Performance of an improved first generation optical CT scanner for 3D dosimetry

NASA Astrophysics Data System (ADS)

Qian, Xin; Adamovics, John; Wuu, Cheng-Shie

2013-12-01

Performance analysis of a modified 3D dosimetry optical scanner based on the first generation optical CT scanner OCTOPUS is presented. The system consists of PRESAGE™ dosimeters, the modified 3D scanner, and a new developed in-house user control panel written in Labview program which provides more flexibility to optimize mechanical control and data acquisition technique. The total scanning time has been significantly reduced from initial 8 h to ∼2 h by using the modified scanner. The functional performance of the modified scanner has been evaluated in terms of the mechanical integrity uncertainty of the data acquisition process. Optical density distribution comparison between the modified scanner, OCTOPUS and the treatment plan system has been studied. It has been demonstrated that the agreement between the modified scanner and treatment plans is comparable with that between the OCTOPUS and treatment plans.

A comparative evaluation of intraoral and extraoral digital impressions: An in vivo study.

PubMed

Sason, Gursharan Kaur; Mistry, Gaurang; Tabassum, Rubina; Shetty, Omkar

2018-01-01

The accuracy of a dental impression is determined by two factors: "trueness" and "precision." The scanners used in dentistry are relatively new in market, and very few studies have compared the "precision" and "trueness" of intraoral scanner with the extraoral scanner. The aim of this study was to evaluate and compare accuracy of intraoral and extraoral digital impressions. Ten dentulous participants (male/female) aged 18-45 years with an asymptomatic endodontically treated mandibular first molars with adjacent teeth present were selected for this study. The prepared test tooth was measured using a digital Vernier caliper to obtain reference datasets. The tooth was then scanned using the intraoral scanner, and the extraoral scans were obtained using the casts made from the impressions. The datasets were divided into four groups and then statistically analyzed. The test tooth preparation was done, and dimples were made using a round diamond point on the bucco-occlusal, mesio-occlusal, disto-occlusal, and linguo-occlusal lines angles, and these were used to obtain reference datasets intraorally using a digital Vernier caliper. The test tooth was then scanned with the IO scanner (CS 3500, Carestream dental) thrice and also impressions were made using addition silicone impression material (3M™ ESPE) and dental casts were poured in Type IV dental stone (Kalrock-Kalabhai Karson India Pvt. Ltd., India) which were later scanned with the EO scanner (LAVA™ Scan ST Design system [3M™ ESPE]) thrice. The Datasets obtained from Intraoral and Extraoral scanner were exported to Dental Wings software and readings were obtained. Repeated measures ANOVA test was used to compare differences between the groups and independent t -test for comparison between the readings of intraoral and extraoral scanner. Least significant difference test was used for comparison between reference datasets with intraoral and extraoral scanner, respectively. A level of statistical significance of P < 0.05 was set. The precision values ranged from 20.7 to 33.35 μm for intraoral scanner and 19.5 to 37 μm for extraoral scanner. The mean deviations for intraoral scanner were 19.6 μm mesiodistally (MD) and 16.4 μm buccolingually (BL) and 24.0 μm MD and 22.5 μm BL for extraoral scanner. The mean values of the intraoral scanner (413 μm) for trueness were closest to the actual measurements (459 μm) than the extraoral scanner (396 μm). The intraoral scanner showed higher "precision" and "trueness" values when compared with the extraoral scanner.

51. View of upper radar scanner switch in radar scanner ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

51. View of upper radar scanner switch in radar scanner building 105 from upper catwalk level showing emanating waveguides from upper switch (upper one-fourth of photograph) and emanating waveguides from lower radar scanner switch in vertical runs. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

High throughput solar cell ablation system

DOEpatents

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2014-10-14

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

High throughput solar cell ablation system

DOEpatents

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2012-09-11

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Qualification of the RSRM field joint CF case-to-insulation bondline inspection using the Thiokol Corporation ultrasonic RSRM bondline inspection system

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Qualification testing of Combustion Engineering's AMDATA Intraspect/98 Data Acquisition and Imaging System that applies to the redesigned solid rocket motor field joint capture feature case-to-insulation bondline inspection was performed. Testing was performed at M-111, the Thiokol Corp. Inert Parts Preparation Building. The purpose of the inspection was to verify the integrity of the capture feature area case-to-insulation bondline. The capture feature scanner was calibrated over an intentional 1.0 to 1.0 in. case-to-insulation unbond. The capture feature scanner was then used to scan 60 deg of a capture feature field joint. Calibration of the capture feature scanner was then rechecked over the intentional unbond to ensure that the calibration settings did not change during the case scan. This procedure was successfully performed five times to qualify the unbond detection capability of the capture feature scanner. The capture feature scanner qualified in this test contains many points of mechanical instability that can affect the overall ultrasonic signal response. A new generation scanner, designated the sigma scanner, should be implemented to replace the current configuration scanner. The sigma scanner eliminates the unstable connection points of the current scanner and has additional inspection capabilities.

A Simple X-Y Scanner.

ERIC Educational Resources Information Center

Halse, M. R.; Hudson, W. J.

1986-01-01

Describes an X-Y scanner used to create acoustic holograms. Scanner is computer controlled and can be adapted to digitize pictures. Scanner geometry is discussed. An appendix gives equipment details. The control program in ATOM BASIC and 6502 machine code is available from the authors. (JM)

Effect of echo spacing and readout bandwidth on basic performances of EPI-fMRI acquisition sequences implemented on two 1.5 T MR scanner systems.

PubMed

Giannelli, Marco; Diciotti, Stefano; Tessa, Carlo; Mascalchi, Mario

2010-01-01

Although in EPI-fMRI analyses typical acquisition parameters (TR, TE, matrix, slice thickness, etc.) are generally employed, various readout bandwidth (BW) values are used as a function of gradients characteristics of the MR scanner. Echo spacing (ES) is another fundamental parameter of EPI-fMRI acquisition sequences but the employed ES value is not usually reported in fMRI studies. In the present work, the authors investigated the effect of ES and BW on basic performances of EPI-fMRI sequences in terms of temporal stability and overall image quality of time series acquisition. EPI-fMRI acquisitions of the same water phantom were performed using two clinical MR scanner systems (scanners A and B) with different gradient characteristics and functional designs of radiofrequency coils. For both scanners, the employed ES values ranged from 0.75 to 1.33 ms. The used BW values ranged from 125.0 to 250.0 kHz/64pixels and from 78.1 to 185.2 kHz/64pixels for scanners A and B, respectively. The temporal stability of EPI-fMRI sequence was assessed measuring the signal-to-fluctuation noise ratio (SFNR) and signal drift (DR), while the overall image quality was assessed evaluating the signal-to-noise ratio (SNR(ts)) and nonuniformity (NU(ts)) of the time series acquisition. For both scanners, no significant effect of ES and BW on signal drift was revealed. The SFNR, NU(ts) and SNR(ts) values of scanner A did not significantly vary with ES. On the other hand, the SFNR, NU(ts), and SNR(ts) values of scanner B significantly varied with ES. SFNR (5.8%) and SNR(ts) (5.9%) increased with increasing ES. SFNR (25% scanner A, 32% scanner B) and SNR(ts) (26.2% scanner A, 30.1% scanner B) values of both scanners significantly decreased with increasing BW. NU(ts) values of scanners A and B were less than 3% for all BW and ES values. Nonetheless, scanner A was characterized by a significant upward trend (3% percentage of variation) of time series nonuniformity with increasing BW while NU(ts) of scanner B significantly increased (19% percentage of variation) with increasing ES. Temporal stability (SFNR and DR) and overall image quality (NU(ts) and SNR(ts)) of EPI-fMRI time series can significantly vary with echo spacing and readout bandwidth. The specific pattern of variation may depend on the performance of each single MR scanner system in terms of gradients characteristics, EPI sequence calibrations (eddy currents, shimming, etc.), and functional design of radiofrequency coil. Our results indicate that the employment of low BW improves not only the signal-to-noise ratio of EPI-fMRI time series but also the temporal stability of functional acquisitions. The use of minimum ES values is not entirely advantageous when the MR scanner system is characterized by gradients with low performances and suboptimal EPI sequence calibration. Since differences in basic performances of MR scanner system are potential source of variability for fMRI activation, phantom measurements of SFNR, DR, NU(ts), and SNR(ts) can be executed before subjects acquisitions to monitor the stability of MR scanner performances in clinical group comparison and longitudinal studies.

Measurements agreement between low-cost and high-level handheld 3D scanners to scan the knee for designing a 3D printed knee brace

PubMed Central

2018-01-01

Use of additive manufacturing is growing rapidly in the orthotics field. This technology allows orthotics to be designed directly on digital scans of limbs. However, little information is available about scanners and 3D scans. The aim of this study is to look at the agreement between manual measurements, high-level and low-cost handheld 3D scanners. We took two manual measurements and three 3D scans with each scanner from 14 lower limbs. The lower limbs were divided into 17 sections of 30mm each from 180mm above the mid-patella to 300mm below. Time to record and to process the three 3D scans for scanners methods were compared with Student t-test while Bland-Altman plots were used to study agreement between circumferences of each section from the three methods. The record time was 97s shorter with high-level scanner than with the low-cost (p = .02) while the process time was nine times quicker with the low-cost scanner (p < .01). An overestimation of 2.5mm was found in high-level scanner compared to manual measurement, but with a better repeatability between measurements. The low-cost scanner tended to overestimate the circumferences from 0.1% to 1.5%, overestimation being greater for smaller circumferences. In conclusion, 3D scanners provide more information about the shape of the lower limb, but the reliability depends on the 3D scanner and the size of the scanned segment. Low-cost scanners could be useful for clinicians because of the simple and fast process, but attention should be focused on accuracy, which depends on the scanned body segment. PMID:29320560

Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner.

PubMed

Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-Ichi; Sugihara, Naoki; Tsukagoshi, Shinsuke; Saito, Yasuo; Kazama, Masahiro; Ashizawa, Kazuto; Awai, Kazuo; Honda, Osamu; Ishikawa, Hiroyuki; Koizumi, Naoya; Komoto, Daisuke; Moriya, Hiroshi; Oda, Seitaro; Oshiro, Yasuji; Yanagawa, Masahiro; Tomiyama, Noriyuki; Asamura, Hisao

2015-01-01

The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.

Scanner OPC signatures: automatic vendor-to-vendor OPE matching

NASA Astrophysics Data System (ADS)

Renwick, Stephen P.

2009-03-01

As 193nm lithography continues to be stretched and the k1 factor decreases, optical proximity correction (OPC) has become a vital part of the lithographer's tool kit. Unfortunately, as is now well known, the design variations of lithographic scanners from different vendors cause them to have slightly different optical-proximity effect (OPE) behavior, meaning that they print features through pitch in distinct ways. This in turn means that their response to OPC is not the same, and that an OPC solution designed for a scanner from Company 1 may or may not work properly on a scanner from Company 2. Since OPC is not inexpensive, that causes trouble for chipmakers using more than one brand of scanner. Clearly a scanner-matching procedure is needed to meet this challenge. Previously, automatic matching has only been reported for scanners of different tool generations from the same manufacturer. In contrast, scanners from different companies have been matched using expert tuning and adjustment techniques, frequently requiring laborious test exposures. Automatic matching between scanners from Company 1 and Company 2 has remained an unsettled problem. We have recently solved this problem and introduce a novel method to perform the automatic matching. The success in meeting this challenge required three enabling factors. First, we recognized the strongest drivers of OPE mismatch and are thereby able to reduce the information needed about a tool from another supplier to that information readily available from all modern scanners. Second, we developed a means of reliably identifying the scanners' optical signatures, minimizing dependence on process parameters that can cloud the issue. Third, we carefully employed standard statistical techniques, checking for robustness of the algorithms used and maximizing efficiency. The result is an automatic software system that can predict an OPC matching solution for scanners from different suppliers without requiring expert intervention.

Measurements agreement between low-cost and high-level handheld 3D scanners to scan the knee for designing a 3D printed knee brace.

PubMed

Dessery, Yoann; Pallari, Jari

2018-01-01

Use of additive manufacturing is growing rapidly in the orthotics field. This technology allows orthotics to be designed directly on digital scans of limbs. However, little information is available about scanners and 3D scans. The aim of this study is to look at the agreement between manual measurements, high-level and low-cost handheld 3D scanners. We took two manual measurements and three 3D scans with each scanner from 14 lower limbs. The lower limbs were divided into 17 sections of 30mm each from 180mm above the mid-patella to 300mm below. Time to record and to process the three 3D scans for scanners methods were compared with Student t-test while Bland-Altman plots were used to study agreement between circumferences of each section from the three methods. The record time was 97s shorter with high-level scanner than with the low-cost (p = .02) while the process time was nine times quicker with the low-cost scanner (p < .01). An overestimation of 2.5mm was found in high-level scanner compared to manual measurement, but with a better repeatability between measurements. The low-cost scanner tended to overestimate the circumferences from 0.1% to 1.5%, overestimation being greater for smaller circumferences. In conclusion, 3D scanners provide more information about the shape of the lower limb, but the reliability depends on the 3D scanner and the size of the scanned segment. Low-cost scanners could be useful for clinicians because of the simple and fast process, but attention should be focused on accuracy, which depends on the scanned body segment.

FormScanner: Open-Source Solution for Grading Multiple-Choice Exams

NASA Astrophysics Data System (ADS)

Young, Chadwick; Lo, Glenn; Young, Kaisa; Borsetta, Alberto

2016-01-01

The multiple-choice exam remains a staple for many introductory physics courses. In the past, people have graded these by hand or even flaming needles. Today, one usually grades the exams with a form scanner that utilizes optical mark recognition (OMR). Several companies provide these scanners and particular forms, such as the eponymous "Scantron." OMR scanners combine hardware and software—a scanner and OMR program—to read and grade student-filled forms.

Applications of Optical Scanners in an Academic Center.

ERIC Educational Resources Information Center

Molinari, Carol; Tannenbaum, Robert S.

1995-01-01

Describes optical scanners, including how the technology works; applications in data management and research; development of instructional materials; and providing community services. Discussion includes the three basic types of optical scanners: optical character recognition (OCR), optical mark readers (OMR), and graphic scanners. A sidebar…

A multilevel multispectral data set analysis in the visible and infrared wavelength regions. [for land use remote sensing

NASA Technical Reports Server (NTRS)

Biehl, L. L.; Silva, L. F.

1975-01-01

Skylab multispectral scanner data, digitized Skylab color infrared (IR) photography, digitized Skylab black and white multiband photography, and Earth Resources Technology Satellite (ERTS) multispectral scanner data collected within a 24-hr time period over an area in south-central Indiana near Bloomington on June 9 and 10, 1973, were compared in a machine-aided land use analysis of the area. The overall classification performance results, obtained with nine land use classes, were 87% correct classification using the 'best' 4 channels of the Skylab multispectral scanner, 80% for the channels on the Skylab multispectral scanner which are spectrally comparable to the ERTS multispectral scanner, 88% for the ERTS multispectral scanner, 83% for the digitized color IR photography, and 76% for the digitized black and white multiband photography. The results indicate that the Skylab multispectral scanner may yield even higher classification accuracies when a noise-filtered multispectral scanner data set becomes available in the near future.

Efficient system modeling for a small animal PET scanner with tapered DOI detectors.

PubMed

Zhang, Mengxi; Zhou, Jian; Yang, Yongfeng; Rodríguez-Villafuerte, Mercedes; Qi, Jinyi

2016-01-21

A prototype small animal positron emission tomography (PET) scanner for mouse brain imaging has been developed at UC Davis. The new scanner uses tapered detector arrays with depth of interaction (DOI) measurement. In this paper, we present an efficient system model for the tapered PET scanner using matrix factorization and a virtual scanner geometry. The factored system matrix mainly consists of two components: a sinogram blurring matrix and a geometrical matrix. The geometric matrix is based on a virtual scanner geometry. The sinogram blurring matrix is estimated by matrix factorization. We investigate the performance of different virtual scanner geometries. Both simulation study and real data experiments are performed in the fully 3D mode to study the image quality under different system models. The results indicate that the proposed matrix factorization can maintain image quality while substantially reduce the image reconstruction time and system matrix storage cost. The proposed method can be also applied to other PET scanners with DOI measurement.

Scanners for analytic print measurement: the devil in the details

NASA Astrophysics Data System (ADS)

Zeise, Eric K.; Williams, Don; Burns, Peter D.; Kress, William C.

2007-01-01

Inexpensive and easy-to-use linear and area-array scanners have frequently substituted as colorimeters and densitometers for low-frequency (i.e., large area) hard copy image measurement. Increasingly, scanners are also being used for high spatial frequency, image microstructure measurements, which were previously reserved for high performance microdensitometers. In this paper we address characteristics of flatbed reflection scanners in the evaluation of print uniformity, geometric distortion, geometric repeatability and the influence of scanner MTF and noise on analytic measurements. Suggestions are made for the specification and evaluation of scanners to be used in print image quality standards that are being developed.

Space-multiplexed optical scanner.

PubMed

Riza, Nabeel A; Yaqoob, Zahid

2004-05-01

A low-loss two-dimensional optical beam scanner that is capable of delivering large (e.g., > 10 degrees) angular scans along the elevation as well as the azimuthal direction is presented. The proposed scanner is based on a space-switched parallel-serial architecture that employs a coarse-scanner module and a fine-scanner module that produce an ultrahigh scan space-fill factor, e.g., 900 x 900 distinguishable beams in a 10 degrees (elevation) x 10 degrees (azimuth) scan space. The experimentally demonstrated one-dimensional version of the proposed scanner has a supercontinuous scan, 100 distinguishable beam spots in a 2.29 degrees total scan range, and 1.5-dB optical insertion loss.

A Prospective, Matched Comparison Study of SUV Measurements From Time-of-Flight Versus Non-Time-of-Flight PET/CT Scanners.

PubMed

Thompson, Holly M; Minamimoto, Ryogo; Jamali, Mehran; Barkhodari, Amir; von Eyben, Rie; Iagaru, Andrei

2016-07-01

As quantitative F-FDG PET numbers and pooling of results from different PET/CT scanners become more influential in the management of patients, it becomes imperative that we fully interrogate differences between scanners to fully understand the degree of scanner bias on the statistical power of studies. Participants with body mass index (BMI) greater than 25, scheduled on a time-of-flight (TOF)-capable PET/CT scanner, had a consecutive scan on a non-TOF-capable PET/CT scanner and vice versa. SUVmean in various tissues and SUVmax of malignant lesions were measured from both scans, matched to each subject. Data were analyzed using a mixed-effects model, and statistical significance was determined using equivalence testing, with P < 0.05 being significant. Equivalence was established in all baseline organs, except the cerebellum, matched per patient between scanner types. Mixed-effects method analysis of lesions, repeated between scan types and matched per patient, demonstrated good concordance between scanner types. Patients could be scanned on either a TOF or non-TOF-capable PET/CT scanner without clinical compromise to quantitative SUV measurements.

21 CFR 892.1300 - Nuclear rectilinear scanner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear rectilinear scanner. 892.1300 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1300 Nuclear rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in...

21 CFR 892.1300 - Nuclear rectilinear scanner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear rectilinear scanner. 892.1300 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1300 Nuclear rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in...

A support vector machine classifier reduces interscanner variation in the HRCT classification of regional disease pattern in diffuse lung disease: Comparison to a Bayesian classifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Yongjun; Lim, Jonghyuck; Kim, Namkug

2013-05-15

Purpose: To investigate the effect of using different computed tomography (CT) scanners on the accuracy of high-resolution CT (HRCT) images in classifying regional disease patterns in patients with diffuse lung disease, support vector machine (SVM) and Bayesian classifiers were applied to multicenter data. Methods: Two experienced radiologists marked sets of 600 rectangular 20 Multiplication-Sign 20 pixel regions of interest (ROIs) on HRCT images obtained from two scanners (GE and Siemens), including 100 ROIs for each of local patterns of lungs-normal lung and five of regional pulmonary disease patterns (ground-glass opacity, reticular opacity, honeycombing, emphysema, and consolidation). Each ROI was assessedmore » using 22 quantitative features belonging to one of the following descriptors: histogram, gradient, run-length, gray level co-occurrence matrix, low-attenuation area cluster, and top-hat transform. For automatic classification, a Bayesian classifier and a SVM classifier were compared under three different conditions. First, classification accuracies were estimated using data from each scanner. Next, data from the GE and Siemens scanners were used for training and testing, respectively, and vice versa. Finally, all ROI data were integrated regardless of the scanner type and were then trained and tested together. All experiments were performed based on forward feature selection and fivefold cross-validation with 20 repetitions. Results: For each scanner, better classification accuracies were achieved with the SVM classifier than the Bayesian classifier (92% and 82%, respectively, for the GE scanner; and 92% and 86%, respectively, for the Siemens scanner). The classification accuracies were 82%/72% for training with GE data and testing with Siemens data, and 79%/72% for the reverse. The use of training and test data obtained from the HRCT images of different scanners lowered the classification accuracy compared to the use of HRCT images from the same scanner. For integrated ROI data obtained from both scanners, the classification accuracies with the SVM and Bayesian classifiers were 92% and 77%, respectively. The selected features resulting from the classification process differed by scanner, with more features included for the classification of the integrated HRCT data than for the classification of the HRCT data from each scanner. For the integrated data, consisting of HRCT images of both scanners, the classification accuracy based on the SVM was statistically similar to the accuracy of the data obtained from each scanner. However, the classification accuracy of the integrated data using the Bayesian classifier was significantly lower than the classification accuracy of the ROI data of each scanner. Conclusions: The use of an integrated dataset along with a SVM classifier rather than a Bayesian classifier has benefits in terms of the classification accuracy of HRCT images acquired with more than one scanner. This finding is of relevance in studies involving large number of images, as is the case in a multicenter trial with different scanners.« less

Quantitation of clinical feedback on image quality differences between two CT scanner models.

PubMed

Bache, Steven T; Stauduhar, Paul J; Liu, Xinming; Loyer, Evelyne M; John, Rong X

2017-03-01

The aim of this work was to quantitate differences in image quality between two GE CT scanner models - the LightSpeed VCT ("VCT") and Discovery HD750 ("HD") - based upon feedback from radiologists at our institution. First, 3 yrs of daily QC images of the manufacturer-provided QC phantom from 10 scanners - five of each model - were analyzed for both noise magnitude, measured as CT-number standard deviation, and noise power spectrum within the uniform water section. The same phantom was then scanned on four of each model and analyzed for low contrast detectability (LCD) using a built-in LCD tool at the scanner console. An anthropomorphic phantom was scanned using the same eight scanners. A slice within the abdomen section was chosen and three ROIs were placed in regions representing liver, stomach, and spleen. Both standard deviation of CT-number and LCD value was calculated for each image. Noise magnitude was 8.5% higher in HD scanners compared to VCT scanners. An associated increase in the magnitude of the noise power spectra were also found, but both peak and mean NPS frequency were not different between the two models. VCT scanners outperformed HD scanners with respect to LCD by an average of 13.1% across all scanners and phantoms. Our results agree with radiologist feedback, and necessitate a closer look at our body CT protocols among different scanner models at our institution. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

21 CFR 882.1925 - Ultrasonic scanner calibration test block.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic scanner calibration test block. 882... Ultrasonic scanner calibration test block. (a) Identification. An ultrasonic scanner calibration test block is a block of material with known properties used to calibrate ultrasonic scanning devices (e.g., the...

21 CFR 892.1330 - Nuclear whole body scanner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear whole body scanner. 892.1330 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of...

21 CFR 892.1330 - Nuclear whole body scanner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear whole body scanner. 892.1330 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of...

Design and implementation of an inexpensive target scanner for the growth of thin films by the laser-ablation process

NASA Astrophysics Data System (ADS)

Rao, A. M.; Moodera, J. S.

1991-04-01

The design of a target scanner that is inexpensive and easy to construct is described. Our target scanner system does not require an expensive personal computer to raster the laser beam uniformily over the target material, unlike the computer driven target scanners that are currently being used in the thin-film industry. The main components of our target scanner comprise a bidirectional motor, a two-position switch, and a standard optical mirror mount.

Side scanner for supermarkets: a new scanner design standard

NASA Astrophysics Data System (ADS)

Cheng, Charles K.; Cheng, J. K.

1996-09-01

High speed UPC bar code has become a standard mode of data capture for supermarkets in the US, Europe, and Japan. The influence of the ergonomics community on the design of the scanner is evident. During the past decade the ergonomic issues of cashier in check-outs has led to occupational hand-wrist cumulative trauma disorders, in most cases causing carpal tunnel syndrome, a permanent hand injury. In this paper, the design of a side scanner to resolve the issues is discussed. The complex optical module and the sensor for aforesaid side scanner is described. The ergonomic advantages offer the old counter mounted vertical scanner has been experimentally proved by the industrial funded study at an independent university.

Dual mode scanner-tracker

NASA Astrophysics Data System (ADS)

Mongeon, R. J.

1984-11-01

The beam of a laser radar is moved over the field of view by means of a pair of scanner/trackers arranged in cascade along the laser beam. One of the scanner/trackers operates at high speed, with high resolution and a wide field and is located in the demagnified portion of the laser beam. The two scanner/trackers complement each other to achieve high speed, high resolution scanning as well as tracking of moving targets. A beam steering telescope for an airborne laser radar which incorporates the novel dual mode scanner/tracker is also shown. The other scanner/tracker operates at low speed with low resolution and a wide field and is located in the magnified portion of the laser beam.

Evaluation of resolution and periodic errors of a flatbed scanner used for digitizing spectroscopic photographic plates

PubMed Central

Wyatt, Madison; Nave, Gillian

2017-01-01

We evaluated the use of a commercial flatbed scanner for digitizing photographic plates used for spectroscopy. The scanner has a bed size of 420 mm by 310 mm and a pixel size of about 0.0106 mm. Our tests show that the closest line pairs that can be resolved with the scanner are 0.024 mm apart, only slightly larger than the Nyquist resolution of 0.021 mm expected by the 0.0106 mm pixel size. We measured periodic errors in the scanner using both a calibrated length scale and a photographic plate. We find no noticeable periodic errors in the direction parallel to the linear detector in the scanner, but errors with an amplitude of 0.03 mm to 0.05 mm in the direction perpendicular to the detector. We conclude that large periodic errors in measurements of spectroscopic plates using flatbed scanners can be eliminated by scanning the plates with the dispersion direction parallel to the linear detector by placing the plate along the short side of the scanner. PMID:28463262

Laser identification system based on acousto-optical barcode scanner principles

NASA Astrophysics Data System (ADS)

Khansuvarov, Ruslan A.; Korol, Georgy I.; Preslenev, Leonid N.; Bestugin, Aleksandr R.; Paraskun, Arthur S.

2016-09-01

The main purpose of the bar code in the modern world is the unique identification of the product, service, or any of their features, so personal and stationary barcode scanners so widely used. One of the important parameters of bar code scanners is their reliability, accuracy of the barcode recognition, response time and performance. Nowadays, the most popular personal barcode scanners contain a mechanical part, which extremely impairs the reliability indices. Group of SUAI engineers has proposed bar code scanner based on laser beam acoustic deflection effect in crystals [RU patent No 156009 issued 4/16/2015] Through the use of an acousto-optic deflector element in barcode scanner described by a group of engineers SUAI, it can be implemented in the manual form factor, and the stationary form factor of a barcode scanner. Being a wave electronic device, an acousto-optic element in the composition of the acousto-optic barcode scanner allows you to clearly establish a mathematical link between the encoded function of the bar code with the accepted input photodetector intensities function that allows you to speak about the great probability of a bar code clear definition. This paper provides a description of the issued patent, the description of the principles of operation based on the mathematical analysis, a description of the layout of the implemented scanner.

Evaluation of portable CT scanners for otologic image-guided surgery

PubMed Central

Balachandran, Ramya; Schurzig, Daniel; Fitzpatrick, J Michael; Labadie, Robert F

2011-01-01

Purpose Portable CT scanners are beneficial for diagnosis in the intensive care unit, emergency room, and operating room. Portable fixed-base versus translating-base CT systems were evaluated for otologic image-guided surgical (IGS) applications based on geometric accuracy and utility for percutaneous cochlear implantation. Methods Five cadaveric skulls were fitted with fiducial markers and scanned using both a translating-base, 8-slice CT scanner (CereTom®) and a fixed-base, flat-panel, volume-CT (fpVCT) scanner (Xoran xCAT®). Images were analyzed for: (a) subjective quality (i.e. noise), (b) consistency of attenuation measurements (Hounsfield units) across similar tissue, and (c) geometric accuracy of fiducial marker positions. The utility of these scanners in clinical IGS cases was tested. Results Five cadaveric specimens were scanned using each of the scanners. The translating-base, 8-slice CT scanner had spatially consistent Hounsfield units, and the image quality was subjectively good. However, because of movement variations during scanning, the geometric accuracy of fiducial marker positions was low. The fixed-base, fpVCT system had high spatial resolution, but the images were noisy and had spatially inconsistent attenuation measurements; while the geometric representation of the fiducial markers was highly accurate. Conclusion Two types of portable CT scanners were evaluated for otologic IGS. The translating-base, 8-slice CT scanner provided better image quality than a fixed-base, fpVCT scanner. However, the inherent error in three-dimensional spatial relationships by the translating-based system makes it suboptimal for otologic IGS use. PMID:21779768

Technical Report on the Modification of 3-Dimensional Non-contact Human Body Laser Scanner for the Measurement of Anthropometric Dimensions: Verification of its Accuracy and Precision.

PubMed

Jafari Roodbandi, Akram Sadat; Naderi, Hamid; Hashenmi-Nejad, Naser; Choobineh, Alireza; Baneshi, Mohammad Reza; Feyzi, Vafa

2017-01-01

Introduction: Three-dimensional (3D) scanners are widely used in medicine. One of the applications of 3D scanners is the acquisition of anthropometric dimensions for ergonomics and the creation of an anthropometry data bank. The aim of this study was to evaluate the precision and accuracy of a modified 3D scanner fabricated in this study. Methods: In this work, a 3D scan of the human body was obtained using DAVID Laser Scanner software and its calibration background, a linear low-power laser, and one advanced webcam. After the 3D scans were imported to the Geomagic software, 10 anthropometric dimensions of 10 subjects were obtained. The measurements of the 3D scanner were compared to the measurements of the same dimensions by a direct anthropometric method. The precision and accuracy of the measurements of the 3D scanner were then evaluated. The obtained data were analyzed using an independent sample t test with the SPSS software. Results: The minimum and maximum measurement differences from three consecutive scans by the 3D scanner were 0.03 mm and 18 mm, respectively. The differences between the measurements by the direct anthropometry method and the 3D scanner were not statistically significant. Therefore, the accuracy of the 3D scanner is acceptable. Conclusion: Future studies will need to focus on the improvement of the scanning speed and the quality of the scanned image.

Technical Report on the Modification of 3-Dimensional Non-contact Human Body Laser Scanner for the Measurement of Anthropometric Dimensions: Verification of its Accuracy and Precision

PubMed Central

Jafari Roodbandi, Akram Sadat; Naderi, Hamid; Hashenmi-Nejad, Naser; Choobineh, Alireza; Baneshi, Mohammad Reza; Feyzi, Vafa

2017-01-01

Introduction: Three-dimensional (3D) scanners are widely used in medicine. One of the applications of 3D scanners is the acquisition of anthropometric dimensions for ergonomics and the creation of an anthropometry data bank. The aim of this study was to evaluate the precision and accuracy of a modified 3D scanner fabricated in this study. Methods: In this work, a 3D scan of the human body was obtained using DAVID Laser Scanner software and its calibration background, a linear low-power laser, and one advanced webcam. After the 3D scans were imported to the Geomagic software, 10 anthropometric dimensions of 10 subjects were obtained. The measurements of the 3D scanner were compared to the measurements of the same dimensions by a direct anthropometric method. The precision and accuracy of the measurements of the 3D scanner were then evaluated. The obtained data were analyzed using an independent sample t test with the SPSS software. Results: The minimum and maximum measurement differences from three consecutive scans by the 3D scanner were 0.03 mm and 18 mm, respectively. The differences between the measurements by the direct anthropometry method and the 3D scanner were not statistically significant. Therefore, the accuracy of the 3D scanner is acceptable. Conclusion: Future studies will need to focus on the improvement of the scanning speed and the quality of the scanned image. PMID:28912940

Method to evaluate the noise of 3D intra-oral scanner.

PubMed

Desoutter, Alban; Yusuf Solieman, Osama; Subsol, Gérard; Tassery, Hervé; Cuisinier, Frédéric; Fages, Michel

2017-01-01

In dentistry, 3D intra-oral scanners are gaining increasing popularity essentially for the production of dental prostheses. However, there is no normalized procedure to evaluate their basic performance and enable comparisons among intra-oral scanners. The noise value highlights the trueness of a 3D intra-oral scanner and its capacity to plan prosthesis with efficient clinical precision. The aim of the present study is to develop a reproducible methodology for determining the noise of an intra-oral scanner. To this aim, and as a reference, an ultra-flat and ultra-smooth alumina wafer is used as a blank test. The roughness is calculated using an AFM (atomic force microscope) and interferometric microscope measurements to validate this ultra-flat characteristic. Then, two intra-oral scanners (Carestream CS3500 and Trios 3Shape) are used. The wafer is imaged by the two intra-oral scanners with three different angles and two different directions, 10 times for each parameter, given a total of 50 3D-meshes per intra-oral scanner. RMS (root mean square), representing the noise, is evaluated and compared for each angle/direction and each intra-oral scanner, for the whole mesh, and then in a central ROI (region of interest). In this study, we obtained RMS values ranging between 5.29 and 12.58 micrometers. No statistically significant differences were found between the mean RMS of the two intra-oral scanners, but significant differences in angulation and orientations were found between different 3D intra-oral scanners. This study shows that the evaluation of RMS can be an indicator of the value of the noise, which can be easily assessed by applying the present methodology.

Technical Note: Rod phantom analysis for comparison of PET detector sampling and reconstruction methods.

PubMed

Wollenweber, Scott D; Kemp, Brad J

2016-11-01

This investigation aimed to develop a scanner quantification performance methodology and compare multiple metrics between two scanners under different imaging conditions. Most PET scanners are designed to work over a wide dynamic range of patient imaging conditions. Clinical constraints, however, often impact the realization of the entitlement performance for a particular scanner design. Using less injected dose and imaging for a shorter time are often key considerations, all while maintaining "acceptable" image quality and quantitative capability. A dual phantom measurement including resolution inserts was used to measure the effects of in-plane (x, y) and axial (z) system resolution between two PET/CT systems with different block detector crystal dimensions. One of the scanners had significantly thinner slices. Several quantitative measures, including feature contrast recovery, max/min value, and feature profile accuracy were derived from the resulting data and compared between the two scanners and multiple phantoms and alignments. At the clinically relevant count levels used, the scanner with thinner slices had improved performance of approximately 2%, averaged over phantom alignments, measures, and reconstruction methods, for the head-sized phantom, mainly demonstrated with the rods aligned perpendicular to the scanner axis. That same scanner had a slightly decreased performance of -1% for the larger body-size phantom, mostly due to an apparent noise increase in the images. Most of the differences in the metrics between the two scanners were less than 10%. Using the proposed scanner performance methodology, it was shown that smaller detector elements and a larger number of image voxels require higher count density in order to demonstrate improved image quality and quantitation. In a body imaging scenario under typical clinical conditions, the potential advantages of the design must overcome increases in noise due to lower count density.

Quantitative image feature variability amongst CT scanners with a controlled scan protocol

NASA Astrophysics Data System (ADS)

Ger, Rachel B.; Zhou, Shouhao; Chi, Pai-Chun Melinda; Goff, David L.; Zhang, Lifei; Lee, Hannah J.; Fuller, Clifton D.; Howell, Rebecca M.; Li, Heng; Stafford, R. Jason; Court, Laurence E.; Mackin, Dennis S.

2018-02-01

Radiomics studies often analyze patient computed tomography (CT) images acquired from different CT scanners. This may result in differences in imaging parameters, e.g. different manufacturers, different acquisition protocols, etc. However, quantifiable differences in radiomics features can occur based on acquisition parameters. A controlled protocol may allow for minimization of these effects, thus allowing for larger patient cohorts from many different CT scanners. In order to test radiomics feature variability across different CT scanners a radiomics phantom was developed with six different cartridges encased in high density polystyrene. A harmonized protocol was developed to control for tube voltage, tube current, scan type, pitch, CTDIvol, convolution kernel, display field of view, and slice thickness across different manufacturers. The radiomics phantom was imaged on 18 scanners using the control protocol. A linear mixed effects model was created to assess the impact of inter-scanner variability with decomposition of feature variation between scanners and cartridge materials. The inter-scanner variability was compared to the residual variability (the unexplained variability) and to the inter-patient variability using two different patient cohorts. The patient cohorts consisted of 20 non-small cell lung cancer (NSCLC) and 30 head and neck squamous cell carcinoma (HNSCC) patients. The inter-scanner standard deviation was at least half of the residual standard deviation for 36 of 49 quantitative image features. The ratio of inter-scanner to patient coefficient of variation was above 0.2 for 22 and 28 of the 49 features for NSCLC and HNSCC patients, respectively. Inter-scanner variability was a significant factor compared to patient variation in this small study for many of the features. Further analysis with a larger cohort will allow more thorough analysis with additional variables in the model to truly isolate the interscanner difference.

Color accuracy and reproducibility in whole slide imaging scanners

PubMed Central

Shrestha, Prarthana; Hulsken, Bas

2014-01-01

Abstract We propose a workflow for color reproduction in whole slide imaging (WSI) scanners, such that the colors in the scanned images match to the actual slide color and the inter-scanner variation is minimum. We describe a new method of preparation and verification of the color phantom slide, consisting of a standard IT8-target transmissive film, which is used in color calibrating and profiling the WSI scanner. We explore several International Color Consortium (ICC) compliant techniques in color calibration/profiling and rendering intents for translating the scanner specific colors to the standard display (sRGB) color space. Based on the quality of the color reproduction in histopathology slides, we propose the matrix-based calibration/profiling and absolute colorimetric rendering approach. The main advantage of the proposed workflow is that it is compliant to the ICC standard, applicable to color management systems in different platforms, and involves no external color measurement devices. We quantify color difference using the CIE-DeltaE2000 metric, where DeltaE values below 1 are considered imperceptible. Our evaluation on 14 phantom slides, manufactured according to the proposed method, shows an average inter-slide color difference below 1 DeltaE. The proposed workflow is implemented and evaluated in 35 WSI scanners developed at Philips, called the Ultra Fast Scanners (UFS). The color accuracy, measured as DeltaE between the scanner reproduced colors and the reference colorimetric values of the phantom patches, is improved on average to 3.5 DeltaE in calibrated scanners from 10 DeltaE in uncalibrated scanners. The average inter-scanner color difference is found to be 1.2 DeltaE. The improvement in color performance upon using the proposed method is apparent with the visual color quality of the tissue scans. PMID:26158041

Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

PubMed Central

Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-ichi; Sugihara, Naoki; Tsukagoshi, Shinsuke; Saito, Yasuo; Kazama, Masahiro; Ashizawa, Kazuto; Awai, Kazuo; Honda, Osamu; Ishikawa, Hiroyuki; Koizumi, Naoya; Komoto, Daisuke; Moriya, Hiroshi; Oda, Seitaro; Oshiro, Yasuji; Yanagawa, Masahiro; Tomiyama, Noriyuki; Asamura, Hisao

2015-01-01

Purpose The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners. PMID:26352144

A new PET scanner with semiconductor detectors enables better identification of intratumoral inhomogeneity.

PubMed

Shiga, Tohru; Morimoto, Yuichi; Kubo, Naoki; Katoh, Norio; Katoh, Chietsugu; Takeuchi, Wataru; Usui, Reiko; Hirata, Kenji; Kojima, Shinichi; Umegaki, Kikuo; Shirato, Hiroki; Tamaki, Nagara

2009-01-01

An autoradiography method revealed intratumoral inhomogeneity in various solid tumors. It is becoming increasingly important to estimate intratumoral inhomogeneity. However, with low spatial resolution and high scatter noise, it is difficult to detect intratumoral inhomogeneity in clinical settings. We developed a new PET system with CdTe semiconductor detectors to provide images with high spatial resolution and low scatter noise. Both phantom images and patients' images were analyzed to evaluate intratumoral inhomogeneity. This study was performed with a cold spot phantom that had 6-mm-diameter cold sphenoid defects, a dual-cylinder phantom with an adjusted concentration of 1:2, and an "H"-shaped hot phantom. These were surrounded with water. Phantom images and (18)F-FDG PET images of patients with nasopharyngeal cancer were compared with conventional bismuth germanate PET images. Profile curves for the phantoms were measured as peak-to-valley ratios to define contrast. Intratumoral inhomogeneity and tumor edge sharpness were evaluated on the images of the patients. The contrast obtained with the semiconductor PET scanner (1.53) was 28% higher than that obtained with the conventional scanner (1.20) for the 6-mm-diameter cold sphenoid phantom. The contrast obtained with the semiconductor PET scanner (1.43) was 27% higher than that obtained with the conventional scanner (1.13) for the dual-cylinder phantom. Similarly, the 2-mm cold region between 1-mm hot rods was identified only by the new PET scanner and not by the conventional scanner. The new PET scanner identified intratumoral inhomogeneity in more detail than the conventional scanner in 6 of 10 patients. The tumor edge was sharper on the images obtained with the new PET scanner than on those obtained with the conventional scanner. These phantom and clinical studies suggested that this new PET scanner has the potential for better identification of intratumoral inhomogeneity, probably because of its high spatial resolution and low scatter noise.

Accuracy in contouring of small and low contrast lesions: Comparison between diagnostic quality computed tomography scanner and computed tomography simulation scanner-A phantom study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Yick Wing, E-mail: mpr@hksh.com; Wong, Wing Kei Rebecca; Yu, Siu Ki

2012-01-01

To evaluate the accuracy in detection of small and low-contrast regions using a high-definition diagnostic computed tomography (CT) scanner compared with a radiotherapy CT simulation scanner. A custom-made phantom with cylindrical holes of diameters ranging from 2-9 mm was filled with 9 different concentrations of contrast solution. The phantom was scanned using a 16-slice multidetector CT simulation scanner (LightSpeed RT16, General Electric Healthcare, Milwaukee, WI) and a 64-slice high-definition diagnostic CT scanner (Discovery CT750 HD, General Electric Healthcare). The low-contrast regions of interest (ROIs) were delineated automatically upon their full width at half maximum of the CT number profile inmore » Hounsfield units on a treatment planning workstation. Two conformal indexes, CI{sub in}, and CI{sub out}, were calculated to represent the percentage errors of underestimation and overestimation in the automated contours compared with their actual sizes. Summarizing the conformal indexes of different sizes and contrast concentration, the means of CI{sub in} and CI{sub out} for the CT simulation scanner were 33.7% and 60.9%, respectively, and 10.5% and 41.5% were found for the diagnostic CT scanner. The mean differences between the 2 scanners' CI{sub in} and CI{sub out} were shown to be significant with p < 0.001. A descending trend of the index values was observed as the ROI size increases for both scanners, which indicates an improved accuracy when the ROI size increases, whereas no observable trend was found in the contouring accuracy with respect to the contrast levels in this study. Images acquired by the diagnostic CT scanner allow higher accuracy on size estimation compared with the CT simulation scanner in this study. We recommend using a diagnostic CT scanner to scan patients with small lesions (<1 cm in diameter) for radiotherapy treatment planning, especially for those pending for stereotactic radiosurgery in which accurate delineation of small-sized, low-contrast regions is important for dose calculation.« less

Out of lab calibration of a rotating 2D scanner for 3D mapping

NASA Astrophysics Data System (ADS)

Koch, Rainer; Böttcher, Lena; Jahrsdörfer, Maximilian; Maier, Johannes; Trommer, Malte; May, Stefan; Nüchter, Andreas

2017-06-01

Mapping is an essential task in mobile robotics. To fulfil advanced navigation and manipulation tasks a 3D representation of the environment is required. Applying stereo cameras or Time-of-flight cameras (TOF cameras) are one way to archive this requirement. Unfortunately, they suffer from drawbacks which makes it difficult to map properly. Therefore, costly 3D laser scanners are applied. An inexpensive way to build a 3D representation is to use a 2D laser scanner and rotate the scan plane around an additional axis. A 3D point cloud acquired with such a custom device consists of multiple 2D line scans. Therefore the scanner pose of each line scan need to be determined as well as parameters resulting from a calibration to generate a 3D point cloud. Using external sensor systems are a common method to determine these calibration parameters. This is costly and difficult when the robot needs to be calibrated outside the lab. Thus, this work presents a calibration method applied on a rotating 2D laser scanner. It uses a hardware setup to identify the required parameters for calibration. This hardware setup is light, small, and easy to transport. Hence, an out of lab calibration is possible. Additional a theoretical model was created to test the algorithm and analyse impact of the scanner accuracy. The hardware components of the 3D scanner system are an HOKUYO UTM-30LX-EW 2D laser scanner, a Dynamixel servo-motor, and a control unit. The calibration system consists of an hemisphere. In the inner of the hemisphere a circular plate is mounted. The algorithm needs to be provided with a dataset of a single rotation from the laser scanner. To achieve a proper calibration result the scanner needs to be located in the middle of the hemisphere. By means of geometric formulas the algorithms determine the individual deviations of the placed laser scanner. In order to minimize errors, the algorithm solves the formulas in an iterative process. First, the calibration algorithm was tested with an ideal hemisphere model created in Matlab. Second, laser scanner was mounted differently, the scanner position and the rotation axis was modified. In doing so, every deviation, was compared with the algorithm results. Several measurement settings were tested repeatedly with the 3D scanner system and the calibration system. The results show that the length accuracy of the laser scanner is most critical. It influences the required size of the hemisphere and the calibration accuracy.

Multispectral scanner system for ERTS: Four-band scanner system. Volume 1: System description and performance

NASA Technical Reports Server (NTRS)

Norwood, V. T.; Fermelia, L. R.; Tadler, G. A.

1972-01-01

The four-band Multispectral Scanner System (MSS) is discussed. Included is a description of the MSS with major emphasis on the flight subsystem (scanner and multiplexer), the theory for the MSS calibration system processing techniques, system calibration data, and a summary of the performance of the two four-band MSS systems.

Scanner imaging systems, aircraft

NASA Technical Reports Server (NTRS)

Ungar, S. G.

1982-01-01

The causes and effects of distortion in aircraft scanner data are reviewed and an approach to reduce distortions by modelling the effect of aircraft motion on the scanner scene is discussed. With the advent of advanced satellite borne scanner systems, the geometric and radiometric correction of aircraft scanner data has become increasingly important. Corrections are needed to reliably simulate observations obtained by such systems for purposes of evaluation. It is found that if sufficient navigational information is available, aircraft scanner coordinates may be related very precisely to planimetric ground coordinates. However, the potential for a multivalue remapping transformation (i.e., scan lines crossing each other), adds an inherent uncertainty, to any radiometric resampling scheme, which is dependent on the precise geometry of the scan and ground pattern.

