBCT) on the image matching accuracy with an optical dental scan image. CBCT and optical scan images of a dry human mandible were obtained. Different CBCT settings were used: tube voltage, 60, 80, and 100 kVp; tube current, 6 and 8 mA; and voxel size, 100, 200, and 300 μm. Image matching between the CBCT and optical scan images was performed using implant planning software by dental professionals ( n = 18 ). The image matching accuracy in each combination of CBCT settings was evaluated by assessing the linear discrepancy between the three-dimensionally reconstructed radiological image and the registered optical scan image using an image analysis software program. The Kruskal-Wallis test and a post hoc Mann–Whitney U test with Bonferroni correction were used to compare the accuracy of image registration between the groups ( α = 0.05 ). Overall, the image matching accuracy was not significantly different between tube voltage and current settings; however, significantly higher image registration errors were found at the combination of 100 kVp tube voltage/8 mA tube current ( F = 8.44 , P < 0.001 ). Changes in voxel sizes did not significantly interfere with the image registration results. No interaction was found among voltage, current, and voxel size in terms of image registration accuracy ( F = 2.022 , P = 0.091 ). Different exposure parameter settings in tube voltage and tube current did not significantly influence the image matching accuracy between CBCT and optical dental scan images; however, a high radiation dose could be inappropriate. The image matching accuracy was not significantly affected by changing the voxel sizes of CBCT.

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Green, R. E. "Real-Time X-Ray Diffraction For Materials Process Control." MRS Bulletin 13, no. 4 (April 1988): 44–48. http://dx.doi.org/10.1557/s0883769400065891.

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As useful as classical x-ray diffraction techniques have been, the ability to obtain x-ray diffraction images with extremely short exposure rimes opens up new opportunities for materials scientists, including real-time materials process control. This article briefly describes state-of-the-art systems for obtaining extremely rapid and real-time x-ray diffraction images and gives several examples of their applications for materials process control.Two generic electro-optical methods permit real-time viewing and recording of x-ray diffraction images. The first uses a low-intensity conventional x-ray tube source leading to a low-intensity diffraction image, which requires a high-gain electro-optical imaging system. The second uses either a high-intensity rotating anode, synchrotron, or flash x-ray source. Such a high-intensity source produces a high-intensity diffraction image, permitting use of a low-gain high-resolution electro-optical imaging system.Figure 1 schematically shows two types of image intensifier tubes which have been most often used to view x-ray diffraction images. By cascading three individual first generation image tube stages (Figure 1a), light gains as high as several million can be obtained. The second generation microchannel-plate image intensifier tube (Figure 1b) is similar to a single-stage first generation device except for the extremely important addition of a microchannel plate.

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Strauss, Lourens Jochemus, and William ID Rae. "Image quality dependence on image processing software in computed radiography." South African Journal of Radiology 16, no. 2 (June 12, 2012): 44–48. http://dx.doi.org/10.4102/sajr.v16i2.305.

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Background. Image post-processing gives computed radiography (CR) a considerable advantage over film-screen systems. After digitisation of information from CR plates, data are routinely processed using manufacturer-specific software. Agfa CR readers use MUSICA software, and an upgrade with significantly different image appearance was recently released: MUSICA2. Aim. This study quantitatively compares the image quality of images acquired without post-processing (flatfield) with images processed using these two software packages. Methods. Four aspects of image quality were evaluated. An aluminium step-wedge was imaged using constant mA at tube voltages varying from 40 to 117kV. Signal-to-noise ratios (SNRs) and contrast-to-noise Ratios (CNRs) were calculated from all steps. Contrast variation with object size was evaluated with visual assessment of images of a Perspex contrast-detail phantom, and an image quality figure (IQF) was calculated. Resolution was assessed using modulation transfer functions (MTFs). Results. SNRs for MUSICA2 were generally higher than the other two methods. The CNRs were comparable between the two software versions, although MUSICA2 had slightly higher values at lower kV. The flatfield CNR values were better than those for the processed images. All images showed a decrease in CNRs with tube voltage. The contrast-detail measurements showed that both MUSICA programmes improved the contrast of smaller objects. MUSICA2 was found to give the lowest (best) IQF; MTF measurements confirmed this, with values at 3.5 lp/mm of 10% for MUSICA2, 8% for MUSICA and 5% for flatfield. Conclusion. Both MUSICA software packages produced images with better contrast resolution than unprocessed images. MUSICA2 has slightly improved image quality than MUSICA.

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Moore, Craig Steven, Tim Wood, Ged Avery, Steve Balcam, Liam Needler, Hiten Joshi, Najeeb Ahmed, John Saunderson, and Andrew Beavis. "Use of a computer simulator to investigate optimized tube voltage for chest imaging of average patients with a digital radiography (DR) imaging system." British Journal of Radiology 92, no. 1104 (December 2019): 20190470. http://dx.doi.org/10.1259/bjr.20190470.

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Objective: The aim of this study was to investigate via computer simulation a proposed improvement to clinical practice by deriving an optimized tube voltage (kVp) range for digital radiography (DR) chest imaging. Methods: A digitally reconstructed radiograph algorithm was used which was capable of simulating DR chest radiographs containing clinically relevant anatomy. Five experienced image evaluators graded clinical image criteria, i.e. overall quality, rib, lung, hilar, spine, diaphragm and lung nodule in images of 20 patients at tube voltages across the diagnostic energy range. These criteria were scored against corresponding images of the same patient reconstructed at a specific reference kVp. Evaluators were blinded to kVp. Evaluator score for each criterion was modelled with a linear mixed effects algorithm and compared with the score for the reference image. Results: Score was dependent on tube voltage and image criteria in a statistically significant manner for both. Overall quality, hilar, diaphragm and spine criteria performed poorly at low and high tube voltages, peaking at 80–100 kVp. Lung and lung nodule demonstrated little variation. Rib demonstrated superiority at low kVp. Conclusion: A virtual clinical trial has been performed with simulated chest DR images. Results indicate mid-range tube voltages of 80–100 kVp are optimum for average adults. Advances in knowledge: There are currently no specific recommendations for optimized tube voltage parameters for DR chest imaging. This study, validated with images containing realistic anatomical noise, has investigated and recommended an optimal tube voltage range.

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Konuma, H., K. Kuroki, K. Kurosawa, and N. Saitoh. "Low Energy X-Ray Transmission Images by using a Microfocus X-Ray Tube and a be-Window X-Ray Image Intensifier(XRII)." Microscopy and Microanalysis 4, S2 (July 1998): 494–95. http://dx.doi.org/10.1017/s1431927600022595.

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Photographs of x-ray transmission images by x-ray films have been used for observing the inside nondestructively. Further, Imaging Plates(IP) are used for precise measurements of x-ray diffraction patterns. But, these integrating area detectors are not suitable for real time nor time resolved measurements. For real time and time resolved measurements, the X-Ray Image Intensifier(XRII, a large image tube that converts an x-ray image into a visible image) is used for biological x-ray TV systems, x-ray nondestructive inspection systems etc. These TV x-ray image systems require high energy x-rays, x-ray tube voltage of 30 to 150 kV, and show faint contrast for x-ray images of light element substances owing to its low absorption coefficients. However, light elements have intense x-ray absorption coefficients in a low energy x-ray region, x-ray tube voltage of 5 to 20 kV, and give fine contrast for x-ray images of light element substances.

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Papadakis, Antonios E., and John Damilakis. "Evaluation of an organ-based tube current modulation tool in pediatric CT examinations." European Radiology 30, no. 10 (May 20, 2020): 5728–37. http://dx.doi.org/10.1007/s00330-020-06888-5.

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Abstract Objectives To investigate the effect of an organ-based tube current modulation (OTCM) technique on organ absorbed dose and assess image quality in pediatric CT examinations. Methods Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old were used. Standard head and thorax acquisitions were performed with automatic tube current modulation (ATCM) and ATCM+OTCM. Dose calculations were performed by means of Monte Carlo simulations. Radiation dose was measured for superficial and centrally located radiosensitive organs. The angular range of the OTCM exposure window was determined for different tube rotation times (t) by means of a solid-state detector. Image noise was measured as the standard deviation of the Hounsfield unit value in regions of interest drawn at selected anatomical sites. Results ATCM+OTCM resulted in a reduction of radiation dose to all radiosensitive organs. In head, eye lens dose was reduced by up to 13% in ATCM+OTCM compared with ATCM. In thorax, the corresponding reduction for breast dose was up to 10%. The angular range of the OTCM exposure window decreased with t. For t = 0.4 s, the angular range was limited to 74° in head and 135° for thorax. Image noise was significantly increased in ATCM+OTCM acquisitions across most examined phantoms (p < 0.05). Conclusions OTCM reduces radiation dose to exposed radiosensitive organs with the eye lens and breast buds exhibiting the highest dose reduction. The OTCM exposure window is narrowed at short t. An increase in noise is inevitable in images located within the OTCM-activated imaged volume. Key Points • In pediatric CT, organ-based tube current modulation reduces radiation dose to all major primarily exposed radiosensitive organs. • Image noise increases within the organ-based tube current modulation enabled imaged volume. • The angular range of the organ-based tube current modulation low exposure window is reduced with tube rotation time.

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Söderman, M., B. Hansson, and B. Axelsson. "Radiation Dose and Image Quality in Neuroangiography: Effects of Increased Tube Voltage, Added X-Ray Filtration and Antiscatter Grid Removal." Interventional Neuroradiology 4, no. 3 (September 1998): 199–207. http://dx.doi.org/10.1177/159101999800400304.

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During endovascular treatment the patient may be subject to fluoroscopy for long periods as well as multiple x-ray exposures. The radiation dose to the patient can be considerable, and cause local deterministic effects such as alopecia or even skin burn. The potential carcinogenic effects should also be noted, being especially important in the paediatric population. We measured radiation doses to patients and personnel during neuroendovascular procedures and diagnostic neuroangiography. We also tried to reduce the radiation dose to the patient utilising increased tube voltage, additional primary X-ray filtration and by removing the antiscatter grid in front of the image intensifier, employing air gap technique. We investigated radiation doses to patient and personnel during neuroangiographic procedures and optimized the examination technique with regard to radiation dose with maintained image quality. Radiation exposure to patients and personnel was measured with thermoluminescent dosimeters and permanently mounted KermaDose-Area-Product meters in front of the X-ray tubes during 13 cerebral angiographies and six neuroendovascular procedures. We performed experiments with radiation dose measurements and evaluation of image quality with 80 and 90 kV tube voltage during image acquisition and 75 and 85 kV during fluoroscopy, as well as with different primary X-ray filtration. Images from patient studies acquired with the original grid in front of the image intensifier were compared with images from patient studies acquired with the grid removed and air gap technique (30 cm). Images from patient studies acquired with the original examination technique were compared to images from patient studies acquired with increased x-ray tube voltage, increased x-ray filtering and with the antiscatter grid removed using an airgap as scatter reduction method. Radiation exposure to personnel was very low using standard protective devices. Measurable doses were recorded only on the hands and forehead of the neuroradiologist. Maximum entrance skin dose was about 1 Gy on the side of the patientspatient's forehead during an endovascular procedure. Increasing the tube voltage from 75 to 85 – 85 and 90 kV, exchanging the original 0.5 mm aluminium primary filtration for 0.2 mm copper and removing the antiscatter grid allowed us to reduce entrance skin dose to the patient by 70% with unchanged or slightly improved image quality.

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Sawall, S., L. Klein, E. Wehrse, L. T. Rotkopf, C. Amato, J. Maier, H. P. Schlemmer, C. H. Ziener, S. Heinze, and M. Kachelrieß. "Threshold-dependent iodine imaging and spectral separation in a whole-body photon-counting CT system." European Radiology 31, no. 9 (March 13, 2021): 6631–39. http://dx.doi.org/10.1007/s00330-021-07786-0.

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Abstract Objective To evaluate the dual-energy (DE) performance and spectral separation with respect to iodine imaging in a photon-counting CT (PCCT) and compare it to dual-source CT (DSCT) DE imaging. Methods A semi-anthropomorphic phantom extendable with fat rings equipped with iodine vials is measured in an experimental PCCT. The system comprises a PC detector with two energy bins (20 keV, T) and (T, eU) with threshold T and tube voltage U. Measurements using the PCCT are performed at all available tube voltages (80 to 140 kV) and threshold settings (50–90 keV). Further measurements are performed using a conventional energy-integrating DSCT. Spectral separation is quantified as the relative contrast media ratio R between the energy bins and low/high images. Image noise and dose-normalized contrast-to-noise ratio (CNRD) are evaluated in resulting iodine images. All results are validated in a post-mortem angiography study. Results R of the PC detector varies between 1.2 and 2.6 and increases with higher thresholds and higher tube voltage. Reference R of the EI DSCT is found as 2.20 on average overall phantoms. Maximum CNRD in iodine images is found for T = 60/65/70/70 keV for 80/100/120/140 kV. The highest CNRD of the PCCT is obtained using 140 kV and is decreasing with decreasing tube voltage. All results could be confirmed in the post-mortem angiography study. Conclusion Intrinsically acquired DE data are able to provide iodine images similar to conventional DSCT. However, PCCT thresholds should be chosen with respect to tube voltage to maximize image quality in retrospectively derived image sets. Key Points • Photon-counting CT allows for the computation of iodine images with similar quality compared to conventional dual-source dual-energy CT. • Thresholds should be chosen as a function of the tube voltage to maximize iodine contrast-to-noise ratio in derived image sets. • Image quality of retrospectively computed image sets can be maximized using optimized threshold settings.

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Ramdan, Raden Dadan, Deni Suwardhi, and Rochim Suratman. "Prospect of Identification of Different Corrosion Product by Near-IR Photography." Advanced Materials Research 718-720 (July 2013): 1185–90. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.1185.

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The present work is a preliminary work on the development of NIR camera photograph as alternative tool for corrosion product identification. Corrosion products were taken from two different carbon steel tubes side, one is from thinning tube side, the other is from normal tube side. From optical microscope data, it was observed that the thinning tube side surface has elongated microstructure while the other has normal microstructure. It was also observed that more stable oxide in the form of hematite formed on the thinning tube side, while the other side has siderite and magnetite as the corrosion product. From NIR camera photograph on the scale of both tubes side, it was obtained significant differences in the digital image number. It is expected that after further comprehensive collecting digital image number data on the various corrosion product as well as thickness layer, NIR camera photograph can be used as an alternative method for corrosion product identification.