High-tech breakthrough DNA scanner for reading sequence and detecting gene mutation: A powerful 1 lb, 20 {mu}m resolution, 16-bit personal scanner (PS) that scans 17inch x 14inch x-ray film in 48 s, with laser, uv and white light sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeineh, J.A.; Zeineh, M.M.; Zeineh, R.A.

1993-06-01

The 17inch x 14inch X-ray film, gels, and blots are widely used in DNA research. However, DNA laser scanners are costly and unaffordable for the majority of surveyed biotech scientists who need it. The high-tech breakthrough analytical personal scanner (PS) presented in this report is an inexpensive 1 lb hand-held scanner priced at 2-4% of the bulky and costly 30-95 lb conventional laser scanners. This PS scanner is affordable from an operation budget and biotechnologists, who originate most science breakthroughs, can acquire it to enhance their speed, accuracy, and productivity. Compared to conventional laser scanners that are currently available onlymore » through hard-to-get capital-equipment budgets, the new PS scanner offers improved spatial resolution of 20 {mu}m, higher speed (scan up to 17inch x 14inch molecular X-ray film in 48 s), 1-32,768 gray levels (16-bits), student routines, versatility, and, most important, affordability. Its programs image the film, read DNA sequences automatically, and detect gene mutation. In parallel to the wide laboratory use of PC computers instead of mainframes, this PS scanner might become an integral part of a PC-PS powerful and cost-effective system where the PS performs the digital imaging and the PC acts on the data.« less

A novel optical scanner for laser radar

NASA Astrophysics Data System (ADS)

Yao, Shunyu; Peng, Renjun; Gao, Jianshuang

2013-09-01

Laser radar are ideally suitable for recognizing objects, detection, target tracking or obstacle avoidance, because of the high angular and range resolution. In recent years, scannerless ladar has developed rapidly. In contrast with traditional scanner ladar, scannerless ladar has distinct characteristics such as small, compact, high frame rate, wide field of view and high reliability. However, the scannerless ladar is still in the stage of laboratory and the performance cannot meet the demands of practical applications. Hence, traditional scanner laser radar is still mainly applied. In scanner ladar system, optical scanner is the key component which can deflect the direction of laser beam to the target. We investigated a novel scanner based on the characteristic of fiber's light-conductive. The fiber bundles are arranged in a special structure which connected to a motor. When motor working properly, the laser passes through the fibers on incident plane and the location of laser spot on output plane will move along with a straight line in a constant speed. The direction of light will be deflected by taking advantage of transmitting optics, then the linear sweeping of the target can be achieved. A laser radar scheme with high speed and large field of view can be realized. Some researches on scanner are simply introduced on section1. The structure of the optical scanner will be described and the practical applications of the scanner in transmitting and receiving optical paths are discussed in section2. Some characteristic of scanner is calculated in section3. In section4, we report the simulation and experiment of our prototype.

Application of a laser scanner to three dimensional visual sensing tasks

NASA Technical Reports Server (NTRS)

Ryan, Arthur M.

1992-01-01

The issues are described which are associated with using a laser scanner for visual sensing and the methods developed by the author to address them. A laser scanner is a device that controls the direction of a laser beam by deflecting it through a pair of orthogonal mirrors, the orientations of which are specified by a computer. If a calibrated laser scanner is combined with a calibrated camera, it is possible to perform three dimensional sensing by directing the laser at objects within the field of view of the camera. There are several issues associated with using a laser scanner for three dimensional visual sensing that must be addressed in order to use the laser scanner effectively. First, methods are needed to calibrate the laser scanner and estimate three dimensional points. Second, methods to estimate three dimensional points using a calibrated camera and laser scanner are required. Third, methods are required for locating the laser spot in a cluttered image. Fourth, mathematical models that predict the laser scanner's performance and provide structure for three dimensional data points are necessary. Several methods were developed to address each of these and has evaluated them to determine how and when they should be applied. The theoretical development, implementation, and results when used in a dual arm eighteen degree of freedom robotic system for space assembly is described.

Oceanographic scanner system design study, volume 1

NASA Technical Reports Server (NTRS)

1971-01-01

The design is reported of a dual mode multispectral scanner, capable of satisfying both overland and oceanographic requirements. A complete system description and performance summary of the scanner are given. In addition, subsystem and component descriptions and performance analyses are treated in individual sections. The design of the scanner, with minimum modifications, interfaces to the ERTS spacecraft and the ground data handling system.

Modeling and measurement of the detector presampling MTF of a variable resolution x-ray CT scanner.

PubMed

Melnyk, Roman; DiBianca, Frank A

2007-03-01

The detector presampling modulation transfer function (MTF) of a 576-channel variable resolution x-ray (VRX) computed tomography (CT) scanner was evaluated in this study. The scanner employs a VRX detector, which provides increased spatial resolution by matching the scanner's field of view (FOV) to the size of an object being imaged. Because spatial resolution is the parameter the scanner promises to improve, the evaluation of this resolution is important. The scanner's pre-reconstruction spatial resolution, represented by the detector presampling MTF, was evaluated using both modeling (Monte Carlo simulation) and measurement (the moving slit method). The theoretical results show the increase in the cutoff frequency of the detector presampling MTF from 1.39 to 43.38 cycles/mm as the FOV of the VRX CT scanner decreases from 32 to 1 cm. The experimental results are in reasonable agreement with the theoretical data. Some discrepancies between the measured and the modeled detector presampling MTFs can be explained by the limitations of the model. At small FOVs (1-8 cm), the MTF measurements were limited by the size of the focal spot. The obtained results are important for further development of the VRX CT scanner.

Towards System Calibration of Panoramic Laser Scanners from a Single Station

PubMed Central

Medić, Tomislav; Holst, Christoph; Kuhlmann, Heiner

2017-01-01

Terrestrial laser scanner measurements suffer from systematic errors due to internal misalignments. The magnitude of the resulting errors in the point cloud in many cases exceeds the magnitude of random errors. Hence, the task of calibrating a laser scanner is important for applications with high accuracy demands. This paper primarily addresses the case of panoramic terrestrial laser scanners. Herein, it is proven that most of the calibration parameters can be estimated from a single scanner station without a need for any reference information. This hypothesis is confirmed through an empirical experiment, which was conducted in a large machine hall using a Leica Scan Station P20 panoramic laser scanner. The calibration approach is based on the widely used target-based self-calibration approach, with small modifications. A new angular parameterization is used in order to implicitly introduce measurements in two faces of the instrument and for the implementation of calibration parameters describing genuine mechanical misalignments. Additionally, a computationally preferable calibration algorithm based on the two-face measurements is introduced. In the end, the calibration results are discussed, highlighting all necessary prerequisites for the scanner calibration from a single scanner station. PMID:28513548

On the Influence of Confounding Factors in Multisite Brain Morphometry Studies of Developmental Pathologies: Application to Autism Spectrum Disorder.

PubMed

Auzias, G; Takerkart, S; Deruelle, C

2016-05-01

Pooling data acquired on different MR scanners is a commonly used practice to increase the statistical power of studies based on MRI-derived measurements. Such studies are very appealing since they should make it possible to detect more subtle effects related to pathologies. However, the influence of confounds introduced by scanner-related variations remains unclear. When studying brain morphometry descriptors, it is crucial to investigate whether scanner-induced errors can exceed the effect of the disease itself. More specifically, in the context of developmental pathologies such as autism spectrum disorders (ASD), it is essential to evaluate the influence of the scanner on age-related effects. In this paper, we studied a dataset composed of 159 anatomical MR images pooled from three different scanners, including 75 ASD patients and 84 healthy controls. We quantitatively assessed the effects of the age, pathology, and scanner factors on cortical thickness measurements. Our results indicate that scan pooling from different sites would be less fruitful in some cortical regions than in others. Although the effect of age is consistent across scanners, the interaction between the age and scanner factors is important and significant in some specific cortical areas.

Two-dimensional scanner apparatus. [flaw detector in small flat plates

NASA Technical Reports Server (NTRS)

Kurtz, G. W.; Bankston, B. F. (Inventor)

1984-01-01

An X-Y scanner utilizes an eddy current or ultrasonic current test probe to detect surface defects in small flat plates and the like. The apparatus includes a scanner which travels on a pair of slide tubes in the X-direction. The scanner, carried on a carriage which slides in the Y-direction, is driven by a helix shaft with a closed-loop helix groove in which a follower pin carried by scanner rides. The carriage is moved incrementally in the Y-direction upon the completion of travel of the scanner back and forth in the X-direction by means of an indexing actuator and an indexing gear. The actuator is in the form of a ratchet which engages ratchet gear upon return of the scanner to the indexing position. The indexing gear is rotated a predetermined increment along a crack gear to move carriage incrementally in the Y-direction. Thus, simplified highly responsive mechanical motion may be had in a small lightweight portable unit for accurate scanning of small area.

Forensics for flatbed scanners

NASA Astrophysics Data System (ADS)

Gloe, Thomas; Franz, Elke; Winkler, Antje

2007-02-01

Within this article, we investigate possibilities for identifying the origin of images acquired with flatbed scanners. A current method for the identification of digital cameras takes advantage of image sensor noise, strictly speaking, the spatial noise. Since flatbed scanners and digital cameras use similar technologies, the utilization of image sensor noise for identifying the origin of scanned images seems to be possible. As characterization of flatbed scanner noise, we considered array reference patterns and sensor line reference patterns. However, there are particularities of flatbed scanners which we expect to influence the identification. This was confirmed by extensive tests: Identification was possible to a certain degree, but less reliable than digital camera identification. In additional tests, we simulated the influence of flatfielding and down scaling as examples for such particularities of flatbed scanners on digital camera identification. One can conclude from the results achieved so far that identifying flatbed scanners is possible. However, since the analyzed methods are not able to determine the image origin in all cases, further investigations are necessary.

Spacecraft attitude sensor

NASA Technical Reports Server (NTRS)

Davidson, A. C.; Grant, M. M. (Inventor)

1973-01-01

A system for sensing the attitude of a spacecraft includes a pair of optical scanners having a relatively narrow field of view rotating about the spacecraft x-y plane. The spacecraft rotates about its z axis at a relatively high angular velocity while one scanner rotates at low velocity, whereby a panoramic sweep of the entire celestial sphere is derived from the scanner. In the alternative, the scanner rotates at a relatively high angular velocity about the x-y plane while the spacecraft rotates at an extremely low rate or at zero angular velocity relative to its z axis to provide a rotating horizon scan. The positions of the scanners about the x-y plane are read out to assist in a determination of attitude. While the satellite is spinning at a relatively high angular velocity, the angular positions of the bodies detected by the scanners are determined relative to the sun by providing a sun detector having a field of view different from the scanners.

Biomedical applications of a real-time terahertz color scanner

PubMed Central

Schirmer, Markus; Fujio, Makoto; Minami, Masaaki; Miura, Jiro; Araki, Tsutomu; Yasui, Takeshi

2010-01-01

A real-time THz color scanner has the potential to further expand the application scope of THz spectral imaging based on its rapid image acquisition rate. We demonstrated three possible applications of a THz color scanner in the biomedical field: imaging of pharmaceutical tablets, human teeth, and human hair. The first application showed the scanner’s potential in total inspection for rapid quality control of pharmaceutical tablets moving on a conveyor belt. The second application demonstrated that the scanner can be used to identify a potential indicator for crystallinity of dental tissue. In the third application, the scanner was successfully used to visualize the drying process of wet hairs. These demonstrations indicated the high potential of the THz color scanner for practical applications in the biomedical field. PMID:21258472

A COST EFFECTIVE MULTI-SPECTRAL SCANNER FOR NATURAL GAS DETECTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yudaya Sivathanu; Jongmook Lim; Vinoo Narayanan

The objective of this project is to design, fabricate and field demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first six months of the project, the design for a laboratory version of the multispectral scanner was completed. The optical, mechanical, and electronic design for the scanner was completed. The optical design was analyzed using Zeemax Optical Design software and found to provide sufficiently resolved performance for the scanner. The electronic design was evaluated using a bread board and very high signal to noise ratios were obtained. Fabrication of a laboratorymore » version of the multi-spectral scanner is currently in progress. A technology status report and a research management plan was also completed during the same period.« less

Input Scanners: A Growing Impact In A Diverse Marketplace

NASA Astrophysics Data System (ADS)

Marks, Kevin E.

1989-08-01

Just as newly invented photographic processes revolutionized the printing industry at the turn of the century, electronic imaging has affected almost every computer application today. To completely emulate traditionally mechanical means of information handling, computer based systems must be able to capture graphic images. Thus, there is a widespread need for the electronic camera, the digitizer, the input scanner. This paper will review how various types of input scanners are being used in many diverse applications. The following topics will be covered: - Historical overview of input scanners - New applications for scanners - Impact of scanning technology on select markets - Scanning systems issues

11. SITE BUILDING 002 SCANNER BUILDING EVAPORATIVE COOLING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. SITE BUILDING 002 - SCANNER BUILDING - EVAPORATIVE COOLING TOWER SYSTEM IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Comparison of Epson scanner quality for radiochromic film evaluation

PubMed Central

Alnawaf, Hani; Yu, Peter K.N.

2012-01-01

Epson Desktop scanners have been quoted as devices which match the characteristics required for the evaluation of radiation dose exposure by radiochromic films. Specifically, models such as the 10000XL have been used successfully for image analysis and are recommended by ISP for dosimetry purposes. This note investigates and compares the scanner characteristics of three Epson desktop scanner models including the Epson 10000XL, V700, and V330. Both of the latter are substantially cheaper models capable of A4 scanning. As the price variation between the V330 and the 10000XL is 20‐fold (based on Australian recommended retail price), cost savings by using the cheaper scanners may be warranted based on results. By a direct comparison of scanner uniformity and reproducibility we can evaluate the accuracy of these scanners for radiochromic film dosimetry. Results have shown that all three scanners can produce adequate scanner uniformity and reproducibility, with the inexpensive V330 producing a standard deviation variation across its landscape direction of 0.7% and 1.2% in the portrait direction (reflection mode). This is compared to the V700 in reflection mode of 0.25% and 0.5% for landscape and portrait directions, respectively, and 0.5% and 0.8% for the 10000XL. In transmission mode, the V700 is comparable in reproducibility to the 10000XL for portrait and landscape mode, whilst the V330 is only capable of scanning in the landscape direction and produces a standard deviation in this direction of 1.0% compared to 0.6% (V700) and 0.25% (10000XL). Results have shown that the V700 and 10000XL are comparable scanners in quality and accuracy with the 10000XL obviously capable of imaging over an A3 area as opposed to an A4 area for the V700. The V330 scanner produced slightly lower accuracy and quality with uncertainties approximately twice as much as the other scanners. However, the results show that the V330 is still an adequate scanner and could be used for radiation dosimetry purposes. As such, if budgetary requirements are limited, the V700 scanner would be the recommended option at a price eight times cheaper than the 10000XL; however, the V330 produces adequate results at a price which is 2.5 times cheaper again. This may be a consideration for smaller institutions or individuals working with radiochromic film dosimetry. PACS number: 87.55.Qr; 87.56.Fc PMID:22955661

Comparison of Epson scanner quality for radiochromic film evaluation.

PubMed

Alnawaf, Hani; Yu, Peter K N; Butson, Martin

2012-09-06

Epson Desktop scanners have been quoted as devices which match the characteristics required for the evaluation of radiation dose exposure by radiochromic films. Specifically, models such as the 10000XL have been used successfully for image analysis and are recommended by ISP for dosimetry purposes. This note investigates and compares the scanner characteristics of three Epson desktop scanner models including the Epson 10000XL, V700, and V330. Both of the latter are substantially cheaper models capable of A4 scanning. As the price variation between the V330 and the 10000XL is 20-fold (based on Australian recommended retail price), cost savings by using the cheaper scanners may be warranted based on results. By a direct comparison of scanner uniformity and reproducibility we can evaluate the accuracy of these scanners for radiochromic film dosimetry. Results have shown that all three scanners can produce adequate scanner uniformity and reproducibility, with the inexpensive V330 producing a standard deviation variation across its landscape direction of 0.7% and 1.2% in the portrait direction (reflection mode). This is compared to the V700 in reflection mode of 0.25% and 0.5% for landscape and portrait directions, respectively, and 0.5% and 0.8% for the 10000XL. In transmission mode, the V700 is comparable in reproducibility to the 10000XL for portrait and landscape mode, whilst the V330 is only capable of scanning in the landscape direction and produces a standard deviation in this direction of 1.0% compared to 0.6% (V700) and 0.25% (10000XL). Results have shown that the V700 and 10000XL are comparable scanners in quality and accuracy with the 10000XL obviously capable of imaging over an A3 area as opposed to an A4 area for the V700. The V330 scanner produced slightly lower accuracy and quality with uncertainties approximately twice as much as the other scanners. However, the results show that the V330 is still an adequate scanner and could be used for radiation dosimetry purposes. As such, if budgetary requirements are limited, the V700 scanner would be the recommended option at a price eight times cheaper than the 10000XL; however, the V330 produces adequate results at a price which is 2.5 times cheaper again. This may be a consideration for smaller institutions or individuals working with radiochromic film dosimetry.

TH-CD-207B-12: Quantification of Clinical Feedback On Image Quality Differences Between Two CT Scanner Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bache, S; Liu, X; Loyer, E

Purpose: This work sought to quantify a radiology team’s assessment of image quality differences between two CT scanner models currently in clinical use, with emphasis on noise and low-contrast detectability (LCD). Methods: A water phantom and a Kagaku anthropomorphic body phantom were scanned on GE Discovery CT750 HD and LightSpeed VCT scanners (4 each) with identical scan parameters and reconstructed to 2.5mm/5.0mm thicknesses. Images of water phantom were analyzed at the scanner console with a built-in LCD tool that uses statistical methods to compute requisite CT-number contrast for 95% confidence in detection of a user-defined object size. LCD value wasmore » computed for 5mm, 3mm, and 1mm objects. Analysis of standard deviation and LCD values were performed on Kagaku phantom images within liver, stomach, and spleen. LCD value was computed for 4mm, 3mm, and 1mm objects using a benchmarked MATLAB implementation of the GE scanner-console tool. Results: Water LCD values were larger (poorer performance) for all HD scanners compared to VCT scanners. Mean scanner model difference in requisite CT-number contrast for 5mm, 3mm, and 1mm objects for 5.0mm/2.5mm images was 3.0%/3.4% (p=0.02/p=0.10), 5.3%/5.7% (0.00002/0.02), and 8.5%/8.2% (0.0004/0.002), respectively. Mean standard deviations within Kagaku phantom ROIs were greater in HD compared to VCT images, with mean differences for the liver, stomach, and spleen for 5.0mm/2.5mm of 16%/12% (p=0.04/0.10), 8%/12% (0.15/0.11), and 16%/15% (0.05/0.11), respectively. Mean LCD value difference between HD and VCT scanners over all ROIs for 4mm, 3m, and 1mm objects and 5.0mm/2.5mm was 34%/9%, 16%/8%, and 18%/10%, respectively. HD scanners outperformed VCT scanners only for the 4mm stomach object. Conclusion: Using both water and anthropomorphic phantoms, it was shown that HD scanners are outperformed by VCT scanners with respect to noise and LCD in a consistent and in most cases statistically significant manner. The relationship between statistical and clinical significance demands further work.« less

Integrated Electro-optical Laser-Beam Scanners

NASA Technical Reports Server (NTRS)

Boord, Warren T.

1990-01-01

Scanners using solid-state devices compact, consume little power, and have no moving parts. Integrated electro-optical laser scanner, in conjunction with external lens, points outgoing beam of light in any number of different directions, depending on number of upper electrodes. Offers beam-deflection angles larger than those of acousto-optic scanners. Proposed for such diverse applications as nonimpact laser printing, color imaging, ranging, barcode reading, and robotic vision.

Development of a 3D Brain PET Scanner Using CdTe Semiconductor Detectors and Its First Clinical Application

NASA Astrophysics Data System (ADS)

Morimoto, Y.; Ueno, Y.; Takeuchi, W.; Kojima, S.; Matsuzaki, K.; Ishitsu, T.; Umegaki, K.; Kiyanagi, Y.; Kubo, N.; Katoh, C.; Shiga, T.; Shirato, H.; Tamaki, N.

2011-10-01

Targeting improved spatial resolution, a three-dimensional positron-emission-tomography (PET) scanner employing CdTe semiconductor detectors and using depth-of-interaction (DOI) information was developed, and its physical performance was evaluated. This PET scanner is the first to use semiconductor detectors dedicated to the human brain and head-and-neck region. Imaging performance of the scanner used for 18F -fluorodeoxy glucose (FDG) scans of phantoms and human brains was evaluated. The gantry of the scanner has a 35.0-cm-diameter patient port, the trans-axial field of view (FOV) is 31.0 cm, and the axial FOV is 24.6 cm. The energy resolution averaged over all detector channels and timing resolution were 4.1% and 6.8 ns (each in FWHM), respectively. Spatial resolution measured at the center of FOV was 2.3-mm FWHM-which is one of the best resolutions achieved by human PET scanners. Noise-equivalent count ratio (NEC2R) has a maximum in the energy window of 390 to 540 keV and is 36 kcps/Bq/cm3 at 3.7 kBq/cm3 . The sensitivity of the system according to NEMA 1994 was 25.9 cps/Bq/cm3. Scatter fraction of the scanner is 37% for the energy window of 390 to 540 keV and 23% for 450 to 540 keV. Images of a hot-rod phantom and images of brain glucose metabolism show that the structural accuracy of the images obtained with the semiconductor PET scanner is higher than that possible with a conventional Bismuth Germanium Oxide (BGO) PET scanner. In addition, the developed scanner permits better delineation of the head-and-neck cancer. These results show that the semiconductor PET scanner will play a major role in the upcoming era of personalized medicine.

Automatic extraction of forward stroke volume using dynamic PET/CT: a dual-tracer and dual-scanner validation in patients with heart valve disease.

PubMed

Harms, Hendrik Johannes; Tolbod, Lars Poulsen; Hansson, Nils Henrik Stubkjær; Kero, Tanja; Orndahl, Lovisa Holm; Kim, Won Yong; Bjerner, Tomas; Bouchelouche, Kirsten; Wiggers, Henrik; Frøkiær, Jørgen; Sörensen, Jens

2015-12-01

The aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners. 35 subjects underwent a dynamic (11)C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic (15)O-water PET and (11)C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase-contrast cardiovascular magnetic resonance (CMR). FSVPET correlated highly with FSVCMR (r = 0.87, slope = 0.90 for scanner I, r = 0.87, slope = 1.65, and r = 0.85, slope = 1.69 for scanner II for (15)O-water and (11)C-acetate, respectively) although a systematic bias was observed for both scanners (p < 0.001 for all). FSV based on (11)C-acetate and (15)O-water correlated highly (r = 0.99, slope = 1.03) with no significant difference between FSV estimates (p = 0.14). FSV can be obtained automatically using dynamic PET/CT and cluster analysis. Results are almost identical for (11)C-acetate and (15)O-water. A scanner-dependent bias was observed, and a scanner calibration factor is required for multi-scanner studies. Generalization of the method to other tracers and scanners requires further validation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynch, Bart D.; Kozelka, Jakub; Ranade, Manisha K.

In this study, we present three significant artifacts that have the potential to negatively impact the accuracy and precision of film dosimetry measurements made using GAFCHROMIC[reg] EBT radiochromic film when read out with CCD flatbed scanners. Films were scanned using three commonly employed instruments: a Macbeth TD932 spot densitometer, an Epson Expression 1680 CCD array scanner, and a Microtek ScanMaker i900 CCD array scanner. For the two scanners we assessed the variation in optical density (OD) of GAFCHROMIC EBT film with scanning bed position, angular rotation of the film with respect to the scan line direction, and temperature inside themore » scanner due to repeated scanning. Scanning uniform radiochromic films demonstrated a distinct bowing effect in profiles in the direction of the CCD array with a nonuniformity of up to 17%. Profiles along a direction orthogonal to the CCD array demonstrated a 7% variation. A strong angular dependence was found in measurements made with the flatbed scanners; the effect could not be reproduced with the spot densitometer. An IMRT quality assurance film was scanned twice rotating the film 90 deg. between the scans. For films scanned on the Epson scanner, up to 12% variation was observed in unirradiated EBT films rotated between 0 deg. and 90 deg. , which decreased to approximately 8% for EBT films irradiated to 300 cGy. Variations of up to 80% were observed for films scanned with the Microtek scanner. The scanners were found to significantly increase the film temperature with repeated scanning. Film temperature between 18 and 33 deg. C caused OD changes of approximately 7%. Considering these effects, we recommend adherence to a strict scanning protocol that includes: maintaining the orientation of films scanned on flatbed scanners, limiting scanning to the central portion of the scanner bed, and limiting the number of consecutive scans to minimize changes in OD caused by film heating.« less

Dynamics of thin-film piezoelectric microactuators with large vertical stroke subject to multi-axis coupling and fabrication asymmetries

NASA Astrophysics Data System (ADS)

Choi, Jongsoo; Wang, Thomas; Oldham, Kenn

2018-01-01

The high performance and small size of MEMS based scanners has allowed various optical imaging techniques to be realized in a small form factor. Many such devices are resonant scanners, and thus their linear and nonlinear dynamic behaviors have been studied in the past. Thin-film piezoelectric materials, in contrast, provide sufficient energy density to achieve both large static displacements and high-frequency resonance, but large deformation can in turn influence dynamic scanner behavior. This paper reports on the influence of very large stroke translation of a piezoelectric vertical actuator on its resonant behavior, which may not be otherwise explained fully by common causes of resonance shift such as beam stiffening or nonlinear forcing. To examine the change of structural compliance over the course of scanner motion, a model has been developed that includes internal forces from residual stress and the resultant additional multi-axis coupling among actuator leg structures. Like some preceding vertical scanning micro-actuators, the scanner of this work has four legs, with each leg featuring four serially connected thin-film PZT unimorphs that allow the scanner to generate larger than 400 µm of vertical displacement at 14 V DC. Using an excitation near one or more resonances, the input voltage can be lowered, and complementary multi-axis rotations can be also generated, but change of the resonant frequencies with scanner height needs to be understood to maximize scanner performance. The presented model well predicts the experimental observation of the decrease of the resonant frequencies of the scanner with the increase of a dc bias voltage. Also, the effects of the magnitude and uniformity of residual stress across the scanner structure on the natural frequencies have been studied.

Computer-aided analysis of digital dental impressions obtained from intraoral and extraoral scanners.

PubMed

Bohner, Lauren Oliveira Lima; De Luca Canto, Graziela; Marció, Bruno Silva; Laganá, Dalva Cruz; Sesma, Newton; Tortamano Neto, Pedro

2017-11-01

The internal and marginal adaptation of a computer-aided design and computer-aided manufacturing (CAD-CAM) prosthesis relies on the quality of the 3-dimensional image. The quality of imaging systems requires evaluation. The purpose of this in vitro study was to evaluate and compare the trueness of intraoral and extraoral scanners in scanning prepared teeth. Ten acrylic resin teeth to be used as a reference dataset were prepared according to standard guidelines and scanned with an industrial computed tomography system. Data were acquired with 4 scanner devices (n=10): the Trios intraoral scanner (TIS), the D250 extraoral scanner (DES), the Cerec Bluecam intraoral scanner (CBIS), and the Cerec InEosX5 extraoral scanner (CIES). For intraoral scanners, each tooth was digitized individually. Extraoral scanning was obtained from dental casts of each prepared tooth. The discrepancy between each scan and its respective reference model was obtained by deviation analysis (μm) and volume/area difference (μm). Statistical analysis was performed using linear models for repeated measurement factors test and 1-way ANOVA (α=.05). No significant differences in deviation values were found among scanners. For CBIS and CIES, the deviation was significantly higher (P<.05) for occlusal and cervical surfaces. With regard to volume differences, no statistically significant differences were found (TIS=340 ±230 μm; DES=380 ±360 μm; CBIS=780 ±770 μm; CIES=340 ±300 μm). Intraoral and extraoral scanners showed similar trueness in scanning prepared teeth. Higher discrepancies are expected to occur in the cervical region and on the occlusal surface. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method.

PubMed

Hara, Takanori; Urikura, Atsushi; Ichikawa, Katsuhiro; Hoshino, Takashi; Nishimaru, Eiji; Niwa, Shinji

2016-04-01

To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of <1.0 was almost equal to the gantry rotation time, whereas with pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/P=0.285/1.5) and 0.074s (R/P=0.285/3.2), and the maximum TR values of the 64×0.5- and 160×0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/P=0.275/1.375) and 0.195s (R/P=0.3/0.6), respectively. Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Enter Words and Pictures the Easy Way--Scan Them.

ERIC Educational Resources Information Center

Olivas, Jerry

1989-01-01

Discusses image scanning and optical character recognition. Describes how computer scanners work. Summarizes scan quality, scanning speed requirements, and hardware requirements for scanners. Surveys the range of scanners currently available. (MVL)

33. SITE BUILDING 002 SCANNER BUILDING MECHANICAL ROOM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. SITE BUILDING 002 - SCANNER BUILDING - MECHANICAL ROOM 105, VIEW OF CHILLER ROOM MOTOR CONTROL CENTER. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

NS001MS - Landsat-D thematic mapper band aircraft scanner

NASA Technical Reports Server (NTRS)

Richard, R. R.; Merkel, R. F.; Meeks, G. R.

1978-01-01

The thematic mapper is a multispectral scanner which will be launched aboard Landsat-D in the early 1980s. Compared with previous Landsat scanners, this instrument will have an improved spatial resolution (30 m) and new spectral bands. Designated NS001MS, the scanner is designed to duplicate the thematic mapper spectral bands plus two additional bands (1.0 to 1.3 microns and 2.08 to 2.35 microns) in an aircraft scanner for evaluation and investigation prior to design and launch of the final thematic mapper. Applicable specifications used in defining the thematic mapper were retained in the NS001MS design, primarily with respect to spectral bandwidths, noise equivalent reflectance, and noise equivalent difference temperature. The technical design and operational characteristics of the multispectral scanner (with thematic mapper bands) are discussed.

Quantitative quality assurance in a multicenter HARDI clinical trial at 3T.

PubMed

Zhou, Xiaopeng; Sakaie, Ken E; Debbins, Josef P; Kirsch, John E; Tatsuoka, Curtis; Fox, Robert J; Lowe, Mark J

2017-01-01

A phantom-based quality assurance (QA) protocol was developed for a multicenter clinical trial including high angular resolution diffusion imaging (HARDI). A total of 27 3T MR scanners from 2 major manufacturers, GE (Discovery and Signa scanners) and Siemens (Trio and Skyra scanners), were included in this trial. With this protocol, agar phantoms doped to mimic relaxation properties of brain tissue are scanned on a monthly basis, and quantitative procedures are used to detect spiking and to evaluate eddy current and Nyquist ghosting artifacts. In this study, simulations were used to determine alarm thresholds for minimal acceptable signal-to-noise ratio (SNR). Our results showed that spiking artifact was the most frequently observed type of artifact. Overall, Trio scanners exhibited less eddy current distortion than GE scanners, which in turn showed less distortion than Skyra scanners. This difference was mainly caused by the different sequences used on these scanners. The SNR for phantom scans was closely correlated with the SNR from volunteers. Nearly all of the phantom measurements with artifact-free images were above the alarm threshold, suggesting that the scanners are stable longitudinally. Software upgrades and hardware replacement sometimes affected SNR substantially but sometimes did not. In light of these results, it is important to monitor longitudinal SNR with phantom QA to help interpret potential effects on in vivo measurements. Our phantom QA procedure for HARDI scans was successful in tracking scanner performance and detecting unwanted artifacts. Copyright © 2016 Elsevier Inc. All rights reserved.

Data-driven CT protocol review and management—experience from a large academic hospital.

PubMed

Zhang, Da; Savage, Cristy A; Li, Xinhua; Liu, Bob

2015-03-01

Protocol review plays a critical role in CT quality assurance, but large numbers of protocols and inconsistent protocol names on scanners and in exam records make thorough protocol review formidable. In this investigation, we report on a data-driven cataloging process that can be used to assist in the reviewing and management of CT protocols. We collected lists of scanner protocols, as well as 18 months of recent exam records, for 10 clinical scanners. We developed computer algorithms to automatically deconstruct the protocol names on the scanner and in the exam records into core names and descriptive components. Based on the core names, we were able to group the scanner protocols into a much smaller set of "core protocols," and to easily link exam records with the scanner protocols. We calculated the percentage of usage for each core protocol, from which the most heavily used protocols were identified. From the percentage-of-usage data, we found that, on average, 18, 33, and 49 core protocols per scanner covered 80%, 90%, and 95%, respectively, of all exams. These numbers are one order of magnitude smaller than the typical numbers of protocols that are loaded on a scanner (200-300, as reported in the literature). Duplicated, outdated, and rarely used protocols on the scanners were easily pinpointed in the cataloging process. The data-driven cataloging process can facilitate the task of protocol review. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Quantitative Quality Assurance in a Multicenter HARDI Clinical Trial at 3T

PubMed Central

Zhou, Xiaopeng; Sakaie, Ken E.; Debbins, Josef P.; Kirsch, John E.; Tatsuoka, Curtis; Fox, Robert J.; Lowe, Mark J.

2016-01-01

A phantom-based quality assurance (QA) protocol was developed for a multicenter clinical trial including high angular resolution diffusion imaging (HARDI). A total of 27 3T MR scanners from 2 major manufacturers, GE (Discovery and Signa scanners) and Siemens (Trio and Skyra scanners), were included in this trial. With this protocol, agar phantoms doped to mimic relaxation properties of brain tissue are scanned on a monthly basis, and quantitative procedures are used to detect spiking and to evaluate eddy current and Nyquist ghosting artifacts. In this study, simulations were used to determine alarm thresholds for minimal acceptable signal-to-noise ratio (SNR). Our results showed that spiking artifact was the most frequently observed type of artifact. Overall, Trio scanners exhibited less eddy current distortion than GE scanners, which in turn showed less distortion than Skyra scanners. This difference was mainly caused by the different sequences used on these scanners. The SNR for phantom scans was closely correlated with the SNR from volunteers. Nearly all of the phantom measurements with artifact-free images were above the alarm threshold, suggesting that the scanners are stable longitudinally. Software upgrades and hardware replacement sometimes affected SNR substantially but sometimes did not. In light of these results, it is important to monitor longitudinal SNR with phantom QA to help interpret potential effects on in vivo measurements. Our phantom QA procedure for HARDI scans was successful in tracking scanner performance and detecting unwanted artifacts. PMID:27587227

Computer-aided analysis of Skylab multispectral scanner data in mountainous terrain for land use, forestry, water resource, and geologic applications

NASA Technical Reports Server (NTRS)

Hoffer, R. M. (Principal Investigator)

1975-01-01

The author has identified the following significant results. One of the most significant results of this Skylab research involved the geometric correction and overlay of the Skylab multispectral scanner data with the LANDSAT multispectral scanner data, and also with a set of topographic data, including elevation, slope, and aspect. The Skylab S192 multispectral scanner data had distinct differences in noise level of the data in the various wavelength bands. Results of the temporal evaluation of the SL-2 and SL-3 photography were found to be particularly important for proper interpretation of the computer-aided analysis of the SL-2 and SL-3 multispectral scanner data. There was a quality problem involving the ringing effect introduced by digital filtering. The modified clustering technique was found valuable when working with multispectral scanner data involving many wavelength bands and covering large geographic areas. Analysis of the SL-2 scanner data involved classification of major cover types and also forest cover types. Comparison of the results obtained wth Skylab MSS data and LANDSAT MSS data indicated that the improved spectral resolution of the Skylab scanner system enabled a higher classification accuracy to be obtained for forest cover types, although the classification performance for major cover types was not significantly different.

Relationships between patient size, dose and image noise under automatic tube current modulation systems.

PubMed

Sookpeng, S; Martin, C J; Gentle, D J; Lopez-Gonzalez, M R

2014-03-01

Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles of ATCM operation are different in CT scanners from different manufacturers. Toshiba and GE scanners base the current modulation on a target noise setting, while Philips and Siemens scanners use reference image and reference mAs concepts respectively. Knowledge of the relationships between patient size, dose and image noise are important for CT patient dose optimisation. In this study, the CT patient doses were surveyed for 14 CT scanners from four different CT scanner manufacturers. The patient cross sectional area, the tube current modulation and the image noise from the CT images were analysed using in-house software. The Toshiba and GE scanner results showed that noise levels are relatively constant but tube currents are dependent on patient size. As a result of this there is a wide range in tube current values across different patient sizes, and doses for large patients are significantly higher in these scanners. In contrast, in the Philips and Siemens scanners, tube currents are less dependent on patient size, the range in tube current is narrower, and the doses for larger patients are not as high. Image noise is more dependent on the patient size.

Comparison of working efficiency of terrestrial laser scanner in day and night conditions

NASA Astrophysics Data System (ADS)

Arslan, A. E.; Kalkan, K.

2013-10-01

Terrestrial Laser Scanning is a popular and widely used technique to scan existing objects, document historical sites and items, and remodel them if and when needed. Their ability to collect thousands of point data per second makes them an invaluable tool in many areas from engineering to historical reconstruction. There are many scanners in the market with different technical specifications. One main technical specification of laser scanners is range and illumination. In this study, it is tested to be determined the optimal working times of a laser scanner and the scanners consistency with its specifications sheet. In order to conduct this work, series of GNSS measurements in Istanbul Technical University have been carried out, connected to the national reference network, to determine precise positions of target points and the scanner, which makes possible to define a precise distance between the scanner and targets. Those ground surveys has been used for calibration and registration purposes. Two different scan campaigns conducted at 12 am and 11 pm to compare working efficiency of laser scanner in different illumination conditions and targets are measured with a handheld spectro-radiometer in order to determine their reflective characteristics. The obtained results are compared and their accuracies have been analysed.

An operational multispectral scanner for bathymetric surveys - The ABS NORDA scanner

NASA Technical Reports Server (NTRS)

Haimbach, Stephen P.; Joy, Richard T.; Hickman, G. Daniel

1987-01-01

The Naval Ocean Research and Development Activity (NORDA) is developing the Airborne Bathymetric Survey (ABS) system, which will take shallow water depth soundings from a Navy P-3 aircraft. The system combines active and passive sensors to obtain optical measurements of water depth. The ABS NORDA Scanner is the systems passive multispectral scanner whose design goal is to provide 100 percent coverage of the seafloor, to depths of 20 m in average coastal waters. The ABS NORDA Scanner hardware and operational environment is discussed in detail. The optical model providing the basis for depth extraction is reviewed and the proposed data processing routine discussed.

18. SITE BUILDING 002 SCANNER BUILDING VIEW OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. SITE BUILDING 002 - SCANNER BUILDING - VIEW OF SITE SECURITY OFFICE ACCESS DOOR FROM EXTERIOR OF OFFICE. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

24. SITE BUILDING 002 SCANNER BUILDING OPERATIONS CENTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. SITE BUILDING 002 - SCANNER BUILDING - OPERATIONS CENTER -- MWOC IN OPEARATION AT 1924 ZULU TIME. 26 OCTOBER, 1999. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Evaluation of scattered radiation emitted from X-ray security scanners on occupational dose to airport personnel

NASA Astrophysics Data System (ADS)

Dalah, Entesar; Fakhry, Angham; Mukhtar, Asma; Al Salti, Farah; Bader, May; Khouri, Sara; Al-Zahmi, Reem

2017-06-01

Based on security issues and regulations airports are provided with luggage cargo scanners. These scanners utilize ionizing radiation that in principle present health risks toward humans. The study aims to investigate the amount of backscatter produced by passenger luggage and cargo toward airport personnel who are located at different distances from the scanners. To approach our investigation a Thermo Electron Radeye-G probe was used to quantify the backscattered radiation measured in terms of dose-rate emitted from airport scanners, Measurements were taken at the entrance and exit positions of the X-ray tunnel at three different distances (0, 50, and 100 cm) for two different scanners; both scanners include shielding curtains that reduce scattered radiation. Correlation was demonstrated using the Pearson coefficient test. Measurements confirmed an inverse relationship between dose rate and distance. An estimated occupational accumulative dose of 0.88 mSv/y, and 2.04 mSv/y were obtained for personnel working in inspection of carry-on, and cargo, respectively. Findings confirm that the projected dose of security and engineering staff are being well within dose limits.

Reprint of 'Evaluation of Scattered Radiation Emitted From X-ray Security Scanners on Occupational Dose to Airport Personnel'

NASA Astrophysics Data System (ADS)

Dalah, Entesar; Fakhry, Angham; Mukhtar, Asma; Al Salti, Farah; Bader, May; Khouri, Sara; Al-Zahmi, Reem

2017-11-01

Based on security issues and regulations airports are provided with luggage cargo scanners. These scanners utilize ionizing radiation that in principle present health risks toward humans. The study aims to investigate the amount of backscatter produced by passenger luggage and cargo toward airport personnel who are located at different distances from the scanners. To approach our investigation a Thermo Electron Radeye-G probe was used to quantify the backscattered radiation measured in terms of dose-rate emitted from airport scanners, Measurements were taken at the entrance and exit positions of the X-ray tunnel at three different distances (0, 50, and 100 cm) for two different scanners; both scanners include shielding curtains that reduce scattered radiation. Correlation was demonstrated using the Pearson coefficient test. Measurements confirmed an inverse relationship between dose rate and distance. An estimated occupational accumulative dose of 0.88 mSv/y, and 2.04 mSv/y were obtained for personnel working in inspection of carry-on, and cargo, respectively. Findings confirm that the projected dose of security and engineering staff are being well within dose limits.

2. SITE BUILDING 002 SCANNER BUILDING VIEW IS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. SITE BUILDING 002 - SCANNER BUILDING - VIEW IS LOOKING NORTH 80° WEST "B" FACE ALONG BUILDING "A" FACE. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

23. SITE BUILDING 002 SCANNER BUILDING RADAR CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. SITE BUILDING 002 - SCANNER BUILDING - RADAR CONTROL INTERFACE "RCL NO. 2" WITH COMPUTER CONTROL DISC DRIVE UNITS IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Evaluation of Scanners for C-Scan Imaging for Nondestructive Inspection of Aircraft

DTIC Science & Technology

1994-09-01

mechanized and nonmechanized designs. * The basic scanner designs were divided for the purposes of this report into eight different Stypes. These are 1...electronic switching through the transducer elements of the array. The basic scanner designs were divided for the purposes of this report into eight...of this project was to evaluate all the basic scanner types that are appropriate for aircraft NDI examinations. A number of vendors sell very similar

Galileo spacecraft autonomous attitude determination using a V-slit star scanner

NASA Technical Reports Server (NTRS)

Mobasser, Sohrab; Lin, Shuh-Ren

1991-01-01

The autonomous attitude determination system of Galileo spacecraft, consisting of a radiation hardened star scanner and a processing algorithm is presented. The algorithm applying to this system are the sequential star identification and attitude estimation. The star scanner model is reviewed in detail and the flight software parameters that must be updated frequently during flight, due to degradation of the scanner response and the star background change are identified.

Determining density of maize canopy. 3: Temporal considerations

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F.; Anuta, P. E.; Cipra, J. E.

1972-01-01

Multispectral scanner data were collected in two flights over ground cover plots at an altitude of 305 m. Eight ground reflectance panels in close proximity to the ground cover plots were used to normalize the scanner data obtained on different dates. Separate prediction equations were obtained for both flight dates for all eleven reflective wavelength bands of the multispectral scanner. Ratios of normalized scanner data were related to leaf area index over time. Normalized scanner data were used to plot relative reflectance versus wavelength for the ground cover plots. Spectral response curves were similar to those for bare soil and green vegetation as determined by laboratory measurements. The spectral response curves from the normalized scanner data indicated that reflectance in the 0.72 to 1.3 micron wavelength range increased as leaf area index increased. A decrease in reflectance was observed in the 0.65 micron chlorophyll absorption band as leaf area index increased.

The response of the Seasat and Magsat infrared horizon scanners to cold clouds

NASA Technical Reports Server (NTRS)

Bilanow, S.; Phenneger, M.

1980-01-01

Cold clouds over the Earth are shown to be the principal cause of pitch and roll measurement noise in flight data from the infrared horizon scanners onboard Seasat and Magsat. The observed effects of clouds on the fixed threshold horizon detection logic of the Magsat scanner and on the variable threshold detection logic of the Seasat scanner are discussed. National Oceanic and Atmospheric Administration (NOAA) Earth photographs marked with the scanner ground trace clearly confirm the relationship between measurement errors and Earth clouds. A one to one correspondence can be seen between excursion in the pitch and roll data and cloud crossings. The characteristics of the cloud-induced noise are discussed, and the response of the satellite control systems to the cloud errors is described. Changes to the horizon scanner designs that would reduce the effects of clouds are noted.

High-speed two-dimensional laser scanner based on Bragg gratings stored in photothermorefractive glass.

PubMed

Yaqoob, Zahid; Arain, Muzammil A; Riza, Nabeel A

2003-09-10

A high-speed free-space wavelength-multiplexed optical scanner with high-speed wavelength selection coupled with narrowband volume Bragg gratings stored in photothermorefractive (PTR) glass is reported. The proposed scanner with no moving parts has a modular design with a wide angular scan range, accurate beam pointing, low scanner insertion loss, and two-dimensional beam scan capabilities. We present a complete analysis and design procedure for storing multiple tilted Bragg-grating structures in a single PTR glass volume (for normal incidence) in an optimal fashion. Because the scanner design is modular, many PTR glass volumes (each having multiple tilted Bragg-grating structures) can be stacked together, providing an efficient throughput with operations in both the visible and the infrared (IR) regions. A proof-of-concept experimental study is conducted with four Bragg gratings in independent PTR glass plates, and both visible and IR region scanner operations are demonstrated.

Quantitative PET/CT scanner performance characterization based upon the society of nuclear medicine and molecular imaging clinical trials network oncology clinical simulator phantom.