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Guo, Xiang, Xin Su, Yingtao Yuan, Tao Suo, and Yan Liu. "A Novel Method for the Complex Tube System Reconstruction and Measurement." Sensors 21, no. 6 (March 22, 2021): 2207. http://dx.doi.org/10.3390/s21062207.

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Pipe structures are at the base of the entire industry. In the industry structure, heat and vibration are transmitted in each pipe. The minimum distance between each pipe is significant to the security. The assembly error and the deformation of the pipeline positions after multiple runs are significant problems. The reconstruction of the multi-pipe system is a critical technical difficulty in the complex tube system. In this paper, a new method for the multi-pipes structure inspection is presented. Images of the tube system are acquired from several positions. The photogrammetry technology calculates positions, and the necessary coordination of the structure is reconstructed. A convolution neural network is utilized to detect edges of tube-features. The new algorithm for tube identification and reconstruction is presented to extract the tube feature in the image and reconstruct the 3D parameters of all tubes in a multi-pipes structure. The accuracy of the algorithm is verified by simulation experiments. An actual engine of the aircraft is measured to verify the proposed method.

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Clark, Peter J., Giuseppe Forte, Mark J. H. Simmons, and E. Hugh Stitt. "Towards 3D-Electrical Capacitance Tomography for Interface Detection." Johnson Matthey Technology Review 60, no. 2 (April 1, 2016): 164–75. http://dx.doi.org/10.1595/205651316x691537.

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The application of three-dimensional electrical capacitance tomography (3D-ECT) for the in situ monitoring of a hard boundary or interface has been investigated using imaged phantoms that simulate real-life processes. A cylinder-in-tube phantom manufactured from polyethylene (PE), a low di-electric and non-conductive material, was imaged using the linear back projection (LBP) algorithm with the larger tube immersed at varying intervals to test the ability of the technique to image interfaces axially through the sensor. The interface between PE and air is clearly imaged and correlates to the known tube penetration within the sensor. The cylinder phantom is imaged in the centre of the sensor; however, the reduction in measurement density towards the centre of the ECT sensor results in reduced accuracy. A thresholding method, previously applied to binary systems to improve the imaged accuracy of a hard boundary between two separate phases, has been applied to the 3D-ECT tomograms that represent the PE phantom. This approach has been shown to improve the accuracy of the acquired image of a cylinder of air within a non-conductive PE tube.

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Hagen, Florian, Antonia Mair, Michael Bitzer, Hans Bösmüller, and Marius Horger. "Fully automated whole-liver volume quantification on CT-image data: Comparison with manual volumetry using enhanced and unenhanced images as well as two different radiation dose levels and two reconstruction kernels." PLOS ONE 16, no. 8 (August 2, 2021): e0255374. http://dx.doi.org/10.1371/journal.pone.0255374.

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Objectives To evaluate the accuracy of fully automated liver volume quantification vs. manual quantification using unenhanced as well as enhanced CT-image data as well as two different radiation dose levels and also two image reconstruction kernels. Material and methods The local ethics board gave its approval for retrospective data analysis. Automated liver volume quantification in 300 consecutive livers in 164 male and 103 female oncologic patients (64±12y) performed at our institution (between January 2020 and May 2020) using two different dual-energy helicals: portal-venous phase enhanced, ref. tube current 300mAs (CARE Dose4D) for tube A (100 kV) and ref. 232mAs tube current for tube B (Sn140kV), slice collimation 0.6mm, reconstruction kernel I30f/1, recon. thickness of 0.6mm and 5mm, 80–100 mL iodine contrast agent 350 mg/mL, (flow 2mL/s) and unenhanced ref. tube current 100mAs (CARE Dose4D) for tube A (100 kV) and ref. 77mAs tube current for tube B (Sn140kV), slice collimation 0.6mm (kernel Q40f) were analyzed. The post-processing tool (syngo.CT Liver Analysis) is already FDA-approved. Two resident radiologists with no and 1-year CT-experience performed both the automated measurements independently from each other. Results were compared with those of manual liver volume quantification using the same software which was supervised by a senior radiologist with 30-year CT-experience (ground truth). Results In total, a correlation of 98% was obtained for liver volumetry based on enhanced and unenhanced data sets compared to the manual liver quantification. Radiologist #1 and #2 achieved an inter-reader agreement of 99.8% for manual liver segmentation (p<0.0001). Automated liver volumetry resulted in an overestimation (>5% deviation) of 3.7% for unenhanced CT-image data and 4.0% for contrast-enhanced CT-images. Underestimation (<5%) of liver volume was 2.0% for unenhanced CT-image data and 1.3% for enhanced images after automated liver volumetry. Number and distribution of erroneous volume measurements using either thin or thick slice reconstructions was exactly the same, both for the enhanced as well for the unenhanced image data sets (p> 0.05). Conclusion Results of fully automated liver volume quantification are accurate and comparable with those of manual liver volume quantification and the technique seems to be confident even if unenhanced lower-dose CT image data is used.

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Vodovatov, A. V. "Evaluation of the dose reduction capabilities in digital radiography of the chest using contrast-detail phantom." Radiatsionnaya Gygiena = Radiation Hygiene 12, no. 1 (March 27, 2019): 62–73. http://dx.doi.org/10.21514/1998-426x-2019-12-1-62-73.

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Assessment of the quality of the images obtained using optimized (low-dose) protocols is the inherent part of the optimization in X-ray diagnostics. To perform the objective quantitative image quality assessment one can use dedicated test-objects, including several components for the simultaneous measurement of the different physical image characteristics (contrast and spatial resolution). The use of such test objects allows estimating and assessing the relations between the patient dose, parameter of the X-ray examination and image quality. That is especially important for the optimization of the digital radiographic examinations performed with automated exposure control. The aim of the current study was to evaluate the possibilities of the patient dose reduction using “contrast-detail” test-object for the digital radiography of the chest in posterior-anterior projection performed with automated exposure control. The study was performed in St-Petersburg Mariinsky hospital on a digital X-ray unit “ARC-Electron” with a flat-panel detector. The combination of a test-object and a tissue-equivalent phantom were imaged on a range of chest X-ray protocols: on a 60–150 kV tube voltage range with automated exposure control; and using fixed 90 kV tube voltage on a range of 2–100 mAs tube current-exposure time product. Dose-area product (cGy×cm2) was measured for each exposure; effective dose (mSv) was estimated for each exposure based on dose-area product. A dedicated software was developed for the automated image quality assessment. The results of the study indicate that the use of a high tube voltage (140–150 kV) with current automated exposure control settings would lead to 60% and 95% reduction of the dose-area product and effective dose, respectively, compared to the standard protocol. The adjustment of the current automated exposure control settings with the reduction of the tube current-exposure time product from 11,2 mAs to the 4,2 mAs for the tube voltage of 90 kV would lead to the reduction of both the dose-area product and effective dose up to a factor of three, compared to the standard protocol. For both scenarios image quality characteristics decreased by less than 15%. The proposed low-dose protocols are under the clinical approbation at Mariinsky hospital. The proposed method of image quality assessment and development of low-dose protocols is recommended for inclusion in the quality assurance program for the radiography examinations.