PubMed

Sunderland, John J; Christian, Paul E

2015-01-01

The Clinical Trials Network (CTN) of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) operates a PET/CT phantom imaging program using the CTN's oncology clinical simulator phantom, designed to validate scanners at sites that wish to participate in oncology clinical trials. Since its inception in 2008, the CTN has collected 406 well-characterized phantom datasets from 237 scanners at 170 imaging sites covering the spectrum of commercially available PET/CT systems. The combined and collated phantom data describe a global profile of quantitative performance and variability of PET/CT data used in both clinical practice and clinical trials. Individual sites filled and imaged the CTN oncology PET phantom according to detailed instructions. Standard clinical reconstructions were requested and submitted. The phantom itself contains uniform regions suitable for scanner calibration assessment, lung fields, and 6 hot spheric lesions with diameters ranging from 7 to 20 mm at a 4:1 contrast ratio with primary background. The CTN Phantom Imaging Core evaluated the quality of the phantom fill and imaging and measured background standardized uptake values to assess scanner calibration and maximum standardized uptake values of all 6 lesions to review quantitative performance. Scanner make-and-model-specific measurements were pooled and then subdivided by reconstruction to create scanner-specific quantitative profiles. Different makes and models of scanners predictably demonstrated different quantitative performance profiles including, in some cases, small calibration bias. Differences in site-specific reconstruction parameters increased the quantitative variability among similar scanners, with postreconstruction smoothing filters being the most influential parameter. Quantitative assessment of this intrascanner variability over this large collection of phantom data gives, for the first time, estimates of reconstruction variance introduced into trials from allowing trial sites to use their preferred reconstruction methodologies. Predictably, time-of-flight-enabled scanners exhibited less size-based partial-volume bias than non-time-of-flight scanners. The CTN scanner validation experience over the past 5 y has generated a rich, well-curated phantom dataset from which PET/CT make-and-model and reconstruction-dependent quantitative behaviors were characterized for the purposes of understanding and estimating scanner-based variances in clinical trials. These results should make it possible to identify and recommend make-and-model-specific reconstruction strategies to minimize measurement variability in cancer clinical trials. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Feasibility of Clinician-Facilitated Three-Dimensional Printing of Synthetic Cranioplasty Flaps.

PubMed

Panesar, Sandip S; Belo, Joao Tiago A; D'Souza, Rhett N

2018-05-01

Integration of three-dimensional (3D) printing and stereolithography into clinical practice is in its nascence, and concepts may be esoteric to the practicing neurosurgeon. Currently, creation of 3D printed implants involves recruitment of offsite third parties. We explored a range of 3D scanning and stereolithographic techniques to create patient-specific synthetic implants using an onsite, clinician-facilitated approach. We simulated bilateral craniectomies in a single cadaveric specimen. We devised 3 methods of creating stereolithographically viable virtual models from removed bone. First, we used preoperative and postoperative computed tomography scanner-derived bony window models from which the flap was extracted. Second, we used an entry-level 3D light scanner to scan and render models of the individual bone pieces. Third, we used an arm-mounted, 3D laser scanner to create virtual models using a real-time approach. Flaps were printed from the computed tomography scanner and laser scanner models only in a ultraviolet-cured polymer. The light scanner did not produce suitable virtual models for printing. The computed tomography scanner-derived models required extensive postfabrication modification to fit the existing defects. The laser scanner models assumed good fit within the defects without any modification. The methods presented varying levels of complexity in acquisition and model rendering. Each technique required hardware at varying in price points from $0 to approximately $100,000. The laser scanner models produced the best quality parts, which had near-perfect fit with the original defects. Potential neurosurgical applications of this technology are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Measuring temporal stability of positron emission tomography standardized uptake value bias using long-lived sources in a multicenter network.

PubMed

Byrd, Darrin; Christopfel, Rebecca; Arabasz, Grae; Catana, Ciprian; Karp, Joel; Lodge, Martin A; Laymon, Charles; Moros, Eduardo G; Budzevich, Mikalai; Nehmeh, Sadek; Scheuermann, Joshua; Sunderland, John; Zhang, Jun; Kinahan, Paul

2018-01-01

Positron emission tomography (PET) is a quantitative imaging modality, but the computation of standardized uptake values (SUVs) requires several instruments to be correctly calibrated. Variability in the calibration process may lead to unreliable quantitation. Sealed source kits containing traceable amounts of [Formula: see text] were used to measure signal stability for 19 PET scanners at nine hospitals in the National Cancer Institute's Quantitative Imaging Network. Repeated measurements of the sources were performed on PET scanners and in dose calibrators. The measured scanner and dose calibrator signal biases were used to compute the bias in SUVs at multiple time points for each site over a 14-month period. Estimation of absolute SUV accuracy was confounded by bias from the solid phantoms' physical properties. On average, the intrascanner coefficient of variation for SUV measurements was 3.5%. Over the entire length of the study, single-scanner SUV values varied over a range of 11%. Dose calibrator bias was not correlated with scanner bias. Calibration factors from the image metadata were nearly as variable as scanner signal, and were correlated with signal for many scanners. SUVs often showed low intrascanner variability between successive measurements but were also prone to shifts in apparent bias, possibly in part due to scanner recalibrations that are part of regular scanner quality control. Biases of key factors in the computation of SUVs were not correlated and their temporal variations did not cancel out of the computation. Long-lived sources and image metadata may provide a check on the recalibration process.

Planning guidelines for computerized transaxial tomography (CT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-11-23

Guidelines to assist local communities in review and decisionmaking related to computerized tomography (CT) 'head' and 'whole body' scanner needs and placement are presented. Although medical benefits for head scanning are well established, the proper role of whole body scanning in relation to other diagnostic procedures has not been determined. It is recommended that a 20 percent weighted consideration could be given to a potential CT scanner applicant's present capabilities in diagnostic 'body' work. The following guidelines for CT are recommended for use in assessing work qualifications of potential CT scanner applicants: (1) The facility must have an active neurosurgicalmore » service, with a geographically full-time board - certified neurosurgeon and at least 50 intracranial procedures performed annually. (2) The facility must have an active neurological service, with a geographically full-time board - certified neurologist. (3) The facility must have on staff a qualified neuroradiologist. It is recommended that the CT scanner utilization level be a minimum of 3,000 examinations per year per unit of new equipment. The applicant must submit financial data and must be committed to providing care to all patients, independent of ability to pay. The applicant must submit letters from area hospitals agreeing to utilize the scanner services. Additional criteria are given for body scanning work and for the number of scanners in a specific area. Detailed information is presented about scanner development and use in southeastern Pennsylvania and neighboring planning areas, and the cost of scanner operations is compared with revenues. The CT scanner committee membership is included.« less

Linear terrestrial laser scanning using array avalanche photodiodes as detectors for rapid three-dimensional imaging.

PubMed

Cai, Yinqiao; Tong, Xiaohua; Tong, Peng; Bu, Hongyi; Shu, Rong

2010-12-01

As an active remote sensor technology, the terrestrial laser scanner is widely used for direct generation of a three-dimensional (3D) image of an object in the fields of geodesy, surveying, and photogrammetry. In this article, a new laser scanner using array avalanche photodiodes, as designed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, is introduced for rapid collection of 3D data. The system structure of the new laser scanner is first presented, and a mathematical model is further derived to transform the original data to the 3D coordinates of the object in a user-defined coordinate system. The performance of the new laser scanner is tested through a comprehensive experiment. The result shows that the new laser scanner can scan a scene with a field view of 30° × 30° in 0.2 s and that, with respect to the point clouds obtained on the wall and ground floor surfaces, the root mean square errors for fitting the two planes are 0.21 and 0.01 cm, respectively. The primary advantages of the developed laser scanner include: (i) with a line scanning mode, the new scanner achieves simultaneously the 3D coordinates of 24 points per single laser pulse, which enables it to scan faster than traditional scanners with a point scanning mode and (ii) the new scanner makes use of two galvanometric mirrors to deflect the laser beam in both the horizontal and the vertical directions. This capability makes the instrument smaller and lighter, which is more acceptable for users.

Investigation of a Dedicated, High Resolution PET/CT Scanner for Staging and Treatment Planning of Head and Neck Cancer

NASA Astrophysics Data System (ADS)

Raylman, Raymond R.; Stolin, Alexander V.; Sompalli, Prashanth; Randall, Nicole Bunda; Martone, Peter F.; Clinthorne, Neal H.

2015-10-01

Staging of head and neck cancer (HNC) is often hindered by the limited resolution of standard whole body PET scanners, which can make it challenging to detect small areas of metastatic disease in regional lymph nodes and accurately delineate tumor boundaries. In this investigation, the performance of a proposed high resolution PET/CT scanner designed specifically for imaging of the head and neck region was explored. The goal is to create a dedicated PET/CT system that will enhance the staging and treatment of HNCs. Its performance was assessed by simulating the scanning of a three-dimensional Rose-Burger contrast phantom. To extend the results from the simulation studies, an existing scanner with a similar geometry to the dedicated system and a whole body, clinical PET/CT scanner were used to image a Rose-Burger contrast phantom and a phantom simulating the neck of an HNC patient (out-of-field-of-view sources of activity were not included). Images of the contrast detail phantom acquired with Breast-PET/CT and simulated head and neck scanner both produced object contrasts larger than the images created by the clinical scanner. Images of a neck phantom acquired with the Breast-PET/CT scanner permitted the identification of all of the simulated metastases, while it was not possible to identify any of the simulated metastasis with the clinical scanner. The initial results from this study demonstrate the potential benefits of high-resolution PET systems for improving the diagnosis and treatment of HNC.

Experimental evaluation of ballistic hazards in imaging diagnostic center.

PubMed

Karpowicz, Jolanta; Gryz, Krzysztof

2013-04-01

Serious hazards for human health and life and devices in close proximity to the magnetic resonance scanners (MRI scanners) include the effects of being hit by ferromagnetic objects attracted by static magnetic field (SMF) produced by scanner magnet - the so-called ballistic hazards classified among indirect electromagnetic hazards. International safety guidelines and technical literature specify different SMF threshold values regarding ballistic hazards - e.g. 3 mT (directive 2004/40/EC, EN 60601-2-33), and 30 mT (BMAS 2009, directive proposal 2011). Investigations presented in this article were performed in order to experimentally verify SMF threshold for ballistic hazards near MRI scanners used in Poland. Investigations were performed with the use of a laboratory source of SMF (0-30 mT) and MRI scanners of various types. The levels of SMF in which metal objects of various shapes and 0.4-500 g mass are moved by the field influence were investigated. The distance from the MRI scanners (0.2-3T) where hazards may occur were also investigated. Objects investigated under laboratory conditions were moved by SMF of 2.2-15 mT magnetic flux density when they were freely suspended, but were moved by the SMF of 5.6-22 mT when they were placed on a smooth surface. Investigated objects were moved in fields of 3.5-40 mT by MRI scanners. Distances from scanner magnet cover, where ballistic hazards might occur are: up to 0.5 m for 0.2-0.3T scanners; up to 1.3 m for 0.5T scanners; up to 2.0 m for 1.5T scanners and up to 2.5 m for 3T scanners (at the front and back of the magnet). It was shown that SMF of 3 mT magnetic flux density should be taken as the threshold for ballistic hazards. Such level is compatible with SMF limit value regarding occupational safety and health-protected areas/zones, where according to the Polish labor law the procedures of work environment inspection and prevention measures regarding indirect electromagnetic hazards should be applied. Presented results do not support the increase up to 30 mT of the SMF limit for protected area.

Thermal Infrared Multispectral Scanner (TIMS): An investigator's guide to TIMS data

NASA Technical Reports Server (NTRS)

Palluconi, F. D.; Meeks, G. R.

1985-01-01

The Thermal Infrared Multispectral Scanner (TIMS) is a NASA aircraft scanner providing six channel spectral capability in the thermal infrared region of the electromagnetic spectrum. Operating in the atmospheric window region (8 to 12 micrometers) with a channel sensitivity of approximately 0.1 C, TIMS may be used whenever an accurate measure of the Earth's surface is needed. A description of this scanner is provided as well as a discussion of data acquisition and reduction.

52. View from ground level showing lower radar scanner switch ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

52. View from ground level showing lower radar scanner switch with open port door in radar scanner building 105 showing emanating waveguides from lower switch in vertical run; photograph also shows catwalk to upper scanner switch in upper left side of photograph and structural supports. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

The TT-PET project: a thin TOF-PET scanner based on fast novel silicon pixel detectors

NASA Astrophysics Data System (ADS)

Bandi, Y.; Benoit, M.; Cadoux, F. R.; Forshaw, D. C.; Hänni, R.; Hayakawa, D.; Iacobucci, G.; Michal, S.; Miucci, A.; Paolozzi, L.; Ratib, O.; Ripiccini, E.; Tognina, C.; Valerio, P.; Weber, M.

2018-01-01

The TT-PET project aims at developing a compact Time-of-flight PET scanner with 30ps time resolution, capable of withstanding high magnetic fields and allowing for integration in a traditional MRI scanner, providing complimentary real-time PET images. The very high timing resolution of the TT-PET scanner is achieved thanks to a new generation of Silicon-Germanium (Si-Ge) amplifiers, which are embedded in monolithic pixel sensors. The scanner is composed of 16 detection towers as well as cooling blocks, arranged in a ring structure. The towers are composed of multiple ultra-thin pixel modules stacked on top of each other. Making it possible to perform depth of interaction measurements and maximize the spatial resolution along the line of flight of the two photons emitted within a patient. This will result in improved image quality, contrast, and uniformity while drastically reducing backgrounds within the scanner. Allowing for a reduction in the amount of radioactivity delivered to the patient. Due to an expected data rate of about 250 MB/s a custom readout system for high data throughput has been developed, which includes noise filtering and reduced data pressure. The realisation of a first scanner prototype for small animals is foreseen by 2019. A general overview of the scanner will be given including, technical details concerning the detection elements, mechanics, DAQ readout, simulation and results.

A combined positron emission tomography (PET)-electron paramagnetic resonance imaging (EPRI) system: initial evaluation of a prototype scanner

NASA Astrophysics Data System (ADS)

Tseytlin, Mark; Stolin, Alexander V.; Guggilapu, Priyaankadevi; Bobko, Andrey A.; Khramtsov, Valery V.; Tseytlin, Oxana; Raylman, Raymond R.

2018-05-01

The advent of hybrid scanners, combining complementary modalities, has revolutionized the application of advanced imaging technology to clinical practice and biomedical research. In this project, we investigated the melding of two complementary, functional imaging methods: positron emission tomography (PET) and electron paramagnetic resonance imaging (EPRI). PET radiotracers can provide important information about cellular parameters, such as glucose metabolism. While EPR probes can provide assessment of tissue microenvironment, measuring oxygenation and pH, for example. Therefore, a combined PET/EPRI scanner promises to provide new insights not attainable with current imagers by simultaneous acquisition of multiple components of tissue microenvironments. To explore the simultaneous acquisition of PET and EPR images, a prototype system was created by combining two existing scanners. Specifically, a silicon photomultiplier (SiPM)-based PET scanner ring designed as a portable scanner was combined with an EPRI scanner designed for the imaging of small animals. The ability of the system to obtain simultaneous images was assessed with a small phantom consisting of four cylinders containing both a PET tracer and EPR spin probe. The resulting images demonstrated the ability to obtain contemporaneous PET and EPR images without cross-modality interference. Given the promising results from this initial investigation, the next step in this project is the construction of the next generation pre-clinical PET/EPRI scanner for multi-parametric assessment of physiologically-important parameters of tissue microenvironments.

Monte Carlo proton dose calculations using a radiotherapy specific dual-energy CT scanner for tissue segmentation and range assessment

NASA Astrophysics Data System (ADS)

Almeida, Isabel P.; Schyns, Lotte E. J. R.; Vaniqui, Ana; van der Heyden, Brent; Dedes, George; Resch, Andreas F.; Kamp, Florian; Zindler, Jaap D.; Parodi, Katia; Landry, Guillaume; Verhaegen, Frank

2018-06-01

Proton beam ranges derived from dual-energy computed tomography (DECT) images from a dual-spiral radiotherapy (RT)-specific CT scanner were assessed using Monte Carlo (MC) dose calculations. Images from a dual-source and a twin-beam DECT scanner were also used to establish a comparison to the RT-specific scanner. Proton ranges extracted from conventional single-energy CT (SECT) were additionally performed to benchmark against literature values. Using two phantoms, a DECT methodology was tested as input for GEANT4 MC proton dose calculations. Proton ranges were calculated for different mono-energetic proton beams irradiating both phantoms; the results were compared to the ground truth based on the phantom compositions. The same methodology was applied in a head-and-neck cancer patient using both SECT and dual-spiral DECT scans from the RT-specific scanner. A pencil-beam-scanning plan was designed, which was subsequently optimized by MC dose calculations, and differences in proton range for the different image-based simulations were assessed. For phantoms, the DECT method yielded overall better material segmentation with  >86% of the voxel correctly assigned for the dual-spiral and dual-source scanners, but only 64% for a twin-beam scanner. For the calibration phantom, the dual-spiral scanner yielded range errors below 1.2 mm (0.6% of range), like the errors yielded by the dual-source scanner (<1.1 mm, <0.5%). With the validation phantom, the dual-spiral scanner yielded errors below 0.8 mm (0.9%), whereas SECT yielded errors up to 1.6 mm (2%). For the patient case, where the absolute truth was missing, proton range differences between DECT and SECT were on average in  ‑1.2  ±  1.2 mm (‑0.5%  ±  0.5%). MC dose calculations were successfully performed on DECT images, where the dual-spiral scanner resulted in media segmentation and range accuracy as good as the dual-source CT. In the patient, the various methods showed relevant range differences.

A phantom study for the comparison of different brands of computed tomography scanners and software packages for endovascular aneurysm repair sizing and planning.

PubMed

Velu, Juliëtte F; Groot Jebbink, Erik; de Vries, Jean-Paul Pm; van der Palen, Job Am; Slump, Cornelis H; Geelkerken, Robert H

2018-04-01

Objectives Correct sizing of endoprostheses used for the treatment of abdominal aortic aneurysms is important to prevent endoleaks and migration. Sizing requires several steps and each step introduces a possible sizing error. The goal of this study was to investigate the magnitude of these errors compared to the golden standard: a vessel phantom. This study focuses on the errors in sizing with three different brands of computed tomography angiography scanners in combination with three reconstruction software packages. Methods Three phantoms with a different diameter, altitude and azimuth were scanned with three computed tomography scanners: Toshiba Aquilion 64-slice, Philips Brilliance iCT 256-slice and Siemens Somatom Sensation 64-slice. The phantom diameters were determined in the stretched view after central lumen line reconstruction by three observers using Simbionix PROcedure Rehearsal Studio, 3mensio and TeraRecon planning software. The observers, all novices in sizing endoprostheses using planning software, measured 108 slices each. Two senior vascular surgeons set the tolerated error margin of sizing on ±1.0 mm. Results In total, 11.3% of the measurements (73/648) were outside the set margins of ±1.0 mm from the phantom diameter, with significant differences between the scanner types (14.8%, 12.1%, 6.9% for the Siemens scanner, Philips scanner and Toshiba scanner, respectively, p-value = 0.032), but not between the software packages (8.3%, 11.1%, 14.4%, p-value = 0.141) or the observers (10.6%, 9.7%, 13.4%, p-value = 0.448). Conclusions It can be concluded that the errors in sizing were independent of the used software packages, but the phantoms scanned with Siemens scanner were significantly more measured incorrectly than the phantoms scanned with the Toshiba scanner. Consequently, awareness on the type of computed tomography scanner and computed tomography scanner setting is necessary, especially in complex abdominal aortic aneurysms sizing for fenestrated or branched endovascular aneurysm repair if appropriate the sizing is of upmost importance.

Generation of realistic virtual nodules based on three-dimensional spatial resolution in lung computed tomography: A pilot phantom study.

PubMed

Narita, Akihiro; Ohkubo, Masaki; Murao, Kohei; Matsumoto, Toru; Wada, Shinichi

2017-10-01

The aim of this feasibility study using phantoms was to propose a novel method for obtaining computer-generated realistic virtual nodules in lung computed tomography (CT). In the proposed methodology, pulmonary nodule images obtained with a CT scanner are deconvolved with the point spread function (PSF) in the scan plane and slice sensitivity profile (SSP) measured for the scanner; the resultant images are referred to as nodule-like object functions. Next, by convolving the nodule-like object function with the PSF and SSP of another (target) scanner, the virtual nodule can be generated so that it has the characteristics of the spatial resolution of the target scanner. To validate the methodology, the authors applied physical nodules of 5-, 7- and 10-mm-diameter (uniform spheres) included in a commercial CT test phantom. The nodule-like object functions were calculated from the sphere images obtained with two scanners (Scanner A and Scanner B); these functions were referred to as nodule-like object functions A and B, respectively. From these, virtual nodules were generated based on the spatial resolution of another scanner (Scanner C). By investigating the agreement of the virtual nodules generated from the nodule-like object functions A and B, the equivalence of the nodule-like object functions obtained from different scanners could be assessed. In addition, these virtual nodules were compared with the real (true) sphere images obtained with Scanner C. As a practical validation, five types of laboratory-made physical nodules with various complicated shapes and heterogeneous densities, similar to real lesions, were used. The nodule-like object functions were calculated from the images of these laboratory-made nodules obtained with Scanner A. From them, virtual nodules were generated based on the spatial resolution of Scanner C and compared with the real images of laboratory-made nodules obtained with Scanner C. Good agreement of the virtual nodules generated from the nodule-like object functions A and B of the phantom spheres was found, suggesting the validity of the nodule-like object functions. The virtual nodules generated from the nodule-like object function A of the phantom spheres were similar to the real images obtained with Scanner C; the root mean square errors (RMSEs) between them were 10.8, 11.1, and 12.5 Hounsfield units (HU) for 5-, 7-, and 10-mm-diameter spheres, respectively. The equivalent results (RMSEs) using the nodule-like object function B were 15.9, 16.8, and 16.5 HU, respectively. These RMSEs were small considering the high contrast between the sphere density and background density (approximately 674 HU). The virtual nodules generated from the nodule-like object functions of the five laboratory-made nodules were similar to the real images obtained with Scanner C; the RMSEs between them ranged from 6.2 to 8.6 HU in five cases. The nodule-like object functions calculated from real nodule images would be effective to generate realistic virtual nodules. The proposed method would be feasible for generating virtual nodules that have the characteristics of the spatial resolution of the CT system used in each institution, allowing for site-specific nodule generation. © 2017 American Association of Physicists in Medicine.

Cross-vendor harmonization of T2 -relaxation-under-spin-tagging (TRUST) MRI for the assessment of cerebral venous oxygenation.

PubMed

Jiang, Dengrong; Liu, Peiying; Li, Yang; Mao, Deng; Xu, Cuimei; Lu, Hanzhang

2018-09-01

Cerebral venous oxygenation (Y v ) is an important physiological parameter and has potential clinical application in many brain diseases. T 2 -relaxation-under-spin-tagging (TRUST) is a commonly used MRI method to measure Y v . Harmonization of this technique across MRI vendors is important for dissemination and multicenter studies of brain oxygenation and metabolism as a disease biomarker. TRUST pulse sequence components and imaging parameters were carefully matched between two major MRI vendors, Philips and Siemens. Each subject (N = 10) was scanned on both scanners within a 2.5-h period. On each scanner, the subject was scanned in two sessions to assess intersession reproducibility. A hyperoxia challenge was also included in both sessions and on both scanners to evaluate the sensitivity of the technique to Y v changes. Measured Y v values, confidence interval of Y v estimates ( εYv), as well as intrasession and intersession coefficient of variation (CoV) of Y v , were compared between the two scanners. Y v measured on the two vendors were highly compatible and strongly correlated (R 2  = 0.957). Y v changes associated with hyperoxia challenge were significant on both scanners (P < 0.001) and were also correlated across scanners (P = 0.007). Intrasession and intersession CoV of measured Y v were less than 3% and showed no difference between scanners. εYv were less than 1% on both scanners and showed no difference between scanners when echo times were matched on the two scanners. This work suggests that harmonized TRUST MRI can yield highly compatible Y v measurements across different vendors. Magn Reson Med 80:1125-1131, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

Handheld laser scanner automatic registration based on random coding

NASA Astrophysics Data System (ADS)

He, Lei; Yu, Chun-ping; Wang, Li

2011-06-01

Current research on Laser Scanner often focuses mainly on the static measurement. Little use has been made of dynamic measurement, that are appropriate for more problems and situations. In particular, traditional Laser Scanner must Keep stable to scan and measure coordinate transformation parameters between different station. In order to make the scanning measurement intelligently and rapidly, in this paper ,we developed a new registration algorithm for handleheld laser scanner based on the positon of target, which realize the dynamic measurement of handheld laser scanner without any more complex work. the double camera on laser scanner can take photograph of the artificial target points to get the three-dimensional coordinates, this points is designed by random coding. And then, a set of matched points is found from control points to realize the orientation of scanner by the least-square common points transformation. After that the double camera can directly measure the laser point cloud in the surface of object and get the point cloud data in an unified coordinate system. There are three major contributions in the paper. Firstly, a laser scanner based on binocular vision is designed with double camera and one laser head. By those, the real-time orientation of laser scanner is realized and the efficiency is improved. Secondly, the coding marker is introduced to solve the data matching, a random coding method is proposed. Compared with other coding methods,the marker with this method is simple to match and can avoid the shading for the object. Finally, a recognition method of coding maker is proposed, with the use of the distance recognition, it is more efficient. The method present here can be used widely in any measurement from small to huge obiect, such as vehicle, airplane which strengthen its intelligence and efficiency. The results of experiments and theory analzing demonstrate that proposed method could realize the dynamic measurement of handheld laser scanner. Theory analysis and experiment shows the method is reasonable and efficient.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melnyk, Roman; DiBianca, Frank A.

The detector presampling modulation transfer function (MTF) of a 576-channel variable resolution x-ray (VRX) computed tomography (CT) scanner was evaluated in this study. The scanner employs a VRX detector, which provides increased spatial resolution by matching the scanner's field of view (FOV) to the size of an object being imaged. Because spatial resolution is the parameter the scanner promises to improve, the evaluation of this resolution is important. The scanner's pre-reconstruction spatial resolution, represented by the detector presampling MTF, was evaluated using both modeling (Monte Carlo simulation) and measurement (the moving slit method). The theoretical results show the increase inmore » the cutoff frequency of the detector presampling MTF from 1.39 to 43.38 cycles/mm as the FOV of the VRX CT scanner decreases from 32 to 1 cm. The experimental results are in reasonable agreement with the theoretical data. Some discrepancies between the measured and the modeled detector presampling MTFs can be explained by the limitations of the model. At small FOVs (1-8 cm), the MTF measurements were limited by the size of the focal spot. The obtained results are important for further development of the VRX CT scanner.« less

Immersion and dry scanner extensions for sub-10nm production nodes

NASA Astrophysics Data System (ADS)

Weichselbaum, Stefan; Bornebroek, Frank; de Kort, Toine; Droste, Richard; de Graaf, Roelof F.; van Ballegoij, Rob; Botter, Herman; McLaren, Matthew G.; de Boeij, Wim P.

2015-03-01

Progressing towards the 10nm and 7nm imaging node, pattern-placement and layer-to-layer overlay requirements keep on scaling down and drives system improvements in immersion (ArFi) and dry (ArF/KrF) scanners. A series of module enhancements in the NXT platform have been introduced; among others, the scanner is equipped with exposure stages with better dynamics and thermal control. Grid accuracy improvements with respect to calibration, setup, stability, and layout dependency tighten MMO performance and enable mix and match scanner operation. The same platform improvements also benefit focus control. Improvements in detectability and reproducibility of low contrast alignment marks enhance the alignment solution window for 10nm logic processes and beyond. The system's architecture allows dynamic use of high-order scanner optimization based on advanced actuators of projection lens and scanning stages. This enables a holistic optimization approach for the scanner, the mask, and the patterning process. Productivity scanner design modifications esp. stage speeds and optimization in metrology schemes provide lower layer costs for customers using immersion lithography as well as conventional dry technology. Imaging, overlay, focus, and productivity data is presented, that demonstrates 10nm and 7nm node litho-capability for both (immersion & dry) platforms.

5. SITE BUILDING 002 SCANNER BUILDING AT "A" ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. SITE BUILDING 002 - SCANNER BUILDING - AT "A" FACE (ON SOUTH SIDE) LOOKING DIRECTLY UP RADAR SYSTEM EMITTER/ANTENNA ARRAY FACE WITH 90MM STANDARD LENS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

MR-Guided Near Infrared Spectroscopy for Reducing Breast Cancer False Positives

DTIC Science & Technology

2009-09-01

an Invivo breast coil in a (b) Philips scanner , and (b) a USA Instruments coil in a (d) GE scanner . 8 Quantitative accuracy in optical imaging...reconstruction [7], which includes a weighting term to account for the accuracy of the MR scanner in determining water and fat images. The advantage of... scanner used in this study. These methods were tested in a 86mm diameter gelatin phantom, shown in Figure 6, with porcine blood added to mimic the

Prolongation of ERP latency and reaction time (RT) in simultaneous EEG/fMRI data acquisition.

PubMed

Chun, Jinsoo; Peltier, Scott J; Yoon, Daehyun; Manschreck, Theo C; Deldin, Patricia J

2016-08-01

Recording EEG and fMRI data simultaneously inside a fully-operating scanner has been recognized as a novel approach in human brain research. Studies have demonstrated high concordance between the EEG signals and hemodynamic response. However, a few studies reported altered cognitive process inside the fMRI scanner such as delayed reaction time (RT) and reduced and/or delayed N100 and P300 event-related brain potential (ERP) components. The present study investigated the influence of electromagnetic field (static magnetic field, radio frequency (RF) pulse, and gradient switching) and experimental environment on posterior N100 and P300 ERP components in four different settings with six healthy subjects using a visual oddball task: (1) classic fMRI acquisition inside the scanner (e.g., supine position, mirror glasses for stimulus presentation), (2) standard behavioral experiment outside the scanner (e.g., seated position, keyboard response), (3) controlled fMRI acquisition inside the scanner (e.g., organic light-emitting diode (OLED) goggles for stimulus presentation) inside; and (4) modified behavioral experiment outside the scanner (e.g., supine position, OLED goggles). The study findings indicated that the experimental environment in simultaneous EEG/fMRI acquisition could substantially delay N1P, P300 latency, and RT inside the scanner, and was associated with a reduced N1P amplitude. There was no effect of electromagnetic field in the prolongation of RT, N1P and P300 latency inside the scanner. N1P, but not P300, latency was sensitive to stimulus presentation method inside the scanner. Future simultaneous EEG/fMRI data collection should consider experimental environment in both design and analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Accuracy and efficiency of full-arch digitalization and 3D printing: A comparison between desktop model scanners, an intraoral scanner, a CBCT model scan, and stereolithographic 3D printing.

PubMed

Wesemann, Christian; Muallah, Jonas; Mah, James; Bumann, Axel

2017-01-01

The primary objective of this study was to compare the accuracy and time efficiency of an indirect and direct digitalization workflow with that of a three-dimensional (3D) printer in order to identify the most suitable method for orthodontic use. A master model was measured with a coordinate measuring instrument. The distances measured were the intercanine width, the intermolar width, and the dental arch length. Sixty-four scans were taken with each of the desktop scanners R900 and R700 (3Shape), the intraoral scanner TRIOS Color Pod (3Shape), and the Promax 3D Mid cone beam computed tomography (CBCT) unit (Planmeca). All scans were measured with measuring software. One scan was selected and printed 37 times on the D35 stereolithographic 3D printer (Innovation MediTech). The printed models were measured again using the coordinate measuring instrument. The most accurate results were obtained by the R900. The R700 and the TRIOS intraoral scanner showed comparable results. CBCT-3D-rendering with the Promax 3D Mid CBCT unit revealed significantly higher accuracy with regard to dental casts than dental impressions. 3D printing offered a significantly higher level of deviation than digitalization with desktop scanners or an intraoral scanner. The chairside time required for digital impressions was 27% longer than for conventional impressions. Conventional impressions, model casting, and optional digitization with desktop scanners remains the recommended workflow process. For orthodontic demands, intraoral scanners are a useful alternative for full-arch scans. For prosthodontic use, the scanning scope should be less than one quadrant and three additional teeth.

Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT

NASA Astrophysics Data System (ADS)

Jansen, Jan T. M.; Shrimpton, Paul C.

2016-07-01

The ImPACT (imaging performance assessment of CT scanners) CT patient dosimetry calculator is still used world-wide to estimate organ and effective doses (E) for computed tomography (CT) examinations, although the tool is based on Monte Carlo calculations reflecting practice in the early 1990’s. Subsequent developments in CT scanners, definitions of E, anthropomorphic phantoms, computers and radiation transport codes, have all fuelled an urgent need for updated organ dose conversion factors for contemporary CT. A new system for such simulations has been developed and satisfactorily tested. Benchmark comparisons of normalised organ doses presently derived for three old scanners (General Electric 9800, Philips Tomoscan LX and Siemens Somatom DRH) are within 5% of published values. Moreover, calculated normalised values of CT Dose Index for these scanners are in reasonable agreement (within measurement and computational uncertainties of  ±6% and  ±1%, respectively) with reported standard measurements. Organ dose coefficients calculated for a contemporary CT scanner (Siemens Somatom Sensation 16) demonstrate potential deviations by up to around 30% from the surrogate values presently assumed (through a scanner matching process) when using the ImPACT CT Dosimetry tool for newer scanners. Also, illustrative estimates of E for some typical examinations and a range of anthropomorphic phantoms demonstrate the significant differences (by some 10’s of percent) that can arise when changing from the previously adopted stylised mathematical phantom to the voxel phantoms presently recommended by the International Commission on Radiological Protection (ICRP), and when following the 2007 ICRP recommendations (updated from 1990) concerning tissue weighting factors. Further simulations with the validated dosimetry system will provide updated series of dose coefficients for a wide range of contemporary scanners.

Evaluation of PeneloPET Simulations of Biograph PET/CT Scanners

NASA Astrophysics Data System (ADS)

Abushab, K. M.; Herraiz, J. L.; Vicente, E.; Cal-González, J.; España, S.; Vaquero, J. J.; Jakoby, B. W.; Udías, J. M.

2016-06-01

Monte Carlo (MC) simulations are widely used in positron emission tomography (PET) for optimizing detector design, acquisition protocols, and evaluating corrections and reconstruction methods. PeneloPET is a MC code based on PENELOPE, for PET simulations which considers detector geometry, acquisition electronics and materials, and source definitions. While PeneloPET has been successfully employed and validated with small animal PET scanners, it required a proper validation with clinical PET scanners including time-of-flight (TOF) information. For this purpose, we chose the family of Biograph PET/CT scanners: the Biograph True-Point (B-TP), Biograph True-Point with TrueV (B-TPTV) and the Biograph mCT. They have similar block detectors and electronics, but a different number of rings and configuration. Some effective parameters of the simulations, such as the dead-time and the size of the reflectors in the detectors, were adjusted to reproduce the sensitivity and noise equivalent count (NEC) rate of the B-TPTV scanner. These parameters were then used to make predictions of experimental results such as sensitivity, NEC rate, spatial resolution, and scatter fraction (SF), from all the Biograph scanners and some variations of them (energy windows and additional rings of detectors). Predictions agree with the measured values for the three scanners, within 7% (sensitivity and NEC rate) and 5% (SF). The resolution obtained for the B-TPTV is slightly better (10%) than the experimental values. In conclusion, we have shown that PeneloPET is suitable for simulating and investigating clinical systems with good accuracy and short computational time, though some effort tuning of a few parameters of the scanners modeled may be needed in case that the full details of the scanners studied are not available.

Comparative analysis on reproducibility among 5 intraoral scanners: sectional analysis according to restoration type and preparation outline form

PubMed Central

2016-01-01

PURPOSE The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs). MATERIALS AND METHODS The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (α=.05). RESULTS The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups. CONCLUSION Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized. PMID:27826385

Accuracy of four different digital intraoral scanners: effects of the presence of orthodontic brackets and wire.

PubMed

Jung, Yoo-Ran; Park, Ji-Man; Chun, Youn-Sic; Lee, Kkot-Nim; Kim, Minji

The objective of this study was to compare the accuracy of four different digital intraoral scanners and the effects of buccal brackets and orthodontic wire. For this study, three sets of models (Control model, BKT model with buccal bracket, and WBKT model with buccal bracket and orthodontic wire) were scanned using four different types of intraoral scanners: E4D dentist, iTero, Trios, and Zfx IntraScan. The mesiodistal width of the teeth, intercanine width, and intermolar width measured by four scanners were compared. Three-dimensional (3D) images of the brackets were taken using the four scanners. Data were analyzed with one-way ANOVA, independent t test, and post-hoc Tukey test at a significance level of P < 0.05. When comparing the 3D images with manual measurements using a traditional caliper, iTero and Trios showed the highest accuracy in horizontal measurements.iTero had the lowest values in Devmax-min of maxillary intermolar and intercanine widths (0.16 mm and 0.20 mm, respectively), whereas Trios had the lowest values in Devmax-min of mandibular intermolar and intercanine widths (0.36 mm and 0.14 mm, respectively). The horizontal variables were barely affected by the presence of buccal brackets and orthodontic wire. Comparison of 3D bracket images scanned by the four scanners showed differences in image distortion among the scanners. Bracket characteristics did not affect the 3D bracket images. The four intraoral scanners used in this study differed in accuracy. However, the results acquired by iTero and Trios were more reliable. Effects of buccal brackets and orthodontic wire on the 3D images taken by intraoral scanners were not clinically significant.

Spectra of clinical CT scanners using a portable Compton spectrometer.

PubMed

Duisterwinkel, H A; van Abbema, J K; van Goethem, M J; Kawachimaru, R; Paganini, L; van der Graaf, E R; Brandenburg, S

2015-04-01

Spectral information of the output of x-ray tubes in (dual source) computer tomography (CT) scanners can be used to improve the conversion of CT numbers to proton stopping power and can be used to advantage in CT scanner quality assurance. The purpose of this study is to design, validate, and apply a compact portable Compton spectrometer that was constructed to accurately measure x-ray spectra of CT scanners. In the design of the Compton spectrometer, the shielding materials were carefully chosen and positioned to reduce background by x-ray fluorescence from the materials used. The spectrum of Compton scattered x-rays alters from the original source spectrum due to various physical processes. Reconstruction of the original x-ray spectrum from the Compton scattered spectrum is based on Monte Carlo simulations of the processes involved. This reconstruction is validated by comparing directly and indirectly measured spectra of a mobile x-ray tube. The Compton spectrometer is assessed in a clinical setting by measuring x-ray spectra at various tube voltages of three different medical CT scanner x-ray tubes. The directly and indirectly measured spectra are in good agreement (their ratio being 0.99) thereby validating the reconstruction method. The measured spectra of the medical CT scanners are consistent with theoretical spectra and spectra obtained from the x-ray tube manufacturer. A Compton spectrometer has been successfully designed, constructed, validated, and applied in the measurement of x-ray spectra of CT scanners. These measurements show that our compact Compton spectrometer can be rapidly set-up using the alignment lasers of the CT scanner, thereby enabling its use in commissioning, troubleshooting, and, e.g., annual performance check-ups of CT scanners.

The mechatronic design of a fast wire scanner in IHEP U-70 accelerator

NASA Astrophysics Data System (ADS)

Baranov, V. T.; Makhov, S. S.; Savin, D. A.; Terekhov, V. I.

2016-10-01

This paper presents the mechatronic design of a fast wire scanner based on a servomotor. The design of the wire scanner is motivated by the need to measure the transverse profile of the high power proton and carbon beams at the IHEP U-70 accelerator. This paper formulates the requirements to the fast wire scanner system for the high intensity proton beam at the U-70 accelerator. The results on the design of electro-mechanical device for the wire scanner with a wire traveling speed 10-20 m/s are presented. The solution consists in a brushless servomotor and standard motor control electronics. High radiation levels in the accelerator enclosure dictate the use of a resolver as the position feedback element.

Superwide-angle coverage code-multiplexed optical scanner.

PubMed

Riza, Nabeel A; Arain, Muzammil A

2004-05-01

A superwide-angle coverage code-multiplexed optical scanner is presented that has the potential to provide 4 pi-sr coverage. As a proof-of-concept experiment, an angular scan range of 288 degrees for six randomly distributed beams is demonstrated. The proposed scanner achieves its superwide coverage by exploiting a combination of phase-encoded transmission and reflection holography within an in-line hologram recording-retrieval geometry. The basic scanner unit consists of one phase-only digital mode spatial light modulator for code entry (i.e., beam scan control) and a holographic material from which we obtained what we believe is the first-of-a-kind extremely wide coverage, low component count, high speed (e.g., microsecond domain), and large aperture (e.g., > 1-cm diameter) scanner.

Whole-body 3D scanner and scan data report

NASA Astrophysics Data System (ADS)

Addleman, Stephen R.

1997-03-01

With the first whole-body 3D scanner now available the next adventure confronting the user is what to do with all of the data. While the system was built for anthropologists, it has created interest among users from a wide variety of fields. Users with applications in the fields of anthropology, costume design, garment design, entertainment, VR and gaming have a need for the data in formats unique to their fields. Data from the scanner is being converted to solid models for art and design and NURBS for computer graphics applications. Motion capture has made scan data move and dance. The scanner has created a need for advanced application software just as other scanners have in the past.

6. SITE BUILDING 002 SCANNER BUILDING AT "A" ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. SITE BUILDING 002 - SCANNER BUILDING - AT "A" FACE (ON SOUTH SIDE) LOOKING DIRECTLY UP RADAR SYSTEM EMITTER/ANTENNA ARRAY FACE WITH 65MM WIDE ANGLE LENS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

A fully automated and scalable timing probe-based method for time alignment of the LabPET II scanners

NASA Astrophysics Data System (ADS)

Samson, Arnaud; Thibaudeau, Christian; Bouchard, Jonathan; Gaudin, Émilie; Paulin, Caroline; Lecomte, Roger; Fontaine, Réjean

2018-05-01

A fully automated time alignment method based on a positron timing probe was developed to correct the channel-to-channel coincidence time dispersion of the LabPET II avalanche photodiode-based positron emission tomography (PET) scanners. The timing probe was designed to directly detect positrons and generate an absolute time reference. The probe-to-channel coincidences are recorded and processed using firmware embedded in the scanner hardware to compute the time differences between detector channels. The time corrections are then applied in real-time to each event in every channel during PET data acquisition to align all coincidence time spectra, thus enhancing the scanner time resolution. When applied to the mouse version of the LabPET II scanner, the calibration of 6 144 channels was performed in less than 15 min and showed a 47% improvement on the overall time resolution of the scanner, decreasing from 7 ns to 3.7 ns full width at half maximum (FWHM).

A LabVIEW® based generic CT scanner control software platform.

PubMed

Dierick, M; Van Loo, D; Masschaele, B; Boone, M; Van Hoorebeke, L

2010-01-01

UGCT, the Centre for X-ray tomography at Ghent University (Belgium) does research on X-ray tomography and its applications. This includes the development and construction of state-of-the-art CT scanners for scientific research. Because these scanners are built for very different purposes they differ considerably in their physical implementations. However, they all share common principle functionality. In this context a generic software platform was developed using LabVIEW® in order to provide the same interface and functionality on all scanners. This article describes the concept and features of this software, and its potential for tomography in a research setting. The core concept is to rigorously separate the abstract operation of a CT scanner from its actual physical configuration. This separation is achieved by implementing a sender-listener architecture. The advantages are that the resulting software platform is generic, scalable, highly efficient, easy to develop and to extend, and that it can be deployed on future scanners with minimal effort.

Moths on the Flatbed Scanner: The Art of Joseph Scheer

PubMed Central

Buchmann, Stephen L.

2011-01-01

During the past decade a few artists and even fewer entomologists discovered flatbed scanning technology, using extreme resolution graphical arts scanners for acquiring high magnification digital images of plants, animals and inanimate objects. They are not just for trip receipts anymore. The special attributes of certain scanners, to image thick objects is discussed along with the technical features of the scanners including magnification, color depth and shadow detail. The work of pioneering scanner artist, Joseph Scheer from New York's Alfred University is highlighted. Representative flatbed-scanned images of moths are illustrated along with techniques to produce them. Collecting and preparing moths, and other objects, for scanning are described. Highlights of the Fulbright sabbatical year of professor Scheer in Arizona and Sonora, Mexico are presented, along with comments on moths in science, folklore, art and pop culture. The use of flatbed scanners is offered as a relatively new method for visualizing small objects while acquiring large files for creating archival inkjet prints for display and sale. PMID:26467835

Basic study of entire whole-body PET scanners based on the OpenPET geometry

NASA Astrophysics Data System (ADS)

Yoshida, Eiji; Yamaya, Taiga; Nishikido, Fumihiko; Inadama, Naoko; Murayama, Hideo

2010-09-01

A conventional PET scanner has a 15-25 cm axial field-of-view (FOV) and images a whole body using about six bed positions. An OpenPET geometry can extend the axial FOV with a limited number of detectors. The entire whole-body PET scanner must be able to process a large amount of data effectively. In this work, we study feasibility of the fully 3D entire whole-body PET scanner using the GATE simulation. The OpenPET has 12 block detector rings with the ring diameter of 840 mm and each block detector ring consists of 48 depth-of-interaction (DOI) detectors. The OpenPET has the axial length of 895.95 mm with five parts of 58.95 mm open gaps. The OpenPET has higher single data loss than a conventional PET scanner at grouping circuits. NECR of the OpenPET decreases by single data loss. But single data loss is mitigated by separating the axially arranged detector into two parts. Also, multiple coincidences are found to be important for the entire whole-body PET scanner. The entire whole-body PET scanner with the OpenPET geometry promises to provide a large axial FOV with the open space and to have sufficient performance values. But single data loss at the grouping circuits and multiple coincidences are limited to the peak noise equivalent count rate (NECR) for the entire whole-body PET scanner.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rickey, Daniel; Sasaki, David; Dubey, Arbind

Purpose: Three-dimensional printing has been implemented at our institution to create customized treatment accessories including shielding and bolus. In order to effectively use 3D printing, the topography of the patient must first be acquired. To this end, we have evaluated a low-cost structured-light 3D scanner in order to assess the clinical viability of this technology. Methods: For ease of use, the scanner (3D Systems, Sense 3D Scanner) was mounted in a simple gantry that guided its motion and maintained an optimum distance between the scanner and the object. To characterise the spatial accuracy of the scanner, we used a geometricmore » phantom and an anthropomorphic head phantom. The geometric phantom was machined from plastic and had overall dimensions of 24 cm by 15 cm and included a hemispherical and a tetrahedron protrusion roughly the dimensions of an average forehead and nose respectively. Meshes acquired by the optical scanner were compared to meshes generated from high-resolution CT images. Results: Scans were acquired in under one minute. Most of the optical scans contained noticeable artefacts although in most instances these were considered minor. Using an algorithm that calculated distances between the two meshes, we found most of the optical scanner measurements agreed with those from CT to within about 1 mm for the geometric phantom and to within about 2 mm for the head phantom. Conclusion: In summary, we deemed this scanner to be clinically acceptable and it has been used to design treatment accessories for several skin cancer patients.« less

A Study on Possibility of Clinical Application for Color Measurements of Shade Guides Using an Intraoral Digital Scanner.