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Moore, Craig Steven, Tim Wood, Stephen Balcam, Liam Needler, Tim Guest, Wee Ping Ngu, Lee Wun Chong, John Saunderson, and Andrew Beavis. "Optimisation of tube voltage range (kVp) for AP abdomen, pelvis and spine imaging of average patients with a digital radiography (DR) imaging system using a computer simulator." British Journal of Radiology 93, no. 1114 (October 1, 2020): 20200565. http://dx.doi.org/10.1259/bjr.20200565.

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Objectives: To investigate via computer simulation, an optimised tube voltage (kVp) range for caesium iodide (CsI)-based digital radiography (DR) of the abdomen, pelvis and lumbar spine. Methods: Software capable of simulating abdomen, pelvis and spine radiographs was used. Five evaluators graded clinical image criteria in images of 20 patients at tube voltages ranging from 60 to 120 kVp in 10 kVp increments. These criteria were scored blindly against the same patient reconstructed at a specific reference kVp. Linear mixed effects analysis was used to evaluate image scores for each criterion and test for statistical significance. Results: Score was dependent on tube voltage and image criteria; both were statistically significant. All criteria for all anatomies scored very poorly at 60 kVp. Scores for abdomen, pelvis and spine imaging peaked at 70, 70 and 100 kVp, respectively, but other kVp values were not significantly poorer. Conclusions: Results indicate optimum tube voltages of 70 kVp for abdomen and pelvis (with an optimum range 70–120 kVp), and 100 kVp (optimum range 80–120 kVp) for lumbar spine. Advances in knowledge: There are no recommendations for optimised tube voltage parameters for DR abdomen, pelvis or lumbar spine imaging. This study has investigated and recommended an optimal tube voltage range.

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Snyder, Austin, Silvia Salamone, Nicholas J. Reid, Tristan Yeung, John Di Capua, Avik Som, Dania Daye, and Raul Uppot. "Retrospective evaluation of image-guided cholecystostomy tube utilization and outcomes during the first wave of the COVID-19 pandemic." American Journal of Interventional Radiology 5 (August 11, 2021): 13. http://dx.doi.org/10.25259/ajir_11_2021.

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Objectives: During the COVID-19 pandemic, there was a perceived increase in the number of cholecystostomy tube placements. We have retrospectively analyzed the incidence and outcomes of cholecystostomy tube placement during the COVID-19 pandemic surge. Material and Methods: Cholecystostomy tube placement and overall interventional radiology (IR) case volume were analyzed at our tertiary care center during the pandemic (March 15, 2020–July 30, 2020) and compared to the same time period in 2019. In addition, an age- and gender-matched control study of outcomes for 40 patients (25 from our home institution and 15 from our affiliated hospitals) grouped by COVID-19 status who received percutaneous cholecystostomy tubes between March 15, 2020, and July 30, 2020, was performed. Results: We observed a significant increase in relative cholecystostomy tube volume during the pandemic, despite a decrease in total IR case volume. There was no significant difference in pre- or post-procedural laboratory data, vital signs, imaging, or mortality between COVID-positive and COVID-negative patients who received cholecystostomy tubes. Conclusion: Percutaneous cholecystostomy tube placement is likely a safe treatment for acalculous cholecystitis in patients with COVID-19 with equivalent outcomes to patients without COVID-19.

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Karaś, Marcin, Daniel Zając, and Roman Ulbrich. "Experimental investigation of heat transfer performance coefficient in tube bundle of shell and tube heat exchanger in two-phase flow." Archives of Thermodynamics 35, no. 1 (March 1, 2014): 87–98. http://dx.doi.org/10.2478/aoter-2014-0006.

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Abstract This paper presents the results of studies in two phase gasliquid flow around tube bundle in the model of shell tube heat exchanger. Experimental investigations of heat transfer coefficient on the tubes surface were performed with the aid of electrochemical technique. Chilton-Colburn analogy between heat and mass transfer was used. Twelve nickel cathodes were mounted on the outside surface of one of the tubes. Measurement of limiting currents in the cathodic reduction of ferricyanide ions on nickel electrodes in aqueous solution of equimolar quantities of K3Fe(CN)6 and K4Fe(CN)6 in the presence of NaOH basic solution were applied to determine the mass transfer coefficient. Controlled diffusion from ions at the electrode was observed and limiting current plateau was measured. Measurements were performed with data acquisition equipment controlled by software created for this experiment. Mass transfer coefficient was calculated on the basis of the limiting current measurements. Results of mass transfer experiments (mass transfer coefficient) were recalculated to heat transfer coefficient. During the experiments, simultaneously conducted was the the investigation of two-phase flow structures around tubes with the use of digital particle image velocimetry. Average velocity fields around tubes were created with the use of a number of flow images and compared with the results of heat transfer coefficient calculations.

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Anchugov, O. V., V. L. Dorokhov, G. Ya Kurkin, E. I. Zinin, P. A. Molyavin, O. I. Meshkov, D. A. Shvedov, et al. "Calibration of an image-tube picosecond dissector." Optoelectronics, Instrumentation and Data Processing 52, no. 3 (May 2016): 304–10. http://dx.doi.org/10.3103/s8756699016030146.

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Patton, Stanley B. "High-resolution microchannel plate image tube results." Journal of Electronic Imaging 1, no. 3 (July 1, 1992): 252. http://dx.doi.org/10.1117/12.59959.

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Ji, Li, Jun Le Qu, Zhou Jun Lan, Q. L. Yang, H. Zhang, and H. Niu. "Sampling-image streak framing technique and its special streak image tube." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 489, no. 1-3 (August 2002): 241–46. http://dx.doi.org/10.1016/s0168-9002(02)00573-9.

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Precht, Helle, Claus Bjørn Outzen, Martin Weber Kusk, Malene Bisgaard, and Dag Waaler. "COMPARISON OF CONVENTIONAL HAND EXAMINATION ON SIX OPTIMISED DR SYSTEMS." Radiation Protection Dosimetry 194, no. 1 (March 2021): 27–35. http://dx.doi.org/10.1093/rpd/ncab067.

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Abstract The purpose of this study was to investigate the challenges in comparing digital radiography (DR) systems from different vendors for various combinations of exposure factors in posterior–anterior hand radiographs. Image quality was evaluated for a range of tube voltages and tube current-time products using a technical contrast-detail (CDRAD) phantom and an anthropomorphic hand phantom. 900 technical CDRAD images were analysed providing quality figures of merit (IQFinv) and two experienced reporting radiographers using visual grading analysis (VGA) scored 108 anthropomorphic images. This study demonstrates the differences between the DR systems included. When compensating for variations in dose, Canon showed superior results for technical image quality and Fuji for visual image quality for a standard dose point at DR hand examination (ln(DAP) 1.1, 50 kV and 2.5 mAs).

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Yin, Yong Lan, Qing Gao, Bai Fa Zhu, and Ming Li. "Characteristics of Central Vertical Tubes of the Gravity Film Exchanger in Hybrid GSHP and UTES Systems." Advanced Materials Research 171-172 (December 2010): 61–66. http://dx.doi.org/10.4028/www.scientific.net/amr.171-172.61.

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As key factor to the heat transfer efficiency of the gravity film exchanger, the wave characteristics of gravity films were studied in the experimental setup. The water from the high level storage tank flowed down the vertical circular tube to form the gravity films. The images of the gravity films were captured with the aids of the plane light source and the high speed image technology, and recorded in computers in real time. With the image processing software, the wave profiles varied with time and the height of the tube were both shaped from the images of film thickness fluctuations. The experimental results showed the significant effect of the film Reynolds numbers on the wave characteristics in various positions of the vertical tube. The probability density distributions of the film thickness were also analyzed for different Reynolds numbers.

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Cristino, Valentino AM, Joao P. Magrinho, Gabriel Centeno, Maria Beatriz Silva, and Paulo AF Martins. "A digital image correlation based methodology to characterize formability in tube forming." Journal of Strain Analysis for Engineering Design 54, no. 2 (January 11, 2019): 139–48. http://dx.doi.org/10.1177/0309324718823629.

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This article describes a methodology to characterize the failure limits by necking and fracture, and to determine the critical value of ductile damage in tube forming. The methodology makes use of digital image correlation, thickness measurements and force–displacement evolutions to obtain the strain loading paths and the strain values at the onsets of failure by necking and fracture. The onset of failure by necking is determined by a new technique that combines the strain and force–displacement evolutions whereas the fracture strains at the cracked regions of the tubes are obtained by a similar technique utilized by the authors in sheet metal forming. Transformation of the strain loading paths from principal strain space into the space of effective strain versus stress-triaxiality allows determining the critical experimental value of ductile damage at the onset of failure by necking. The methodology is applied to tube expansion with circular, elliptical and square cross-section punches and results confirm its importance and helpfulness for researchers and engineers involved in the development and optimization of industrial tube forming processes.

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Sedgewick, Jerry. "Image Stitching Using Photoshop." Microscopy Today 12, no. 1 (January 2004): 22–25. http://dx.doi.org/10.1017/s1551929500051774.

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Several images can be stitched together (sometimes referred to as “montaging”) through the use of Photoshop. Edges of the images can be feathered and the process automated to reduce the hours of work that can go into this procedure.Before going any further, let me be quick to say that more than one company has developed protocols to accomplish image stitching. When your lab is looking at large fields, while needing to resolve fine details, then I would strongly recommend the purchase of a system designed for this purpose. Issues surrounding motorized stage accuracy, problems with tilting when a camera is perched on a long optical tube, and image to image correction for contrast, color and uneven illumination can all contribute to confounding issues when image stitching. These companies have worked through these problems with off-the-shelf systems.

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Fatmayanti, Halinda, Kusworo Adi, and Yeti Kartikasari. "Utilization of sinogram affirmed iterative reconstruction on 128 multi slice computed tomography scan to reduce radiation dose and improve image quality on thorax multi slice computed tomography scan: chest phantom study." International Journal Of Community Medicine And Public Health 6, no. 10 (September 26, 2019): 4533. http://dx.doi.org/10.18203/2394-6040.ijcmph20194525.

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Background: Thorax MSCT examination is a diagnostic imaging that is capable of displaying both normal and pathological lung and respiratory organs. MSCT examination also has a better level of sensitivity and specificity compared to other modalities, but the radiation exposure given is very high, so the radiation dose given to patients is high. The reduction in radiation dose is very important because of the direct exposure to sensitive tissue. One method of reducing radiation dose is by reducing the tube voltage. However, the decrease in tube voltage causes a decrease in image quality as indicated by increased noise and decreased CNR. To maintain the quality of the image at low tube voltage setting, an IR reconstruction of SAFIRE was used. The purpose of this research is to know the impact of using SAFIRE on dose radiation and image quality of thorax MSCT.Methods: This study was an experimental study with a quasi-experimental study design. The object used was the N-1 Lungman chest phantom in which an artificial tumor was attached. Radiation dose assessment used CTDI value, while image quality assessment used noise and CNR. Data processing was conducted using linear regression test.Results: There was an effect of tube voltage setting and SAFIRE setting on radiation dose and image quality.Conclusions: Tube voltage ssetting and SAFIRE setting had an effect on radiation dose and image quality. Tube voltage setting and SAFIRE strength level setting that were able to provide optimal radiation dose and image quality were tube voltage of 80 kVp and SAFIRE strength levels 3 and 4 (S3 and S4).

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Gottwald, Martin, and Gerhard von der Emde. "Bio-Inspired Active Electrolocation Sensors for Inspection of Tube Systems." Advances in Science and Technology 84 (September 2012): 45–50. http://dx.doi.org/10.4028/www.scientific.net/ast.84.45.

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At night, weakly electric fish Gnathonemus petersii use active electrolocation to scan their environment with self generated electric fields. Nearby objects distort the electric fields and are recognized as electric images on the electroreceptive skin surface of the animal. By analyzing the electric image, G. petersii can sense an object’s distance, dimensions and electrical properties. The principles and algorithms of active electrolocation can be applied to catheter-based sensor systems for analysing wall changes in fluid filled tube systems, for example atherosclerotic plaques of the coronary blood vessels. We used a basic atherosclerosis model of synthetic blood vessels and plaques, which were scanned with a ring electrode catheter applying active electrolocation. Based on the electric images of the plaques and the evaluation of bio-inspired image parameters, the plaque’s fine-structure could be assessed. Our results show that imaging through active electrolocation principally has the potential to detect and characterize atherosclerotic lesions.

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Chen Tao, 陈韬, 胡盺 Hu Xin, and 刘慎业 Liu Shenye. "Numerical simulation of X-ray image converter tube." High Power Laser and Particle Beams 22, no. 11 (2010): 2593–95. http://dx.doi.org/10.3788/hplpb20102211.2593.

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TOMINAGA, Akira. "Some Image of Fluid Oscillation in Resonator Tube." TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 36, no. 4 (2001): 170–77. http://dx.doi.org/10.2221/jcsj.36.170.

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张, 晓辉, 宏昌程, 欣. 郭, 聪. 单, 峰. 石, 磊. 闫, 洋. 罗, and 晖. 刘. "Limiting Resolution of AlGaN Photocathode Image Intensifier Tube." Infrared Technoiogy 42, no. 8 (August 1, 2020): 729–34. http://dx.doi.org/10.3724/sp.j.7102614853.

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Corbett, Mel, Ms Isobel Hughes, John O'Shea, Ms Jane Savage, Fintan Wallis, and Joseph Hughes. "Image based prediction of best size tracheostomy tube." Trends in Anaesthesia and Critical Care 30 (February 2020): e43. http://dx.doi.org/10.1016/j.tacc.2019.12.108.

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Schelev, M. Ya. "Pico-femtosecond image-tube photography in quantum electronics." Quantum Electronics 31, no. 6 (June 30, 2001): 477–82. http://dx.doi.org/10.1070/qe2001v031n06abeh001983.

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Alkurt, Meryem Toraman, Likay Peker, Gülten Usalan, and Bülent Altunkaynak. "Clinical Evaluation of Dose Reduction on Image Quality of Panoramic Radiographs." Journal of Contemporary Dental Practice 9, no. 5 (2008): 34–41. http://dx.doi.org/10.5005/jcdp-9-5-34.