PubMed

Yoon, Hyung-In; Bae, Ji-Won; Park, Ji-Man; Chun, Youn-Sic; Kim, Mi-Ae; Kim, Minji

2016-11-07

To assess if color measurement with intraoral scanner correlates with digital colorimeter and to evaluate the possibility of application of a digital scanner for shade selection. The L*a*b* values of the five shade tabs (A1, A2, A3, A3.5, and A4) were obtained with an intraoral scanner (TRIOS Pod) and a colorimeter (ShadeEye). Both devices were calibrated according to the manufacturer's instructions before measurements. Color measurement values were compared with paired t-test, and a Pearson's correlation analysis was performed to evaluate the relationship of two methods. The L*a*b* values of the colorimeter were significantly different from those of the digital scanner (p < 0.001). The L* and b* values of both methods were strongly correlated with each other (both p < 0.05). The device repeatability in both methods were reported to be excellent (p < 0.05). Within the limitations of this study, color measurements with digital intraoral scanners and computer-assisted image analysis were in accordance with those of the colorimeter with respect to L* and b* values; however, all the coordinates of shade tabs were significantly different between two methods. The digital intraoral scanner may not be used as the primary method of color selection in clinical practices, considering significant differences in color parameters with colorimeter. The scanner's capability in shade selection should be further evaluated. © 2016 by the American College of Prosthodontists.

A survey on abnormal uterine bleeding among radiographers with frequent MRI exposure using intrauterine contraceptive devices.

PubMed

Huss, A; Schaap, K; Kromhout, H

2018-02-01

Based on a previous case report of menometrorrhagia (prolonged/excessive uterine bleeding, occurring at irregular and/or frequent intervals) in MRI workers with intrauterine devices (IUDs), it was evaluated whether this association could be confirmed. A survey was performed among 381 female radiographers registered with their national association. Logistic regression was used to analyze associations of abnormal uterine bleeding with the frequency of working with MRI scanners, presence near the scanner/in the scanner room during image acquisition, and with scanner strength or type. A total of 68 women reported using IUDs, and 72 reported abnormal uterine bleeding. Compared with unexposed women not using IUDs, the odds ratio in women with IUDs working with MRI scanners was 2.09 (95% confidence interval 0.83-3.66). Associations were stronger if women working with MRI reported being present during image acquisition (odds ratio 3.43, 95% CI 1.26-9.34). Associations with scanner strength or type were not consistent. Radiographers using IUDs who are occupationally exposed to stray fields from MRI scanners report abnormal uterine bleeding more often than their co-workers without an IUD, or nonexposed co-workers with an IUD. In particular, radiographers present inside the scanner room during image acquisition showed an increased risk. Magn Reson Med 79:1083-1089, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

9. SITE BUILDING 002 SCANNER BUILDING LOOKING AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. SITE BUILDING 002 - SCANNER BUILDING - LOOKING AT "C" FACE RADAR SYSTEM EMITTER/ANTENNA. VIEW IS LOOKING SOUTH 30° EAST (NOTE: "C" FACE NOT IN USE AT FACILITY). - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

34. SITE BUILDING 002 SCANNER BUILDING ROOM 105 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. SITE BUILDING 002 - SCANNER BUILDING - ROOM 105 - CHILLER ROOM, SHOWING SINGLE COMPRESSOR, LIQUID CHILLERS AND "CHILLED WATER RETURN", COOLING TOWER 'TOWER WATER RETURN" AND 'TOWER WATER SUPPLY" LINES. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

25. SITE BUILDING 002 SCANNER BUILDING OPERATIONS CENTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. SITE BUILDING 002 - SCANNER BUILDING - OPERATIONS CENTER - MWOC IN OPERATION AT 1930 ZULU TIME, 26 OCTOBER, 1999. MWOC SCREEN ALSO SHOWS RADAR "FACE A" AND "FACE B" ACTIVE STATUS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

29. SITE BUILDING 002 SCANNER BUILDING FLOOR 3A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. SITE BUILDING 002 - SCANNER BUILDING - FLOOR 3A ("A" FACE) AT SYSTEM LAYOUT GRID 17. GENERAL OBLIQUE VIEW OF "A" FACE INTERIOR SHOWING RADAR EMITTER/ANTENNA INTERFACE ELECTRONICS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

10. SITE BUILDING 002 SCANNER BUILDING LOOKING AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. SITE BUILDING 002 - SCANNER BUILDING - LOOKING AT SOUTHWEST CORNER "B" FACE AND "C" FACE ON WEST AND EVAPORATIVE COOLING TOWER AT NORTH. VIEW IS LOOKING NORTH 45° EAST. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

19. SITE BUILDING 002 SCANNER BUILDING AIR POLICE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. SITE BUILDING 002 - SCANNER BUILDING - AIR POLICE SITE SECURITY OFFICE WITH "SITE PERIMETER STATUS PANEL" AND REAL TIME VIDEO DISPLAY OUTPUT FROM VIDEO CAMERA SYSTEM AT SECURITY FENCE LOCATIONS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Choosing a Scanner: Points To Consider before Buying a Scanner.

ERIC Educational Resources Information Center

Raby, Chris

1998-01-01

Outlines ten factors to consider before buying a scanner: size of document; type of document; color; speed and volume; resolution; image enhancement; image compression; optical character recognition; scanning subsystem; and the option to use a commercial bureau service. The importance of careful analysis of requirements is emphasized. (AEF)

21 CFR 862.2400 - Densitometer/scanner (integrating, reflectance, TLC, or radiochromatogram) for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Densitometer/scanner (integrating, reflectance, TLC, or radiochromatogram) for clinical use. 862.2400 Section 862.2400 Food and Drugs FOOD AND DRUG... CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2400 Densitometer/scanner (integrating...

Scanner Art and Links to Physics

ERIC Educational Resources Information Center

Russell, David

2005-01-01

A photocopier or scanner can be used to produce not only the standard motion graphs of physics, but a variety of other graphs that resemble gravitational and electrical fields. This article presents a starting point for exploring scanner graphics, which brings together investigation in art and design, physics, mathematics, and information…

20. SITE BUILDING 002 SCANNER BUILDING IN COMPUTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. SITE BUILDING 002 - SCANNER BUILDING - IN COMPUTER ROOM LOOKING AT "CONSOLIDATED MAINTENANCE OPERATIONS CENTER" JOB AREA AND OPERATION WORK CENTER. TASKS INCLUDE RADAR MAINTENANCE, COMPUTER MAINTENANCE, CYBER COMPUTER MAINTENANCE AND RELATED ACTIVITIES. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

The coude spectrograph and echelle scanner of the 2.7 m telescope at McDonald Observatory.

NASA Technical Reports Server (NTRS)

Tull, R. G.

1972-01-01

Discussion of certain design aspects of the coude spectrograph, and description of the coude scanner that uses some of the spectrograph optics. The configuration of the large echelle grating used is reviewed along with the systems of computer scanner control and data handling.

The Coude spectrograph and echelle scanner of the 2.7 m telescope at McDonald observatory

NASA Technical Reports Server (NTRS)

Tull, R. G.

1972-01-01

The design of the Coude spectrograph of the 2.7 m McDonald telescope is discussed. A description is given of the Coude scanner which uses the spectrograph optics, the configuration of the large echelle and the computer scanner control and data systems.

Eddy current X-Y scanner system

NASA Technical Reports Server (NTRS)

Kurtz, G. W.

1983-01-01

The Nondestructive Evaluation Branch of the Materials and Processes Laboratory became aware of a need for a miniature, portable X-Y scanner capable of performing eddy current or other nondestructive testing scanning operations such as ultrasonic, or small areas of flat plate. The technical description and operational theory of the X-Y scanner system designed and built to fulfill this need are covered. The scanner was given limited testing and performs according to its design intent, which is to scan flat plate areas of approximately 412 sq cm (64 sq in) during each complete cycle of scanning.

Scanning properties of a resonant fiber-optic piezoelectric scanner

NASA Astrophysics Data System (ADS)

Li, Zhi; Yang, Zhe; Fu, Ling

2011-12-01

We develop a resonant fiber-optic scanner using four piezoelectric elements arranged as a square tube, which is efficient to manufacture and drive. Using coupled-field model based on finite element method, scanning properties of the scanner, including vibration mode, resonant frequency, and scanning range, are numerically studied. We also physically measure the effects of geometry sizes and drive signals on the scanning properties, thus providing a foundation for general purpose designs. A scanner adopted in a prototype of imaging system, with a diameter of ˜2 mm and driven by a voltage of 10 V (peak to peak), demonstrates the scanning performance by obtaining an image of resolution target bars. The proposed fiber-optic scanner can be applied to micro-endoscopy that requires two-dimensional scanning of fibers.

Active Damping of a Piezoelectric Tube Scanner using Self-Sensing Piezo Actuation

PubMed Central

Kuiper, S.; Schitter, G.

2010-01-01

In most Atomic Force Microscopes (AFM), a piezoelectric tube scanner is used to position the sample underneath the measurement probe. Oscillations stemming from the weakly damped resonances of the tube scanner are a major source of image distortion, putting a limitation on the achievable imaging speed. This paper demonstrates active damping of these oscillations in multiple scanning axes without the need for additional position sensors. By connecting the tube scanner in a capacitive bridge circuit the scanner oscillations can be measured in both scanning axes, using the same piezo material as an actuator and sensor simultaneously. In order to compensate for circuit imbalance caused by hysteresis in the piezo element, an adaptive balancing circuit is used. The obtained measurement signal is used for feedback control, reducing the resonance peaks in both scanning axes by 18 dB and the cross-coupling at those frequencies by 30 dB. Experimental results demonstrate a significant reduction in scanner oscillations when applying the typical triangular scanning signals, as well as a strong reduction in coupling induced oscillations. Recorded AFM images show a considerable reduction in image distortion due to the proposed control method, enabling artifact free AFM imaging at a speed of 122 lines per second with a standard piezoelectric tube scanner. PMID:26412944

Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

NASA Astrophysics Data System (ADS)

Adeleye, Bamise; Chetty, Naven

2017-12-01

The preference for computed tomography (CT) for the clinical assessment of pulmonary tuberculosis (PTB) infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05) between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05) and female patients (r2 = 0.989, P < 0.05). The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively). These variations provide an indication that the use of a scanner optimizing protocol is imperative.

Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy.

PubMed

Zhao, Yi-Jiao; Xiong, Yu-Xue; Wang, Yong

2017-01-01

In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial "line-laser" scanner (Faro), as the reference model and two test models were obtained, via a "stereophotography" (3dMD) and a "structured light" facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and "3D error" as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use.

Dataset variability leverages white-matter lesion segmentation performance with convolutional neural network

NASA Astrophysics Data System (ADS)

Ravnik, Domen; Jerman, Tim; Pernuš, Franjo; Likar, Boštjan; Å piclin, Žiga

2018-03-01

Performance of a convolutional neural network (CNN) based white-matter lesion segmentation in magnetic resonance (MR) brain images was evaluated under various conditions involving different levels of image preprocessing and augmentation applied and different compositions of the training dataset. On images of sixty multiple sclerosis patients, half acquired on one and half on another scanner of different vendor, we first created a highly accurate multi-rater consensus based lesion segmentations, which were used in several experiments to evaluate the CNN segmentation result. First, the CNN was trained and tested without preprocessing the images and by using various combinations of preprocessing techniques, namely histogram-based intensity standardization, normalization by whitening, and train dataset augmentation by flipping the images across the midsagittal plane. Then, the CNN was trained and tested on images of the same, different or interleaved scanner datasets using a cross-validation approach. The results indicate that image preprocessing has little impact on performance in a same-scanner situation, while between-scanner performance benefits most from intensity standardization and normalization, but also further by incorporating heterogeneous multi-scanner datasets in the training phase. Under such conditions the between-scanner performance of the CNN approaches that of the ideal situation, when the CNN is trained and tested on the same scanner dataset.

Uncertainty Propagation for Terrestrial Mobile Laser Scanner

NASA Astrophysics Data System (ADS)

Mezian, c.; Vallet, Bruno; Soheilian, Bahman; Paparoditis, Nicolas

2016-06-01

Laser scanners are used more and more in mobile mapping systems. They provide 3D point clouds that are used for object reconstruction and registration of the system. For both of those applications, uncertainty analysis of 3D points is of great interest but rarely investigated in the literature. In this paper we present a complete pipeline that takes into account all the sources of uncertainties and allows to compute a covariance matrix per 3D point. The sources of uncertainties are laser scanner, calibration of the scanner in relation to the vehicle and direct georeferencing system. We suppose that all the uncertainties follow the Gaussian law. The variances of the laser scanner measurements (two angles and one distance) are usually evaluated by the constructors. This is also the case for integrated direct georeferencing devices. Residuals of the calibration process were used to estimate the covariance matrix of the 6D transformation between scanner laser and the vehicle system. Knowing the variances of all sources of uncertainties, we applied uncertainty propagation technique to compute the variance-covariance matrix of every obtained 3D point. Such an uncertainty analysis enables to estimate the impact of different laser scanners and georeferencing devices on the quality of obtained 3D points. The obtained uncertainty values were illustrated using error ellipsoids on different datasets.

Comparative calibration of IP scanning equipment

NASA Astrophysics Data System (ADS)

Ingenito, F.; Andreoli, P.; Batani, D.; Boutoux, G.; Cipriani, M.; Consoli, F.; Cristofari, G.; Curcio, A.; De Angelis, R.; Di Giorgio, G.; Ducret, J.; Forestier-Colleoni, P.; Hulin, S.; Jakubowska, K.; Rabhi, N.

2016-05-01

Imaging Plates (IP) are diagnostic devices which contain a photostimulable phosphor layer that stores the incident radiation dose as a latent image. The image is read with a scanner which stimulates the decay of electrons, previously excited by the incident radiation, by exposition to a laser beam. This results in emitted light, which is detected by photomultiplier tubes; so the latent image is reconstructed. IPs have the interesting feature that can be reused many times, after erasing stored information. Algorithms to convert signals stored in the detector to Photostimulated luminescence (PSL) counts depend on the scanner and are not available on every model. A comparative cross-calibration of the IP scanner Dürr CR35 BIO, used in ABC laboratory, was performed, using the Fujifilm FLA 7000 scanner as a reference, to find the equivalence between grey-scale values given by the Dürr scanner to PSL counts. Using an IP and a 55Fe β-source, we produced pairs of samples with the same exposition times, which were analysed by both scanners, placing particular attention to fading times of the image stored on IPs. Data analysis led us to the determine a conversion formula which can be used to compare data of experiments obtained in different laboratories and to use IP calibrations available, till now, only for Fujifilm scanners.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu-Tsao, S; Chan, M

Purpose: To study the effect of film scanning orientation for new EBT-XD film using Vidar and Epson scanners, compared with EBT3 films. Methods: The EBT-XD (lot#01081501) and EBT3 films (lot#11031501) were cut into 4cm×7cm pieces and each film piece was uniformly exposed to a 6MV photon beam (15×15cm{sup 2}) at 5 cm depth and 100cm SAD in polystyrene phantom, one at a time. The doses delivered were 0,2.5,5,10,20,30,40 and 50 Gy for EBT-XD films, and 0,0.5,1,2,4,8,12 and 16 Gy for EBT3 films, respectively. All films were scanned at least 16 hours after irradiation, one at a time, in portrait ormore » landscape orientation, using a Vidar DosimetryPro Advantage Red and an Epson 10000XL scanner (red channel). Each film piece was positioned at the center of a frame (36cm×36cm) with a cutout slightly larger than the film size for scanning. The scanned data (71 dpi), were analyzed using ImageJ and the average in the ROI (3cm×3cm) of each film at the center was obtained. Results: Dose response curves (netOD vs. dose) were established and compared with EBT-XD and EBT3 film in portrait or landscape orientation using these two scanners. The portrait to landscape (P/L) ratio for each film/scanner combination was determined. The EBT-XD film is about three times less sensitive than EBT3 film. The netOD is higher for portrait than landscape orientation for all the film/scanner combinations. For EBT-XD and EBT3, the average P/L ratios are 1.02 and 1.03 using Vidar scanner, and 1.03 and 1.05 using Epson scanner (red channel), respectively. Conclusion: The effect of film scanning orientation for new EBT-XD film using Vidar Advantage Red and Epson 10000XL scanners has been studied, in comparison with EBT3 film. The portrait/landscape ratios are the lowest for EBT-XD film using Vidar Advantage Red scanner among the four film/scanner combinations.« less

An RF dosimeter for independent SAR measurement in MRI scanners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.

2013-12-15

Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independentmore » SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.« less

MEMS temperature scanner: principles, advances, and applications

NASA Astrophysics Data System (ADS)

Otto, Thomas; Saupe, Ray; Stock, Volker; Gessner, Thomas

2010-02-01

Contactless measurement of temperatures has gained enormous significance in many application fields, ranging from climate protection over quality control to object recognition in public places or military objects. Thereby measurement of linear or spatially temperature distribution is often necessary. For this purposes mostly thermographic cameras or motor driven temperature scanners are used today. Both are relatively expensive and the motor drive devices are limited regarding to the scanning rate additionally. An economic alternative are temperature scanner devices based on micro mirrors. The micro mirror, attached in a simple optical setup, reflects the emitted radiation from the observed heat onto an adapted detector. A line scan of the target object is obtained by periodic deflection of the micro scanner. Planar temperature distribution will be achieved by perpendicularly moving the target object or the scanner device. Using Planck radiation law the temperature of the object is calculated. The device can be adapted to different temperature ranges and resolution by using different detectors - cooled or uncooled - and parameterized scanner parameters. With the basic configuration 40 spatially distributed measuring points can be determined with temperatures in a range from 350°C - 1000°C. The achieved miniaturization of such scanners permits the employment in complex plants with high building density or in direct proximity to the measuring point. The price advantage enables a lot of applications, especially new application in the low-price market segment This paper shows principle, setup and application of a temperature measurement system based on micro scanners working in the near infrared range. Packaging issues and measurement results will be discussed as well.

Do we really need to thank the Beatles for the financing of the development of the computed tomography scanner?

PubMed

Maizlin, Zeev V; Vos, Patrick M

2012-01-01

It is commonly believed that the revenues from the selling of the Beatles' records by Electric and Musical Industries (EMI) allowed the company to develop the computed tomography (CT) scanner. Some went to define this as the Beatles' gift to medicine. However, significant controversies and discrepancies arise from analysis of this statement, making its correctness doubtful. The details of financing required for the CT development and the part of EMI in financial input have never been publicly announced. This work analyzes the financial contributions to the CT development and investigates if the revenues received from the sales of the Beatles' records were used for the creation of the CT scanner. Timeline of the development of the EMI CT scanner and the financial inputs of EMI and British Department of Health and Social Security (DHSS) were assessed. Without salary expenses to Godfrey Hounsfield and his team, the development of the CT scanner cost EMI approximately £100,000. The British DHSS's expenses were £606,000. Hence, the financial contribution of DHSS into the development of the CT scanner was significantly bigger than that of EMI. Accordingly, British tax payers and officials of British DHSS are to be thanked for the CT scanner. The Beatles' input into the world's culture is valuable and does not require decoration by nonexistent connection to the development of CT. A positive aspect to this misconception is that it keeps in public memory the name of the company that developed the CT scanner.

Laser excited confocal microscope fluorescence scanner and method

DOEpatents

Mathies, R.A.; Peck, K.

1992-02-25

A fluorescent scanner is designed for scanning the fluorescence from a fluorescence labeled separated sample on a sample carrier. The scanner includes a confocal microscope for illuminating a predetermined volume of the sample carrier and/or receiving and processing fluorescence emissions from the volume to provide a display of the separated sample. 8 figs.

Using a Flatbed Scanner to Measure Detergency: A Cost-Effective Undergraduate Laboratory

ERIC Educational Resources Information Center

Poce-Fatou, J. A.; Bethencourt, M.; Moreno-Dorado, F. J.; Palacios-Santander, J. M.

2011-01-01

The efficiency of a laundry-washing process is typically assessed using reflection measurements. A spectrometer and an integrating sphere are used to obtain the reflection data. The similarities between this equipment and a commercially available flatbed scanner are examined, and the way a flatbed scanner can be used to obtain detergent…

FormScanner: Open-Source Solution for Grading Multiple-Choice Exams

ERIC Educational Resources Information Center

Young, Chadwick; Lo, Glenn; Young, Kaisa; Borsetta, Alberto

2016-01-01

The multiple-choice exam remains a staple for many introductory physics courses. In the past, people have graded these by hand or even flaming needles. Today, one usually grades the exams with a form scanner that utilizes optical mark recognition (OMR). Several companies provide these scanners and particular forms, such as the eponymous…

26. SITE BUILDING 002 SCANNER BUILDING OPERATIONS CENTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. SITE BUILDING 002 - SCANNER BUILDING - OPERATIONS CENTER - MWOC IN OPERATION AT 1945 ZULU TIME, 26 OCTOBER, 1999. "SPACE TRACK BOARD" DATA SHOWING ITEMS #16609 MIR (RUSSIA) AND #25544 ISS (INTERNATIONAL SPACE STATION) BEING TRACKED. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Quantitative Assay for Starch by Colorimetry Using a Desktop Scanner

ERIC Educational Resources Information Center

Matthews, Kurt R.; Landmark, James D.; Stickle, Douglas F.

2004-01-01

The procedure to produce standard curve for starch concentration measurement by image analysis using a color scanner and computer for data acquisition and color analysis is described. Color analysis is performed by a Visual Basic program that measures red, green, and blue (RGB) color intensities for pixels within the scanner image.

21. SITE BUILDING 002 SCANNER BUILDING LOOKING AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. SITE BUILDING 002 - SCANNER BUILDING - LOOKING AT DISC STORAGE SYSTEMS A AND B (A OR B ARE REDUNDANT SYSTEMS), ONE MAINFRAME COMPUTER ON LINE, ONE ON STANDBY WITH STORAGE TAPE, ONE ON STANDBY WITHOUT TAPE INSTALLED. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Panoramic attitude sensor for Radio Astronomy Explorer B

NASA Technical Reports Server (NTRS)

Thomsen, R.

1973-01-01

An instrument system to acquire attitude determination data for the RAE-B spacecraft was designed and built. The system consists of an electronics module and two optical scanner heads. Each scanner head has an optical scanner with a field of view of 0.7 degrees diameter which scans the sky and measures the position of the moon, earth and sun relative to the spacecraft. This scanning is accomplished in either of two modes. When the spacecraft is spinning, the scanner operates in spherical mode, with the spacecraft spin providing the slow sweep of lattitude to scan the entire sky. After the spacecraft is placed in lunar orbit and despun, the scanner will operate in planar mode, advancing at a rate of 5.12 seconds per revolution in a fixed plane parallel to the spacecraft Z axis. This scan will cross and measure the moon horizons with every revolution. Each scanner head also has a sun slit which is aligned parallel to the spin axis of the spacecraft and which provides a sun pulse each revolution of the spacecraft. The electronics module provides the command and control, data processing and housekeeping functions.

Analysis of the Performance of a Laser Scanner for Predictive Automotive Applications

NASA Astrophysics Data System (ADS)

Zeisler, J.; Maas, H.-G.

2015-08-01

In this paper we evaluate the use of a laser scanner for future advanced driver assistance systems. We focus on the important task of predicting the target vehicle for longitudinal ego vehicle control. Our motivation is to decrease the reaction time of existing systems during cut-in maneuvers of other traffic participants. A state-of-the-art laser scanner, the Ibeo Scala B2 R , is presented, providing its sensing characteristics and the subsequent high level object data output. We evaluate the performance of the scanner towards object tracking with the help of a GPS real time kinematics system on a test track. Two designed scenarios show phases with constant distance and velocity as well as dynamic motion of the vehicles. We provide the results for the error in position and velocity of the scanner and furthermore, review our algorithm for target vehicle prediction. Finally we show the potential of the laser scanner with the estimated error, that leads to a decrease of up to 40% in reaction time with best conditions.

Large area high-speed metrology SPM system.

PubMed

Klapetek, P; Valtr, M; Picco, L; Payton, O D; Martinek, J; Yacoot, A; Miles, M

2015-02-13

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm(2) regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Large area high-speed metrology SPM system

NASA Astrophysics Data System (ADS)

Klapetek, P.; Valtr, M.; Picco, L.; Payton, O. D.; Martinek, J.; Yacoot, A.; Miles, M.

2015-02-01

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm2 regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Using flatbed scanners in the undergraduate optics laboratory—An example of frugal science

NASA Astrophysics Data System (ADS)

Koopman, Thomas; Gopal, Venkatesh

2017-05-01

We describe the use of a low-cost commercial flatbed scanner in the undergraduate teaching laboratory to image large (˜25 cm) interference and diffraction patterns in two dimensions. Such scanners usually have an 8-bit linear photosensor array that can scan large areas (˜28 cm × 22 cm) at very high spatial resolutions (≥100 Megapixels), which makes them versatile large-format imaging devices. We describe how the scanner can be used to image interference and diffraction from rectangular single-slit, double-slit, and circular apertures. The experiments are very simple to setup and require no specialized components besides a small laser and a flatbed scanner. Due to the presence of Automatic Gain Control in the scanner, which we were not able to override, we were unable to get an excellent fit to the data. Interestingly, we found that the less-than-ideal data were actually pedagogically superior as it forced the students to think about the process of data acquisition in much greater detail instead of simply performing the experiment mechanically.

Application of multispectral scanner data to the study of an abandoned surface coal mine

NASA Technical Reports Server (NTRS)

Spisz, E. W.

1978-01-01

The utility of aircraft multispectral scanner data for describing the land cover features of an abandoned contour-mined coal mine is considered. The data were obtained with an 11 band multispectral scanner at an altitude of 1.2 kilometers. Supervised, maximum-likelihood statistical classifications of the data were made to establish land-cover classes and also to describe in more detail the barren surface features as they may pertain to the reclamation or restoration of the area. The scanner data for the surface-water areas were studied to establish the variability and range of the spectral signatures. Both day and night thermal images of the area are presented. The results of the study show that a high degree of statistical separation can be obtained from the multispectral scanner data for the various land-cover features.

Feasibility Study of an Axially Extendable Multiplex Cylinder PET

NASA Astrophysics Data System (ADS)

Yoshida, Eiji; Hirano, Yoshiyuki; Tashima, Hideaki; Inadama, Naoko; Nishikido, Fumihiko; Murayama, Hideo; Ito, Hiroshi; Yamaya, Taiga

2013-10-01

Current clinical PET scanners have a 15-22 cm axial field-of-view (FOV). These scanners image the whole body using six or more bed positions. We designed an axially extendable multiplex cylinder (AEMC) PET scanner to provide high versatility for clinical and research studies using semiconductor photo-sensor based, depth-of-interaction (DOI) detectors. Since silicon-photomultipliers (Si-PMs) have high gain like conventional photomultiplier tubes and a compact design, the Si-PM-based detector is particularly expected to enable various new detector arrangements. The AEMC-PET scanner consists of multiple independent and laminated detector rings using the DOI detectors. The AEMC-PET scanner can extend the axial FOV as each stacked detector ring can be slid sideways. When this PET scanner is used for the four-layer DOI detector, its minimum axial FOV is 24 cm and its maximum crystal thickness is 3 cm. On the other hand, the axial FOV can be extended to 96 cm when laminated detector rings are slid sideways, but the crystal thickness must be 1/4 of 3 cm. In this work, we evaluated performance characteristics of the PET scanner with a variable axial FOV using Monte Carlo simulation. From the simulation of the 180-cm line source, the 96-cm axial FOV was found to have two-fold better sensitivity compared to the 24-cm axial FOV. For extension of the axial FOV, scatter and attenuation of oblique lines-of-response reduced the yield of true coincidences, but effects of scatter and attenuation were small. Conclusive results were obtained showing the 52.8-cm axial FOV yielded an increase in the noise equivalent count rate of approximately 30% relative to the 24-cm axial FOV. We expect the designed AEMC-PET scanner will provide high versatility in applications such as for measuring whole-body tracer uptakes while keeping the continuous axial FOV; as well, the scan time for static images will be reduced for a comparable number of detectors as conventional PET scanners.

Incorporation of a laser range scanner into image-guided liver surgery: surface acquisition, registration, and tracking.

PubMed

Cash, David M; Sinha, Tuhin K; Chapman, William C; Terawaki, Hiromi; Dawant, Benoit M; Galloway, Robert L; Miga, Michael I

2003-07-01

As image guided surgical procedures become increasingly diverse, there will be more scenarios where point-based fiducials cannot be accurately localized for registration and rigid body assumptions no longer hold. As a result, procedures will rely more frequently on anatomical surfaces for the basis of image alignment and will require intraoperative geometric data to measure and compensate for tissue deformation in the organ. In this paper we outline methods for which a laser range scanner may be used to accomplish these tasks intraoperatively. A laser range scanner based on the optical principle of triangulation acquires a dense set of three-dimensional point data in a very rapid, noncontact fashion. Phantom studies were performed to test the ability to link range scan data with traditional modes of image-guided surgery data through localization, registration, and tracking in physical space. The experiments demonstrate that the scanner is capable of localizing point-based fiducials to within 0.2 mm and capable of achieving point and surface based registrations with target registration error of less than 2.0 mm. Tracking points in physical space with the range scanning system yields an error of 1.4 +/- 0.8 mm. Surface deformation studies were performed with the range scanner in order to determine if this device was capable of acquiring enough information for compensation algorithms. In the surface deformation studies, the range scanner was able to detect changes in surface shape due to deformation comparable to those detected by tomographic image studies. Use of the range scanner has been approved for clinical trials, and an initial intraoperative range scan experiment is presented. In all of these studies, the primary source of error in range scan data is deterministically related to the position and orientation of the surface within the scanner's field of view. However, this systematic error can be corrected, allowing the range scanner to provide a rapid, robust method of acquiring anatomical surfaces intraoperatively.

Evaluation of the accuracy of extraoral laboratory scanners with a single-tooth abutment model: A 3D analysis.

PubMed

Mandelli, Federico; Gherlone, Enrico; Gastaldi, Giorgio; Ferrari, Marco

2017-10-01

The aim of this study was to compare the accuracy of different laboratory scanners using a calibrated coordinate measuring machine as reference. A sand blasted titanium reference model (RM) was scanned with an industrial 3D scanner in order to obtain a reference digital model (dRM) that was saved in the standard tessellation format (.stl). RM was scanned ten times with each one of the tested scanners (GC Europe Aadva, Zfx Evolution, 3Shape D640, 3Shape D700, NobilMetal Sinergia, EGS DScan3, Open Technologies Concept Scan Top) and all the scans were exported in .stl format for the comparison. All files were imported in a dedicated software (Geomagic Qualify 2013). Accuracy was evaluated calculating trueness and precision. Trueness values (μm [95% confidence interval]) were: Aadva 7,7 [6,8-8,5]; Zfx Evolution 9,2 [8,6-9,8]; D640 18,1 [12,2-24,0]; D700 12,8 [12,4-13,3]; Sinergia 31,1 [26,3-35,9]; DScan3 15,6 [11,5-19,7]; Concept Scan Top 28,6 [25,6-31,6]. Differences between scanners were statistically significant (p<.0005). Precision values (μm [95% CI]) were: Aadva 4,0 [3,8-4,2]; Zfx Evolution 5,1 [4,4-5,9]; D640 12,7 [12,4-13,1]; D700 11,0 [10,7-11,3]; Sinergia 16,3 [15,0-17,5]; DScan3 9,5 [8,3-10,6]; Concept Scan Top 19,5 [19,1-19,8]. Differences between scanners were statistically significant (p<.0005). The use a standardized scanning procedure fabricating a titanium reference model is useful to compare trueness and precision of different laboratory scanners; two laboratory scanners (Aadva, Zfx Evolution) were significantly better that other tested scanners. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Simulation study of a D-shape PET scanner for improved sensitivity and reduced cost in whole-body imaging

NASA Astrophysics Data System (ADS)

Ahmed, Abdella M.; Tashima, Hideaki; Yamaya, Taiga

2017-05-01

Much research effort is being made to increase the sensitivity and improve the imaging performance of positron emission tomography (PET) scanners. Conventionally, sensitivity can be increased by increasing the number of detector rings in the axial direction (but at high cost) or reducing the diameter of the scanner (with the disadvantages of reducing the space for patients and degrading the spatial resolution due to the parallax error). In this study, we proposed a PET scanner with a truncated ring and an array of detectors that can be arranged in a straight line below the bed. We called this system ‘D-PET’ as it resembles the letter ‘D’ when it is rotated by 90° in the counterclockwise direction. The basic design idea was to cut the unused space under the patient’s bed; this area is usually not in use in clinical diagnosis. We conducted Monte Carlo simulations of the D-PET scanner and compared its performance with a cylindrical PET scanner. The scanners were constructed from 4-layer depth-of-interaction detectors which consisted of a 16  ×  16  ×  4 LYSO crystal array with dimensions of 2.85  ×  2.85  ×  5 mm3. The results showed that the D-PET had an increase in sensitivity and peak-NECR of 30% and 18%, respectively. The D-PET had low noise in the reconstructed images throughout the field-of-view compared to the cylindrical PET. These were achieved while keeping sufficient space for the patient, and also without a severe effect on the spatial resolution. Furthermore, the number of detectors (and hence the cost) of the D-PET scanner was reduced by 12% compared to the cylindrical PET scanner.

Investigation of spatial resolution improvement by use of a mouth-insert detector in the helmet PET scanner.

PubMed

Ahmed, Abdella M; Tashima, Hideaki; Yamaya, Taiga

2018-03-01

The dominant factor limiting the intrinsic spatial resolution of a positron emission tomography (PET) system is the size of the crystal elements in the detector. To increase sensitivity and achieve high spatial resolution, it is essential to use advanced depth-of-interaction (DOI) detectors and arrange them close to the subject. The DOI detectors help maintain high spatial resolution by mitigating the parallax error caused by the thickness of the scintillator near the peripheral regions of the field-of-view. As an optimal geometry for a brain PET scanner, with high sensitivity and spatial resolution, we proposed and developed the helmet-chin PET scanner using 54 four-layered DOI detectors consisting of a 16 × 16 × 4 array of GSOZ scintillator crystals with dimensions of 2.8 × 2.8 × 7.5 mm 3 . All the detectors used in the helmet-chin PET scanner had the same spatial resolution. In this study, we conducted a feasibility study of a new add-on detector arrangement for the helmet PET scanner by replacing the chin detector with a segmented crystal cube, having high spatial resolution in all directions, which can be placed inside the mouth. The crystal cube (which we have named the mouth-insert detector) has an array of 20 × 20 × 20 LYSO crystal segments with dimensions of 1 × 1 × 1 mm 3 . Thus, the scanner is formed by the combination of the helmet and mouth-insert detectors, and is referred to as the helmet-mouth-insert PET scanner. The results show that the helmet-mouth-insert PET scanner has comparable sensitivity and improved spatial resolution near the center of the hemisphere, compared to the helmet-chin PET scanner.

MR Scanner Systems Should Be Adequately Characterized in Diffusion-MRI of the Breast

PubMed Central

Giannelli, Marco; Sghedoni, Roberto; Iacconi, Chiara; Iori, Mauro; Traino, Antonio Claudio; Guerrisi, Maria; Mascalchi, Mario; Toschi, Nicola; Diciotti, Stefano

2014-01-01

Breast imaging represents a relatively recent and promising field of application of quantitative diffusion-MRI techniques. In view of the importance of guaranteeing and assessing its reliability in clinical as well as research settings, the aim of this study was to specifically characterize how the main MR scanner system-related factors affect quantitative measurements in diffusion-MRI of the breast. In particular, phantom acquisitions were performed on three 1.5 T MR scanner systems by different manufacturers, all equipped with a dedicated multi-channel breast coil as well as acquisition sequences for diffusion-MRI of the breast. We assessed the accuracy, inter-scan and inter-scanner reproducibility of the mean apparent diffusion coefficient measured along the main orthogonal directions () as well as of diffusion-tensor imaging (DTI)-derived mean diffusivity (MD) measurements. Additionally, we estimated spatial non-uniformity of (NU) and MD (NUMD) maps. We showed that the signal-to-noise ratio as well as overall calibration of high strength diffusion gradients system in typical acquisition sequences for diffusion-MRI of the breast varied across MR scanner systems, introducing systematic bias in the measurements of diffusion indices. While and MD values were not appreciably different from each other, they substantially varied across MR scanner systems. The mean of the accuracies of measured and MD was in the range [−2.3%,11.9%], and the mean of the coefficients of variation for and MD measurements across MR scanner systems was 6.8%. The coefficient of variation for repeated measurements of both and MD was < 1%, while NU and NUMD values were <4%. Our results highlight that MR scanner system-related factors can substantially affect quantitative diffusion-MRI of the breast. Therefore, a specific quality control program for assessing and monitoring the performance of MR scanner systems for diffusion-MRI of the breast is highly recommended at every site, especially in multicenter and longitudinal studies. PMID:24489711

Optical instruments

NASA Technical Reports Server (NTRS)

Abel, I. R. (Inventor)

1974-01-01

A wide angle, low focal ratio, high resolution, catoptric, image plane scanner is described. The scanner includes the following features: (1) a reflective improvement on the Schmidt principle, (2) a polar line scanner in which all field elements are brought to and corrected on axis, and (3) a scanner arrangement in which the aperture stop of the system is imaged at the center of curvature of a spherical primary mirror. The system scans are a large radial angle and an extremely high rate of speed with relatively small scanning mirrors. Because the system is symmetrical about the optical axis, the obscuration is independent of the scan angle.

Land use classification utilizing remote multispectral scanner data and computer analysis techniques

NASA Technical Reports Server (NTRS)

Leblanc, P. N.; Johannsen, C. J.; Yanner, J. E.

1973-01-01

An airborne multispectral scanner was used to collect the visible and reflective infrared data. A small subdivision near Lafayette, Indiana was selected as the test site for the urban land use study. Multispectral scanner data were collected over the subdivision on May 1, 1970 from an altitude of 915 meters. The data were collected in twelve wavelength bands from 0.40 to 1.00 micrometers by the scanner. The results indicated that computer analysis of multispectral data can be very accurate in classifying and estimating the natural and man-made materials that characterize land uses in an urban scene.

A general solution for the registration of optical multispectral scanners

NASA Technical Reports Server (NTRS)

Rader, M. L.

1974-01-01

The paper documents a general theory for registration (mapping) of data sets gathered by optical scanners such as the ERTS satellite MSS and the Skylab S-192 MSS. This solution is generally applicable to scanners which have rotating optics. Navigation data and ground control points are used in a statistically weighted adjustment based on a mathematical model of the dynamics of the spacecraft and the scanner system. This adjustment is very similar to the well known photogrammetric adjustments used in aerial mapping. Actual tests have been completed on NASA aircraft 24 channel MSS data, and the results are very encouraging.

MFP scanner motion characterization using self-printed target

NASA Astrophysics Data System (ADS)

Kim, Minwoong; Bauer, Peter; Wagner, Jerry K.; Allebach, Jan P.

2015-01-01

Multifunctional printers (MFP) are products that combine the functions of a printer, scanner, and copier. Our goal is to help customers to be able to easily diagnose scanner or print quality issues with their products by developing an automated diagnostic system embedded in the product. We specifically focus on the characterization of scanner motions, which may be defective due to irregular movements of the scan-head. The novel design of our test page and two-stage diagnostic algorithm are described in this paper. The most challenging issue is to evaluate the scanner performance properly when both printer and scanner units contribute to the motion errors. In the first stage called the uncorrected-print-error-stage, aperiodic and periodic motion behaviors are characterized in both the spatial and frequency domains. Since it is not clear how much of the error is contributed by each unit, the scanned input is statistically analyzed in the second stage called the corrected-print-error-stage. Finally, the described diagnostic algorithms output the estimated scan error and print error separately as RMS values of the displacement of the scan and print lines, respectively, from their nominal positions in the scanner or printer motion direction. We validate our test page design and approaches by ground truth obtained from a high-precision, chrome-on-glass reticle manufactured using semiconductor chip fabrication technologies.

Experimental flat-panel high-spatial-resolution volume CT of the temporal bone.

PubMed

Gupta, Rajiv; Bartling, Soenke H; Basu, Samit K; Ross, William R; Becker, Hartmut; Pfoh, Armin; Brady, Thomas; Curtin, Hugh D

2004-09-01

A CT scanner employing a digital flat-panel detector is capable of very high spatial resolution as compared with a multi-section CT (MSCT) scanner. Our purpose was to determine how well a prototypical volume CT (VCT) scanner with a flat-panel detector system defines fine structures in temporal bone. Four partially manipulated temporal-bone specimens were imaged by use of a prototypical cone-beam VCT scanner with a flat-panel detector system at an isometric resolution of 150 microm at the isocenter. These specimens were also depicted by state-of-the-art multisection CT (MSCT). Forty-two structures imaged by both scanners were qualitatively assessed and rated, and scores assigned to VCT findings were compared with those of MSCT. Qualitative assessment of anatomic structures, lesions, cochlear implants, and middle-ear hearing aids indicated that image quality was significantly better with VCT (P < .001). Structures near the spatial-resolution limit of MSCT (e.g., bony covering of the tympanic segment of the facial canal, the incudo-stapedial joint, the proximal vestibular aqueduct, the interscalar septum, and the modiolus) had higher contrast and less partial-volume effect with VCT. The flat-panel prototype provides better definition of fine osseous structures of temporal bone than that of currently available MSCT scanners. This study provides impetus for further research in increasing spatial resolution beyond that offered by the current state-of-the-art scanners.

A simple way to higher speed atomic force microscopy by retrofitting with a novel high-speed flexure-guided scanner

NASA Astrophysics Data System (ADS)

Ouma Alunda, Bernard; Lee, Yong Joong; Park, Soyeun

2018-06-01

A typical line-scan rate for a commercial atomic force microscope (AFM) is about 1 Hz. At such a rate, more than four minutes of scanning time is required to obtain an image of 256 × 256 pixels. Despite control electronics of most commercial AFMs permit faster scan rates, default piezoelectric X–Y scanners limit the overall speed of the system. This is a direct consequence of manufacturers choosing a large scan range over the maximum operating speed for a X–Y scanner. Although some AFM manufacturers offer reduced-scan area scanners as an option, the speed improvement is not significant because such scanners do not have large enough reduction in the scan range and are mainly targeted to reducing the overall cost of the AFM systems. In this article, we present a simple parallel-kinematic substitute scanner for a commercial atomic force microscope to afford a higher scanning speed with no other hardware or software upgrade to the original system. Although the scan area reduction is unavoidable, our modified commercial XE-70 AFM from Park Systems has achieved a line scan rate of over 50 Hz, more than 10 times faster than the original, unmodified system. Our flexure-guided X–Y scanner can be a simple drop-in replacement option for enhancing the speed of various aging atomic force microscopes.

In vitro evaluation of prosthodontic impression on natural dentition: a comparison between traditional and digital techniques

PubMed Central

MALAGUTI, G.; ROSSI, R.; MARZIALI, B.; ESPOSITO, A.; BRUNO, G.; DARIOL, C.; DI FIORE, A.

2016-01-01

SUMMARY Objectives The aim of this in vitro study is to evaluate the marginal and internal fit of zirconia core crowns manufactured following different digital and traditional workflows. Methods A 6° taper shoulder prepared abutment tooth was used to produce 20 zirconia core crowns using four different scanning techniques: scanned directly with the extraoral lab scanner, scanned with intraoral scanner, dental impressions using individual dental tray and polyether, dental casts from a polyether impressions. Marginal and internal fits were evaluated with digital photography and the silicone replica method. Results Medium marginal gaps were 76,00 μm ± 28.9 for extraoral lab scanner, 80.50 μm ± 36,2 for intraoral scanner, 88.10 μm ± 34,8 for dental impression scan and 112,4 μm ± 37,2 for dental cast scan. Medium internal gaps were 23.20 μm ± 10,3 for extraoral lab scanner, 16.20 μm ± 8.3 for intraoral scanner, 27.20 μm ± 16.7 for dental impression scan and 30.20 μm ± 12.7 for dental cast scan. Conclusion Internal gap were extensively lower than 70 μm described in literature. Marginal fit was higher than ideal values for all the techniques but within the limit of clinical success. Intraoral scanners obtained the best results for internal gap. PMID:28280529

Performance Evaluation of a PEM Scanner Using the NEMA NU 4—2008 Small Animal PET Standards

NASA Astrophysics Data System (ADS)

Luo, Weidong; Anashkin, Edward; Matthews, Christopher G.

2010-02-01

The recently published NEMA NU 4-2008 Standards has been specially designed for evaluating the performance of small animal PET scanners used in preclinical applications. In this paper, we report on the NU 4 performance of a clinical positron emission mammography (PEM) system. Since there are no PEM specific performance test protocols available, and the NU 2 protocol (intended for whole-body PET scanners) cannot be applied without modification due to the compact design of the PEM scanner, we decided to evaluate the NU 4 Standards as an alternative. We obtained the following results: Trans-axial spatial resolution 1.8 mm FWHM for high resolution reconstruction mode and 2.4 mm FWHM for standard resolution reconstruction mode with no significant variation within the field of view. The total system sensitivity was 0.16 cps/Bq. In image quality testing, the uniformity was found to be 3.9% STD at the standard resolution mode and 5.6% at the high resolution mode when measured with a 34 mm paddle separation. The NEMA NU 4-2008 Standards were found to be a practicable tool to evaluate the performance of the PEM scanner after some modifications to address the specifics of its detector configuration. Furthermore, the PEM scanner's in-plane spatial resolution was comparable to other small animal PET scanners with good image quality.

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND MAINTENANCE OF DATA SCANNERS (UA-D-32.1)

EPA Science Inventory

The purpose of this SOP is to define the steps needed to operate the data scanners that were used during the Arizona NHEXAS project and the "Border" study. Keywords: data; equipment; scanner.

The National Human Exposure Assessment Survey (NHEXAS) is a federal interagency resear...

Technology as an Occasion for Structuring: Evidence from Observations of CT Scanners and the Social Order of Radiology Departments.

ERIC Educational Resources Information Center

Barley, Stephen R.