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Abstract Aim The purpose of this study was to evaluate the effect of tube current reduction on image quality using medium and regular intensifying screens as well as a digital system for panoramic radiography. Methods and Materials A total of 150 panoramic images of 75 patients were obtained in the study. The initial images were taken at standard exposure settings, and secondary images were exposed with the tube current reduced at different rates. Results There was no statistically significant difference (p>0.05) between the two exposures for Group 3 (the rate of dose reduction 25%) while a statistically significant difference (p<0.05) was found in Group 4 (the rate of dose reduction 50%) using medium intensifying screens for all observers. No statistically significant difference was found between the two exposures on digital panoramic images. Conclusion According to the results of this study a dose reduction of 25% was achieved for medium intensifying screens and for digital panoramic images without any loss of image quality. Clinical Significance A substantial reduction in radiation exposure can be achieved in conventional panoramic radiography using a medium intensifying screen and in digital panoramic radiography without any loss of image quality needed for radiological evaluation of anatomical structures and pathological conditions. Citation Alkurt MT, Peker I, Usalan G, Altunkaynak B. Clinical Evaluation of Dose Reduction on Image Quality of Panoramic Radiographs. J Contemp Dent Pract 2008 July; (9)5:034-041.

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Takei, Yoshiki, Hajime Monzen, Kenji Matsumoto, Kohei Hanaoka, Mikoto Tamura, and Yasumasa Nishimura. "Registration accuracy with the low dose kilovoltage cone-beam CT: A phantom study." BJR|Open 1, no. 1 (July 2019): 20190028. http://dx.doi.org/10.1259/bjro.20190028.

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Objective: The aim of this study was to investigate low-dose kilovoltage cone-beam CT (kV-CBCT) for image-guided radiotherapy, with a particular focus on the accuracy of image registration with low-dose protocols. Methods: Imaging doses were measured with a NOMEX semiconductor detector positioned at the front of head, thorax, and pelvis human body phantoms while kV-CBCT scans were acquired at different tube currents. Aspects of image quality (spatial resolution, noise, uniformity, contrast, geometric distortion, and Hounsfield unit sensitivity) and image registration accuracy using bone and soft tissue were evaluated. Results: With preset and the lowest tube currents, the imaging doses were 0.16 and 0.08 mGy, 5.29 and 2.80 mGy, and 18.23 and 2.69 mGy for head, thorax, and pelvis, respectively. Noise was the only quality aspect directly dependent on tube current, being increased by 1.5 times with a tube current half that of the preset in head and thorax, and by 2.2 times with a tube current 1/8 of the preset in the pelvis. Accurate auto-bone matching was performed within 1 mm at the lowest tube current. The auto-soft tissue matching could not be performed with the lowest tube current; however, manual-soft tissue matching could still be performed within 2 mm or less. Conclusion: Noise was the only image quality aspect dependent on the imaging dose. Auto-bone and manual-soft tissue matching could still be performed at the lowest imaging dose. Advances in knowledge: When optimizing kV-CBCT imaging dose, the impact on bone and soft tissue image registration accuracy should be evaluated.

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Zhaoshuo Tian, Zhaoshuo Tian, Zihao Cui Zihao Cui, Liting Zhang Liting Zhang, Tianci Xu Tianci Xu, Yanchao Zhang Yanchao Zhang, and Shiyou Fu Shiyou Fu. "Control and image processing for streak tube imaging lidar based on VB and MATLAB." Chinese Optics Letters 12, no. 6 (2014): 060015–60018. http://dx.doi.org/10.3788/col201412.060015.

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Sun, Jihang, Qifeng Zhang, Zuofu Zhou, Chenguang Jia, Wei Yang, Haoyan Li, and Yun Peng. "Optimal tube voltage for abdominal enhanced CT in children: a self-controlled study." Acta Radiologica 61, no. 1 (June 4, 2019): 101–9. http://dx.doi.org/10.1177/0284185119847683.

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Background The use of weight-adapted pediatric computed tomography (CT) tube voltage protocols has been suggested, but a consensus standard has not been established and clinical available studies are not sufficient. Purpose To determine the best tube voltage for low dose abdominal CT imaging in children. Material and Methods Eighty-seven cases who needed three CT exams in a 1–3-month interval between scans were enrolled (mean age = 4.69 ± 3.20 years). The three scans were performed with three different tube voltages at 80 kV, 100 kV, and 120 kV, keeping the same radiation dose and same contrast injection protocol. Patients were divided into five groups for analysis based on their body weight. The subjective image quality of the three exams were evaluated using a 4-point scale (4 being the best) for image noise and image quality. The objective evaluation in terms of CT values and standard deviation in aorta, liver, spleen, pancreas, and kidney were measured to calculate the degree of enhancement and contrast-to-noise ratio (CNR) of organs. One-way ANOVA was used to compare the subjective and objective image quality with respect to different tube voltages and different patient weights. Result The 80-kV tube voltage provided the highest overall enhancement and CNR for the entire patient population and the best objective image quality for the 6.1–28.0 kg subgroup. Conclusion Patient weight-dependent tube voltage selection maximizes image quality for abdominal enhanced CT in children. The optimal tube voltage for children with weight <28 kg is 80 kV; higher voltages should be selected for children weighing 28.1–50.0 kg.

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Yin, Bo Hua, Dai Xie Chen, Yun Sheng Lin, Ying Ying Gao, Han Li, and Dong Han. "Large Scanning Range and Rapid AFM for Biological Cell Topography Imaging." Key Engineering Materials 562-565 (July 2013): 697–700. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.697.

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The small spatial displacement of the piezo tube scanner limits the AFM(Atomic Force Microscopy) scanning range, especially when facing up to cell topography scanning. And the low dynamic property of normal AFM tube scanner tube restricts the imaging speed. In order to achieve large scanning range and rapid scanning motion simultaneously, a special atomic force microscopy is designed. The 100um scanning range is obtained by the new scanner which is composed of the flexure guide structure instead of peizo tube. Furthermore, a new acquiring image method is used to eliminating AFM nonlinearity error. Using this scanning system, some large biological cells are imaged in liquid environments with 30 lines per second.

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Wang, Zhan Xu. "Image Analysis of a Moving Bubble Train in a Tube." Applied Mechanics and Materials 487 (January 2014): 440–43. http://dx.doi.org/10.4028/www.scientific.net/amm.487.440.

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A tube with varying cross sections can capture some essential features of the motion of foam in porous media. In this paper, experiments were carried out concerning a moving bubbles train through cylindrical ducts with sinusoidal cross-section. The test tube has total length of 1.14 m and has constrictions at interval of 0.0095 m. The visual images of a single lamella motion were recorded and were interpreted. It is found the lamella decelerates in the diverging portion while accelerates in the converging part of the tube.

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Okumura, Miwa, Takamasa Ota, Kazuhisa Kainuma, James W. Sayre, Michael McNitt-Gray, and Kazuhiro Katada. "Effect of Edge-Preserving Adaptive Image Filter on Low-Contrast Detectability in CT Systems: Application of ROC Analysis." International Journal of Biomedical Imaging 2008 (2008): 1–6. http://dx.doi.org/10.1155/2008/379486.