1986-01-01

New technologies such as the CT scanner are challenging traditional role relations among radiology workers and may be altering the organizational and occupational structure of radiological work. This paper expands recent sociological thought by showing how identical CT scanners occasion similar structuring processes and created divergent forms of…

SU-G-206-07: Dual-Energy CT Inter- and Intra-Scanner Variability Within One Make and Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobsen, M; Wood, C; Cody, D

Purpose: It can be logistically quite difficult to scan patients on the same exact device for their repeat visits in multi-scanner facilities. The reliability between dual-energy CT scanners’ quantitative results is not known, nor is their individual repeatability. Therefore, we evaluated inter- and intra-scanner variability with respect to several key clinical quantitative metrics specific to dual-energy CT. Methods: Eleven identical GE HD-750 CT scanners in a busy clinical environment were used to perform dual-energy (DE) CT scans of a large elliptical quality control (QC) phantom (Gammex, Inc.; Middleton, WI) which contains many standard insert materials. The DE-QC phantom was scannedmore » bi-weekly during 2016; 3 to 4 scans were obtained from each scanner (a total of 35 data sets were used for analysis). Iodine accuracy for the 2mg/ml, 5mg/ml and 15mg/ml rods (from the Iodine(Water) image set) and soft tissue HU (40 HU based on NIST constants) from the 50keV data set were used to assess inter- and intra-scanner variability (standard deviation). Results: Intra-scanner variability average for 2mg/ml Iodine was 0.10 mg/ml (range 0.05–0.15 mg/ml), for 5mg/ml Iodine was 0.12 mg/ml (range 0.07–0.16 mg/ml), for 15 mg/ml Iodine was 0.25 mg/ml (range 0.16–0.37 mg/ml), and for the soft tissue inserts was 2.1 HU (range 1.8–2.6 HU). Inter-scanner variability average for 2mg/ml Iodine was 0.16 mg/ml (range 0.11–0.19 mg/ml), for 5mg/ml Iodine was 0.18 mg/ml (range 0.11–0.22 mg/ml), for 15 mg/ml Iodine was 0.35 mg/ml (range 0.23–0.44 mg/ml), and for the soft tissue inserts was 3.8 HU (range 3.1–4.5 HU). Conclusion: Intra-scanner variability for the iodine and soft tissue inserts averaged 3.1% and 5.2% respectively, and inter-scanner variability for these regions analyzed averaged 5.0% and 9.5%, respectively. Future work will include determination of smallest measurable change and acceptable limits for DE-CT scanner variability over longer time intervals. This research has been supported by funds from Dr. William Murphy, Jr., the John S. Dunn, Sr. Distinguished Chair in Diagnostic Imaging at MD Anderson Cancer Center.« less

Scanner qualification with IntenCD based reticle error correction

NASA Astrophysics Data System (ADS)

Elblinger, Yair; Finders, Jo; Demarteau, Marcel; Wismans, Onno; Minnaert Janssen, Ingrid; Duray, Frank; Ben Yishai, Michael; Mangan, Shmoolik; Cohen, Yaron; Parizat, Ziv; Attal, Shay; Polonsky, Netanel; Englard, Ilan

2010-03-01

Scanner introduction into the fab production environment is a challenging task. An efficient evaluation of scanner performance matrices during factory acceptance test (FAT) and later on during site acceptance test (SAT) is crucial for minimizing the cycle time for pre and post production-start activities. If done effectively, the matrices of base line performance established during the SAT are used as a reference for scanner performance and fleet matching monitoring and maintenance in the fab environment. Key elements which can influence the cycle time of the SAT, FAT and maintenance cycles are the imaging, process and mask characterizations involved with those cycles. Discrete mask measurement techniques are currently in use to create across-mask CDU maps. By subtracting these maps from their final wafer measurement CDU map counterparts, it is possible to assess the real scanner induced printed errors within certain limitations. The current discrete measurement methods are time consuming and some techniques also overlook mask based effects other than line width variations, such as transmission and phase variations, all of which influence the final printed CD variability. Applied Materials Aera2TM mask inspection tool with IntenCDTM technology can scan the mask at high speed, offer full mask coverage and accurate assessment of all masks induced source of errors simultaneously, making it beneficial for scanner qualifications and performance monitoring. In this paper we report on a study that was done to improve a scanner introduction and qualification process using the IntenCD application to map the mask induced CD non uniformity. We will present the results of six scanners in production and discuss the benefits of the new method.

Two examples of indication specific radiation dose calculations in dental CBCT and Multidetector CT scanners.

PubMed

Stratis, Andreas; Zhang, Guozhi; Lopez-Rendon, Xochitl; Politis, Constantinus; Hermans, Robert; Jacobs, Reinhilde; Bogaerts, Ria; Shaheen, Eman; Bosmans, Hilde

2017-09-01

To calculate organ doses and estimate the effective dose for justification purposes in patients undergoing orthognathic treatment planning purposes and temporal bone imaging in dental cone beam CT (CBCT) and Multidetector CT (MDCT) scanners. The radiation dose to the ICRP reference male voxel phantom was calculated for dedicated orthognathic treatment planning acquisitions via Monte Carlo simulations in two dental CBCT scanners, Promax 3D Max (Planmeca, FI) and NewTom VGi evo (QR s.r.l, IT) and in Somatom Definition Flash (Siemens, DE) MDCT scanner. For temporal bone imaging, radiation doses were calculated via MC simulations for a CBCT protocol in NewTom 5G (QR s.r.l, IT) and with the use of a software tool (CT-expo) for Somatom Force (Siemens, DE). All procedures had been optimized at the acceptance tests of the devices. For orthognathic protocols, dental CBCT scanners deliver lower doses compared to MDCT scanners. The estimated effective dose (ED) was 0.32mSv for a normal resolution operation mode in Promax 3D Max, 0.27mSv in VGi-evo and 1.18mSv in the Somatom Definition Flash. For temporal bone protocols, the Somatom Force resulted in an estimated ED of 0.28mSv while for NewTom 5G the ED was 0.31 and 0.22mSv for monolateral and bilateral imaging respectively. Two clinical exams which are carried out with both a CBCT or a MDCT scanner were compared in terms of radiation dose. Dental CBCT scanners deliver lower doses for orthognathic patients whereas for temporal bone procedures the doses were similar. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Comparison and use of 3D scanners to improve the quantification of medical images (surface structures and volumes) during follow up of clinical (surgical) procedures

NASA Astrophysics Data System (ADS)

Tokkari, Niki; Verdaasdonk, Rudolf M.; Liberton, Niels; Wolff, Jan; den Heijer, Martin; van der Veen, Albert; Klaessens, John H.

2017-02-01

It is difficult to obtain quantitative measurements as to surface areas and volumes from standard photos of the body parts of patients which is highly desirable for objective follow up of treatments in e.g. dermatology. plastic, aesthetic and reconstructive surgery. Recently, 3-D scanners have become available to provide quantification. Phantoms (3-D printed hand, nose and ear, colored bread sculpture) were developed to compare a range from low-cost (Sense), medium (HP Sprout) to high end (Artec Spider, Vectra M3) scanners using different 3D imaging technologies, as to resolution, working range, surface color representation, user friendliness. The 3D scans files (STL, OBJ) were processed with Artec studio and GOM software as to deviation compared to the high resolution Artec Spider scanner taken as `golden' standard. The HP Spout, which uses a fringe projection, proved to be nearly as good as the Artec, however, needs to be converted for clinical use. Photogrammetry as used by the Vectra M3 scanner is limited to provide sufficient data points for accurate surface mapping however provides good color/structure representation. The low performance of the Sense is not recommended for clinical use. The Artec scanner was successfully used to measure the structure/volume changes in the face after hormone treatment in transgender patients. 3D scanners can greatly improve quantitative measurements of surfaces and volumes as objective follow up in clinical studies performed by various clinical specialisms (dermatology, aesthetic and reconstructive surgery). New scanning technologies, like fringe projection, are promising for development of low-cost, high precision scanners.

Improved spatial resolution in PET scanners using sampling techniques

PubMed Central

Surti, Suleman; Scheuermann, Ryan; Werner, Matthew E.; Karp, Joel S.

2009-01-01

Increased focus towards improved detector spatial resolution in PET has led to the use of smaller crystals in some form of light sharing detector design. In this work we evaluate two sampling techniques that can be applied during calibrations for pixelated detector designs in order to improve the reconstructed spatial resolution. The inter-crystal positioning technique utilizes sub-sampling in the crystal flood map to better sample the Compton scatter events in the detector. The Compton scatter rejection technique, on the other hand, rejects those events that are located further from individual crystal centers in the flood map. We performed Monte Carlo simulations followed by measurements on two whole-body scanners for point source data. The simulations and measurements were performed for scanners using scintillators with Zeff ranging from 46.9 to 63 for LaBr3 and LYSO, respectively. Our results show that near the center of the scanner, inter-crystal positioning technique leads to a gain of about 0.5-mm in reconstructed spatial resolution (FWHM) for both scanner designs. In a small animal LYSO scanner the resolution improves from 1.9-mm to 1.6-mm with the inter-crystal technique. The Compton scatter rejection technique shows higher gains in spatial resolution but at the cost of reduction in scanner sensitivity. The inter-crystal positioning technique represents a modest acquisition software modification for an improvement in spatial resolution, but at a cost of potentially longer data correction and reconstruction times. The Compton scatter rejection technique, while also requiring a modest acquisition software change with no increased data correction and reconstruction times, will be useful in applications where the scanner sensitivity is very high and larger improvements in spatial resolution are desirable. PMID:19779586

Measurement properties and usability of non-contact scanners for measuring transtibial residual limb volume.

PubMed

Kofman, Rianne; Beekman, Anna M; Emmelot, Cornelis H; Geertzen, Jan H B; Dijkstra, Pieter U

2018-06-01

Non-contact scanners may have potential for measurement of residual limb volume. Different non-contact scanners have been introduced during the last decades. Reliability and usability (practicality and user friendliness) should be assessed before introducing these systems in clinical practice. The aim of this study was to analyze the measurement properties and usability of four non-contact scanners (TT Design, Omega Scanner, BioSculptor Bioscanner, and Rodin4D Scanner). Quasi experimental. Nine (geometric and residual limb) models were measured on two occasions, each consisting of two sessions, thus in total 4 sessions. In each session, four observers used the four systems for volume measurement. Mean for each model, repeatability coefficients for each system, variance components, and their two-way interactions of measurement conditions were calculated. User satisfaction was evaluated with the Post-Study System Usability Questionnaire. Systematic differences between the systems were found in volume measurements. Most of the variances were explained by the model (97%), while error variance was 3%. Measurement system and the interaction between system and model explained 44% of the error variance. Repeatability coefficient of the systems ranged from 0.101 (Omega Scanner) to 0.131 L (Rodin4D). Differences in Post-Study System Usability Questionnaire scores between the systems were small and not significant. The systems were reliable in determining residual limb volume. Measurement systems and the interaction between system and residual limb model explained most of the error variances. The differences in repeatability coefficient and usability between the four CAD/CAM systems were small. Clinical relevance If accurate measurements of residual limb volume are required (in case of research), modern non-contact scanners should be taken in consideration nowadays.

Free-space wavelength-multiplexed optical scanner demonstration.

PubMed

Yaqoob, Zahid; Riza, Nabeel A

2002-09-10

Experimental demonstration of a no-moving-parts free-space wavelength-multiplexed optical scanner (W-MOS) is presented. With fast tunable lasers or optical filters and planar wavelength dispersive elements such as diffraction gratings, this microsecond-speed scanner enables large several-centimeter apertures for subdegree angular scans. The proposed W-MOS design incorporates a unique optical amplifier and variable optical attenuator combination that enables the calibration and modulation of the scanner response, leading to any desired scanned laser beam power shaping. The experimental setup uses a tunable laser centered at 1560 nm and a 600-grooves/mm blazed reflection grating to accomplish an angular scan of 12.92 degrees as the source is tuned over an 80-nm bandwidth. The values for calculated maximum optical beam divergance, required wavelength resolution, beam-pointing accuracy, and measured scanner insertion loss are 1.076 mrad, 0.172 nm, 0.06 mrad, and 4.88 dB, respectively.

Selecting a CT scanner for cardiac imaging: the heart of the matter.

PubMed

Lewis, Maria A; Pascoal, Ana; Keevil, Stephen F; Lewis, Cornelius A

2016-09-01

Coronary angiography to assess the presence and degree of arterial stenosis is an examination now routinely performed on CT scanners. Although developments in CT technology over recent years have made great strides in improving the diagnostic accuracy of this technique, patients with certain characteristics can still be "difficult to image". The various groups will benefit from different technological enhancements depending on the type of challenge they present. Good temporal and spatial resolution, wide longitudinal (z-axis) detector coverage and high X-ray output are the key requirements of a successful CT coronary angiography (CTCA) scan. The requirement for optimal patient dose is a given. The different scanner models recommended for CTCA all excel in different aspects. The specification data presented here for these scanners and the explanation of the impact of the different features should help in making a more informed decision when selecting a scanner for CTCA.

Spectral signature selection for mapping unvegetated soils

NASA Technical Reports Server (NTRS)

May, G. A.; Petersen, G. W.

1975-01-01

Airborne multispectral scanner data covering the wavelength interval from 0.40-2.60 microns were collected at an altitude of 1000 m above the terrain in southeastern Pennsylvania. Uniform training areas were selected within three sites from this flightline. Soil samples were collected from each site and a procedure developed to allow assignment of scan line and element number from the multispectral scanner data to each sampling location. These soil samples were analyzed on a spectrophotometer and laboratory spectral signatures were derived. After correcting for solar radiation and atmospheric attenuation, the laboratory signatures were compared to the spectral signatures derived from these same soils using multispectral scanner data. Both signatures were used in supervised and unsupervised classification routines. Computer-generated maps using the laboratory and multispectral scanner derived signatures resulted in maps that were similar to maps resulting from field surveys. Approximately 90% agreement was obtained between classification maps produced using multispectral scanner derived signatures and laboratory derived signatures.

Predicting the Impact of Full Body Scanners on Air Travel and Passenger Safety

DTIC Science & Technology

2010-06-01

May 31, 2010, from http://www.tampaairport.com/security/index.asp Travis, A. (2010). New scanners break child porn laws. Guardian.co.uk. Retrieved...May 20, 2010, from http://www.guardian.co.uk/politics/2010/jan/04/new-scanners- child - porn -laws TSA.gov, Transportaion Security Administration. (2010...16 1. Child Pornography and Health ........................................................16 2. Government’s

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND MAINTENANCE OF DATA SCANNERS (UA-D-32.1)

EPA Science Inventory

The purpose of this SOP is to define the steps needed to operate the data scanners that were used during the Arizona NHEXAS project and the Border study. Keywords: data; equipment; scanner.

The U.S.-Mexico Border Program is sponsored by the Environmental Health Workgroup of the...

Design study for Thermal Infrared Multispectral Scanner (TIMS)

NASA Technical Reports Server (NTRS)

Stanich, C. G.; Osterwisch, F. G.; Szeles, D. M.; Houtman, W. H.

1981-01-01

The feasibility of dividing the 8-12 micrometer thermal infrared wavelength region into six spectral bands by an airborne line scanner system was investigated. By combining an existing scanner design with a 6 band spectrometer, a system for the remote sensing of Earth resources was developed. The elements in the spectrometer include an off axis reflective collimator, a reflective diffraction grating, a triplet germanium imaging lens, a photoconductive mercury cadmium telluride sensor array, and the mechanical assembly to hold these parts and maintain their optical alignment across a broad temperature range. The existing scanner design was modified to accept the new spectrometer and two field filling thermal reference sources.

Joint Calibration of 3d Laser Scanner and Digital Camera Based on Dlt Algorithm

NASA Astrophysics Data System (ADS)

Gao, X.; Li, M.; Xing, L.; Liu, Y.

2018-04-01

Design a calibration target that can be scanned by 3D laser scanner while shot by digital camera, achieving point cloud and photos of a same target. A method to joint calibrate 3D laser scanner and digital camera based on Direct Linear Transformation algorithm was proposed. This method adds a distortion model of digital camera to traditional DLT algorithm, after repeating iteration, it can solve the inner and external position element of the camera as well as the joint calibration of 3D laser scanner and digital camera. It comes to prove that this method is reliable.

A new ultrasonic real-time scanner featuring a servo-controlled transducer displaying a sector image.

PubMed

Skolnick, M L; Matzuk, T

1978-08-01

This paper describes a new real-time servo-controlled sector scanner that produces high-resolution images similar to phased-array systems, but possesses the simplicity of design and low cost best achievable in a mechanical sector scanner. Its unique feature is the transducer head which contains a single moving part--the transducer. Frame rates vary from 0 to 30 degrees and the sector angle from 0 to 60 degrees. Abdominal applications include: differentiation of vascular structures, detection of small masses, imaging of diagonally oriented organs. Survey scanning, and demonstration of regions difficult to image with contact scanners. Cardiac uses are also described.

Study of optical techniques for the Ames unitary wind tunnels. Part 4: Model deformation

NASA Technical Reports Server (NTRS)

Lee, George

1992-01-01

A survey of systems capable of model deformation measurements was conducted. The survey included stereo-cameras, scanners, and digitizers. Moire, holographic, and heterodyne interferometry techniques were also looked at. Stereo-cameras with passive or active targets are currently being deployed for model deformation measurements at NASA Ames and LaRC, Boeing, and ONERA. Scanners and digitizers are widely used in robotics, motion analysis, medicine, etc., and some of the scanner and digitizers can meet the model deformation requirements. Commercial stereo-cameras, scanners, and digitizers are being improved in accuracy, reliability, and ease of operation. A number of new systems are coming onto the market.

Hierarchical, Three-Dimensional Measurement System for Crime Scene Scanning.

PubMed

Marcin, Adamczyk; Maciej, Sieniło; Robert, Sitnik; Adam, Woźniak

2017-07-01

We present a new generation of three-dimensional (3D) measuring systems, developed for the process of crime scene documentation. This measuring system facilitates the preparation of more insightful, complete, and objective documentation for crime scenes. Our system reflects the actual requirements for hierarchical documentation, and it consists of three independent 3D scanners: a laser scanner for overall measurements, a situational structured light scanner for more minute measurements, and a detailed structured light scanner for the most detailed parts of tscene. Each scanner has its own spatial resolution, of 2.0, 0.3, and 0.05 mm, respectively. The results of interviews we have conducted with technicians indicate that our developed 3D measuring system has significant potential to become a useful tool for forensic technicians. To ensure the maximum compatibility of our measuring system with the standards that regulate the documentation process, we have also performed a metrological validation and designated the maximum permissible length measurement error E MPE for each structured light scanner. In this study, we present additional results regarding documentation processes conducted during crime scene inspections and a training session. © 2017 American Academy of Forensic Sciences.

An ethics of body scanners: requirements and future challenges from an ethical point of view

NASA Astrophysics Data System (ADS)

Rampp, Benjamin; Wolkenstein, Andreas F. X.; Ammicht Quinn, Regina

2011-05-01

At the moment, body scanners based on terahertz and millimeter-wave technologies are implemented at airports around the world. Thus, challenges of acceptance and acceptability become pressing. In this context, we present the results of an ethical research project on the development and implementation of body scanners. We will show which requirements concerning the system, its developers, and its users should be met in order that the scanners can be acceptable from an ethical point of view. These requirements involve, among others, questions of privacy, health, data protection, and security processes. A special ethical challenge for body scanners, however, still remains: Automatic anonymization processes are based on the assumption of "normal" bodies. Certain groups of persons with "deviant bodies" (e.g. persons with hidden disabilities, persons with aberrant sex characteristics, etc.) are affected in a special way: Their deviation from the standard (for instance their disability) is socially hidden, but eventually exposed by body scanners, even (and even more) if the produced pictures are anonymized. Here, we address the question how the possible discrimination against and exclusion of people with "deviant bodies" could be mitigated or prevented.

Modeling and measurement of the detector presampling MTF of a variable resolution x-ray CT scanner

PubMed Central

Melnyk, Roman; DiBianca, Frank A.

2007-01-01

The detector presampling MTF of a 576-channel variable resolution x-ray (VRX) CT scanner was evaluated in this study. The scanner employs a VRX detector, which provides increased spatial resolution by matching the scanner’s field of view (FOV) to the size of an object being imaged. Because spatial resolution is the parameter the scanner promises to improve, the evaluation of this resolution is important. The scanner’s pre-reconstruction spatial resolution, represented by the detector presampling MTF, was evaluated using both modeling (Monte Carlo simulation) and measurement (the moving slit method). The theoretical results show the increase in the cutoff frequency of the detector presampling MTF from 1.39 cy/mm to 43.38 cy/mm as the FOV of the VRX CT scanner decreases from 32 cm to 1 cm. The experimental results are in reasonable agreement with the theoretical data. Some discrepancies between the measured and the modeled detector presampling MTFs can be explained by the limitations of the model. At small FOVs (1–8 cm), the MTF measurements were limited by the size of the focal spot. The obtained results are important for further development of the VRX CT scanner. PMID:17369872

Timestamp Offset Determination Between AN Actuated Laser Scanner and its Corresponding Motor

NASA Astrophysics Data System (ADS)

Voges, R.; Wieghardt, C. S.; Wagner, B.

2017-05-01

Motor actuated 2D laser scanners are key sensors for many robotics applications that need wide ranging but low cost 3D data. There exist many approaches on how to build a 3D laser scanner using this technique, but they often lack proper synchronization for the timestamps of the actuator and the laser scanner. However, to transform the measurement points into three-dimensional space an appropriate synchronization is mandatory. Thus, we propose two different approaches to accomplish the goal of calculating timestamp offsets between laser scanner and motor prior to and after data acquisition. Both approaches use parts of a SLAM algorithm but apply different criteria to find an appropriate solution. While the approach for offset calculation prior to data acquisition exploits the fact that the SLAM algorithm should not register motion for a stationary system, the approach for offset calculation after data acquisition evaluates the perceived clarity of a point cloud created by the SLAM algorithm. Our experiments show that both approaches yield the same results although operating independently on different data, which demonstrates that the results reflect reality with a high probability. Furthermore, our experiments exhibit the significance of a proper synchronization between laser scanner and actuator.

Structural design of a vertical antenna boresight 18.3 by 18.3-m planar near-field antenna measurement system

NASA Technical Reports Server (NTRS)

Sharp, G. R.; Trimarchi, P. A.; Wanhainen, J. S.

1984-01-01

A large very precise near-field planar scanner was proposed for NASA Lewis Research Center. This scanner would permit near-field measurements over a horizontal scan plane measuring 18.3 m by 18.3 m. Large aperture antennas mounted with antenna boresight vertical could be tested up to 60 GHz. When such a large near field scanner is used for pattern testing, the antenna or antenna system under test does not have to be moved. Hence, such antennas and antenna systems can be positioned and supported to simulate configuration in zero g. Thus, very large and heavy machinery that would be needed to accurately move the antennas are avoided. A preliminary investigation was undertaken to address the mechanical design of such a challenging near-field antenna scanner. The configuration, structural design and results of a parametric NASTRAN structural optimization analysis are contained. Further, the resulting design was dynamically analyzed in order to provide resonant frequency information to the scanner mechanical drive system designers. If other large near field scanners of comparable dimensions are to be constructed, the information can be used for design optimization of these also.

Regulation of X-Ray Security Scanners in Michigan.

PubMed

Parry, Donald E

2016-02-01

In January of 2013 the Transportation Security Administration (TSA) ordered the removal of x-ray security scanners from airports by June of 2013. Since that time several of these scanners have been purchased at a reduced cost by various state and county governments for use in screening individuals entering or leaving their facilities. To address this issue the Radiation Safety Section of the State of Michigan drafted a set of registration conditions for facilities to follow when using these security scanners. Inspection procedures and measurement protocols were developed to estimate the dose to screened individuals. Inspections were performed on nine of the 16 registered backscatter scanners in the state and the one transmission scanner. The average estimated effective dose to screened individuals was ∼11 nSv for a two view scan from a backscatter system. The effective dose was 0.446 μSv, 0.330 μSv, and 0.150 μSv for a transmission system operated in the high, medium, and low dose modes, respectively. The limit suggested in the new registration condition is 0.25 μSv for a general use system and 10 μSv for a limited use system.

Effects of sitting versus standing and scanner type on cashiers.

PubMed

Lehman, K R; Psihogios, J P; Meulenbroek, R G

2001-06-10

In the retail supermarket industry where cashiers perform repetitive, light manual material-handling tasks when scanning and handling products, reports of musculoskeletal disorders and discomfort are high. Ergonomics tradeoffs exist between sitting and standing postures, which are further confounded by the checkstand design and point-of-sale technology, such as the scanner. A laboratory experiment study was conducted to understand the effects of working position (sitting versus standing) and scanner type (bi-optic versus single window) on muscle activity, upper limb and spinal posture, and subjective preference of cashiers. Ten cashiers from a Dutch retailer participated in the study. Cashiers exhibited lower muscle activity in the neck and shoulders when standing and using a bi-optic scanner. Shoulder abduction was also less for standing conditions. In addition, all cashiers preferred using the bi-optic scanner with mixed preferences for sitting (n = 6) and standing (n = 4). Static loading of the muscles was relatively high compared with benchmarks, suggesting that during the task of scanning, cashiers may not have adequate recovery time to prevent fatigue. It is recommended that retailers integrate bi-optic scanners into standing checkstands to minimize postural stress, fatigue and discomfort in cashiers.

An investigation into factors affecting the precision of CT radiation dose profile width measurements using radiochromic films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Baojun, E-mail: Baojunli@bu.edu; Behrman, Richard H.

Purpose: To investigate the impact of x-ray beam energy, exposure intensity, and flat-bed scanner uniformity and spatial resolution on the precision of computed tomography (CT) beam width measurements using Gafchromic XR-QA2 film and an off-the-shelf document scanner. Methods: Small strips of Gafchromic film were placed at isocenter in a CT scanner and exposed at various x-ray beam energies (80–140 kVp), exposure levels (50–400 mA s), and nominal beam widths (1.25, 5, and 10 mm). The films were scanned in reflection mode on a Ricoh MP3501 flat-bed document scanner using several spatial resolution settings (100 to 400 dpi) and at differentmore » locations on the scanner bed. Reflection measurements were captured in digital image files and radiation dose profiles generated by converting the image pixel values to air kerma through film calibration. Beam widths were characterized by full width at half maximum (FWHM) and full width at tenth maximum (FWTM) of dose profiles. Dependences of these parameters on the above factors were quantified in percentage change from the baselines. Results: The uncertainties in both FWHM and FWTM caused by varying beam energy, exposure level, and scanner uniformity were all within 4.5% and 7.6%, respectively. Increasing scanner spatial resolution significantly increased the uncertainty in both FWHM and FWTM, with FWTM affected by almost 8 times more than FWHM (48.7% vs 6.5%). When uncalibrated dose profiles were used, FWHM and FWTM were over-estimated by 11.6% and 7.6%, respectively. Narrower beam width appeared more sensitive to the film calibration than the wider ones (R{sup 2} = 0.68 and 0.85 for FWHM and FWTM, respectively). The global and maximum local background variations of the document scanner were 1.2%. The intrinsic film nonuniformity for an unexposed film was 0.3%. Conclusions: Measurement of CT beam widths using Gafchromic XR-QA2 films is robust against x-ray energy, exposure level, and scanner uniformity. With proper film calibration and scanner resolution setting, it can provide adequate precision for meeting ACR and manufacturer’s tolerances for the measurement of CT dose profiles.« less

Evaluation of an Innovative Digital Assessment Tool in Dental Anatomy.

PubMed

Lam, Matt T; Kwon, So Ran; Qian, Fang; Denehy, Gerald E

2015-05-01

The E4D Compare software is an innovative tool that provides immediate feedback to students' projects and competencies. It should provide consistent scores even when different scanners are used which may have inherent subtle differences in calibration. This study aimed to evaluate potential discrepancies in evaluation using the E4D Compare software based on four different NEVO scanners in dental anatomy projects. Additionally, correlation between digital and visual scores was evaluated. Thirty-five projects of maxillary left central incisors were evaluated. Among these, thirty wax-ups were performed by four operators and five consisted of standard dentoform teeth. Five scores were obtained for each project: one from an instructor that visually graded the project and from four different NEVO scanners. A faculty involved in teaching the dental anatomy course blindly scored the 35 projects. One operator scanned all projects to four NEVO scanners (D4D Technologies, Richardson, TX, USA). The images were aligned to the gold standard, and tolerance set at 0.3 mm to generate a score. The score reflected percentage match between the project and the gold standard. One-way ANOVA with repeated measures was used to determine whether there was a significant difference in scores among the four NEVO scanners. Paired-sample t-test was used to detect any difference between visual scores and the average scores of the four NEVO scanners. Pearson's correlation test was used to assess the relationship between visual and average scores of NEVO scanners. There was no significant difference in mean scores among four different NEVO scanners [F(3, 102) = 2.27, p = 0.0852 one-way ANOVA with repeated measures]. Moreover, the data provided strong evidence that a significant difference existed between visual and digital scores (p = 0.0217; a paired - sample t-test). Mean visual scores were significantly lower than digital scores (72.4 vs 75.1). Pearson's correlation coefficient of 0.85 indicated a strong correlation between visual and digital scores (p < 0.0001). The E4D Compare software provides consistent scores even when different scanners are used and correlates well with visual scores. The use of innovative digital assessment tools in dental education is promising with the E4D Compare software correlating well with visual scores and providing consistent scores even when different scanners are used.

Inter-operator and inter-device agreement and reliability of the SEM Scanner.

PubMed

Clendenin, Marta; Jaradeh, Kindah; Shamirian, Anasheh; Rhodes, Shannon L

2015-02-01

The SEM Scanner is a medical device designed for use by healthcare providers as part of pressure ulcer prevention programs. The objective of this study was to evaluate the inter-rater and inter-device agreement and reliability of the SEM Scanner. Thirty-one (31) volunteers free of pressure ulcers or broken skin at the sternum, sacrum, and heels were assessed with the SEM Scanner. Each of three operators utilized each of three devices to collect readings from four anatomical sites (sternum, sacrum, left and right heels) on each subject for a total of 108 readings per subject collected over approximately 30 min. For each combination of operator-device-anatomical site, three SEM readings were collected. Inter-operator and inter-device agreement and reliability were estimated. Over the course of this study, more than 3000 SEM Scanner readings were collected. Agreement between operators was good with mean differences ranging from -0.01 to 0.11. Inter-operator and inter-device reliability exceeded 0.80 at all anatomical sites assessed. The results of this study demonstrate the high reliability and good agreement of the SEM Scanner across different operators and different devices. Given the limitations of current methods to prevent and detect pressure ulcers, the SEM Scanner shows promise as an objective, reliable tool for assessing the presence or absence of pressure-induced tissue damage such as pressure ulcers. Copyright © 2015 Bruin Biometrics, LLC. Published by Elsevier Ltd.. All rights reserved.

Impact of functional magnetic resonance imaging (fMRI) scanner noise on affective state and attentional performance.

PubMed

Jacob, Shawna N; Shear, Paula K; Norris, Matthew; Smith, Matthew; Osterhage, Jeff; Strakowski, Stephen M; Cerullo, Michael; Fleck, David E; Lee, Jing-Huei; Eliassen, James C

2015-01-01

Previous research has shown that performance on cognitive tasks administered in the scanner can be altered by the scanner environment. There are no previous studies that have investigated the impact of scanner noise using a well-validated measure of affective change. The goal of this study was to determine whether performance on an affective attentional task or emotional response to the task would change in the presence of distracting acoustic noise, such as that encountered in a magnetic resonance imaging (MRI) environment. Thirty-four young adults with no self-reported history of neurologic disorder or mental illness completed three blocks of the affective Posner task outside of the scanner. The task was meant to induce frustration through monetary contingencies and rigged feedback. Participants completed a Self-Assessment Manikin at the end of each block to rate their mood, arousal level, and sense of dominance. During the task, half of the participants heard noise (recorded from a 4T MRI system), and half heard no noise. The affective Posner task led to significant reductions in mood and increases in arousal in healthy participants. The presence of scanner noise did not impact task performance; however, individuals in the noise group did report significantly poorer mood throughout the task. The results of the present study suggest that the acoustic qualities of MRI enhance frustration effects on an affective attentional task and that scanner noise may influence mood during similar functional magnetic resonance imaging (fMRI) tasks.

Subjective perception of safety in healthy individuals working with 7 T MRI scanners: a retrospective multicenter survey.

PubMed

Fatahi, Mahsa; Demenescu, Liliana Ramona; Speck, Oliver

2016-06-01

To retrospectively assess perception of safety of healthy individuals working with human 7 Tesla (T) magnetic resonance imaging (MRI) scanners. A total of 66 healthy individuals with a mean age of 31 ± 7 years participated in this retrospective multicentre survey study. Nonparametric correlation analysis was conducted to evaluate the relation between self-reported perception of safety and prevalence of sensory effects while working with 7 T MRI scanners for an average 47 months. The results indicated that 98.5 % of the study participants had a neutral or positive feeling about safety aspects at 7 T MRI scanners. 45.5 % reported that they feel very safe and none of the participants stated that they feel moderately or very unsafe while working with 7 T MRI scanners. Perception of safety was not affected by the number of hours per week spent in the vicinity of the 7 T MRI scanner or the duration of experience with 7 T MRI. More than 50 % of individuals experienced vertigo and metallic taste while working with 7 T MRI scanners. However, participants' perceptions of safety were not affected by the prevalence of MR-related symptoms. The overall data indicated an average perception of a moderately safe work environment. To our knowledge, this study delineates the first attempt to assess the subjective safety perception among 7 T MRI workers and suggests further investigations are indicated.

The 3D scanner prototype utilize object profile imaging using line laser and octave software

NASA Astrophysics Data System (ADS)

Nurdini, Mugi; Manunggal, Trikarsa Tirtadwipa; Samsi, Agus

2016-11-01

Three-dimensional scanner or 3D Scanner is a device to reconstruct the real object into digital form on a computer. 3D Scanner is a technology that is being developed, especially in developed countries, where the current 3D Scanner devices is the advanced version with a very expensive prices. This study is basically a simple prototype of 3D Scanner with a very low investment costs. 3D Scanner prototype device consists of a webcam, a rotating desk system controlled by a stepper motor and Arduino UNO, and a line laser. Objects that limit the research is the object with same radius from its center point (object pivot). Scanning is performed by using object profile imaging by line laser which is then captured by the camera and processed by a computer (image processing) using Octave software. On each image acquisition, the scanned object on a rotating desk rotated by a certain degree, so for one full turn multiple images of a number of existing side are finally obtained. Then, the profile of the entire images is extracted in order to obtain digital object dimension. Digital dimension is calibrated by length standard, called gage block. Overall dimensions are then digitally reconstructed into a three-dimensional object. Validation of the scanned object reconstruction of the original object dimensions expressed as a percentage error. Based on the results of data validation, horizontal dimension error is about 5% to 23% and vertical dimension error is about +/- 3%.

Mathematical modelling of scanner-specific bowtie filters for Monte Carlo CT dosimetry

NASA Astrophysics Data System (ADS)

Kramer, R.; Cassola, V. F.; Andrade, M. E. A.; de Araújo, M. W. C.; Brenner, D. J.; Khoury, H. J.

2017-02-01

The purpose of bowtie filters in CT scanners is to homogenize the x-ray intensity measured by the detectors in order to improve the image quality and at the same time to reduce the dose to the patient because of the preferential filtering near the periphery of the fan beam. For CT dosimetry, especially for Monte Carlo calculations of organ and tissue absorbed doses to patients, it is important to take the effect of bowtie filters into account. However, material composition and dimensions of these filters are proprietary. Consequently, a method for bowtie filter simulation independent of access to proprietary data and/or to a specific scanner would be of interest to many researchers involved in CT dosimetry. This study presents such a method based on the weighted computer tomography dose index, CTDIw, defined in two cylindrical PMMA phantoms of 16 cm and 32 cm diameter. With an EGSnrc-based Monte Carlo (MC) code, ratios CTDIw/CTDI100,a were calculated for a specific CT scanner using PMMA bowtie filter models based on sigmoid Boltzmann functions combined with a scanner filter factor (SFF) which is modified during calculations until the calculated MC CTDIw/CTDI100,a matches ratios CTDIw/CTDI100,a, determined by measurements or found in publications for that specific scanner. Once the scanner-specific value for an SFF has been found, the bowtie filter algorithm can be used in any MC code to perform CT dosimetry for that specific scanner. The bowtie filter model proposed here was validated for CTDIw/CTDI100,a considering 11 different CT scanners and for CTDI100,c, CTDI100,p and their ratio considering 4 different CT scanners. Additionally, comparisons were made for lateral dose profiles free in air and using computational anthropomorphic phantoms. CTDIw/CTDI100,a determined with this new method agreed on average within 0.89% (max. 3.4%) and 1.64% (max. 4.5%) with corresponding data published by CTDosimetry (www.impactscan.org) for the CTDI HEAD and BODY phantoms, respectively. Comparison with results calculated using proprietary data for the PHILIPS Brilliance 64 scanner showed agreement on average within 2.5% (max. 5.8%) and with data measured for that scanner within 2.1% (max. 3.7%). Ratios of CTDI100,c/CTDI100, p for this study and corresponding data published by CTDosimetry (www.impactscan.org) agree on average within about 11% (max. 28.6%). Lateral dose profiles calculated with the proposed bowtie filter and with proprietary data agreed within 2% (max. 5.9%), and both calculated data agreed within 5.4% (max. 11.2%) with measured results. Application of the proposed bowtie filter and of the exactly modelled filter to human phantom Monte Carlo calculations show agreement on the average within less than 5% (max. 7.9%) for organ and tissue absorbed doses.

LANDSAT-4 multispectral scanner (MSS) subsystem radiometric characterization

NASA Technical Reports Server (NTRS)

Alford, W. (Editor); Barker, J. (Editor); Clark, B. P.; Dasgupta, R.

1983-01-01

The multispectral band scanner (mass) and its spectral characteristics are described and methods are given for relating video digital levels on computer compatible tapes to radiance into the sensor. Topics covered include prelaunch calibration procedures and postlaunch radiometric processng. Examples of current data resident on the MSS image processing system are included. The MSS on LANDSAT 4 is compared with the scanners on earlier LANDSAT satellites.

Fusion of Terrestrial and Airborne Laser Data for 3D modeling Applications

NASA Astrophysics Data System (ADS)

Mohammed, Hani Mahmoud

This thesis deals with the 3D modeling phase of the as-built large BIM projects. Among several means of BIM data capturing, such as photogrammetric or range tools, laser scanners have been one of the most efficient and practical tool for a long time. They can generate point clouds with high resolution for 3D models that meet nowadays' market demands. The current 3D modeling projects of as-built BIMs are mainly focused on using one type of laser scanner data, such as Airborne or Terrestrial. According to the literatures, no significant (few) efforts were made towards the fusion of heterogeneous laser scanner data despite its importance. The importance of the fusion of heterogeneous data arises from the fact that no single type of laser data can provide all the information about BIM, especially for large BIM projects that are existing on a large area, such as university buildings, or Heritage places. Terrestrial laser scanners are able to map facades of buildings and other terrestrial objects. However, they lack the ability to map roofs or higher parts in the BIM project. Airborne laser scanner on the other hand, can map roofs of the buildings efficiently and can map only small part of the facades. Short range laser scanners can map the interiors of the BIM projects, while long range scanners are used for mapping wide exterior areas in BIM projects. In this thesis the long range laser scanner data obtained in the Stop-and-Go mapping mode, the short range laser scanner data, obtained in a fully static mapping mode, and the airborne laser data are all fused together to bring a complete effective solution for a large BIM project. Working towards the 3D modeling of BIM projects, the thesis framework starts with the registration of the data, where a new fast automatic registration algorithm were developed. The next step is to recognize the different objects in the BIM project (classification), and obtain 3D models for the buildings. The last step is the development of an occlusion removal algorithm to efficiently retain parts of the buildings occluded by surrounding objects such as trees, vehicles, or street poles.

Dose reduction in 64-row whole-body CT in multiple trauma: an optimized CT protocol with iterative image reconstruction on a gemstone-based scintillator.

PubMed

Geyer, Lucas L; Körner, Markus; Harrieder, Andreas; Mueck, Fabian G; Deak, Zsuzsanna; Wirth, Stefan; Linsenmaier, Ulrich

2016-01-01

Evaluation of potential dose savings by implementing adaptive statistical iterative reconstruction (ASiR) on a gemstone-based scintillator in a clinical 64-row whole-body CT (WBCT) protocol after multiple trauma. Dose reports of 152 WBCT scans were analysed for two 64-row multidetector CT scanners (Scanners A and B); the main scanning parameters were kept constant. ASiR and a gemstone-based scintillator were used in Scanner B, and the noise index was adjusted (head: 5.2 vs 6.0; thorax/abdomen: 29.0 vs 46.0). The scan length, CT dose index (CTDI) and dose-length product (DLP) were analysed. The estimated mean effective dose was calculated using normalized conversion factors. Student's t-test was used for statistics. Both the mean CTDI (mGy) (Scanner A: 53.8 ± 2.0, 10.3 ± 2.5, 14.4 ± 3.7; Scanner B: 48.7 ± 2.2, 7.1 ± 2.3, 9.1 ± 3.6; p < 0.001, respectively) and the mean DLP (mGy cm) (Scanner A: 1318.9 ± 167.8, 509.3 ± 134.7, 848.8 ± 254.0; Scanner B: 1190.6 ± 172.6, 354.6 ± 128.3, 561.0 ± 246.7; p < 0.001, respectively) for the head, thorax and abdomen were significantly reduced with Scanner B. There was no relevant difference in scan length. The total mean effective dose (mSv) was significantly decreased with Scanner B (24.4 ± 6.0, 17.2 ± 5.8; p < 0.001). The implementation of ASiR and a gemstone-based scintillator allows for significant dose savings in a clinical WBCT protocol. Recent technical developments can significantly reduce radiation dose of WBCT in multiple trauma. Dose reductions of 10-34% can be achieved.

SU-E-I-22: A Comprehensive Investigation of Noise Variations Between the GE Discovery CT750 HD and GE LightSpeed VCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bache, S; Loyer, E; Stauduhar, P

2015-06-15

Purpose: To quantify and compare the noise properties between two GE CT models-the Discovery CT750 HD (aka HD750) and LightSpeed VCT, with the overall goal of assessing the impact in clinical diagnostic practice. Methods: Daily QC data from a fleet of 9 CT scanners currently in clinical use were investigated – 5 HD750 and 4 VCT (over 600 total acquisitions for each scanner). A standard GE QC phantom was scanned daily using two sets of scan parameters with each scanner over 1 year. Water CT number and standard deviation were recorded from the image of water section of the QCmore » phantom. The standard GE QC scan parameters (Pitch = 0.516, 120kVp, 0.4s, 335mA, Small Body SFOV, 5mm thickness) and an in-house developed protocol (Axial, 120kVp, 1.0s, 240mA, Head SFOV, 5mm thickness) were used, with Standard reconstruction algorithm. Noise was measured as the standard deviation in the center of the water phantom image. Inter-model noise distributions and tube output in mR/mAs were compared to assess any relative differences in noise properties. Results: With the in-house protocols, average noise for the five HD750 scanners was ∼9% higher than the VCT scanners (5.8 vs 5.3). For the GE QC protocol, average noise with the HD750 scanners was ∼11% higher than with the VCT scanners (4.8 vs 4.3). This discrepancy in noise between the two models was found despite the tube output in mR/mAs being comparable with the HD750 scanners only having ∼4% lower output (8.0 vs 8.3 mR/mAs). Conclusion: Using identical scan protocols, average noise in images from the HD750 group was higher than that from the VCT group. This confirms feedback from an institutional radiologist’s feedback regarding grainier patient images from HD750 scanners. Further investigation is warranted to assess the noise texture and distribution, as well as clinical impact.« less

Optimal whole-body PET scanner configurations for different volumes of LSO scintillator: a simulation study.

PubMed

Poon, Jonathan K; Dahlbom, Magnus L; Moses, William W; Balakrishnan, Karthik; Wang, Wenli; Cherry, Simon R; Badawi, Ramsey D

2012-07-07

The axial field of view (AFOV) of the current generation of clinical whole-body PET scanners range from 15-22 cm, which limits sensitivity and renders applications such as whole-body dynamic imaging or imaging of very low activities in whole-body cellular tracking studies, almost impossible. Generally, extending the AFOV significantly increases the sensitivity and count-rate performance. However, extending the AFOV while maintaining detector thickness has significant cost implications. In addition, random coincidences, detector dead time, and object attenuation may reduce scanner performance as the AFOV increases. In this paper, we use Monte Carlo simulations to find the optimal scanner geometry (i.e. AFOV, detector thickness and acceptance angle) based on count-rate performance for a range of scintillator volumes ranging from 10 to 93 l with detector thickness varying from 5 to 20 mm. We compare the results to the performance of a scanner based on the current Siemens Biograph mCT geometry and electronics. Our simulation models were developed based on individual components of the Siemens Biograph mCT and were validated against experimental data using the NEMA NU-2 2007 count-rate protocol. In the study, noise-equivalent count rate (NECR) was computed as a function of maximum ring difference (i.e. acceptance angle) and activity concentration using a 27 cm diameter, 200 cm uniformly filled cylindrical phantom for each scanner configuration. To reduce the effect of random coincidences, we implemented a variable coincidence time window based on the length of the lines of response, which increased NECR performance up to 10% compared to using a static coincidence time window for scanners with a large maximum ring difference values. For a given scintillator volume, the optimal configuration results in modest count-rate performance gains of up to 16% compared to the shortest AFOV scanner with the thickest detectors. However, the longest AFOV of approximately 2 m with 20 mm thick detectors resulted in performance gains of 25-31 times higher NECR relative to the current Siemens Biograph mCT scanner configuration.

Optimal whole-body PET scanner configurations for different volumes of LSO scintillator: a simulation study

PubMed Central

Poon, Jonathan K; Dahlbom, Magnus L; Moses, William W; Balakrishnan, Karthik; Wang, Wenli; Cherry, Simon R; Badawi, Ramsey D

2013-01-01

The axial field of view (AFOV) of the current generation of clinical whole-body PET scanners range from 15–22 cm, which limits sensitivity and renders applications such as whole-body dynamic imaging, or imaging of very low activities in whole-body cellular tracking studies, almost impossible. Generally, extending the AFOV significantly increases the sensitivity and count-rate performance. However, extending the AFOV while maintaining detector thickness has significant cost implications. In addition, random coincidences, detector dead time, and object attenuation may reduce scanner performance as the AFOV increases. In this paper, we use Monte Carlo simulations to find the optimal scanner geometry (i.e. AFOV, detector thickness and acceptance angle) based on count-rate performance for a range of scintillator volumes ranging from 10 to 90 l with detector thickness varying from 5 to 20 mm. We compare the results to the performance of a scanner based on the current Siemens Biograph mCT geometry and electronics. Our simulation models were developed based on individual components of the Siemens Biograph mCT and were validated against experimental data using the NEMA NU-2 2007 count-rate protocol. In the study, noise-equivalent count rate (NECR) was computed as a function of maximum ring difference (i.e. acceptance angle) and activity concentration using a 27 cm diameter, 200 cm uniformly filled cylindrical phantom for each scanner configuration. To reduce the effect of random coincidences, we implemented a variable coincidence time window based on the length of the lines of response, which increased NECR performance up to 10% compared to using a static coincidence time window for scanners with large maximum ring difference values. For a given scintillator volume, the optimal configuration results in modest count-rate performance gains of up to 16% compared to the shortest AFOV scanner with the thickest detectors. However, the longest AFOV of approximately 2 m with 20 mm thick detectors resulted in performance gains of 25–31 times higher NECR relative to the current Siemens Biograph mCT scanner configuration. PMID:22678106

Optimal whole-body PET scanner configurations for different volumes of LSO scintillator: a simulation study

NASA Astrophysics Data System (ADS)

Poon, Jonathan K.; Dahlbom, Magnus L.; Moses, William W.; Balakrishnan, Karthik; Wang, Wenli; Cherry, Simon R.; Badawi, Ramsey D.