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Objective. For the multislice CT (MSCT) systems with a larger number of detector rows, it is essential to employ dose-reduction techniques. As reported in previous studies, edge-preserving adaptive image filters, which selectively eliminate only the noise elements that are increased when the radiation dose is reduced without affecting the sharpness of images, have been developed. In the present study, we employed receiver operating characteristic (ROC) analysis to assess the effects of the quantum denoising system (QDS), which is an edge-preserving adaptive filter that we have developed, on low-contrast resolution, and to evaluate to what degree the radiation dose can be reduced while maintaining acceptable low-contrast resolution.Materials and Methods. The low-contrast phantoms (Catphan 412) were scanned at various tube current settings, and ROC analysis was then performed for the groups of images obtained with/without the use of QDS at each tube current to determine whether or not a target could be identified. The tube current settings for which the area under the ROC curve (Az value) was approximately 0.7 were determined for both groups of images with/without the use of QDS. Then, the radiation dose reduction ratio when QDS was used was calculated by converting the determined tube current to the radiation dose.Results. The use of the QDS edge-preserving adaptive image filter allowed the radiation dose to be reduced by up to 38%.Conclusion. The QDS was found to be useful for reducing the radiation dose without affecting the low-contrast resolution in MSCT studies.

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Chen, Ya. "Digital Image Acquisition and Presentation for High Resolution SEM." Microscopy and Microanalysis 4, S2 (July 1998): 68–69. http://dx.doi.org/10.1017/s1431927600020468.

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Images obtained from an analog SEM are traditionally viewed and recorded from a cathode-ray tube (CRT). Many laboratories use instant film (e.g. Polaroid #52, #55 instant film) to justify image quality and obtain permanent image quickly. Digital imaging provides an alternative approach for image acquisition and recording. One major advantage of digital SEM is image averaging that allows one to improve the signal-to-noise ratio (SNR) from a noisy quick-scan image to reduce charging. SEM signal yield is proportional to incident beam intensity, image acquisition time or duration of beam interaction with specimen (dwell time). The higher beam intensity, or longer the dwell time, the more signal generated. However, for high-resolution SEM imaging, the beam dose and dwell time are limited by drafting, radiation damage, and contamination. Therefore high-resolution biological SEM images invariably have poor SNR.

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Xie, Yong, and Shushu Zhang. "The Role of Spiral CT Pulmonary Angiography in the Diagnosis of Postoperative Complications in Patients with Acute Pulmonary Embolism." Journal of Medical Imaging and Health Informatics 10, no. 9 (August 1, 2020): 2118–23. http://dx.doi.org/10.1166/jmihi.2020.3144.

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The purpose is to explore the effect of iterative model reconstruction (IMR) algorithm on improving quality of spiral computed tomography angiography (SCTA) image and its clinical application in the diagnosis of acute pulmonary embolism (PE) complications. 88 patients with acute PE who visited Chongqing Zhongxian People’s Hospital hospital from October 2017 to October 2019 were selected as the study objects, and their CT values, standard deviation (SD) value of background noise, CT volume dose index, and dose length product of pulmonary artery trunk and the erector spines of the spinal column were measured by spiral CT scanning at the tube voltage of 80 kv and 100 kv, respectively. As for image reconstruction, IMR, IDose4 algorithm in hybrid iterative reconstruction (HIR) and Filtering back-projection (FBP) were utilized. By comparing signal-noise ratio (SNR), contrast-noise ratio (CNR) and figure of merit (FOM), the image quality, radiation dose, sensitivity and specificity of different reconstruction algorithms in diagnosis of acute PE were analyzed. The results showed that the background noise of the IMR reconstruction algorithm was lower than that of IDose4 and FBP, and the difference was statistically significant (P < 0.05). The CT value of IMR reconstruction algorithm was significantly higher than that of IDose4 and FBP reconstruction algorithm, and the difference was not statistically significant (P > 0.05). The SNR and CNR of IMR were significantly higher than those of IDose4 and FBP, and the difference was statistically significant (P < 0.05). The FOM values of IMR were significantly higher than those of IDose4 and FBP, and the differences were statistically significant (P < 0.05). CT volume dose index, dose length product, and effective dose of the 80 kv tube voltage group were all lower than that of the 100 kv tube voltage group, accounting for 49.34%, 50.50%, and 52.53% of the 100 kv tube voltage group. And the FOM of 80 kv tube voltage group was higher than that of 100 kv tube voltage group. The sensitivity and specificity of IMR reconstructed images in diagnosis of acute PE complications were higher than those of reconstructed images of IDose4 and FBP, which were 97.67% and 92.0%, respectively. Therefore, the improved SCTA information technology based on the IMR algorithm has better image quality than the IDose4 and FBP reconstruction algorithms, and the image quality index of low-dose scan (80 kv) of the improved SCTA information technology based on the IMR algorithm is higher than that of normal-dose scan (100 kv).

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Chipiga, L. A. "Evaluation of tube current modulation programms for the optimization of scan protocols in computed tomography." Radiatsionnaya Gygiena = Radiation Hygiene 12, no. 1 (March 27, 2019): 104–14. http://dx.doi.org/10.21514/1998-426x-2019-12-1-104-114.

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Computed tomography (CT) is commonly associated with relatively high patient doses. In order to keep the patient doses from the CT examinations on the acceptable level it is necessary to apply the principle of optimization. An essential part of optimization is the achievement of the compromise between the patient dose reduction and the maintenance of the image quality that provides accurate diagnostic information. The aim of the study was to determine the relations between the patient doses, CT image quality and the parameters of the tube current modulation program (Auto mA, CareDose and DoseRight) for the examination of the chest. The study was performed on the three most common modern tomographs in Russia: Ingenuity Core 128, Philips; Optima 64, General Electric; Definition AS, Siemens. The anthropomorphic phantom Lungman (Kyoto Kagaku CO., LTD) was used in the study. In order to assess the tube current modulation for the range of tube voltage (80–120 kV), the reference mA∙s (ref. mAs), Noise Index (NI) and Dose Right Index (DRI) were changed for the CareDose (Siemens), Auto mA (GE) and RightDose (Philips), respectively. Estimation of the effective dose was performed using the method from Methodical guidance 2.6.1.2944-11 (MU 2.6.1.2944-11). In order to evaluate the image quality, the noise of a CT image in the mediastinum was selected as the most homogenous for chest region. It was estimated, that for the GE units with Auto mA, the noise of CT image had a liner relationship with NI; the patient dose decreased with the increase of NI. For the Siemens units with CareDose, the noise of CT image decreased with the ref.mAs for the range of tube voltage (80–120 kV); the patient dose was directly proportional to the ref.mAs and increased with the tube voltage. For the Philips units with DoseRight, the noise of CT image decreased with the DRI for the range of tube voltage (80–120 kV); the patient dose was directly proportional to the DRI and had no dependence on the tube voltage. The tube current modulations are proprietary for each manufacturer; it is necessary to consider them for the protocol development. The obtained dependences could be useful for optimization of CT protocols.