2012-07-01

The axial field of view (AFOV) of the current generation of clinical whole-body PET scanners range from 15-22 cm, which limits sensitivity and renders applications such as whole-body dynamic imaging or imaging of very low activities in whole-body cellular tracking studies, almost impossible. Generally, extending the AFOV significantly increases the sensitivity and count-rate performance. However, extending the AFOV while maintaining detector thickness has significant cost implications. In addition, random coincidences, detector dead time, and object attenuation may reduce scanner performance as the AFOV increases. In this paper, we use Monte Carlo simulations to find the optimal scanner geometry (i.e. AFOV, detector thickness and acceptance angle) based on count-rate performance for a range of scintillator volumes ranging from 10 to 93 l with detector thickness varying from 5 to 20 mm. We compare the results to the performance of a scanner based on the current Siemens Biograph mCT geometry and electronics. Our simulation models were developed based on individual components of the Siemens Biograph mCT and were validated against experimental data using the NEMA NU-2 2007 count-rate protocol. In the study, noise-equivalent count rate (NECR) was computed as a function of maximum ring difference (i.e. acceptance angle) and activity concentration using a 27 cm diameter, 200 cm uniformly filled cylindrical phantom for each scanner configuration. To reduce the effect of random coincidences, we implemented a variable coincidence time window based on the length of the lines of response, which increased NECR performance up to 10% compared to using a static coincidence time window for scanners with a large maximum ring difference values. For a given scintillator volume, the optimal configuration results in modest count-rate performance gains of up to 16% compared to the shortest AFOV scanner with the thickest detectors. However, the longest AFOV of approximately 2 m with 20 mm thick detectors resulted in performance gains of 25-31 times higher NECR relative to the current Siemens Biograph mCT scanner configuration.

Evaluation of a laser scanner for large volume coordinate metrology: a comparison of results before and after factory calibration

NASA Astrophysics Data System (ADS)

Ferrucci, M.; Muralikrishnan, B.; Sawyer, D.; Phillips, S.; Petrov, P.; Yakovlev, Y.; Astrelin, A.; Milligan, S.; Palmateer, J.

2014-10-01

Large volume laser scanners are increasingly being used for a variety of dimensional metrology applications. Methods to evaluate the performance of these scanners are still under development and there are currently no documentary standards available. This paper describes the results of extensive ranging and volumetric performance tests conducted on a large volume laser scanner. The results demonstrated small but clear systematic errors that are explained in the context of a geometric error model for the instrument. The instrument was subsequently returned to the manufacturer for factory calibration. The ranging and volumetric tests were performed again and the results are compared against those obtained prior to the factory calibration.

Portable biochip scanner device

DOEpatents

Perov, Alexander; Sharonov, Alexei; Mirzabekov, Andrei D.

2002-01-01

A portable biochip scanner device used to detect and acquire fluorescence signal data from biological microchips (biochips) is provided. The portable biochip scanner device employs a laser for emitting an excitation beam. An optical fiber delivers the laser beam to a portable biochip scanner. A lens collimates the laser beam, the collimated laser beam is deflected by a dichroic mirror and focused by an objective lens onto a biochip. The fluorescence light from the biochip is collected and collimated by the objective lens. The fluorescence light is delivered to a photomultiplier tube (PMT) via an emission filter and a focusing lens. The focusing lens focuses the fluorescence light into a pinhole. A signal output of the PMT is processed and displayed.

Laser scanning system for object monitoring

DOEpatents

McIntyre, Timothy James [Knoxville, TN; Maxey, Lonnie Curtis [Powell, TN; Chiaro, Jr; John, Peter [Clinton, TN

2008-04-22

A laser scanner is located in a fixed position to have line-of-sight access to key features of monitored objects. The scanner rapidly scans pre-programmed points corresponding to the positions of retroreflecting targets affixed to the key features of the objects. The scanner is capable of making highly detailed scans of any portion of the field of view, permitting the exact location and identity of targets to be confirmed. The security of an object is verified by determining that the cooperative target is still present and that its position has not changed. The retroreflecting targets also modulate the reflected light for purposes of returning additional information back to the location of the scanner.

Feasibility and Accuracy of Digitizing Edentulous Maxillectomy Defects: A Comparative Study.

PubMed

Elbashti, Mahmoud E; Hattori, Mariko; Patzelt, Sebastian Bm; Schulze, Dirk; Sumita, Yuka I; Taniguchi, Hisashi

The aim of this study was to evaluate the feasibility and accuracy of using an intraoral scanner to digitize edentulous maxillectomy defects. A total of 20 maxillectomy models with two defect types were digitized using cone beam computed tomography. Conventional and digital impressions were made using silicone impression material and a laboratory optical scanner as well as a chairside intraoral scanner. The 3D datasets were analyzed using 3D evaluation software. Two-way analysis of variance revealed no interaction between defect types and impression methods, and the accuracy of the impression methods was significantly different (P = .0374). Digitizing edentulous maxillectomy defect models using a chairside intraoral scanner appears to be feasible and accurate.

Effect of Software Version on the Accuracy of an Intraoral Scanning Device.

PubMed

Haddadi, Yasser; Bahrami, Golnosh; Isidor, Flemming

2018-04-06

To investigate the impact of software version on the accuracy of an intraoral scanning device. A master tooth was scanned with a high-precision optical scanner and then 10 times with a CEREC Omnicam scanner with software versions 4.4.0 and 4.4.4. Discrepancies were measured using quality control software. Mean deviation for 4.4.0 was 36.2 ± 35 μm and for 4.4.4 was 20.7 ± 14.2 μm (P ≤ .001). Software version has a significant impact on the accuracy of an intraoral scanner. It is important that researchers also publish the software version of scanners when publishing their findings.

Collation of earth resources data collected by ERIM airborne sensors

NASA Technical Reports Server (NTRS)

Hasell, P. G., Jr.

1975-01-01

Earth resources imagery from nine years of data collection with developmental airborne sensors is cataloged for reference. The imaging sensors include single and multiband line scanners and side-looking radars. The operating wavelengths of the sensors include ultraviolet, visible and infrared band scanners, and X- and L-band radar. Imagery from all bands (radar and scanner) were collected at some sites and many sites had repeated coverage. The multiband scanner data was radiometrically calibrated. Illustrations show how the data can be used in earth resource investigations. References are made to published reports which have made use of the data in completed investigations. Data collection sponsors are identified and a procedure described for gaining access to the data.

Method of estimation of scanning system quality

NASA Astrophysics Data System (ADS)

Larkin, Eugene; Kotov, Vladislav; Kotova, Natalya; Privalov, Alexander

2018-04-01

Estimation of scanner parameters is an important part in developing electronic document management system. This paper suggests considering the scanner as a system that contains two main channels: a photoelectric conversion channel and a channel for measuring spatial coordinates of objects. Although both of channels consist of the same elements, the testing of their parameters should be executed separately. The special structure of the two-dimensional reference signal is offered for this purpose. In this structure, the fields for testing various parameters of the scanner are sp atially separated. Characteristics of the scanner are associated with the loss of information when a document is digitized. The methods to test grayscale transmitting ability, resolution and aberrations level are offered.

Orbit/launch vehicle tradeoff studies. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

An evaluation of the Earth Observatory Satellite (EOS) design, performance, and cost factors which affect the choices of an orbit and a launch vehicle is presented. Primary emphasis is given to low altitude (300 to 900 nautical miles) land resources management applications for which payload design factors are defined. The subjects considered are: (1) a mission model, (2) orbit analysis and characterization, (3) characteristics and capabilities of candidate conventional launch vehicles, and space shuttle support. Recommendations are submitted for the EOS-A mission, the Single Multispectral Scanner payload, the Single Multispectral Scanner plus Thematic Mapper payload, the Dual Multispectral Scanner payload, and the Dual Multispectral Scanner plus Thematic Mapper payload.

Systematic monitoring and evaluation of M7 scanner performance and data quality

NASA Technical Reports Server (NTRS)

Stewart, S.; Christenson, D.; Larsen, L.

1974-01-01

An investigation was conducted to provide the information required to maintain data quality of the Michigan M7 Multispectral scanner by systematic checks on specific system performance characteristics. Data processing techniques which use calibration data gathered routinely every mission have been developed to assess current data quality. Significant changes from past data quality are thus identified and attempts made to discover their causes. Procedures for systematic monitoring of scanner data quality are discussed. In the solar reflective region, calculations of Noise Equivalent Change in Radiance on a permission basis are compared to theoretical tape-recorder limits to provide an estimate of overall scanner performance. M7 signal/noise characteristics are examined.

Biomedical imaging and sensing using flatbed scanners.

PubMed

Göröcs, Zoltán; Ozcan, Aydogan

2014-09-07

In this Review, we provide an overview of flatbed scanner based biomedical imaging and sensing techniques. The extremely large imaging field-of-view (e.g., ~600-700 cm(2)) of these devices coupled with their cost-effectiveness provide unique opportunities for digital imaging of samples that are too large for regular optical microscopes, and for collection of large amounts of statistical data in various automated imaging or sensing tasks. Here we give a short introduction to the basic features of flatbed scanners also highlighting the key parameters for designing scientific experiments using these devices, followed by a discussion of some of the significant examples, where scanner-based systems were constructed to conduct various biomedical imaging and/or sensing experiments. Along with mobile phones and other emerging consumer electronics devices, flatbed scanners and their use in advanced imaging and sensing experiments might help us transform current practices of medicine, engineering and sciences through democratization of measurement science and empowerment of citizen scientists, science educators and researchers in resource limited settings.

Feasibility study using MRI and two optical CT scanners for readout of polymer gel and PresageTM

NASA Astrophysics Data System (ADS)

Svensson, H.; Skyt, P. S.; Ceberg, S.; Doran, S.; Muren, L. P.; Balling, P.; Petersen, J. B. B.; Bäck, S. Å. J.

2013-06-01

The aim of this study was to compare the conventional combination of three-dimensional dosimeter (nPAG gel) and readout method (MRI) with other combinations of three-dimensional dosimeters (nPAG gel/PresageTM) and readout methods (optical CT scanners). In the first experiment, the dose readout of a gel irradiated with a four field-box technique was performed with both an Octopus IQ scanner and MRI. It was seen that the MRI readout agreed slightly better to the TPS. In another experiment, a gel and a PresageTM sample were irradiated with a VMAT field and read out using MRI and a fast laser scanner, respectively. A comparison between the TPS and the volumes revealed that the MRI/gel readout had closer resemblance to the TPS than the optical CT/PresageTM readout. There are clearly potential in the evaluated optical CT scanners, but more time has to be invested in the particular scanning scenario than was possible in this study.

Note: High-speed Z tip scanner with screw cantilever holding mechanism for atomic-resolution atomic force microscopy in liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reza Akrami, Seyed Mohammad; Miyata, Kazuki; Asakawa, Hitoshi

High-speed atomic force microscopy has attracted much attention due to its unique capability of visualizing nanoscale dynamic processes at a solid/liquid interface. However, its usability and resolution have yet to be improved. As one of the solutions for this issue, here we present a design of a high-speed Z-tip scanner with screw holding mechanism. We perform detailed comparison between designs with different actuator size and screw arrangement by finite element analysis. Based on the design giving the best performance, we have developed a Z tip scanner and measured its performance. The measured frequency response of the scanner shows a flatmore » response up to ∼10 kHz. This high frequency response allows us to achieve wideband tip-sample distance regulation. We demonstrate the applicability of the scanner to high-speed atomic-resolution imaging by visualizing atomic-scale calcite crystal dissolution process in water at 2 s/frame.« less

Biomedical Imaging and Sensing using Flatbed Scanners

PubMed Central

Göröcs, Zoltán; Ozcan, Aydogan

2014-01-01

In this Review, we provide an overview of flatbed scanner based biomedical imaging and sensing techniques. The extremely large imaging field-of-view (e.g., ~600–700 cm2) of these devices coupled with their cost-effectiveness provide unique opportunities for digital imaging of samples that are too large for regular optical microscopes, and for collection of large amounts of statistical data in various automated imaging or sensing tasks. Here we give a short introduction to the basic features of flatbed scanners also highlighting the key parameters for designing scientific experiments using these devices, followed by a discussion of some of the significant examples, where scanner-based systems were constructed to conduct various biomedical imaging and/or sensing experiments. Along with mobile phones and other emerging consumer electronics devices, flatbed scanners and their use in advanced imaging and sensing experiments might help us transform current practices of medicine, engineering and sciences through democratization of measurement science and empowerment of citizen scientists, science educators and researchers in resource limited settings. PMID:24965011

Hybrid Dispersion Laser Scanner

PubMed Central

Goda, K.; Mahjoubfar, A.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.

2012-01-01

Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ∼1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100 MHz at 800 nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100 kHz with 27,000 resolvable points. PMID:22685627

Modeling and Calibration of a Novel One-Mirror Galvanometric Laser Scanner

PubMed Central

Yu, Chengyi; Chen, Xiaobo; Xi, Juntong

2017-01-01

A laser stripe sensor has limited application when a point cloud of geometric samples on the surface of the object needs to be collected, so a galvanometric laser scanner is designed by using a one-mirror galvanometer element as its mechanical device to drive the laser stripe to sweep along the object. A novel mathematical model is derived for the proposed galvanometer laser scanner without any position assumptions and then a model-driven calibration procedure is proposed. Compared with available model-driven approaches, the influence of machining and assembly errors is considered in the proposed model. Meanwhile, a plane-constraint-based approach is proposed to extract a large number of calibration points effectively and accurately to calibrate the galvanometric laser scanner. Repeatability and accuracy of the galvanometric laser scanner are evaluated on the automobile production line to verify the efficiency and accuracy of the proposed calibration method. Experimental results show that the proposed calibration approach yields similar measurement performance compared with a look-up table calibration method. PMID:28098844

A comparison of the accuracy of intraoral scanners using an intraoral environment simulator.

PubMed

Park, Hye-Nan; Lim, Young-Jun; Yi, Won-Jin; Han, Jung-Suk; Lee, Seung-Pyo

2018-02-01

The aim of this study was to design an intraoral environment simulator and to assess the accuracy of two intraoral scanners using the simulator. A box-shaped intraoral environment simulator was designed to simulate two specific intraoral environments. The cast was scanned 10 times by Identica Blue (MEDIT, Seoul, South Korea), TRIOS (3Shape, Copenhagen, Denmark), and CS3500 (Carestream Dental, Georgia, USA) scanners in the two simulated groups. The distances between the left and right canines (D3), first molars (D6), second molars (D7), and the left canine and left second molar (D37) were measured. The distance data were analyzed by the Kruskal-Wallis test. The differences in intraoral environments were not statistically significant ( P >.05). Between intraoral scanners, statistically significant differences ( P <.05) were revealed by the Kruskal-Wallis test with regard to D3 and D6. No difference due to the intraoral environment was revealed. The simulator will contribute to the higher accuracy of intraoral scanners in the future.

Lung imaging of laboratory rodents in vivo

NASA Astrophysics Data System (ADS)

Cody, Dianna D.; Cavanaugh, Dawn; Price, Roger E.; Rivera, Belinda; Gladish, Gregory; Travis, Elizabeth

2004-10-01

We have been acquiring respiratory-gated micro-CT images of live mice and rats for over a year with our General Electric (formerly Enhanced Vision Systems) hybrid scanner. This technique is especially well suited for the lung due to the inherent high tissue contrast. Our current studies focus on the assessment of lung tumors and their response to experimental agents, and the assessment of lung damage due to chemotherapy agents. We have recently installed a custom-built dual flat-panel cone-beam CT scanner with the ability to scan laboratory animals that vary in size from mice to large dogs. A breath-hold technique is used in place of respiratory gating on this scanner. The objective of this pilot study was to converge on scan acquisition parameters and optimize the visualization of lung damage in a mouse model of fibrosis. Example images from both the micro-CT scanner and the flat-panel CT scanner will be presented, as well as preliminary data describing spatial resolution, low contrast resolution, and radiation dose parameters.

MSS D Multispectral Scanner System

NASA Technical Reports Server (NTRS)

Lauletta, A. M.; Johnson, R. L.; Brinkman, K. L. (Principal Investigator)

1982-01-01

The development and acceptance testing of the 4-band Multispectral Scanners to be flown on LANDSAT D and LANDSAT D Earth resources satellites are summarized. Emphasis is placed on the acceptance test phase of the program. Test history and acceptance test algorithms are discussed. Trend data of all the key performance parameters are included and discussed separately for each of the two multispectral scanner instruments. Anomalies encountered and their resolutions are included.

Occupational Survey Report. Visual Information, AFSC 3V0X1

DTIC Science & Technology

2000-04-01

of the career ladder include: Scan artwork using flatbed scanners Convert graphic file formats Design layouts Letter certificates using laser...Design layouts Scan artwork using flatbed scanners Produce artwork using mouse or digitizing tablets Design and produce imagery for web pages Produce...DAFSC 3V031 PERSONNEL TASKS A0034 Scan artwork using flatbed scanners C0065 Design layouts A0004 Convert graphic file formats A0006 Create

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study.

PubMed

Stolin, Alexander V; Martone, Peter F; Jaliparthi, Gangadhar; Raylman, Raymond R

2017-01-01

Positron emission tomography (PET) scanners designed for imaging of small animals have transformed translational research by reducing the necessity to invasively monitor physiology and disease progression. Virtually all of these scanners are based on the use of pixelated detector modules arranged in rings. This design, while generally successful, has some limitations. Specifically, use of discrete detector modules to construct PET scanners reduces detection sensitivity and can introduce artifacts in reconstructed images, requiring the use of correction methods. To address these challenges, and facilitate measurement of photon depth-of-interaction in the detector, we investigated a small animal PET scanner (called AnnPET) based on a monolithic annulus of scintillator. The scanner was created by placing 12 flat facets around the outer surface of the scintillator to accommodate placement of silicon photomultiplier arrays. Its performance characteristics were explored using Monte Carlo simulations and sections of the NEMA NU4-2008 protocol. Results from this study revealed that AnnPET's reconstructed spatial resolution is predicted to be [Formula: see text] full width at half maximum in the radial, tangential, and axial directions. Peak detection sensitivity is predicted to be 10.1%. Images of simulated phantoms (mini-hot rod and mouse whole body) yielded promising results, indicating the potential of this system for enhancing PET imaging of small animals.

Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

PubMed Central

Conley, David B.; Tan, Bruce; Bendok, Bernard R.; Batjer, H. Hunt; Chandra, Rakesh; Sidle, Douglas; Rahme, Rudy J.; Adel, Joseph G.; Fishman, Andrew J.

2011-01-01

Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation. PMID:22470270

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, S. N.; Revet, G.; Fuchs, J.

Radiochromic films (RCF) are commonly used in dosimetry for a wide range of radiation sources (electrons, protons, and photons) for medical, industrial, and scientific applications. They are multi-layered, which includes plastic substrate layers and sensitive layers that incorporate a radiation-sensitive dye. Quantitative dose can be retrieved by digitizing the film, provided that a prior calibration exists. Here, to calibrate the newly developed EBT3 and HDv2 RCFs from Gafchromic™, we used the Stanford Medical LINAC to deposit in the films various doses of 10 MeV photons, and by scanning the films using three independent EPSON Precision 2450 scanners, three independent EPSONmore » V750 scanners, and two independent EPSON 11000XL scanners. The films were scanned in separate RGB channels, as well as in black and white, and film orientation was varied. We found that the green channel of the RGB scan and the grayscale channel are in fact quite consistent over the different models of the scanner, although this comes at the cost of a reduction in sensitivity (by a factor ∼2.5 compared to the red channel). To allow any user to extend the absolute calibration reported here to any other scanner, we furthermore provide a calibration curve of the EPSON 2450 scanner based on absolutely calibrated, commercially available, optical density filters.« less

A Two-Dimensional Micro Scanner Integrated with a Piezoelectric Actuator and Piezoresistors

PubMed Central

Zhang, Chi; Zhang, Gaofei; You, Zheng

2009-01-01

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26° × 23°. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively. PMID:22389621

A two-dimensional micro scanner integrated with a piezoelectric actuator and piezoresistors.

PubMed

Zhang, Chi; Zhang, Gaofei; You, Zheng

2009-01-01

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26° × 23°. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively.

Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra provides reduced effect of scanner for cortex volumetry with atlas-based method in healthy subjects.

PubMed

Goto, Masami; Abe, Osamu; Aoki, Shigeki; Hayashi, Naoto; Miyati, Tosiaki; Takao, Hidemasa; Iwatsubo, Takeshi; Yamashita, Fumio; Matsuda, Hiroshi; Mori, Harushi; Kunimatsu, Akira; Ino, Kenji; Yano, Keiichi; Ohtomo, Kuni

2013-07-01

This study aimed to investigate whether the effect of scanner for cortex volumetry with atlas-based method is reduced using Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra (DARTEL) normalization compared with standard normalization. Three-dimensional T1-weighted magnetic resonance images (3D-T1WIs) of 21 healthy subjects were obtained and evaluated for effect of scanner in cortex volumetry. 3D-T1WIs of the 21 subjects were obtained with five MRI systems. Imaging of each subject was performed on each of five different MRI scanners. We used the Voxel-Based Morphometry 8 tool implemented in Statistical Parametric Mapping 8 and WFU PickAtlas software (Talairach brain atlas theory). The following software default settings were used as bilateral region-of-interest labels: "Frontal Lobe," "Hippocampus," "Occipital Lobe," "Orbital Gyrus," "Parietal Lobe," "Putamen," and "Temporal Lobe." Effect of scanner for cortex volumetry using the atlas-based method was reduced with DARTEL normalization compared with standard normalization in Frontal Lobe, Occipital Lobe, Orbital Gyrus, Putamen, and Temporal Lobe; was the same in Hippocampus and Parietal Lobe; and showed no increase with DARTEL normalization for any region of interest (ROI). DARTEL normalization reduces the effect of scanner, which is a major problem in multicenter studies.

MRI Interscanner Agreement of the Association between the Susceptibility Vessel Sign and Histologic Composition of Thrombi.

PubMed

Bourcier, Romain; Détraz, Lili; Serfaty, Jean Michel; Delasalle, Beatrice Guyomarch; Mirza, Mahmood; Derraz, Imad; Toulgoat, Frédérique; Naggara, Olivier; Toquet, Claire; Desal, Hubert

2017-11-01

The susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) is related to thrombus location, composition, and size in acute stroke. No previous study has determined its inter-MRI scanner variability. We aimed to compare the diagnostic accuracy in-vitro of four different MRI scanners for the characterization of histologic thrombus composition. Thirty-five manufactured thrombi analogs of different composition that were histologically categorized as fibrin-dominant, mixed, or red blood cell (RBC)-dominant were scanned on four different MRI units with T2* sequence. Nine radiologists, blinded to thrombus composition and MRI scanner model, classified twice, in a 2-week interval, the SVS of each thrombus as absent, questionable, or present. We calculated the weighted kappa with 95% confidence interval (CI), sensitivity, specificity and accuracy of the SVS on each MRI scanner to detect RBC-dominant thrombi. The SVS was present in 42%, absent in 33%, and questionable in 25% of thrombi. The interscanner agreement was moderate to good, ranging from .45 (CI: .37-.52) to .67 (CI: .61-.74). The correlation between the SVS and the thrombus composition was moderate (κ: .50 [CI: .44-.55]) to good κ: .76 ([CI: .72-.80]). Sensitivity, specificity, and accuracy to identify RBC-dominant clots were significantly different between MRI scanners (P < .001). The diagnostic accuracy of SVS to determine thrombus composition varies significantly among MRI scanners. Normalization of T2*sequences between scanners may be needed to better predict thrombus composition in multicenter studies. Copyright © 2017 by the American Society of Neuroimaging.

Magnetic resonance transverse relaxation time T2 of knee cartilage in osteoarthritis at 3-T: a cross-sectional multicentre, multivendor reproducibility study.

PubMed

Balamoody, Sharon; Williams, Tomos G; Wolstenholme, Chris; Waterton, John C; Bowes, Michael; Hodgson, Richard; Zhao, Sha; Scott, Marietta; Taylor, Chris J; Hutchinson, Charles E

2013-04-01

The transverse relaxation time (T2) in MR imaging has been identified as a potential biomarker of hyaline cartilage pathology. This study investigates whether MR assessments of T2 are comparable between 3-T scanners from three different vendors. Twelve subjects with symptoms of knee osteoarthritis and one or more risk factors had their knee scanned on each of the three vendors' scanners located in three sites in the U.K. MR data acquisition was based on the United States National Institutes of Health Osteoarthritis Initiative protocol. Measures of cartilage T2 and R2 (inverse of T2) were computed for precision error assessment. Intrascanner reproducibility was also assessed with a phantom (all three scanners) and a cohort of 5 subjects (one scanner only). Whole-organ magnetic resonance (WORM) semiquantitative cartilage scores ranged from minimal to advanced degradation. Intrascanner R2 root-mean-square coefficients of variation (RMSCOV) were low, within the range 2.6 to 6.3% for femoral and tibial regions. For one scanner pair, mean T2 differences ranged from -1.2 to 2.8 ms, with no significant difference observed for the medial tibia and patella regions (p < 0.05). T2 values from the third scanner were systematically lower, producing interscanner mean T2 differences within the range 5.4 to 10.0 ms. Significant interscanner cartilage T2 differences were found and should be accounted for before data from scanners of different vendors are compared.

Complementary equipment for controlling multiple laser beams on single scanner MPLSM systems

NASA Astrophysics Data System (ADS)

Helm, P. Johannes; Nase, Gabriele; Heggelund, Paul; Reppen, Trond

2010-02-01

Multi-Photon-Laser-Scanning-Microscopy (MPLSM) now stands as one of the most powerful experimental tools in biology. Specifically, MPLSM based in-vivo studies of structures and processes in the brains of small rodents and imaging in brain-slices have led to considerable progress in the field of neuroscience. Equipment allowing for independent control of two laser-beams, one for imaging and one for photochemical manipulation, strongly enhances any MPLSM platform. Some industrial MPLSM producers have introduced double scanner options in MPLSM systems. Here, we describe the upgrade of a single scanner MPLSM system with equipment that is suitable for independently controlling the beams of two Titanium Sapphire lasers. The upgrade is compatible with any actual MPLSM system and can be combined with any commercial or self assembled system. Making use of the pixel-clock, frame-active and line-active signals provided by the scanner-electronics of the MPLSM, the user can, by means of an external unit, select individual pixels or rectangular ROIs within the field of view of an overview-scan to be exposed, or not exposed, to the beam(s) of one or two lasers during subsequent scans. The switching processes of the laser-beams during the subsequent scans are performed by means of Electro-Optical-Modulators (EOMs). While this system does not provide the flexibility of two-scanner modules, it strongly enhances the experimental possibilities of one-scanner systems provided a second laser and two independent EOMs are available. Even multi-scanner-systems can profit from this development, which can be used to independently control any number of laser beams.

Pin-photodiode array for the measurement of fan-beam energy and air kerma distributions of X-ray CT scanners.

PubMed

Haba, Tomonobu; Koyama, Shuji; Aoyama, Takahiko; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao; Kameyama, Hiroshi; Tsutsumi, Yoshinori

2016-07-01

Patient dose estimation in X-ray computed tomography (CT) is generally performed by Monte Carlo simulation of photon interactions within anthropomorphic or cylindrical phantoms. An accurate Monte Carlo simulation requires an understanding of the effects of the bow-tie filter equipped in a CT scanner, i.e. the change of X-ray energy and air kerma along the fan-beam arc of the CT scanner. To measure the effective energy and air kerma distributions, we devised a pin-photodiode array utilizing eight channels of X-ray sensors arranged at regular intervals along the fan-beam arc of the CT scanner. Each X-ray sensor consisted of two plate type of pin silicon photodiodes in tandem - front and rear photodiodes - and of a lead collimator, which only allowed X-rays to impinge vertically to the silicon surface of the photodiodes. The effective energy of the X-rays was calculated from the ratio of the output voltages of the photodiodes and the dose was calculated from the output voltage of the front photodiode using the energy and dose calibration curves respectively. The pin-photodiode array allowed the calculation of X-ray effective energies and relative doses, at eight points simultaneously along the fan-beam arc of a CT scanner during a single rotation of the scanner. The fan-beam energy and air kerma distributions of CT scanners can be effectively measured using this pin-photodiode array. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Inter-vender and test-retest reliabilities of resting-state functional magnetic resonance imaging: Implications for multi-center imaging studies.

PubMed

An, Hyeong Su; Moon, Won-Jin; Ryu, Jae-Kyun; Park, Ju Yeon; Yun, Won Sung; Choi, Jin Woo; Jahng, Geon-Ho; Park, Jang-Yeon

2017-12-01

This prospective multi-center study aimed to evaluate the inter-vendor and test-retest reliabilities of resting-state functional magnetic resonance imaging (RS-fMRI) by assessing the temporal signal-to-noise ratio (tSNR) and functional connectivity. Study included 10 healthy subjects and each subject was scanned using three 3T MR scanners (GE Signa HDxt, Siemens Skyra, and Philips Achieva) in two sessions. The tSNR was calculated from the time course data. Inter-vendor and test-retest reliabilities were assessed with intra-class correlation coefficients (ICCs) derived from variant component analysis. Independent component analysis was performed to identify the connectivity of the default-mode network (DMN). In result, the tSNR for the DMN was not significantly different among the GE, Philips, and Siemens scanners (P=0.638). In terms of vendor differences, the inter-vendor reliability was good (ICC=0.774). Regarding the test-retest reliability, the GE scanner showed excellent correlation (ICC=0.961), while the Philips (ICC=0.671) and Siemens (ICC=0.726) scanners showed relatively good correlation. The DMN pattern of the subjects between the two sessions for each scanner and between three scanners showed the identical patterns of functional connectivity. The inter-vendor and test-retest reliabilities of RS-fMRI using different 3T MR scanners are good. Thus, we suggest that RS-fMRI could be used in multicenter imaging studies as a reliable imaging marker. Copyright © 2017 Elsevier Inc. All rights reserved.

Radiofrequency artefacts in echoplanar imaging induced by two 1.5 T MR scanners in close proximity.

PubMed

Li, X; Cui, J; Christopasak, S P; Kumar, A; Peng, Z-G

2014-06-01

The purpose of this study was to assess radio frequency (RF) artefacts in echoplanar imaging (EPI) induced by two 1.5 T MR scanners in close proximity and to find an effective method to correct them. Based on the intact shielding of rooms, experiments were performed by two MR scanners with similar centre frequencies. Phantom A (PA) was scanned in one scanner by EPI at different bandwidths (BWs). Simultaneously, phantom B was scanned in a fixed sequence for scanning with the other scanner. RF artefact gaps of PA, scanning time and the image signal-noise ratio (SNR) were measured and recorded. Statistical analysis was performed with the repeated-measures analysis of variance test. Based on findings obtained from PA, three healthy volunteers were studied at a conventional BW and a lower BW to observe the artefact variance. EPI RF artefacts were symmetrically situated in both sides of the image following the phase-encoding direction. The gap size of the artefact became larger and the SNR was significantly improved with a narrower BW. RF artefacts with a lower BW in volunteers presented the same characteristic as PA. For EPI RF artefacts produced by two 1.5 T MR scanners with approximately similar centre frequencies, we can reduce BWs in a suitable range to minimize the effect on MRI. MR scanners with the same field strength installed in the same vicinity might produce RF artefacts in the sequence at larger BWs. Reducing BWs properly is effective to control the position of artefacts and improve the image quality.

SU-G-206-03: CTDI Per KV at Phantom Center and Periphery: Comparison Between Major CT Manufacturers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Senan, R; Demirkaya, O

Purpose: The purpose of this study was to: 1) compare scanners output by measuring normalized CTDIw (mGy/100mAs) in different CT makes and models and at different kV’s, and 2) quantify the relationship between kV and CTDI and compare this relationship between the different manufacturers. Methods: Study included forty scanners of major CT manufacturers and of various models. Exposure was measured at center and 12 o’clock holes of head and body CTDI phantoms, at all available kV’s, and with the largest or second largest available collimation in each scanner. Average measured CTDI’s from each CT manufacturer were also plotted against kVmore » and the fitting equation: CTDIw (normalized) = a.kVb was calculated. The power (b) value may be considered as an indicator of spectral filtration, which affects the degree of beam hardening. Also, HVLs were measured at several scanners. Results: Results showed GE scanners, on average, had higher normalized CTDIw than those of Siemens and Philips, in both phantom sizes and at all kV’s. ANOVA statistic indicated the difference was statistically significant (p < 0.05). Comparison between Philips and Siemens, however, was not statistically significant. Curve fitting showed b values ranged from 2.4 to 2.9 (for Head periphery and center, respectively); and was about 2.8 for Body phantom periphery, and 3.2 at the center of Body phantom. Fitting equations (kV vs. CTDI) will be presented and discussed. GE’s CTDIw vs. HVL showed very strong correlation (r > 0.99). Conclusion: Partial characterization of scanners output was performed which may be helpful in dose estimation to internal organs. The relatively higher output from GE scanners may be attributed to lower filtration. Work is still in progress to obtain CTDI values from other scanners as well as to measure their HVLs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kakinohana, Y; Toita, T; Kasuya, G

Purpose: To compare the dosimetric properties of radiochromic films with different orientation. Methods: A sheet of EBT3 film was cut into eight pieces with the following sizes: 15×15 cm2 (one piece), 5x15 cm{sup 2} (two) and 4×5 cm{sup 2} (five). A set of two EBT3 sheets was used at each dose level. Two sets were used changing the delivered doses (1 and 2 Gy). The 5×15 cm{sup 2} pieces were rotated by 90 degrees in relation to each other, such that one had landscape orientation and the other had portrait orientation. All 5×15 cm2 pieces were irradiated with their longmore » side aligned with the x-axis of the radiation field. The 15×15 cm{sup 2} pieces were irradiated rotated at 90 degrees to each other. Five pieces, (a total of ten from two sheets) were used to obtain a calibration curve. The irradiated films were scanned using an Epson ES-2200 scanner and were analyzed using ImageJ software. In this study, no correction was applied for the nonuniform scanner signal that is evident in the direction of the scanner lamp. Each film piece was scanned both in portrait and landscape orientations. Dosimetric comparisons of the beam profiles were made in terms of the film orientations (portrait and landscape) and scanner bed directions (perpendicular and parallel to the scanner movement). Results: In general, portrait orientation exhibited higher noise than landscape and was adversely affected to a great extent by the nonuniformity in the direction of the scanner lamp. A significant difference in the measured field widths between the perpendicular and parallel directions was found for both orientations. Conclusion: Without correction for the nonuniform scanner signal in the direction of the scanner lamp, a landscape orientation is preferable. A more detailed investigation is planned to evaluate quantitatively the effect of orientation on the dosimetric properties of a film.« less

Sensitivity and daily quality control of a mobile PET/CT scanner operating in 3-dimensional mode.

PubMed

Belakhlef, Abdelfatihe; Church, Clifford; Fraser, Ron; Lakhanpal, Suresh

2007-12-01

This study investigated the stability of the sensitivity of a mobile PET/CT scanner and tested a phantom experiment to improve on the daily quality control recommendations of the manufacturer. Unlike in-house scanners, mobile PET/CT devices are subjected to a harsher, continuously changing environment that can alter their performance. The parameter of sensitivity was investigated because it reflects directly on standardized uptake value, a key factor in cancer evaluation. A (68)Ge phantom of known activity concentration was scanned 6 times a month for 11 consecutive months using a mobile PET/CT scanner that operates in 3-dimensional mode only. The scans were acquired as 2 contiguous bed positions, with raw data obtained and reconstructed using parameters identical to those used for oncology patients, including CT-extracted attenuation coefficients and decay, scatter, geometry, and randoms corrections. After visual inspection of all reconstructed images, identical regions of interest were drawn on each image to obtain the activity concentration of individual slices. The original activity concentration was then decay-corrected to the scanning day, and the percentage sensitivity of the slice was calculated and graphed. The daily average sensitivity of the scanner, over 11 consecutive months, was also obtained and used to evaluate the stability of sensitivity. Our particular scanner showed a daily average sensitivity ranging from -8.6% to 6.5% except for one instance, when the sensitivity dropped by an unacceptable degree, 34.8%. Our 11-mo follow-up of a mobile PET/CT scanner demonstrated that its sensitivity remained within acceptable clinical limits except for one instance, when the scanner had to be serviced before patients could be imaged. To enhance our confidence in the uniformity of sensitivity across slices, we added a phantom scan to the daily quality control recommendations of the manufacturer.

Relationship between resolution and accuracy of four intraoral scanners in complete-arch impressions

PubMed Central

Pascual-Moscardó, Agustín; Camps, Isabel

2018-01-01

Background The scanner does not measure the dental surface continually. Instead, it generates a point cloud, and these points are then joined to form the scanned object. This approximation will depend on the number of points generated (resolution), which can lead to low accuracy (trueness and precision) when fewer points are obtained. The purpose of this study is to determine the resolution of four intraoral digital imaging systems and to demonstrate the relationship between accuracy and resolution of the intraoral scanner in impressions of a complete dental arch. Material and Methods A master cast of the complete maxillary arch was prepared with different dental preparations. Using four digital impression systems, the cast was scanned inside of a black methacrylate box, obtaining a total of 40 digital impressions from each scanner. The resolution was obtained by dividing the number of points of each digital impression by the total surface area of the cast. Accuracy was evaluated using a three-dimensional measurement software, using the “best alignment” method of the casts with a highly faithful reference model obtained from an industrial scanner. Pearson correlation was used for statistical analysis of the data. Results Of the intraoral scanners, Omnicam is the system with the best resolution, with 79.82 points per mm2, followed by True Definition with 54.68 points per mm2, Trios with 41.21 points per mm2, and iTero with 34.20 points per mm2. However, the study found no relationship between resolution and accuracy of the study digital impression systems (P >0.05), except for Omnicam and its precision. Conclusions The resolution of the digital impression systems has no relationship with the accuracy they achieve in the impression of a complete dental arch. The study found that the Omnicam scanner is the system that obtains the best resolution, and that as the resolution increases, its precision increases. Key words:Trueness, precision, accuracy, resolution, intraoral scanner, digital impression. PMID:29750097

SU-F-T-252: An Investigation of Gamma Knife Frame Definition Error When Using a Pre-Planning Workflow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, P

Purpose: To determine causal factors related to high frame definition error when treating GK patients using a pre-planning workflow. Methods: 160 cases were retrospectively reviewed. All patients received treatment using a pre-planning workflow whereby stereotactic coordinates are determined from a CT scan acquired after framing using a fiducial box. The planning software automatically detects the fiducials and compares their location to expected values based on the rigid design of the fiducial system. Any difference is reported as mean and maximum frame definition error. The manufacturer recommends these values be less than 1.0 mm and 1.5 mm. In this study, framemore » definition error was analyzed in comparison with a variety of factors including which neurosurgeon/oncologist/physicist was involved with the procedure, number of post used during framing (3 or 4), type of lesion, and which CT scanner was utilized for acquisition. An analysis of variance (ANOVA) approach was used to statistically evaluate the data and determine causal factors related to instances of high frame definition error. Results: Two factors were identified as significant: number of post (p=0.0003) and CT scanner (p=0.0001). Further analysis showed that one of the four scanners was significantly different than the others. This diagnostic scanner was identified as an older model with localization lasers not tightly calibrated. The average value for maximum frame definition error using this scanner was 1.48 mm (4 posts) and 1.75 mm (3 posts). For the other scanners this value was 1.13 mm (4 posts) and 1.40 mm (3 posts). Conclusion: In utilizing a pre-planning workflow the choice of CT scanner matters. Any scanner utilized for GK should undergo routine QA at a level appropriate for radiation oncology. In terms of 3 vs 4 post, it is hypothesized that three posts provide less stability during CT acquisition. This will be tested in future work.« less

Efficient use of automatic exposure control systems in computed tomography requires correct patient positioning.

PubMed

Gudjonsdottir, J; Svensson, J R; Campling, S; Brennan, P C; Jonsdottir, B

2009-11-01

Image quality and radiation dose to the patient are important factors in computed tomography (CT). To provide constant image quality, tube current modulation (TCM) performed by automatic exposure control (AEC) adjusts the tube current to the patient's size and shape. To evaluate the effects of patient centering on tube current-time product (mAs) and image noise. An oval-shaped acrylic phantom was scanned in various off-center positions, at 30-mm intervals within a 500-mm field of view, using three different CT scanners. Acquisition parameters were similar to routine abdomen examinations at each site. The mAs was recorded and noise measured in the images. The correlation of mAs and noise with position was calculated using Pearson correlation. In all three scanners, the mAs delivered by the AEC changed with y-position of the phantom (P<0.001), with correlation values of 0.98 for scanners A and B and -0.98 for scanner C. With x-position, mAs changes were 4.9% or less. As the phantom moved into the y-positions, compared with the iso-center, the mAs varied by up to +70%, -34%, and +56% in scanners A, B, and C, respectively. For scanners A and B, noise in two regions of interest in the lower part of the phantom decreased with elevation, with correlation factors from -0.95 to -0.86 (P<0.02). In the x-direction, significant noise relationships (P<0.005) were only seen in scanner A. This study demonstrates that patient centering markedly affects the efficacy of AEC function and that tube current changes vary between scanners. Tube position when acquiring the scout projection radiograph is decisive for the direction of the mAs change. Off-center patient positions cause errors in tube current modulation that can outweigh the dose reduction gained by AEC use, and image quality is affected.

TH-AB-207A-03: Skin Dose to Patients Receiving Multiple CTA and CT Exams of the Head

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nawfel, RD; Young, G

Purpose: To measure patient skin dose from CT angiography (CTA) and CT exams of the head, and determine if patients having multiple exams could receive cumulative doses that approach or exceed deterministic thresholds. Methods: This study was HIPAA compliant and conducted with IRB approval. Patient skin doses were measured over a 4 month period using nanoDot OSL dosimeters placed on the head of 52 patients for two CT scanners. On each scanner, 26 patients received CT exams (scanner 1: 10 females, 16 males, mean age 64.2 years; scanner 2: 18 females, 8 males, mean age 61.2 years). CT exam dosemore » metrics, CTDIvol and dose-length product (DLP) were recorded for each exam. Additionally, skin dose was measured on an acrylic skull phantom in each scanner and on a neuro-interventional imaging system using clinical protocols. Measured dose data was used to estimate peak skin dose (PSD) for 4 patients receiving multiple exams including CTA, head CT, and cerebral angiography. Results: For scanner 1, the mean PSD for CTA exams (98.9 ± 5.3 mGy) and for routine head CT exams (39.2 ± 3.7 mGy) agreed reasonably well with the PSD measured on the phantom, 105.4 mGy and 40.0 mGy, respectively. Similarly for scanner 2, the mean PSD for CTA exams (98.8 ± 7.4 mGy) and for routine head CT exams (42.9 ± 9.4 mGy) compared well with phantom measurements, 95.2 mGy and 37.6 mGy, respectively. In addition, the mean PSD was comparable between scanners for corresponding patient exams, CTA and routine head CT respectively. PSD estimates ranged from 1.9 – 4.5 Gy among 4 patients receiving multiple exams. Conclusion: Patients having several exams including both CTA and routine head CT may receive cumulative doses approaching or exceeding the threshold for single dose deterministic effects.« less

SU-F-R-30: Interscanner Variability of Radiomics Features in Computed Tomography (CT) Using a Standard ACR Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shafiq ul Hassan, M; Zhang, G; Moros, E

2016-06-15

Purpose: A simple approach to investigate Interscanner variability of Radiomics features in computed tomography (CT) using a standard ACR phantom. Methods: The standard ACR phantom was scanned on CT scanners from three different manufacturers. Scanning parameters of 120 KVp, 200 mA were used while slice thickness of 3.0 mm on two scanners and 3.27 mm on third scanner was used. Three spherical regions of interest (ROI) from water, medium density and high density inserts were contoured. Ninety four Radiomics features were extracted using an in-house program. These features include shape (11), intensity (22), GLCM (26), GLZSM (11), RLM (11), andmore » NGTDM (5) and 8 fractal dimensions features. To evaluate the Interscanner variability across three scanners, a coefficient of variation (COV) is calculated for each feature group. Each group is further classified according to the COV- by calculating the percentage of features in each of the following categories: COV less than 2%, between 2 and 10% and greater than 10%. Results: For all feature groups, similar trend was observed for three different inserts. Shape features were the most robust for all scanners as expected. 70% of the shape features had COV <2%. For intensity feature group, 2% COV varied from 9 to 32% for three scanners. All features in four groups GLCM, GLZSM, RLM and NGTDM were found to have Interscanner variability ≥2%. The fractal dimensions dependence for medium and high density inserts were similar while it was different for water inserts. Conclusion: We concluded that even for similar scanning conditions, Interscanner variability across different scanners was significant. The texture features based on GLCM, GLZSM, RLM and NGTDM are highly scanner dependent. Since the inserts of the ACR Phantom are not heterogeneous in HU values suggests that matrix based 2nd order features are highly affected by variation in noise. Research partly funded by NIH/NCI R01CA190105-01.« less

Reproducibility of DCE-MRI time-intensity curve-shape analysis in patients with knee arthritis: A comparison with qualitative and pharmacokinetic analyses.

PubMed

van der Leij, Christiaan; Lavini, Cristina; van de Sande, Marleen G H; de Hair, Marjolein J H; Wijffels, Christophe; Maas, Mario

2015-12-01

To compare the between-session reproducibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) combined with time-intensity curve (TIC)-shape analysis in arthritis patients, within one scanner and between two different scanners, and to compare this method with qualitative analysis and pharmacokinetic modeling (PKM). Fifteen knee joint arthritis patients were included and scanned twice on a closed-bore 1.5T scanner (n = 9, group 1), or on a closed-bore 1.5T and on an open-bore 1.0T scanner (n = 6, group 2). DCE-MRI data were postprocessed using in-house developed software ("Dynamo"). Disease activity was assessed. Disease activity was comparable between the two visits. In group 1 qualitative analysis showed the highest reproducibility with intraclass correlation coefficients (ICCs) between 0.78 and 0.98 and root mean square-coefficients of variation (RMS-CoV) of 8.0%-14.9%. TIC-shape analysis showed a slightly lower reproducibility with similar ICCs (0.78-0.97) but higher RMS-CoV (18.3%-42.9%). The PKM analysis showed the lowest reproducibility with ICCs between 0.39 and 0.64 (RMS-CoV 21.5%-51.9%). In group 2 TIC-shape analysis of the two most important TIC-shape types showed the highest reproducibility with ICCs of 0.78 and 0.71 (RMS-CoV 29.8% and 59.4%) and outperformed the reproducibility of the most important qualitative parameter (ICC 0.31, RMS-CoV 45.1%) and the within-scanner reproducibility of PKM analysis. TIC-shape analysis is a robust postprocessing method within one scanner, almost as reproducible as the qualitative analysis. Between scanners, the reproducibility of the most important TIC-shapes outperform that of the most important qualitative parameter and the within-scanner reproducibility of PKM analysis. © 2015 Wiley Periodicals, Inc.

TH-C-18A-06: Combined CT Image Quality and Radiation Dose Monitoring Program Based On Patient Data to Assess Consistency of Clinical Imaging Across Scanner Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christianson, O; Winslow, J; Samei, E

2014-06-15

Purpose: One of the principal challenges of clinical imaging is to achieve an ideal balance between image quality and radiation dose across multiple CT models. The number of scanners and protocols at large medical centers necessitates an automated quality assurance program to facilitate this objective. Therefore, the goal of this work was to implement an automated CT image quality and radiation dose monitoring program based on actual patient data and to use this program to assess consistency of protocols across CT scanner models. Methods: Patient CT scans are routed to a HIPPA compliant quality assurance server. CTDI, extracted using opticalmore » character recognition, and patient size, measured from the localizers, are used to calculate SSDE. A previously validated noise measurement algorithm determines the noise in uniform areas of the image across the scanned anatomy to generate a global noise level (GNL). Using this program, 2358 abdominopelvic scans acquired on three commercial CT scanners were analyzed. Median SSDE and GNL were compared across scanner models and trends in SSDE and GNL with patient size were used to determine the impact of differing automatic exposure control (AEC) algorithms. Results: There was a significant difference in both SSDE and GNL across scanner models (9–33% and 15–35% for SSDE and GNL, respectively). Adjusting all protocols to achieve the same image noise would reduce patient dose by 27–45% depending on scanner model. Additionally, differences in AEC methodologies across vendors resulted in disparate relationships of SSDE and GNL with patient size. Conclusion: The difference in noise across scanner models indicates that protocols are not optimally matched to achieve consistent image quality. Our results indicated substantial possibility for dose reduction while achieving more consistent image appearance. Finally, the difference in AEC methodologies suggests the need for size-specific CT protocols to minimize variability in image quality across CT vendors.« less

Automatic Channel Fault Detection on a Small Animal APD-Based Digital PET Scanner

NASA Astrophysics Data System (ADS)

Charest, Jonathan; Beaudoin, Jean-François; Cadorette, Jules; Lecomte, Roger; Brunet, Charles-Antoine; Fontaine, Réjean

2014-10-01

Avalanche photodiode (APD) based positron emission tomography (PET) scanners show enhanced imaging capabilities in terms of spatial resolution and contrast due to the one to one coupling and size of individual crystal-APD detectors. However, to ensure the maximal performance, these PET scanners require proper calibration by qualified scanner operators, which can become a cumbersome task because of the huge number of channels they are made of. An intelligent system (IS) intends to alleviate this workload by enabling a diagnosis of the observational errors of the scanner. The IS can be broken down into four hierarchical blocks: parameter extraction, channel fault detection, prioritization and diagnosis. One of the main activities of the IS consists in analyzing available channel data such as: normalization coincidence counts and single count rates, crystal identification classification data, energy histograms, APD bias and noise thresholds to establish the channel health status that will be used to detect channel faults. This paper focuses on the first two blocks of the IS: parameter extraction and channel fault detection. The purpose of the parameter extraction block is to process available data on individual channels into parameters that are subsequently used by the fault detection block to generate the channel health status. To ensure extensibility, the channel fault detection block is divided into indicators representing different aspects of PET scanner performance: sensitivity, timing, crystal identification and energy. Some experiments on a 8 cm axial length LabPET scanner located at the Sherbrooke Molecular Imaging Center demonstrated an erroneous channel fault detection rate of 10% (with a 95% confidence interval (CI) of [9, 11]) which is considered tolerable. Globally, the IS achieves a channel fault detection efficiency of 96% (CI: [95, 97]), which proves that many faults can be detected automatically. Increased fault detection efficiency would be advantageous but, the achieved results would already benefit scanner operators in their maintenance task.

Dose uniformity analysis among ten 16-slice same-model CT scanners.

PubMed

Erdi, Yusuf Emre

2012-01-01

With the introduction of multislice scanners, computed tomographic (CT) dose optimization has become important. The patient-absorbed dose may differ among the scanners although they are the same type and model. To investigate the dose output variation of the CT scanners, we designed the study to analyze dose outputs of 10 same-model CT scanners using 3 clinical protocols. Ten GE Lightspeed (GE Healthcare, Waukesha, Wis) 16-slice scanners located at main campus and various satellite locations of our institution have been included in this study. All dose measurements were performed using poly (methyl methacrylate) (PMMA) head (diameter, 16 cm) and body (diameter, 32 cm) phantoms manufactured by Radcal (RadCal Corp, Monrovia, Calif) using a 9095 multipurpose analyzer with 10 × 9-3CT ion chamber both from the same manufacturer. Ion chamber is inserted into the peripheral and central axis locations and volume CT dose index (CTDIvol) is calculated as weighted average of doses at those locations. Three clinical protocol settings for adult head, high-resolution chest, and adult abdomen are used for dose measurements. We have observed up to 9.4% CTDIvol variation for the adult head protocol in which the largest variation occurred among the protocols. However, head protocol uses higher milliampere second values than the other 2 protocols. Most of the measured values were less than the system-stored CTDIvol values. It is important to note that reduction in dose output from tubes as they age is expected in addition to the intrinsic radiation output fluctuations of the same scanner. Although the same model CT scanners were used in this study, it is possible to see CTDIvol variation in standard patient scanning protocols of head, chest, and abdomen. The compound effect of the dose variation may be larger with higher milliampere and multiphase and multilocation CT scans.

Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography.

PubMed

Trattner, Sigal; Halliburton, Sandra; Thompson, Carla M; Xu, Yanping; Chelliah, Anjali; Jambawalikar, Sachin R; Peng, Boyu; Peters, M Robert; Jacobs, Jill E; Ghesani, Munir; Jang, James J; Al-Khalidi, Hussein; Einstein, Andrew J

2018-01-01

This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy -1 cm -1 . Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED. Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol. k-Factors averaged 0.026 mSv·mGy -1 cm -1 (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy -1 cm -1 . The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy -1 cm -1 ). Cardiac k-factors for all scanners and protocols are considerably higher than the k-factor currently used to estimate ED of cardiac CT studies, suggesting that radiation doses from cardiac CT have been significantly and systematically underestimated. Using cardiac-specific factors can more accurately inform the benefit-risk calculus of cardiac-imaging strategies. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Long-term performance evaluation of positron emission tomography: analysis and proposal of a maintenance protocol for long-term utilization.

PubMed

Watanuki, Shoichi; Tashiro, Manabu; Miyake, Masayasu; Ishikawa, Yoichi; Itoh, Masatoshi; Yanai, Kazuhiko; Sakemi, Yasuhiro; Fukuda, Hiroshi; Ishii, Keizo

2010-07-01

Positron emission tomography (PET) scanners require periodic monitoring in order to maintain scanner performance. The aim of the present study was to examine the deterioration of PET scanner performance caused by aging. We retrospectively examined PET scanner performance alterations in terms of sensitivity, spatial resolution, false coincidences due to scatter and random coincidences based on 13 years of follow-up data, including data when the PET scanner underwent an overhaul at the 10th year after installation. Sensitivity and scatter fraction were calculated by using cross calibration factor (CCF) measurement data, which are collected routinely. Efficacy of the examining the sensitivity and scatter was confirmed by NEMA measurements. Trans-axial resolution was measured as full width at half-maximum (FWHM) and full width at tenth-maximum (FWTM) at 0-20 cm offset from the field of view (FOV) center at the time of installation, 8 years after installation, and immediately after the overhaul. Random coincidence rate fraction was measured in a wide range of count rates before and after the overhaul. The results indicated that the total reduction of sensitivity during the first 10 years was 41% of the initial value in terms of NEMA measurement, and that the annual reduction of sensitivity progressed at a rate of 4.7% per year in terms of CCF measurement data. The changes in sensitivity can be calculated using CCF measurement data. Regarding the spatial resolution, mean FWHM and FWTM values were increased by 1.7 and 3.6%, respectively, in 8 years after installation. The relative scatter fraction was significantly increased compared with that before the overhaul. The random fraction decreased by 10-15% after the overhaul within a certain range of random count rates (1-120 kcps). In the case of our scanner, the parameter that displayed the largest change was the sensitivity, and this change was thought to be caused by the reduction of photomultiplier tube (PMT) gain, although the changes in PMT gain can cause various types of performance deterioration, as investigated in this study. We observed that the sensitivity of our PET scanner generally deteriorated due to aging. Sensitivity monitoring using CCF measurements can be an easy and useful method for monitoring and maintaining the performance of PET scanners against aging. Since the data were obtained from a single scanner, the authors would encourage the initiation of a follow-up study involving various scanners.

Biomedical ultrasonoscope

NASA Technical Reports Server (NTRS)

Lee, R. D. (Inventor)

1976-01-01

An instrument with a single ultrasonic transducer probe and a linear array of transducer probes permitting three operator modes is described. An 'A' and an 'M' mode scanner were combined with a 'C' mode scanner and a single receiver is used. The 'C' scanner mode enables two-dimensional cross sections of the viewed organ. Video-produced markers enable measurement of the dimensions of the heart. COS/MOS integrated logic circuit components are used to minimize power consumption and permit battery operation.

Data acquisition system for operational earth observation missions

NASA Technical Reports Server (NTRS)

Deerwester, J. M.; Alexander, D.; Arno, R. D.; Edsinger, L. E.; Norman, S. M.; Sinclair, K. F.; Tindle, E. L.; Wood, R. D.

1972-01-01

The data acquisition system capabilities expected to be available in the 1980 time period as part of operational Earth observation missions are identified. By data acquisition system is meant the sensor platform (spacecraft or aircraft), the sensors themselves and the communication system. Future capabilities and support requirements are projected for the following sensors: film camera, return beam vidicon, multispectral scanner, infrared scanner, infrared radiometer, microwave scanner, microwave radiometer, coherent side-looking radar, and scatterometer.

47. View of "dry air inlets" to waveguides entering scanner ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. View of "dry air inlets" to waveguides entering scanner building 105. Dried air is generated under pressure by Ingersoll-Rand dehumidified/dessicator and compressor system. View is at entrance from passageway that links into corner of scanner building. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Device-independent color scanning

NASA Astrophysics Data System (ADS)

Burger, Rudolph E.

1993-08-01

Color calibration technology is being incorporated into both Apple and Microsoft's operating systems. These color savvy operating systems will produce a market pull towards 'smart color' scanners and printers which, in turn, will lead towards a distributed architecture for color management systems (CMS). Today's desktop scanners produce red-green-blue color signals that do not accurately describe the color of the object being scanned. Future scanners will be self-calibrating and communicate their own 'device profile' to the operating system based CMS. This paper describes some of the key technologies required for this next generation of smart color scanners. Topics covered include a comparison of colorimetric and conventional scanning technologies, and the impact of metamerism, dye fluorescence and chromatic adaptation on device independent color scanning.

Calibration procedure for a laser triangulation scanner with uncertainty evaluation

NASA Astrophysics Data System (ADS)

Genta, Gianfranco; Minetola, Paolo; Barbato, Giulio

2016-11-01

Most of low cost 3D scanning devices that are nowadays available on the market are sold without a user calibration procedure to correct measurement errors related to changes in environmental conditions. In addition, there is no specific international standard defining a procedure to check the performance of a 3D scanner along time. This paper aims at detailing a thorough methodology to calibrate a 3D scanner and assess its measurement uncertainty. The proposed procedure is based on the use of a reference ball plate and applied to a triangulation laser scanner. Experimental results show that the metrological performance of the instrument can be greatly improved by the application of the calibration procedure that corrects systematic errors and reduces the device's measurement uncertainty.

Comparison of rankings for lean meat based on results from a CT scanner and a video image analysis system.

PubMed

Jay, N P; van de Ven, R J; Hopkins, D L

2014-10-01

Coopworth cross lambs born over three years were examined in this study. Differences between two machines; a computer tomography (CT) scanner and a VIAScan® system for the estimation of carcase lean weight in lamb carcases was examined. The CT scanner provided a significantly higher estimate of carcase lean. The rank correlation (0.84) between the CT scanner and the VIAScan® system for the prediction of carcase lean was significant, but there was a different ranking for carcase lean depending on which machine was used. This has important ramifications for the use of VIAScan® data in the New Zealand Sheep Improvement Ltd genetic programme. Copyright © 2014 Elsevier Ltd. All rights reserved.

Accuracy and reproducibility of virtual edentulous casts created by laboratory impression scan protocols.

PubMed

Peng, Lingyan; Chen, Li; Harris, Bryan T; Bhandari, Bikash; Morton, Dean; Lin, Wei-Shao

2018-04-24

Although computer-aided design and computer-aided manufacturing (CAD-CAM) complete removable dental prostheses (CRDPs) have gained popularity, conventional impressions are still common for CAD-CAM CRDP treatment. These need to be digitized and converted into virtual edentulous casts with a laboratory impression scan protocol during prosthesis fabrication. How this can best be accomplished is unclear. The purpose of this in vitro study was to compare the accuracy and reproducibility of virtual edentulous casts created by a dental laboratory laser scanner and a cone-beam computed tomography (CBCT) scanner with a digitized master cast. A master cast was digitized as the virtual reference cast. Ten polyvinyl siloxane impressions were made on the master cast and scanned with the dental laboratory laser scanner and CBCT scanner. The impressions were sprayed with antiglare spray and rescanned. Four groups of virtual study casts (N=40) were created from the impression scans. All virtual study casts and the reference cast were registered with surface-matching software, and the root mean square (RMS) values (representation of overall accuracy) and percentage of measurement data points within 1 standard deviation (SD) of mean RMS values (%, representation of overall reproducibility) among the 4 study groups were measured. Additionally, 95 numeric distance differences (representation of accuracy at each region) were measured in 5 distinct regions: the apex of the denture border, 6 mm from denture border, crest of the ridge, palate, and posterior palatal seal. The repeated-measures ANOVA and post hoc test (t grouping) were used to determine statistical differences (α=.05). The laboratory scanner group had a significantly larger RMS value (4.0 ±0.3 μm, P<.001) and smaller percentage of measurement data points within 1 SD of mean RMS value (77.5 ±1.0%, P<.001). The RMS values between the CBCT scanner (1.2 ±0.3 μm) and CBCT scanner-spray (1.1 ±0.2 μm) groups were not significantly different (P=.968), and the percentage of measurement data points within 1 SD of mean RMS values (90.1 ±1.1% versus 89.5 ±0.8%) were also not significantly different (P=.662). The numeric distance differences across 5 regions were affected by the scanning protocols (P<.001). The laboratory scanner and laboratory scanner-spray groups had significantly higher numeric distance differences at the apex of the denture border and crest of the ridge regions (P<.001). The CBCT scanner created more accurate and reproducible virtual edentulous casts, and the antiglare spray only significantly improved the accuracy and reproducibility of virtual edentulous casts created by the dental laboratory laser scanner. The accuracy of the virtual edentulous casts was different across 5 regions and was affected by the scanning protocols. Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Gu, J.; Bednarz, B.; Caracappa, P. F.; Xu, X. G.

2009-05-01

The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as assessing fetal and organ doses by combining the MDCT scanner model and the pregnant patient phantom.

Assessment of the impact of the scanner-related factors on brain morphometry analysis with Brainvisa

PubMed Central

2011-01-01

Background Brain morphometry is extensively used in cross-sectional studies. However, the difference in the estimated values of the morphometric measures between patients and healthy subjects may be small and hence overshadowed by the scanner-related variability, especially with multicentre and longitudinal studies. It is important therefore to investigate the variability and reliability of morphometric measurements between different scanners and different sessions of the same scanner. Methods We assessed the variability and reliability for the grey matter, white matter, cerebrospinal fluid and cerebral hemisphere volumes as well as the global sulcal index, sulcal surface and mean geodesic depth using Brainvisa. We used datasets obtained across multiple MR scanners at 1.5 T and 3 T from the same groups of 13 and 11 healthy volunteers, respectively. For each morphometric measure, we conducted ANOVA analysis and verified whether the estimated values were significantly different across different scanners or different sessions of the same scanner. The between-centre and between-visit reliabilities were estimated from their contribution to the total variance, using a random-effects ANOVA model. To estimate the main processes responsible for low reliability, the results of brain segmentation were compared to those obtained using FAST within FSL. Results In a considerable number of cases, the main effects of both centre and visit factors were found to be significant. Moreover, both between-centre and between-visit reliabilities ranged from poor to excellent for most morphometric measures. A comparison between segmentation using Brainvisa and FAST revealed that FAST improved the reliabilities for most cases, suggesting that morphometry could benefit from improving the bias correction. However, the results were still significantly different across different scanners or different visits. Conclusions Our results confirm that for morphometry analysis with the current version of Brainvisa using data from multicentre or longitudinal studies, the scanner-related variability must be taken into account and where possible should be corrected for. We also suggest providing some flexibility to Brainvisa for a step-by-step analysis of the robustness of this package in terms of reproducibility of the results by allowing the bias corrected images to be imported from other packages and bias correction step be skipped, for example. PMID:22189342

ERBE Data and Information

Atmospheric Science Data Center

2014-06-20

ERBE Data and Information Earth Radiation Budget Experiment (ERBE) ... (ERBS, NOAA-9, NOAA-10) carrying two ERBE instrument packages (Scanner and NonScanner). The objective was to measure global albedo, ...

MFP scanner diagnostics using a self-printed target to measure the modulation transfer function

NASA Astrophysics Data System (ADS)

Wang, Weibao; Bauer, Peter; Wagner, Jerry; Allebach, Jan P.

2014-01-01

In the current market, reduction of warranty costs is an important avenue for improving profitability by manufacturers of printer products. Our goal is to develop an autonomous capability for diagnosis of printer and scanner caused defects with mid-range laser multifunction printers (MFPs), so as to reduce warranty costs. If the scanner unit of the MFP is not performing according to specification, this issue needs to be diagnosed. If there is a print quality issue, this can be diagnosed by printing a special test page that is resident in the firmware of the MFP unit, and then scanning it. However, the reliability of this process will be compromised if the scanner unit is defective. Thus, for both scanner and printer image quality issues, it is important to be able to properly evaluate the scanner performance. In this paper, we consider evaluation of the scanner performance by measuring its modulation transfer function (MTF). The MTF is a fundamental tool for assessing the performance of imaging systems. Several ways have been proposed to measure the MTF, all of which require a special target, for example a slanted-edge target. It is unacceptably expensive to ship every MFP with such a standard target, and to expect that the customer can keep track of it. To reduce this cost, in this paper, we develop new approach to this task. It is based on a self-printed slanted-edge target. Then, we propose algorithms to improve the results using a self-printed slanted-edge target. Finally, we present experimental results for MTF measurement using self-printed targets and compare them to the results obtained with standard targets.

Methods and apparatus for laser beam scanners with different actuating mechanisms

NASA Astrophysics Data System (ADS)

Chen, Si-hai; Xiang, Si-hua; Wu, Xin; Dong, Shan; Xiao, Ding; Zheng, Xia-wei

2009-07-01

In this paper, 3 types of laser beam scanner are introduced. One is transmissive beam scanner, which is composed of convex and concave microlens arrays (MLAs). By moving the concave lens in the plane vertical to the optical axis, the incident beam can be deflected in two dimensions. Those two kinds of MLAs are fabricated by thermal reflow and replication process. A set of mechanical scanner frame is fabricated with the two MLAs assembling in it. The testing result shown that the beam deflection angles are 9.5° and 9.6°, in the 2 dimension(2D) with the scanning frequency of 2 HZ and 8 HZ, respectively. The second type of laser beam scanner is actuated by voice coil actuators (VCAs). Based on ANSOFT MAXWELL software, we have designed VCAs with small size and large force which have optimized properties. The model of VCAs is built using AutoCAD and is analyzed by Ansoft maxwell. According to the simulation results, high performance VCAs are fabricated and tested. The result is that the force of the VCAs is 6.39N/A, and the displacement is +/-2.5mm. A set up of beam scanner is fabricated and actuated by the designed VCAs. The testing result shown that the two dimensional scanning angle is 15° and 10° respectively at the frequency of 60HZ. The two dimensional scanning angle is 8.3° and 6° respectively at the frequency of 100HZ. The third type of scanner is actuated by amplified piezoelectric actuators (APAs). The scanning mirror is actuated by the piezoelectric (PZ) actuators with the scanning frequency of 700HZ, 250HZ and 87HZ respectively. The optical scanning angle is +/-0.5° at the three frequencies.

Characterization and control of EUV scanner dose uniformity and stability

NASA Astrophysics Data System (ADS)

Robinson, Chris; Corliss, Dan; Meli, Luciana; Johnson, Rick

2018-03-01

The EUV source is an impressive feat of engineering that provides 13.5 nm radiation by vaporizing tin droplets with a high power CO2 laser and focusing the photons produced in the resultant plasma into the scanner illumination system. Great strides have been made in addressing the many potential stability challenges, but there are still residual spatial and temporal dose non-uniformity signatures. Since even small dose errors can impact the yieldable process window for the advanced lithography products that are exposed on EUV scanners it is crucial to monitor and control the dose variability. Using on-board metrology, the EUV scanner outputs valuable metrics that provide real time insight into the dose performance. We have supplemented scanner data collection with a wafer based methodology that provides high throughput, high sensitivity, quantitative characterization of the EUV scanner dose delivery. The technique uses open frame EUV exposures, so it is exclusive of lithographic pattern imaging, exclusive of lithographic mask pattern and not limited by placement of metrology features. Processed wafers are inspected rapidly, providing 20,000 pixels of detail per exposure field in approximately one minute. Exposing the wafer on the scanner with a bit less than the resist E0 (open frame clearing dose) results in good sensitivity to small variations in the EUV dose delivered. The nominal exposure dose can be modulated by field to calibrate the inspection results and provide quantitative assessment of variations with < 1% sensitivity. This technique has been used for dose uniformity assessments. It is also being used for long term dose stability monitoring and has proven valuable for short term dose stability follow up investigations.

Validation of calculation algorithms for organ doses in CT by measurements on a 5 year old paediatric phantom

NASA Astrophysics Data System (ADS)

Dabin, Jérémie; Mencarelli, Alessandra; McMillan, Dayton; Romanyukha, Anna; Struelens, Lara; Lee, Choonsik

2016-06-01

Many organ dose calculation tools for computed tomography (CT) scans rely on the assumptions: (1) organ doses estimated for one CT scanner can be converted into organ doses for another CT scanner using the ratio of the Computed Tomography Dose Index (CTDI) between two CT scanners; and (2) helical scans can be approximated as the summation of axial slices covering the same scan range. The current study aims to validate experimentally these two assumptions. We performed organ dose measurements in a 5 year-old physical anthropomorphic phantom for five different CT scanners from four manufacturers. Absorbed doses to 22 organs were measured using thermoluminescent dosimeters for head-to-torso scans. We then compared the measured organ doses with the values calculated from the National Cancer Institute dosimetry system for CT (NCICT) computer program, developed at the National Cancer Institute. Whereas the measured organ doses showed significant variability (coefficient of variation (CoV) up to 53% at 80 kV) across different scanner models, the CoV of organ doses normalised to CTDIvol substantially decreased (12% CoV on average at 80 kV). For most organs, the difference between measured and simulated organ doses was within  ±20% except for the bone marrow, breasts and ovaries. The discrepancies were further explained by additional Monte Carlo calculations of organ doses using a voxel phantom developed from CT images of the physical phantom. The results demonstrate that organ doses calculated for one CT scanner can be used to assess organ doses from other CT scanners with 20% uncertainty (k  =  1), for the scan settings considered in the study.

Reconstruction artifacts in VRX CT scanner images

NASA Astrophysics Data System (ADS)

Rendon, David A.; DiBianca, Frank A.; Keyes, Gary S.

2008-03-01

Variable Resolution X-ray (VRX) CT scanners allow imaging of different sized anatomy at the same level of detail using the same device. This is achieved by tilting the x-ray detectors so that the projected size of the detecting elements is varied to produce reconstructions of smaller fields of view with higher spatial resolution. As with regular CT scanners, the images obtained with VRX scanners are affected by different kinds of artifacts of various origins. This work studies some of these artifacts and the impact that the VRX effect has on them. For this, computational models of single-arm single-slice VRX scanners are used to produce images with artifacts commonly found in routine use. These images and artifacts are produced using our VRX CT scanner simulator, which allows us to isolate the system parameters that have a greater effect on the artifacts. A study of the behavior of the artifacts at varying VRX opening angles is presented for scanners implemented using two different detectors. The results show that, although varying the VRX angle will have an effect on the severity of each of the artifacts studied, for some of these artifacts the effect of other factors (such as the distribution of the detector cells and the position of the phantom in the reconstruction grid) is overwhelmingly more significant. This is shown to be the case for streak artifacts produced by thin metallic objects. For some artifacts related to beam hardening, their severity was found to decrease along with the VRX angle. These observations allow us to infer that in regular use the effect of the VRX angle artifacts similar to the ones studied here will not be noticeable as it will be overshadowed by parameters that cannot be easily controlled outside of a computational model.

[Evaluation of the quality of three-dimensional data acquired by using two kinds of structure light intra-oral scanner to scan the crown preparation model].

PubMed

Zhang, X Y; Li, H; Zhao, Y J; Wang, Y; Sun, Y C

2016-07-01

To quantitatively evaluate the quality and accuracy of three-dimensional (3D) data acquired by using two kinds of structure intra-oral scanner to scan the typical teeth crown preparations. Eight typical teeth crown preparations model were scanned 3 times with two kinds of structured light intra-oral scanner(A, B), as test group. A high precision model scanner were used to scan the model as true value group. The data above the cervical margin was extracted. The indexes of quality including non-manifold edges, the self-intersections, highly-creased edges, spikes, small components, small tunnels, small holes and the anount of triangles were measured with the tool of mesh doctor in Geomagic studio 2012. The scanned data of test group were aligned to the data of true value group. 3D deviations of the test group compared with true value group were measured for each scanned point, each preparation and each group. Independent-samples Mann-Whitney U test was applied to analyze 3D deviations for each scanned point of A and B group. Correlation analysis was applied to index values and 3D deviation values. The total number of spikes in A group was 96, and that in B group and true value group were 5 and 0 respectively. Trueness: A group 8.0 (8.3) μm, B group 9.5 (11.5) μm(P>0.05). Correlation analysis of the number of spikes with data precision of A group was r=0.46. In the study, the qulity of the scanner B is better than scanner A, the difference of accuracy is not statistically significant. There is correlation between quality and data precision of the data scanned with scanner A.

The use of radiochromic EBT2 film for the quality assurance and dosimetric verification of 3D conformal radiotherapy using Microtek ScanMaker 9800XL flatbed scanner

PubMed Central

Sim, GS; Ng, KH

2013-01-01

Radiochromic and radiographic films are widely used for radiation dosimetry due to the advantage of high spatial resolution and two‐dimensional dose measurement. Different types of scanners, including various models of flatbed scanners, have been used as part of the dosimetry readout procedure. This paper focuses on the characterization of the EBT2 film response in combination with a Microtek ScanMaker 9800XL scanner and the subsequent use in the dosimetric verification of a 3D conformal radiotherapy treatment. The film reproducibility and scanner uniformity of the Microtek ScanMaker 9800XL was studied. A three‐field 3D conformal radiotherapy treatment was planned on an anthropomorphic phantom and EBT2 film measurements were carried out to verify the treatment. The interfilm reproducibility was found to be 0.25%. Over a period of three months, the films darkened by 1%. The scanner reproducibility was ± 2% and a nonuniformity was ±1.9% along the direction perpendicular to the scan direction. EBT2 measurements showed an underdose of 6.2% at high‐dose region compared to TPS predicted dose. This may be due to the inability of the treatment planning system to predict the correct dose distribution in the presence of tissue inhomogeneities and the uncertainty of the scanner reproducibility and uniformity. The use of EBT2 film in conjunction with the axial CT image of the anthropomorphic phantom allows the evaluation of the anatomical location of dose discrepancies between the EBT2 measured dose distribution and TPS predicted dose distribution. PACS number: 87.55.Qr PMID:23835383

PET/CT scanners: a hardware approach to image fusion.

PubMed

Townsend, David W; Beyer, Thomas; Blodgett, Todd M

2003-07-01

New technology that combines positron tomography with x-ray computed tomography (PET/CT) is available from all major vendors of PET imaging equipment: CTI, Siemens, GE, Philips. Although not all vendors have made the same design choices as those described in this review all have in common that their high performance design places a commercial CT scanner in tandem with a commercial PET scanner. The level of physical integration is actually less than that of the original prototype design where the CT and PET components were mounted on the same rotating support. There will undoubtedly be a demand for PET/CT technology with a greater level of integration, and at a reduced cost. This may be achieved through the design of a scanner specifically for combined anatomical and functional imaging, rather than a design combining separate CT and PET scanners, as in the current approaches. By avoiding the duplication of data acquisition and image reconstruction functions, for example, a more integrated design should also allow cost savings over current commercial PET/CT scanners. The goal is then to design and build a device specifically for imaging the function and anatomy of cancer in the most optimal and effective way, without conceptualizing it as combined PET and CT. The development of devices specifically for imaging a particular disease (eg, cancer) differs from the conventional approach of, for example, an all-purpose anatomical imaging device such as a CT scanner. This new concept targets more of a disease management approach rather than the usual division into the medical specialties of radiology (anatomical imaging) and nuclear medicine (functional imaging). Copyright 2003 Elsevier Inc. All rights reserved.

Cardiac Magnetic Resonance Imaging Using an Open 1.0T MR Platform: A Comparative Study with a 1.5T Tunnel System.

PubMed

Fischbach, Katharina; Kosiek, Otrud; Friebe, Björn; Wybranski, Christian; Schnackenburg, Bernhard; Schmeisser, Alexander; Smid, Jan; Ricke, Jens; Pech, Maciej

2017-01-01

Cardiac magnetic resonance imaging (cMRI) has become the non-invasive reference standard for the evaluation of cardiac function and viability. The introduction of open, high-field, 1.0T (HFO) MR scanners offers advantages for examinations of obese, claustrophobic and paediatric patients.The aim of our study was to compare standard cMRI sequences from an HFO scanner and those from a cylindrical, 1.5T MR system. Fifteen volunteers underwent cMRI both in an open HFO and in a cylindrical MR system. The protocol consisted of cine and unenhanced tissue sequences. The signal-to-noise ratio (SNR) for each sequence and blood-myocardium contrast for the cine sequences were assessed. Image quality and artefacts were rated. The location and number of non-diagnostic segments was determined. Volunteers' tolerance to examinations in both scanners was investigated. SNR was significantly lower in the HFO scanner (all p<0.001). However, the contrast of the cine sequence was significantly higher in the HFO platform compared to the 1.5T MR scanner (0.685±0.41 vs. 0.611±0.54; p<0.001). Image quality was comparable for all sequences (all p>0.05). Overall, only few non-diagnostic myocardial segments were recorded: 6/960 (0.6%) by the HFO and 17/960 (1.8%) segments by the cylindrical system. The volunteers expressed a preference for the open MR system (p<0.01). Standard cardiac MRI sequences in an HFO platform offer a high image quality that is comparable to the quality of images acquired in a cylindrical 1.5T MR scanner. An open scanner design may potentially improve tolerance of cardiac MRI and therefore allow to examine an even broader patient spectrum.

EU Directive 2004/40: field measurements of a 1.5 T clinical MR scanner.

PubMed

Riches, S F; Collins, D J; Scuffham, J W; Leach, M O

2007-06-01

The European Union (EU) Physical Agents (EMF) Directive [1] must be incorporated into UK law in 2008. The directive, which applies to employees working in MRI, sets legal exposure limits for two of the three types of EMF exposure employed in MRI; time-varying gradient fields and radiofrequency (RF) fields. Limits on the static field are currently not included but may be added at a later date. Conservative action values have been set for all three types of exposure including the static field. The absolute exposure limits will exclude staff from the scanner bore and adjacent areas during scanning, impacting on many clinical activities such as anaesthetic monitoring during sedated scans, paediatric scanning and interventional MRI. When the legislation comes into force, NHS Trusts, scanner companies and academic institutions will be required to show compliance with the law. We present results of initial measurements performed on a 1.5 T clinical MRI scanner. For the static field, the proposed action value is exceeded at 40 cm from the scanner bore and would be exceeded when positioning a patient for scanning. For the RF field, the action values were only exceeded within the bore at distances of 40 cm from the scanner ends during a very RF intensive sequence; MRI employees are unlikely to be in the bore during an acquisition. For the time-varying gradient fields the action values were exceeded 52 cm out from the mouth of the bore during two clinical sequences, and estimated current densities show the exposure limit to be exceeded at 40 cm for frequencies above 333 Hz. Limiting employees to distances greater than these from the scanner during acquisition will have a severe impact on the future use and development of MRI.

An Automatic Procedure for Combining Digital Images and Laser Scanner Data

NASA Astrophysics Data System (ADS)

Moussa, W.; Abdel-Wahab, M.; Fritsch, D.

2012-07-01

Besides improving both the geometry and the visual quality of the model, the integration of close-range photogrammetry and terrestrial laser scanning techniques directs at filling gaps in laser scanner point clouds to avoid modeling errors, reconstructing more details in higher resolution and recovering simple structures with less geometric details. Thus, within this paper a flexible approach for the automatic combination of digital images and laser scanner data is presented. Our approach comprises two methods for data fusion. The first method starts by a marker-free registration of digital images based on a point-based environment model (PEM) of a scene which stores the 3D laser scanner point clouds associated with intensity and RGB values. The PEM allows the extraction of accurate control information for the direct computation of absolute camera orientations with redundant information by means of accurate space resection methods. In order to use the computed relations between the digital images and the laser scanner data, an extended Helmert (seven-parameter) transformation is introduced and its parameters are estimated. Precedent to that, in the second method, the local relative orientation parameters of the camera images are calculated by means of an optimized Structure and Motion (SaM) reconstruction method. Then, using the determined transformation parameters results in having absolute oriented images in relation to the laser scanner data. With the resulting absolute orientations we have employed robust dense image reconstruction algorithms to create oriented dense image point clouds, which are automatically combined with the laser scanner data to form a complete detailed representation of a scene. Examples of different data sets are shown and experimental results demonstrate the effectiveness of the presented procedures.

Biases in Multicenter Longitudinal PET Standardized Uptake Value Measurements1

PubMed Central

Doot, Robert K; Pierce, Larry A; Byrd, Darrin; Elston, Brian; Allberg, Keith C; Kinahan, Paul E

2014-01-01

This study investigates measurement biases in longitudinal positron-emission tomography/computed tomography (PET/CT) studies that are due to instrumentation variability including human error. Improved estimation of variability between patient scans is of particular importance for assessing response to therapy and multicenter trials. We used National Institute of Standards and Technology-traceable calibration methodology for solid germanium-68/gallium-68 (68Ge/68Ga) sources used as surrogates for fluorine-18 (18F) in radionuclide activity calibrators. One cross-calibration kit was constructed for both dose calibrators and PET scanners using the same 9-month half-life batch of 68Ge/68Ga in epoxy. Repeat measurements occurred in a local network of PET imaging sites to assess standardized uptake value (SUV) errors over time for six dose calibrators from two major manufacturers and for six PET/CT scanners from three major manufacturers. Bias in activity measures by dose calibrators ranged from -50% to 9% and was relatively stable over time except at one site that modified settings between measurements. Bias in activity concentration measures by PET scanners ranged from -27% to 13% with a median of 174 days between the six repeat scans (range, 29 to 226 days). Corresponding errors in SUV measurements ranged from -20% to 47%. SUV biases were not stable over time with longitudinal differences for individual scanners ranging from -11% to 59%. Bias in SUV measurements varied over time and between scanner sites. These results suggest that attention should be paid to PET scanner calibration for longitudinal studies and use of dose calibrator and scanner cross-calibration kits could be helpful for quality assurance and control. PMID:24772207

Deriving stable multi-parametric MRI radiomic signatures in the presence of inter-scanner variations: survival prediction of glioblastoma via imaging pattern analysis and machine learning techniques

NASA Astrophysics Data System (ADS)

Rathore, Saima; Bakas, Spyridon; Akbari, Hamed; Shukla, Gaurav; Rozycki, Martin; Davatzikos, Christos

2018-02-01

There is mounting evidence that assessment of multi-parametric magnetic resonance imaging (mpMRI) profiles can noninvasively predict survival in many cancers, including glioblastoma. The clinical adoption of mpMRI as a prognostic biomarker, however, depends on its applicability in a multicenter setting, which is hampered by inter-scanner variations. This concept has not been addressed in existing studies. We developed a comprehensive set of within-patient normalized tumor features such as intensity profile, shape, volume, and tumor location, extracted from multicenter mpMRI of two large (npatients=353) cohorts, comprising the Hospital of the University of Pennsylvania (HUP, npatients=252, nscanners=3) and The Cancer Imaging Archive (TCIA, npatients=101, nscanners=8). Inter-scanner harmonization was conducted by normalizing the tumor intensity profile, with that of the contralateral healthy tissue. The extracted features were integrated by support vector machines to derive survival predictors. The predictors' generalizability was evaluated within each cohort, by two cross-validation configurations: i) pooled/scanner-agnostic, and ii) across scanners (training in multiple scanners and testing in one). The median survival in each configuration was used as a cut-off to divide patients in long- and short-survivors. Accuracy (ACC) for predicting long- versus short-survivors, for these configurations was ACCpooled=79.06% and ACCpooled=84.7%, ACCacross=73.55% and ACCacross=74.76%, in HUP and TCIA datasets, respectively. The hazard ratio at 95% confidence interval was 3.87 (2.87-5.20, P<0.001) and 6.65 (3.57-12.36, P<0.001) for HUP and TCIA datasets, respectively. Our findings suggest that adequate data normalization coupled with machine learning classification allows robust prediction of survival estimates on mpMRI acquired by multiple scanners.

Impacts of Intelligent Automated Quality Control on a Small Animal APD-Based Digital PET Scanner

NASA Astrophysics Data System (ADS)

Charest, Jonathan; Beaudoin, Jean-François; Bergeron, Mélanie; Cadorette, Jules; Arpin, Louis; Lecomte, Roger; Brunet, Charles-Antoine; Fontaine, Réjean

2016-10-01

Stable system performance is mandatory to warrant the accuracy and reliability of biological results relying on small animal positron emission tomography (PET) imaging studies. This simple requirement sets the ground for imposing routine quality control (QC) procedures to keep PET scanners at a reliable optimal performance level. However, such procedures can become burdensome to implement for scanner operators, especially taking into account the increasing number of data acquisition channels in newer generation PET scanners. In systems using pixel detectors to achieve enhanced spatial resolution and contrast-to-noise ratio (CNR), the QC workload rapidly increases to unmanageable levels due to the number of independent channels involved. An artificial intelligence based QC system, referred to as Scanner Intelligent Diagnosis for Optimal Performance (SIDOP), was proposed to help reducing the QC workload by performing automatic channel fault detection and diagnosis. SIDOP consists of four high-level modules that employ machine learning methods to perform their tasks: Parameter Extraction, Channel Fault Detection, Fault Prioritization, and Fault Diagnosis. Ultimately, SIDOP submits a prioritized faulty channel list to the operator and proposes actions to correct them. To validate that SIDOP can perform QC procedures adequately, it was deployed on a LabPET™ scanner and multiple performance metrics were extracted. After multiple corrections on sub-optimal scanner settings, a 8.5% (with a 95% confidence interval (CI) of [7.6, 9.3]) improvement in the CNR, a 17.0% (CI: [15.3, 18.7]) decrease of the uniformity percentage standard deviation, and a 6.8% gain in global sensitivity were observed. These results confirm that SIDOP can indeed be of assistance in performing QC procedures and restore performance to optimal figures.

Can a barcode scanner for blood collection improve patient identification integrity in the emergency department? A prospective before-and-after study.

PubMed

Spain, David; Crilly, Julia; Pierce, John; Steele, Michael; Scuffham, Paul; Keijzers, Gerben

2015-02-01

To describe the effect of interventions designed to improve patient identification (PI) during pathology collection in the ED. A prospective before-and-after intervention study was conducted between June 2009 and June 2010 in a regional ED in Queensland, Australia. Interventions aimed to improve PI and specimen labelling, and consisted of: (i) education alone; and (ii) education plus an armband scanner that voice-prompted collector behaviour. Main outcomes measured included: frequency of correct key behaviours (KBs) during specimen collection, pathology integrity errors and cost of interventions. Data from 282 ED pathology collections were analysed (before: n = 115, after with education: n = 95, after with education plus armband scanner: n = 72). KBs for PI and labelling improved significantly following education plus armband scanner use. Application of armbands before sample collection increased (36% vs 90%, P < 0.001), as did asking the patient to state their name (25% vs 93%, P < 0.001) and date of birth (22% vs 93%, P < 0.001). These results were similar, albeit less pronounced, when the effect of education only was assessed. No primary patient misidentification was detected in this small study. The annual costs for a hospital to adopt the education programme with and without the armband scanner were $104,045 and $5330 respectively. ED staff had poor behaviours for identifying patients and labelling pathology specimens before intervention. These safety behaviours were considered an assumed skill. Education alone improved critical KBs markedly that was further augmented by the armband scanner. The cost to adopt education alone is relatively low compared to the addition of armband scanner technology. © 2015 The Authors. Emergency Medicine Australasia published by Wiley Publishing Asia Pty Ltd on behalf of Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Automated scanning of plastic nuclear track detectors using the Minnesota star scanner

NASA Technical Reports Server (NTRS)

Fink, P. J.; Waddington, C. J.

1986-01-01

The problems found in an attempt to adapt an automated scanner of astronomical plates, the Minnesota Automated Dual Plate Scanner (APS), to locating and measuring the etch pits produced by ionizing particles in plastic nuclear track detectors (CR-39) are described. A visual study of these pits was made to determine the errors introduced in determining positions and shapes. Measurements made under a low power microscope were compared with those from the APS.

Computerised Axial Tomography (CAT)

DTIC Science & Technology

1990-06-01

commercial market. EMI, which had originally counted on being the only firm selling CT units , subsequently increased its production in order to overtake...to a rough estimate’"’ the number of CT scanners at present working in Italy is about 18 units installed. apart from those in the large cities such as...hGdcl scanners and 198 total body scanners): among othar things, they emphasise that a CT unit , works, on an average, for 5.4 days in the week and

Comparison of the effects of 665 nm low level diode Laser Hat versus and a combination of 665 nm and 808nm low level diode Laser Scanner of hair growth in androgenic alopecia.

PubMed

Barikbin, Behrooz; Khodamrdi, Zeinab; Kholoosi, Leila; Akhgri, Mohammad Reza; Haj Abbasi, Majid; Hajabbasi, Mojgan; Razzaghi, Zahra; Akbarpour, Samaneh

2017-05-17

This study aimed to evaluate the effectiveness of a combined set of low level diode laser scanner (665 nm and 808nm) on hair growth, and assessment of safety and effectiveness of a new laser scanner on hair growth treatment procedure in androgenic alopecia. 90 patients (18 to 70 years) with androgenic alopecia were randomized into three groups. The first group (n=30) received 655 nm red light using laser hat, the second group (n=30) received 655 nm red laser plus 808 nm infrared laser using a laser scanner of hair growth device (with the patent number: 77733) and the third group (n=30) received no laser as the control group. Patients in laser scanner group had better results and showed a higher increase in terminal hair density compared with laser hat group (mean of 9.61 versus 9.16 per cm 2 ). We found significant decrease in terminal hair density from baseline in control group (mean -1.8 per cm 2 , p<0.0001). Results showed a statistically significant improvement in the laser scanner of the hair growth group compared with laser hat and the control group. The study showed that treatment with new laser devise had a promising result without any observable adverse effects.

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

PubMed Central

Stolin, Alexander V.; Martone, Peter F.; Jaliparthi, Gangadhar; Raylman, Raymond R.

2017-01-01

Abstract. Positron emission tomography (PET) scanners designed for imaging of small animals have transformed translational research by reducing the necessity to invasively monitor physiology and disease progression. Virtually all of these scanners are based on the use of pixelated detector modules arranged in rings. This design, while generally successful, has some limitations. Specifically, use of discrete detector modules to construct PET scanners reduces detection sensitivity and can introduce artifacts in reconstructed images, requiring the use of correction methods. To address these challenges, and facilitate measurement of photon depth-of-interaction in the detector, we investigated a small animal PET scanner (called AnnPET) based on a monolithic annulus of scintillator. The scanner was created by placing 12 flat facets around the outer surface of the scintillator to accommodate placement of silicon photomultiplier arrays. Its performance characteristics were explored using Monte Carlo simulations and sections of the NEMA NU4-2008 protocol. Results from this study revealed that AnnPET’s reconstructed spatial resolution is predicted to be ∼1  mm full width at half maximum in the radial, tangential, and axial directions. Peak detection sensitivity is predicted to be 10.1%. Images of simulated phantoms (mini-hot rod and mouse whole body) yielded promising results, indicating the potential of this system for enhancing PET imaging of small animals. PMID:28097210

A large-scan-angle piezoelectric MEMS optical scanner actuated by a Nb-doped PZT thin film

NASA Astrophysics Data System (ADS)

Naono, Takayuki; Fujii, Takamichi; Esashi, Masayoshi; Tanaka, Shuji

2014-01-01

Resonant 1D microelectromechanical systems (MEMS) optical scanners actuated by piezoelectric unimorph actuators with a Nb-doped lead zirconate titanate (PNZT) thin film were developed for endoscopic optical coherence tomography (OCT) application. The MEMS scanners were designed as the resonance frequency was less than 125 Hz to obtain enough pixels per frame in OCT images. The device size was within 3.4 mm × 2.5 mm, which is compact enough to be installed in a side-imaging probe with 4 mm inner diameter. The fabrication process started with a silicon-on-insulator wafer, followed by PNZT deposition by the Rf sputtering and Si bulk micromachining process. The fabricated MEMS scanners showed maximum optical scan angles of 146° at 90 Hz, 148° at 124 Hz, 162° at 180 Hz, and 152° at 394 Hz at resonance in atmospheric pressure. Such wide scan angles were obtained by a drive voltage below 1.3 Vpp, ensuring intrinsic safety in in vivo uses. The scanner with the unpoled PNZT film showed three times as large a scan angle as that with a poled PZT films. A swept-source OCT system was constructed using the fabricated MEMS scanner, and cross-sectional images of a fingertip with image widths of 4.6 and 2.3 mm were acquired. In addition, a PNZT-based angle sensor was studied for feedback operation.