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Tirlapur, Uday K., Monica Scali, Alessandra Moscatelli, Cecilia Del Casino, Gianpiero Cai, Antonio Tiezzi, and Mauro Cresti. "Confocal image analysis of spatial variations in immunocytochemically identified calmodulin during pollen hydration, germination and pollen tube tip growth in Nicotiana tabacum L." Zygote 2, no. 1 (February 1994): 63–68. http://dx.doi.org/10.1017/s0967199400001775.

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SummaryUsing monoclonal anti-calmodulin antibodies in conjunction with confocal scanning laser microscopy we have analysed the spatial variations in the distribution pattern of calmodulin (CaM) during the sequential events of pollen hydration, germination and tube growth in Nicotiana tabacum. These immunocytochemical observations have been complemented by immunochemical studies wherein the anti-calmodulin antibody raised against pea CaM recognises a polypeptide of c. 18 kDa in the pollen extracts. Digitisation of confocally acquired optical sections of immunofluorescence images reveals that in hydrated pollen a high level of CaM is consistently present in the region of the germinal apertures. Subsequently, with the onset of germination a high CaM concentration was found associated with the plasma membrane of the germination bubble and in the cytoplasm in its vicinity, while in the vegetative cytoplasm a weak diffuse and intense punctate signal was registered. CaM immunostain was also detected in association with the plasma membrane of the tube tips in both short and long pollen tubes. Furthermore, the cytosol of the tubes invariably manifested an apically focused CaM gradient. We were, however, unable to detect any vacuolar association of CaM in the older regions of the pollen tubes. Although punctate immunostain was obvious across the pollen tube numerous punctate structures were invariably present in the extreme tip. The possible implications of these findings in development of cell polarity, polarised growth, maintenance of calcium homeostasis and CaM interactions with other mechanochemical motor proteins in effecting propulsion of organelles during pollen hydration, germination and pollen tube growth are discussed.

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Zhan, Xiaohong, Xing Bu, Tao Qin, Haisong Yu, Jie Chen, and Yanhong Wei. "X-ray online detection for laser welding T-joint of Al–Li alloy." Modern Physics Letters B 31, no. 14 (May 18, 2017): 1750154. http://dx.doi.org/10.1142/s0217984917501548.

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In order to detect weld defects in laser welding T-joint of Al–Li alloy, a real-time X-ray image system is set up for quality inspection. Experiments on real-time radiography procedure of the weldment are conducted by using this system. Twin fillet welding seam radiographic arrangement is designed according to the structural characteristics of the weldment. The critical parameters including magnification times, focal length, tube current and tube voltage are studied to acquire high quality weld images. Through the theoretical and data analysis, optimum parameters are settled and expected digital images are captured, which is conductive to automatic defect detection.

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Høg, E., and L. Lindegren. "A CCD Modulation Detector for a Second Hipparcos Mission." Symposium - International Astronomical Union 156 (1993): 31–36. http://dx.doi.org/10.1017/s0074180900172894.

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A CCD modulation detector for a possible Hipparcos-2 mission is described. It is at least 1000 times more light efficient than the image dissector tube system used in the current Hipparcos mission. A beam combiner telescope with 29 cm aperture diameter could measure all 15 million stars brighter than 14th magnitude, providing accurate multi-colour photometry in addition to the astrometric parameters. Using two telescopes with different basic angles will further improve the rigidity of the resulting system of positions and proper motions. An accuracy of 0.5 milli-arcsec up to 10th magnitude is expected for a 2.5 year mission. The modulating grid is imaged on a CCD performing a ‘cophased integration’ of nine separate images of the whole field of view, each image representing a different part of the modulation period.

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Wang, Chun Yan, Hao Sun, and Tao Li. "The Static Tester of Fire Control System Performance Parameters." Key Engineering Materials 552 (May 2013): 319–24. http://dx.doi.org/10.4028/www.scientific.net/kem.552.319.

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This tester is mainly used to test the firepower of armored vehicles weapon equipment, the artillery loosening amount and rigidity of fire control system, the largest mobilization artillery speed and other related static parameters. In this paper, the design of the tester include: static parameters optical probe, the vehicle central control device, the image processing device, the test target and so on. In the static parameter tests of weapon systems, the static probe is installed in the muzzle, the prescriptive force is imposed on the artillery tube to produce movement, CCD camera can photography the relative motion image of the target, then the computer processes images according to the corresponding program, and figures out the trajectory of the artillery tube, thus the corresponding static parameters is calculated. Experimental results show that: The system has reached a very good image quality, and the reliability is very high, Diagonal field of view>4°, the specification requirements are reached.

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Wang, L., and Z. C. Kang. "Spiral carbon tubes grown by a mixed-valent oxide-catalytic carbonization process." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 650–51. http://dx.doi.org/10.1017/s0424820100165719.

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Synthesis of carbon tubes is vitally important in carbon research and applications. In this paper, spiral carbon tubes are grown by a mixed-valent oxide-catalytic carbonization (MVOCC) process. The carbon tubes are highly twisted and have many growth induced nodes. (Fig. 1). The product has high purity and no catalyst particle is found in the product. With the presence of inter-lock structure, the mechanical properties of the material made using the spiral carbon tubes could be significantly improved. The inner tube is not completely hollow but interconnected by graphitic layers. The surfaces of the tubes have many open graphitic edges, thus, a high chemical activity of the tubes is expected. Figure 2 shows a low-magnification TEM image at the initiation side of a carbon tube, where a spiral node is formed. The non-uniform contrast across the node region reflects the spiral geometry at the node.

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Zong Fangke, 宗方轲, 杨勤劳 Yang Qinlao, 顾礼 Gu Li, 李翔 Li Xiang, and 张敬金 Zhang Jingjin. "Design of large-format X-ray framing image tube." High Power Laser and Particle Beams 24, no. 10 (2012): 2386–90. http://dx.doi.org/10.3788/hplpb20122410.2386.

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Zhang, Jingjin, Baoguo Lei, and Qinlao Yang. "Improvement of imaging performance for X-ray image tube." Journal of Shenzhen University Science and Engineering 34, no. 1 (2017): 14. http://dx.doi.org/10.3724/sp.j.1249.2017.01014.

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Lei Yunfei, 雷云飞, 龙井华 Long Jinghua, 刘进元 Liu Jinyuan, 蔡厚智 Cai Houzhi, 廖昱博 Liao Yubo, and 白雁力 Bai Yanli. "Design of Framing Image Tube with Large Detection Area." Chinese Journal of Lasers 43, no. 9 (2016): 0904009. http://dx.doi.org/10.3788/cjl201643.0904009.

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Hsieh, Kai-Sheng, Cheng-Liang Lee, Chu-Chung Lin, Ta-Cheng Huang, Ken-Pen Weng, and Wen-Hsien Lu. "Secondary confirmation of endotracheal tube position by ultrasound image." Critical Care Medicine 32, Supplement (September 2004): S374—S377. http://dx.doi.org/10.1097/01.ccm.0000134354.20449.b2.

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KAWAGUCHI, Hiroshi, Yoshinori HOTTA, and Atsushi MIZUIKE. "ICP-AES with an image dissector tube as detector." Bunseki kagaku 36, no. 7 (1987): 453–55. http://dx.doi.org/10.2116/bunsekikagaku.36.7_453.

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Journal articles on the topic 'Image tube'

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