Giga-pixel fluorescent imaging over an ultra-large field-of-view using a flatbed scanner.

PubMed

Göröcs, Zoltán; Ling, Yuye; Yu, Meng Dai; Karahalios, Dimitri; Mogharabi, Kian; Lu, Kenny; Wei, Qingshan; Ozcan, Aydogan

2013-11-21

We demonstrate a new fluorescent imaging technique that can screen for fluorescent micro-objects over an ultra-wide field-of-view (FOV) of ~532 cm(2), i.e., 19 cm × 28 cm, reaching a space-bandwidth product of more than 2 billion. For achieving such a large FOV, we modified the hardware and software of a commercially available flatbed scanner, and added a custom-designed absorbing fluorescent filter, a two-dimensional array of external light sources for computer-controlled and high-angle fluorescent excitation. We also re-programmed the driver of the scanner to take full control of the scanner hardware and achieve the highest possible exposure time, gain and sensitivity for detection of fluorescent micro-objects through the gradient index self-focusing lens array that is positioned in front of the scanner sensor chip. For example, this large FOV of our imaging platform allows us to screen more than 2.2 mL of undiluted whole blood for detection of fluorescent micro-objects within <5 minutes. This high-throughput fluorescent imaging platform could be useful for rare cell research and cytometry applications by enabling rapid screening of large volumes of optically dense media. Our results constitute the first time that a flatbed scanner has been converted to a fluorescent imaging system, achieving a record large FOV.

NETL CT Imaging Facility

ScienceCinema

None

2018-02-13

NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

A comparison of the accuracy of intraoral scanners using an intraoral environment simulator

PubMed Central

Park, Hye-Nan; Lim, Young-Jun; Yi, Won-Jin

2018-01-01

PURPOSE The aim of this study was to design an intraoral environment simulator and to assess the accuracy of two intraoral scanners using the simulator. MATERIALS AND METHODS A box-shaped intraoral environment simulator was designed to simulate two specific intraoral environments. The cast was scanned 10 times by Identica Blue (MEDIT, Seoul, South Korea), TRIOS (3Shape, Copenhagen, Denmark), and CS3500 (Carestream Dental, Georgia, USA) scanners in the two simulated groups. The distances between the left and right canines (D3), first molars (D6), second molars (D7), and the left canine and left second molar (D37) were measured. The distance data were analyzed by the Kruskal-Wallis test. RESULTS The differences in intraoral environments were not statistically significant (P>.05). Between intraoral scanners, statistically significant differences (P<.05) were revealed by the Kruskal-Wallis test with regard to D3 and D6. CONCLUSION No difference due to the intraoral environment was revealed. The simulator will contribute to the higher accuracy of intraoral scanners in the future. PMID:29503715

Magellan star scanner experiences - What a long, stange trip it's been

NASA Astrophysics Data System (ADS)

Seale, Eric H.

Since its launch to Venus in 1989, the Magellan spacecraft has encountered a variety of interesting phenomena - several related to its star scanner. After much concentration, it was determined that the scanner events were due to environmental effects on the instrument - in particular, its response to solar protons and an unanticipated amount of thermal blanket dust (this dust is, in turn, generated and moved by other environmental forces). In short, while those phenomena were originally an operational nuisance, our scanner has unexpectedly shown new use as a particle and fields detector. Since its simple design makes Magellan's star scanner a good proton detector, a brief description of the charged-particle environment (particularly proton propagation) is also included. Short- and long-term trends in sensor behavior are presented, as are their correlations to the local environment. A summary of results to date is provided in the hope that these may be of help to future operations teams diagnosing similar phenomena. A summary is also given of methods found to reduce the operational impact of these phenomena.

Point Cloud Analysis for Uav-Borne Laser Scanning with Horizontally and Vertically Oriented Line Scanners - Concept and First Results

NASA Astrophysics Data System (ADS)

Weinmann, M.; Müller, M. S.; Hillemann, M.; Reydel, N.; Hinz, S.; Jutzi, B.

2017-08-01

In this paper, we focus on UAV-borne laser scanning with the objective of densely sampling object surfaces in the local surrounding of the UAV. In this regard, using a line scanner which scans along the vertical direction and perpendicular to the flight direction results in a point cloud with low point density if the UAV moves fast. Using a line scanner which scans along the horizontal direction only delivers data corresponding to the altitude of the UAV and thus a low scene coverage. For these reasons, we present a concept and a system for UAV-borne laser scanning using multiple line scanners. Our system consists of a quadcopter equipped with horizontally and vertically oriented line scanners. We demonstrate the capabilities of our system by presenting first results obtained for a flight within an outdoor scene. Thereby, we use a downsampling of the original point cloud and different neighborhood types to extract fundamental geometric features which in turn can be used for scene interpretation with respect to linear, planar or volumetric structures.

System and method of reducing motion-induced noise in the optical detection of an ultrasound signal in a moving body of material

DOEpatents

Habeger, Jr., Charles C.; LaFond, Emmanuel F.; Brodeur, Pierre; Gerhardstein, Joseph P.

2002-01-01

The present invention provides a system and method to reduce motion-induced noise in the detection of ultrasonic signals in a moving sheet or body of material. An ultrasonic signal is generated in a sheet of material and a detection laser beam is moved along the surface of the material. By moving the detection laser in the same direction as the direction of movement of the sheet of material the amount of noise induced in the detection of the ultrasonic signal is reduced. The scanner is moved at approximately the same speed as the moving material. The system and method may be used for many applications, such in a paper making process or steel making process. The detection laser may be directed by a scanner. The movement of the scanner is synchronized with the anticipated arrival of the ultrasonic signal under the scanner. A photodetector may be used to determine when a ultrasonic pulse has been directed to the moving sheet of material so that the scanner may be synchronized the anticipated arrival of the ultrasonic signal.

Multispectral Scanner for Monitoring Plants

NASA Technical Reports Server (NTRS)

Gat, Nahum

2004-01-01

A multispectral scanner has been adapted to capture spectral images of living plants under various types of illumination for purposes of monitoring the health of, or monitoring the transfer of genes into, the plants. In a health-monitoring application, the plants are illuminated with full-spectrum visible and near infrared light and the scanner is used to acquire a reflected-light spectral signature known to be indicative of the health of the plants. In a gene-transfer- monitoring application, the plants are illuminated with blue or ultraviolet light and the scanner is used to capture fluorescence images from a green fluorescent protein (GFP) that is expressed as result of the gene transfer. The choice of wavelength of the illumination and the wavelength of the fluorescence to be monitored depends on the specific GFP.

Cervical spine CT scan

MedlinePlus

... cervical spine; Computed tomography scan of cervical spine; CT scan of cervical spine; Neck CT scan ... table that slides into the center of the CT scanner. Once you are inside the scanner, the ...

Sector-scanning echocardiography

NASA Technical Reports Server (NTRS)

Henry, W. L.; Griffith, J. M.

1975-01-01

The mechanical sector scanner is described in detail, and its clinical application is discussed. Cross sectional images of the heart are obtained in real time using this system. The sector scanner has three major components: (a) hand held scanner, (b) video display, and (c) video recorder. The system provides diagnostic information in a wide spectrum of cardiac diseases, and it quantitates the severity of mitral stenosis by measurement of the mitral valve orifice area in diagnosing infants, children and adults with cyanotic congenital heart disease.

Multispectral scanner system for ERTS: Four band scanner system. Volume 2: Engineering model panoramic pictures and engineering tests

NASA Technical Reports Server (NTRS)

1972-01-01

This document is Volume 2 of three volumes of the Final Report for the four band Multispectral Scanner System (MSS). The results are contained of an analysis of pictures of actual outdoor scenes imaged by the engineering model MSS for spectral response, resolution, noise, and video correction. Also included are the results of engineering tests on the MSS for reflectance and saturation from clouds. Finally, two panoramic pictures of Yosemite National Park are provided.

Visible and infrared imaging radiometers for ocean observations

NASA Technical Reports Server (NTRS)

Barnes, W. L.

1977-01-01

The current status of visible and infrared sensors designed for the remote monitoring of the oceans is reviewed. Emphasis is placed on multichannel scanning radiometers that are either operational or under development. Present design practices and parameter constraints are discussed. Airborne sensor systems examined include the ocean color scanner and the ocean temperature scanner. The costal zone color scanner and advanced very high resolution radiometer are reviewed with emphasis on design specifications. Recent technological advances and their impact on sensor design are examined.

Interceptive Beam Diagnostics - Signal Creation and Materials Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plum, Michael; Spallation Neutron Source, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN

2004-11-10

The focus of this tutorial will be on interceptive beam diagnostics such as wire scanners, screens, and harps. We will start with an overview of the various ways beams interact with materials to create signals useful for beam diagnostics systems. We will then discuss the errors in a harp or wire scanner profile measurement caused by errors in wire position, number of samples, and signal errors. Finally we will apply our results to two design examples-the SNS wire scanner system and the SNS target harp.

Detection of bottled liquid explosives by near infrared

NASA Astrophysics Data System (ADS)

Itozaki, Hide; Miyamura, Ryu; Sato-Akaba, Hideo

2012-10-01

Bottled liquids are limited to be brought in the airplane, because liquid explosives have been used in some terrorist attaches recently. A bottled liquid scanner is expected to be developed. Liquid scanner using near infrared technologies is being developed by us. Many spectrum of liquids have been collected and analyzed by chemometorics in order to separate safe beverage to explosive and dangerous liquids. This bottled liquid scanner had feasibility tests in some international airport in Japan and obtained good review from security people in the airport.

Assessment of Risk Reduction for Lymphedema Following Sentinel Lymph Noded Guided Surgery for Primary Breast Cancer

DTIC Science & Technology

2006-10-01

patients with breast cancer underwent scanning with a hybrid camera which combined a dual-head SPECT camera and a low-dose, single slice CT scanner , (GE...investigated a novel approach which combines the output of a dual-head SPECT camera and a low-dose, single slice CT scanner , (GE Hawkeye®). This... scanner , (Hawkeye®, GE Medical system) is attempted in this study. This device is widely available in cardiology community and has the potential to

Hand-held optical fuel pin scanner

DOEpatents

Kirchner, T.L.; Powers, H.G.

1980-12-07

An optical scanner for indicia arranged in a focal plane perpendicular to an optical system including a rotatable dove prism. The dove prism transmits a rotating image to a stationary photodiode array.

Hand-held optical fuel pin scanner

DOEpatents

Kirchner, Tommy L.; Powers, Hurshal G.

1987-01-01

An optical scanner for indicia arranged in a focal plane perpendicular to an optical system including a rotatable dove prism. The dove prism transmits a rotating image to a stationary photodiode array.

The Economics of Remote Sensing for Planning and Construction

ERIC Educational Resources Information Center

Rottweiler, Kurt A.; Wilson, Jerry C.

1971-01-01

Discusses the latest in remote sensing technology including multispectral scanners, thermal scanners, aero magnetometers and side looking radar. Describes the application of this technology to preconstruction site surveys. (JF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medina, L; Adrada, A; Filipuzzi, M

Purpose: The purpose of this paper is to characterize EBT3 using two types of scanner, analyzing the factors of influence of each dosimetry system. Methods: The film used in this study was GAFCHROMIC EBT3, the films were exposed at a dose range between 0Gy a 9Gy in a solid water phantom, SSD=100cm, 5cm depth and perpendicularly to the 6MV photon beam generated by a Novalis TX linear accelerator equipped with an HDMLC. A Farmer type ion chamber TN30013 (PTW) was used to determine the dose delivered to the film. The films were digitized with a scanner EPSON expression 10000XL andmore » the VIDAR DosimetryPro Adventage RED. Software RIT113v6.1 was used for construction of the calibration curve and analysis. The film characteristics investigated were: response at different dose levels, sensitivity to orientation and side and resolution through the results of the spatial response function by analyzing a step pattern. Additionally, 20 IMRT treatment fields were measured with both scanner and compared with calculated dose using gamma index analysis (3%-3mm). Results: The OD obtained for dose level 2Gy in the orientation portrait of the film on the scanner EPSON is (0,222±0,19) and for Vidar RED (0,252±0,10) and landscape is for EPSON (0,211±0,25) and for Vidar RED (0,250±0,11) . The orientation dependence with respect to film side is about 0,09% for EPSON and about 0.03% for VIDAR. The spatial response function increase in response to the Gaussian function FWHM EPSON scanner (0.18mm) compared with VIDAR scanner function (less than 0.06mm) was observed. We analyzed 20 total plan dose distributions the number of pixels with gamma>1 (3%-3mm) was 0.7%±1.2 [0.1%; 2.82%] for EBT3-VIDAR y 2%±2.9 [0.2%; 3.5%] for EBT3-EPSON. Conclusion: VIDAR scanner shows better sensitivity. EBT3 film shows a different response between portrait and landscape orientation. Step pattern is better reproduce by VIDAR scanner.« less

Design study of an in situ PET scanner for use in proton beam therapy

NASA Astrophysics Data System (ADS)

Surti, S.; Zou, W.; Daube-Witherspoon, M. E.; McDonough, J.; Karp, J. S.

2011-05-01

Proton beam therapy can deliver a high radiation dose to a tumor without significant damage to surrounding healthy tissue or organs. One way of verifying the delivered dose distribution is to image the short-lived positron emitters produced by the proton beam as it travels through the patient. A potential solution to the limitations of PET imaging in proton beam therapy is the development of a high sensitivity, in situ PET scanner that starts PET imaging almost immediately after patient irradiation while the patient is still lying on the treatment bed. A partial ring PET design is needed for this application in order to avoid interference between the PET detectors and the proton beam, as well as restrictions on patient positioning on the couch. A partial ring also allows us to optimize the detector separation (and hence the sensitivity) for different patient sizes. Our goal in this investigation is to evaluate an in situ PET scanner design for use in proton therapy that provides tomographic imaging in a partial ring scanner design using time-of-flight (TOF) information and an iterative reconstruction algorithm. GEANT4 simulation of an incident proton beam was used to produce a positron emitter distribution, which was parameterized and then used as the source distribution inside a water-filled cylinder for EGS4 simulations of a PET system. Design optimization studies were performed as a function of crystal type and size, system timing resolution, scanner angular coverage and number of positron emitter decays. Data analysis was performed to measure the accuracy of the reconstructed positron emitter distribution as well as the range of the positron emitter distribution. We simulated scanners with varying crystal sizes (2-4 mm) and type (LYSO and LaBr3) and our results indicate that 4 mm wide LYSO or LaBr3 crystals (resulting in 4-5 mm spatial resolution) are adequate; for a full-ring, non-TOF scanner we predict a low bias (<0.6 mm) and a good precision (<1 mm) in the estimated range relative to the simulated positron distribution. We then varied the angular acceptance of the scanner ranging from 1/2 to 2/3 of 2π a partial ring TOF imaging with good timing resolution (<=600 ps) is necessary to produce accurate tomographic images. A two-third ring scanner with 300 ps timing resolution leads to a bias of 1.0 mm and a precision of 1.4 mm in the range estimate. With a timing resolution of 600 ps, the bias increases to 2.0 mm while the precision in the range estimate is similar. For a half-ring scanner design, more distortions are present in the image, which is characterized by the increased error in the profile difference estimate. We varied the number of positron decays imaged by the PET scanner by an order of magnitude and we observe some decrease in the precision of the range estimate for lower number of decays, but all partial ring scanner designs studied have a precision <=1.5 mm. The largest number tested, 150 M total positron decays, is considered realistic for a clinical fraction of delivered dose, while the range of positron decays investigated in this work covers a variable number of situations corresponding to delays in scan start time and the total scan time. Thus, we conclude that for partial ring systems, an angular acceptance of at least 1/2 (of 2π) together with timing resolution of 300 ps is needed to achieve accurate and precise range estimates. With 600 ps timing resolution an angular acceptance of 2/3 (of 2π) is required to achieve satisfactory range estimates. These results indicate that it would be feasible to develop a partial-ring dedicated PET scanner based on either LaBr3 or LYSO to accurately characterize the proton dose for therapy planning.

Multi-spectral Line Scanner image of Northern California

NASA Image and Video Library

1973-06-22

S73-34295B (June 1973) --- A vertical view of a portion of northern California reproduced from data taken from the Skylab Multispectral Scanner, experiment S192, in the Skylab space station in Earth orbit. This view is the most westerly one-third of Frame No. 001, Roll No. 518, S192, Skylab 2. Frame No. 001 extends from the Pacific coast at the Eureka area southeasterly 175 nautical miles to the Feather River drainage basin. Included in this view are Lake Shasta, Sacramento River Valley, Redding and Red Bluff. This non-photographic image is a color composite of channels 2 (visible), 7, and 12 (infrared) from the Earth Resources Experiments Package (EREP) S192 scanner. The scanner techniques assist with spectral signature identification and mapping of ground truth targets in agriculture, forestry, geology, hydrology and oceanography. Photo credit: NASA

A variable resolution x-ray detector for computed tomography: II. Imaging theory and performance.

PubMed

DiBianca, F A; Zou, P; Jordan, L M; Laughter, J S; Zeman, H D; Sebes, J

2000-08-01

A computed tomography (CT) imaging technique called variable resolution x-ray (VRX) detection provides variable image resolution ranging from that of clinical body scanning (1 cy/mm) to that of microscopy (100 cy/mm). In this paper, an experimental VRX CT scanner based on a rotating subject table and an angulated storage phosphor screen detector is described and tested. The measured projection resolution of the scanner is > or = 20 lp/mm. Using this scanner, 4.8-s CT scans are made of specimens of human extremities and of in vivo hamsters. In addition, the system's projected spatial resolution is calculated to exceed 100 cy/mm for a future on-line CT scanner incorporating smaller focal spots (0.1 mm) than those currently used and a 1008-channel VRX detector with 0.6-mm cell spacing.

Optimization of PET instrumentation for brain activation studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahlbom, M.; Cherry, S.R.; Hoffman, E.J.

By performing cerebral blood flow studies with positron emission tomography (PET), and comparing blood flow images of different states of activation, functional mapping of the brain is possible. The ability of current commercial instruments to perform such studies is investigated in this work, based on a comparison of noise equivalent count (NEC) rates. Differences in the NEC performance of the different scanners in conjunction with scanner design parameters, provide insights into the importance of block design (size, dead time, crystal thickness) and overall scanner design (sensitivity and scatter fraction) for optimizing data from activation studies. The newer scanners with removablemore » septa, operating with 3-D acquisition, have much higher sensitivity, but require new methodology for optimized operation. Only by administering multiple low doses (fractionation) of the flow tracer can the high sensitivity be utilized.« less

Biochip scanner device

DOEpatents

Perov, Alexander; Belgovskiy, Alexander I.; Mirzabekov, Andrei D.

2001-01-01

A biochip scanner device used to detect and acquire fluorescence signal data from biological microchips or biochips and method of use are provided. The biochip scanner device includes a laser for emitting a laser beam. A modulator, such as an optical chopper modulates the laser beam. A scanning head receives the modulated laser beam and a scanning mechanics coupled to the scanning head moves the scanning head relative to the biochip. An optical fiber delivers the modulated laser beam to the scanning head. The scanning head collects the fluorescence light from the biochip, launches it into the same optical fiber, which delivers the fluorescence into a photodetector, such as a photodiode. The biochip scanner device is used in a row scanning method to scan selected rows of the biochip with the laser beam size matching the size of the immobilization site.

Parameter de-correlation and model-identification in hybrid-style terrestrial laser scanner self-calibration

NASA Astrophysics Data System (ADS)

Lichti, Derek D.; Chow, Jacky; Lahamy, Hervé

One of the important systematic error parameters identified in terrestrial laser scanners is the collimation axis error, which models the non-orthogonality between two instrumental axes. The quality of this parameter determined by self-calibration, as measured by its estimated precision and its correlation with the tertiary rotation angle κ of the scanner exterior orientation, is strongly dependent on instrument architecture. While the quality is generally very high for panoramic-type scanners, it is comparably poor for hybrid-style instruments. Two methods for improving the quality of the collimation axis error in hybrid instrument self-calibration are proposed herein: (1) the inclusion of independent observations of the tertiary rotation angle κ; and (2) the use of a new collimation axis error model. Five real datasets were captured with two different hybrid-style scanners to test each method's efficacy. While the first method achieves the desired outcome of complete decoupling of the collimation axis error from κ, it is shown that the high correlation is simply transferred to other model variables. The second method achieves partial parameter de-correlation to acceptable levels. Importantly, it does so without any adverse, secondary correlations and is therefore the method recommended for future use. Finally, systematic error model identification has been greatly aided in previous studies by graphical analyses of self-calibration residuals. This paper presents results showing the architecture dependence of this technique, revealing its limitations for hybrid scanners.

Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision

PubMed Central

Ender, Andreas; Mehl, Albert

2014-01-01

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base for dental restorations. The current limitation of many reference scanners is the lack of accuracy scanning large objects like full dental arches, or the limited possibility to assess detailed tooth surfaces. A new reference scanner, based on focus variation scanning technique, was evaluated with regards to highest local and general accuracy. A specific scanning protocol was tested to scan original tooth surface from dental impressions. Also, different model materials were verified. The results showed a high scanning accuracy of the reference scanner with a mean deviation of 5.3 ± 1.1 µm for trueness and 1.6 ± 0.6 µm for precision in case of full arch scans. Current dental impression methods showed much higher deviations (trueness: 20.4 ± 2.2 µm, precision: 12.5 ± 2.5 µm) than the internal scanning accuracy of the reference scanner. Smaller objects like single tooth surface can be scanned with an even higher accuracy, enabling the system to assess erosive and abrasive tooth surface loss. The reference scanner can be used to measure differences for a lot of dental research fields. The different magnification levels combined with a high local and general accuracy can be used to assess changes of single teeth or restorations up to full arch changes. PMID:24836007

Preventive maintenance system for the photomultiplier detector blocks of PET scanners

DOEpatents

Levy, A.V.; Warner, D.

1995-01-24

A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The qualitative comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t[sub 0], a time t[sub 1] and a time T, where T>t[sub 1]>t[sub 0], which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner. 40 figures.

Quantitative image reconstruction for total-body PET imaging using the 2-meter long EXPLORER scanner

NASA Astrophysics Data System (ADS)

Zhang, Xuezhu; Zhou, Jian; Cherry, Simon R.; Badawi, Ramsey D.; Qi, Jinyi

2017-03-01

The EXPLORER project aims to build a 2 meter long total-body PET scanner, which will provide extremely high sensitivity for imaging the entire human body. It will possess a range of capabilities currently unavailable to state-of-the-art clinical PET scanners with a limited axial field-of-view. The huge number of lines-of-response (LORs) of the EXPLORER poses a challenge to the data handling and image reconstruction. The objective of this study is to develop a quantitative image reconstruction method for the EXPLORER and compare its performance with current whole-body scanners. Fully 3D image reconstruction was performed using time-of-flight list-mode data with parallel computation. To recover the resolution loss caused by the parallax error between crystal pairs at a large axial ring difference or transaxial radial offset, we applied an image domain resolution model estimated from point source data. To evaluate the image quality, we conducted computer simulations using the SimSET Monte-Carlo toolkit and XCAT 2.0 anthropomorphic phantom to mimic a 20 min whole-body PET scan with an injection of 25 MBq 18F-FDG. We compare the performance of the EXPLORER with a current clinical scanner that has an axial FOV of 22 cm. The comparison results demonstrated superior image quality from the EXPLORER with a 6.9-fold reduction in noise standard deviation comparing with multi-bed imaging using the clinical scanner.

Comparison of multi-arm VRX CT scanners through computer models

NASA Astrophysics Data System (ADS)

Rendon, David A.; DiBianca, Frank A.; Keyes, Gary S.

2007-03-01

Variable Resolution X-ray (VRX) CT scanners allow imaging of different sized anatomy at the same level of detail using the same device. This is achieved by tilting the x-ray detectors so that the projected size of the detecting elements is varied producing reconstructions of smaller fields of view with higher spatial resolution.1 The detector can be divided in two or more separate segments, called arms, which can be placed at different angles, allowing some flexibility for the scanner design. In particular, several arms can be set at different angles creating a target region of considerably higher resolution that can be used to track the evolution of a previously diagnosed condition, while keeping the patient completely inside the field of view (FOV).2 This work presents newly-developed computer models of single-slice VRX scanners that allow us to study and compare different configurations (that is, various types of detectors arranged in any number of arms arranged in different geometries) in terms of spatial and contrast resolution. In particular, we are interested in comparing the performance of various geometric configurations that would otherwise be considered equivalent (using the same equipment, imaging FOVs of the same sizes, and having a similar overall scanner size). For this, a VRX simulator was developed, along with mathematical phantoms for spatial resolution and contrast analysis. These tools were used to compare scanner configurations that can be reproduced with materials presently available in our lab.

Fourier crosstalk analysis of multislice and cone-beam helical CT

NASA Astrophysics Data System (ADS)

La Riviere, Patrick J.

2004-05-01

Multi-slice helical CT scanners allow for much faster scanning and better x-ray utilization than do their single-slice predecessors, but they engender considerably more complicated data sampling patterns due to the interlacing of the samples from different rows as the patient is translated. Characterizing and optimizing this sampling is challenging because the conebeam geometry of such scanners means that the projections measured by each detector row are at least slightly oblique, making it difficult to apply standard multidimensional sampling analyses. In this study, we seek to apply a more general framework for analyzing sampled imaging systems known as Fourier crosstalk analysis. Our purpose in this preliminary work is to compare the information content of the data acquired in three different scanner geometries and operating conditions with ostensibly equivalent volume coverage and average longitudinal sampling interval: a single-slice scanner operating at pitch 1, a four-slice scanner operating at pitch 3 and a 15-slice scanner operating at pitch 15. We find that moving from a single-slice to a multi-slice geometry introduces longitudinal crosstalk characteristic of the longitudinal sampling interval between periods of individual each detector row, and not of the overall interlaced sampling pattern. This is attributed to data inconsistencies caused by the obliqueness of the projections in a multi-slice/conebeam configuration. However, these preliminary results suggest that the significance of this additional crosstalk actually decreases as the number of detector rows increases.

Miniaturized Fourier-plane fiber scanner for OCT endoscopy

NASA Astrophysics Data System (ADS)

Vilches, Sergio; Kretschmer, Simon; Ataman, Çağlar; Zappe, Hans

2017-10-01

A forward-looking endoscopic optical coherence tomography (OCT) probe featuring a Fourier-plane fiber scanner is designed, manufactured and characterized. In contrast to common image-plane fiber scanners, the Fourier-plane scanner is a telecentric arrangement that eliminates vignetting and spatial resolution variations across the image plane. To scan the OCT beam in a spiral pattern, a tubular piezoelectric actuator is used to resonate an optical fiber bearing a collimating GRIN lens at its tip. The free-end of the GRIN lens sits at the back focal plane of an objective lens, such that its rotation replicates the beam angles in the collimated region of a classical telecentric 4f optical system. Such an optical arrangement inherently has a low numerical aperture combined with a relatively large field-of-view, rendering it particularly useful for endoscopic OCT imaging. Furthermore, the optical train of the Fourier-plane scanner is shorter than that of a comparable image-plane scanner by one focal length of the objective lens, significantly shortening the final arrangement. As a result, enclosed within a 3D printed housing of 2.5 mm outer diameter and 15 mm total length, the developed probe is the most compact forward-looking endoscopic OCT imager to date. Due to its compact form factor and compatibility with real-time OCT imaging, the developed probe is also ideal for use in the working channel of flexible endoscopes as a potential optical biopsy tool.

High-field open versus short-bore magnetic resonance imaging of the spine: a randomized controlled comparison of image quality.

PubMed

Enders, Judith; Rief, Matthias; Zimmermann, Elke; Asbach, Patrick; Diederichs, Gerd; Wetz, Christoph; Siebert, Eberhard; Wagner, Moritz; Hamm, Bernd; Dewey, Marc

2013-01-01

The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34-37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. ClinicalTrials.gov NCT00715806.

Design and performance of a multi-pinhole collimation device for small animal imaging with clinical SPECT and SPECT-CT scanners

PubMed Central

DiFilippo, Frank P.

2008-01-01

A multi-pinhole collimation device is developed that uses the gamma camera detectors of a clinical SPECT or SPECT-CT scanner to produce high resolution SPECT images. The device consists of a rotating cylindrical collimator having 22 tungsten pinholes with 0.9 mm diameter apertures and an animal bed inside the collimator that moves linearly to provide helical or ordered-subsets axial sampling. CT images also may be acquired on a SPECT-CT scanner for purposes of image co-registration and SPECT attenuation correction. The device is placed on the patient table of the scanner without attaching to the detectors or scanner gantry. The system geometry is calibrated in-place from point source data and is then used during image reconstruction. The SPECT imaging performance of the device is evaluated with test phantom scans. Spatial resolution from reconstructed point source images is measured to be 0.6 mm full width at half maximum or better. Micro-Derenzo phantom images demonstrate the ability to resolve 0.7 mm diameter rod patterns. The axial slabs of a Micro-Defrise phantom are visualized well. Collimator efficiency exceeds 0.05% at the center of the field of view, and images of a uniform phantom show acceptable uniformity and minimal artifact. The overall simplicity and relatively good imaging performance of the device make it an interesting low-cost alternative to dedicated small animal scanners. PMID:18635899

Preventive maintenance system for the photomultiplier detector blocks of pet scanners

DOEpatents

Levy, Alejandro V.; Warner, Donald

1995-01-24

A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The quantitive comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t.sub.0, a time t.sub.1 and a time T, where T>t.sub.1 >t.sub.0, which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner.

Cochlear Implant Electrode Localization Using an Ultra-High Resolution Scan Mode on Conventional 64-Slice and New Generation 192-Slice Multi-Detector Computed Tomography.

PubMed

Carlson, Matthew L; Leng, Shuai; Diehn, Felix E; Witte, Robert J; Krecke, Karl N; Grimes, Josh; Koeller, Kelly K; Bruesewitz, Michael R; McCollough, Cynthia H; Lane, John I

2017-08-01

A new generation 192-slice multi-detector computed tomography (MDCT) clinical scanner provides enhanced image quality and superior electrode localization over conventional MDCT. Currently, accurate and reliable cochlear implant electrode localization using conventional MDCT scanners remains elusive. Eight fresh-frozen cadaveric temporal bones were implanted with full-length cochlear implant electrodes. Specimens were subsequently scanned with conventional 64-slice and new generation 192-slice MDCT scanners utilizing ultra-high resolution modes. Additionally, all specimens were scanned with micro-CT to provide a reference criterion for electrode position. Images were reconstructed according to routine temporal bone clinical protocols. Three neuroradiologists, blinded to scanner type, reviewed images independently to assess resolution of individual electrodes, scalar localization, and severity of image artifact. Serving as the reference standard, micro-CT identified scalar crossover in one specimen; imaging of all remaining cochleae demonstrated complete scala tympani insertions. The 192-slice MDCT scanner exhibited improved resolution of individual electrodes (p < 0.01), superior scalar localization (p < 0.01), and reduced blooming artifact (p < 0.05), compared with conventional 64-slice MDCT. There was no significant difference between platforms when comparing streak or ring artifact. The new generation 192-slice MDCT scanner offers several notable advantages for cochlear implant imaging compared with conventional MDCT. This technology provides important feedback regarding electrode position and course, which may help in future optimization of surgical technique and electrode design.

Quantitative Image Reconstruction for Total-Body PET Imaging Using the 2-meter Long EXPLORER Scanner

PubMed Central

Zhang, Xuezhu; Zhou, Jian; Cherry, Simon R.; Badawi, Ramsey D.

2017-01-01

The EXPLORER project aims to build a 2-meter long total-body PET scanner, which will provide extremely high sensitivity for imaging the entire human body. It will possess a range of capabilities currently unavailable to state-of-the-art clinical PET scanners with a limited axial field-of-view. The huge number of lines-of-response (LORs) of the EXPLORER poses a challenge to the data handling and image reconstruction. The objective of this study is to develop a quantitative image reconstruction method for the EXPLORER and compare its performance with current whole-body scanners. Fully 3D image reconstruction was performed using time-of-flight list-mode data with parallel computation. To recover the resolution loss caused by the parallax error between crystal pairs at a large axial ring difference or transaxial radial offset, we applied an image domain resolution model estimated from point source data. To evaluate the image quality, we conducted computer simulations using the SimSET Monte-Carlo toolkit and XCAT 2.0 anthropomorphic phantom to mimic a 20-minute whole-body PET scan with an injection of 25 MBq 18F-FDG. We compare the performance of the EXPLORER with a current clinical scanner that has an axial FOV of 22 cm. The comparison results demonstrated superior image quality from the EXPLORER with a 6.9-fold reduction in noise standard deviation comparing with multi-bed imaging using the clinical scanner. PMID:28240215

High-Field Open versus Short-Bore Magnetic Resonance Imaging of the Spine: A Randomized Controlled Comparison of Image Quality

PubMed Central

Zimmermann, Elke; Asbach, Patrick; Diederichs, Gerd; Wetz, Christoph; Siebert, Eberhard; Wagner, Moritz; Hamm, Bernd; Dewey, Marc

2013-01-01

Background The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Methods Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. Results The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34–37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). Conclusions In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. Trial Registration ClinicalTrials.gov NCT00715806 PMID:24391767

Design and performance of a multi-pinhole collimation device for small animal imaging with clinical SPECT and SPECT CT scanners

NASA Astrophysics Data System (ADS)

Di Filippo, Frank P.

2008-08-01

A multi-pinhole collimation device is developed that uses the gamma camera detectors of a clinical SPECT or SPECT-CT scanner to produce high-resolution SPECT images. The device consists of a rotating cylindrical collimator having 22 tungsten pinholes with 0.9 mm diameter apertures and an animal bed inside the collimator that moves linearly to provide helical or ordered-subsets axial sampling. CT images also may be acquired on a SPECT-CT scanner for purposes of image co-registration and SPECT attenuation correction. The device is placed on the patient table of the scanner without attaching to the detectors or scanner gantry. The system geometry is calibrated in-place from point source data and is then used during image reconstruction. The SPECT imaging performance of the device is evaluated with test phantom scans. Spatial resolution from reconstructed point source images is measured to be 0.6 mm full width at half maximum or better. Micro-Derenzo phantom images demonstrate the ability to resolve 0.7 mm diameter rod patterns. The axial slabs of a Micro-Defrise phantom are visualized well. Collimator efficiency exceeds 0.05% at the center of the field of view, and images of a uniform phantom show acceptable uniformity and minimal artifact. The overall simplicity and relatively good imaging performance of the device make it an interesting low-cost alternative to dedicated small animal scanners.

Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakhalkar, H. S.; Oldham, M.

2008-01-15

This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of {approx}5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 {mu}m) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout frommore » the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the 'gold standard' technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few millimeters of the edge of the dosimeter, where edge artifact is predominant. Agreement of line profiles was observed, even along steep dose gradients. Dose difference plots indicated that the CCD scanner dose readout differed from the OCTOPUSscanner readout and ECLIPSE calculations by {approx}10% along steep dose gradients and by {approx}5% along moderate dose gradients. Gamma maps (3% dose-difference and 3 mm distance-to-agreement acceptance criteria) revealed agreement, except for regions within 5 mm of the edge of the dosimeter where the edge artifact occurs. In summary, the data demonstrate feasibility of using the fast, high-resolution CCD scanner for comprehensive 3D dosimetry in all applications, except where dose readout is required close to the edges of the dosimeter. Further work is ongoing to reduce this artifact.« less

Capturing Fine Details Involving Low-Cost Sensors -a Comparative Study

NASA Astrophysics Data System (ADS)

Rehany, N.; Barsi, A.; Lovas, T.

2017-11-01

Capturing the fine details on the surface of small objects is a real challenge to many conventional surveying methods. Our paper discusses the investigation of several data acquisition technologies, such as arm scanner, structured light scanner, terrestrial laser scanner, object line-scanner, DSLR camera, and mobile phone camera. A palm-sized embossed sculpture reproduction was used as a test object; it has been surveyed by all the instruments. The result point clouds and meshes were then analyzed, using the arm scanner's dataset as reference. In addition to general statistics, the results have been evaluated based both on 3D deviation maps and 2D deviation graphs; the latter allows even more accurate analysis of the characteristics of the different data acquisition approaches. Additionally, own-developed local minimum maps were created that nicely visualize the potential level of detail provided by the applied technologies. Besides the usual geometric assessment, the paper discusses the different resource needs (cost, time, expertise) of the discussed techniques. Our results proved that even amateur sensors operated by amateur users can provide high quality datasets that enable engineering analysis. Based on the results, the paper contains an outlook to potential future investigations in this field.

The Function Biomedical Informatics Research Network Data Repository

PubMed Central

Keator, David B.; van Erp, Theo G.M.; Turner, Jessica A.; Glover, Gary H.; Mueller, Bryon A.; Liu, Thomas T.; Voyvodic, James T.; Rasmussen, Jerod; Calhoun, Vince D.; Lee, Hyo Jong; Toga, Arthur W.; McEwen, Sarah; Ford, Judith M.; Mathalon, Daniel H.; Diaz, Michele; O’Leary, Daniel S.; Bockholt, H. Jeremy; Gadde, Syam; Preda, Adrian; Wible, Cynthia G.; Stern, Hal S.; Belger, Aysenil; McCarthy, Gregory; Ozyurt, Burak; Potkin, Steven G.

2015-01-01

The Function Biomedical Informatics Research Network (FBIRN) developed methods and tools for conducting multi-scanner functional magnetic resonance imaging (fMRI) studies. Method and tool development were based on two major goals: 1) to assess the major sources of variation in fMRI studies conducted across scanners, including instrumentation, acquisition protocols, challenge tasks, and analysis methods, and 2) to provide a distributed network infrastructure and an associated federated database to host and query large, multi-site, fMRI and clinical datasets. In the process of achieving these goals the FBIRN test bed generated several multi-scanner brain imaging data sets to be shared with the wider scientific community via the BIRN Data Repository (BDR). The FBIRN Phase 1 dataset consists of a traveling subject study of 5 healthy subjects, each scanned on 10 different 1.5 to 4 Tesla scanners. The FBIRN Phase 2 and Phase 3 datasets consist of subjects with schizophrenia or schizoaffective disorder along with healthy comparison subjects scanned at multiple sites. In this paper, we provide concise descriptions of FBIRN’s multi-scanner brain imaging data sets and details about the BIRN Data Repository instance of the Human Imaging Database (HID) used to publicly share the data. PMID:26364863

Development and testing of laser Doppler system components for wake vortex monitoring. Volume 1: Scanner development, laboratory and field testing and system modeling

NASA Technical Reports Server (NTRS)

Wilson, D. J.; Krause, M. C.; Coffey, E. W.; Huang, C. C.; Edwards, B. B.; Shrider, K. R.; Jetton, J. L.; Morrison, L. K.

1974-01-01

A servo-controlled range/elevation scanner for the laser Doppler velocimeter (LDV) was developed and tested in the field to assess its performance in detecting and monitoring aircraft trailing vortices in an airport environment. The elevation scanner provides a capability to manually point the LDV telescope at operator chosen angles from 3.2 deg. to 89.6 deg within 0.2 deg, or to automatically scan the units between operator chosen limits at operator chosen rates of 0.1 Hz to 0.5 Hz. The range scanner provides a capability to manually adjust the focal point of the system from a range of 32 meters to a range of 896 meters under operator control, or to scan between operator chosen limits and at rates from 0.1 Hz to 6.9 Hz. The scanner controls are designed to allow simulataneous range and elevation scanning so as to provide finger scan patterns, arc scan patterns, and vertical line scan patterns. The development and testing of the unit is discussed, along with a fluid dynamic model of the wake vortex developed in a laser Doppler vortex sensor simulation program.

3D WindScanner lidar measurements of wind and turbulence around wind turbines, buildings and bridges

NASA Astrophysics Data System (ADS)

Mikkelsen, T.; Sjöholm, M.; Angelou, N.; Mann, J.

2017-12-01

WindScanner is a distributed research infrastructure developed at DTU with the participation of a number of European countries. The research infrastructure consists of a mobile technically advanced facility for remote measurement of wind and turbulence in 3D. The WindScanners provide coordinated measurements of the entire wind and turbulence fields, of all three wind components scanned in 3D space. Although primarily developed for research related to on- and offshore wind turbines and wind farms, the facility is also well suited for scanning turbulent wind fields around buildings, bridges, aviation structures and of flow in urban environments. The mobile WindScanner facility enables 3D scanning of wind and turbulence fields in full scale within the atmospheric boundary layer at ranges from 10 meters to 5 (10) kilometers. Measurements of turbulent coherent structures are applied for investigation of flow pattern and dynamical loads from turbines, building structures and bridges and in relation to optimization of the location of, for example, wind farms and suspension bridges. This paper presents our achievements to date and reviews briefly the state-of-the-art of the WindScanner measurement technology with examples of uses for wind engineering applications.

FPGA-Based Front-End Electronics for Positron Emission Tomography

PubMed Central

Haselman, Michael; DeWitt, Don; McDougald, Wendy; Lewellen, Thomas K.; Miyaoka, Robert; Hauck, Scott

2010-01-01

Modern Field Programmable Gate Arrays (FPGAs) are capable of performing complex discrete signal processing algorithms with clock rates above 100MHz. This combined with FPGA’s low expense, ease of use, and selected dedicated hardware make them an ideal technology for a data acquisition system for positron emission tomography (PET) scanners. Our laboratory is producing a high-resolution, small-animal PET scanner that utilizes FPGAs as the core of the front-end electronics. For this next generation scanner, functions that are typically performed in dedicated circuits, or offline, are being migrated to the FPGA. This will not only simplify the electronics, but the features of modern FPGAs can be utilizes to add significant signal processing power to produce higher resolution images. In this paper two such processes, sub-clock rate pulse timing and event localization, will be discussed in detail. We show that timing performed in the FPGA can achieve a resolution that is suitable for small-animal scanners, and will outperform the analog version given a low enough sampling period for the ADC. We will also show that the position of events in the scanner can be determined in real time using a statistical positioning based algorithm. PMID:21961085

Developments in holographic-based scanner designs

NASA Astrophysics Data System (ADS)

Rowe, David M.

1997-07-01

Holographic-based scanning systems have been used for years in the high resolution prepress markets where monochromatic lasers are generally utilized. However, until recently, due to the dispersive properties of holographic optical elements (HOEs), along with the high cost associated with recording 'master' HOEs, holographic scanners have not been able to penetrate major scanning markets such as the laser printer and digital copier markets, low to mid-range imagesetter markets, and the non-contact inspection scanner market. Each of these markets has developed cost effective laser diode based solutions using conventional scanning approaches such as polygon/f-theta lens combinations. In order to penetrate these markets, holographic-based systems must exhibit low cost and immunity to wavelength shifts associated with laser diodes. This paper describes recent developments in the design of holographic scanners in which multiple HOEs, each possessing optical power, are used in conjunction with one curved mirror to passively correct focal plane position errors and spot size changes caused by the wavelength instability of laser diodes. This paper also describes recent advancements in low cost production of high quality HOEs and curved mirrors. Together these developments allow holographic scanners to be economically competitive alternatives to conventional devices in every segment of the laser scanning industry.

Developing patient-specific dose protocols for a CT scanner and exam using diagnostic reference levels.

PubMed

Strauss, Keith J

2014-10-01

The management of image quality and radiation dose during pediatric CT scanning is dependent on how well one manages the radiographic techniques as a function of the type of exam, type of CT scanner, and patient size. The CT scanner's display of expected CT dose index volume (CTDIvol) after the projection scan provides the operator with a powerful tool prior to the patient scan to identify and manage appropriate CT techniques, provided the department has established appropriate diagnostic reference levels (DRLs). This paper provides a step-by-step process that allows the development of DRLs as a function of type of exam, of actual patient size and of the individual radiation output of each CT scanner in a department. Abdomen, pelvis, thorax and head scans are addressed. Patient sizes from newborns to large adults are discussed. The method addresses every CT scanner regardless of vendor, model or vintage. We cover adjustments to techniques to manage the impact of iterative reconstruction and provide a method to handle all available voltages other than 120 kV. This level of management of CT techniques is necessary to properly monitor radiation dose and image quality during pediatric CT scans.

Free-space wavelength-multiplexed optical scanner.

PubMed

Yaqoob, Z; Rizvi, A A; Riza, N A

2001-12-10

A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

30. SITE BUILDING 002 SCANNER BUILDING FLOOR 3A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. SITE BUILDING 002 - SCANNER BUILDING - FLOOR 3A ("A" FACE) INTERIOR BETWEEN GRIDS 17-A1 AND 18-A1, SHOWING REAR OF RADAR EMITTER ELECTRONIC INTERFACE TERMINAL NO. 3147-20, "RECEIVER TRANSMITTER RADAR" MODULE. VIEW IS ALSO SHOWING BUILDING FIRE STOP MATERIAL AT BOTTOM OF FLOOR. NOTE: WALL SLOPES BOTTOM TO TOP INWARD; STRUCTURAL ELEMENT IN FOREGROUND. VIEW ALSO SHOWS PIPING GRID OF CHILLED WATER LINES FOR ELECTRONIC SYSTEMS COOLING. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

Sample size requirements for estimating effective dose from computed tomography using solid-state metal-oxide-semiconductor field-effect transistor dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trattner, Sigal; Cheng, Bin; Pieniazek, Radoslaw L.

2014-04-15

Purpose: Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (MOSFET) solid-state dosimeters have been placed to enable organ dose measurements. Here a statistical framework is established to determine the sample size (number of scans) needed for estimating ED to a desired precision and confidence, for a particular scanner and scan protocol, subject to practical limitations. Methods: The statistical scheme involves solving equations which minimize the sample sizemore » required for estimating ED to desired precision and confidence. It is subject to a constrained variation of the estimated ED and solved using the Lagrange multiplier method. The scheme incorporates measurement variation introduced both by MOSFET calibration, and by variation in MOSFET readings between repeated CT scans. Sample size requirements are illustrated on cardiac, chest, and abdomen–pelvis CT scans performed on a 320-row scanner and chest CT performed on a 16-row scanner. Results: Sample sizes for estimating ED vary considerably between scanners and protocols. Sample size increases as the required precision or confidence is higher and also as the anticipated ED is lower. For example, for a helical chest protocol, for 95% confidence and 5% precision for the ED, 30 measurements are required on the 320-row scanner and 11 on the 16-row scanner when the anticipated ED is 4 mSv; these sample sizes are 5 and 2, respectively, when the anticipated ED is 10 mSv. Conclusions: Applying the suggested scheme, it was found that even at modest sample sizes, it is feasible to estimate ED with high precision and a high degree of confidence. As CT technology develops enabling ED to be lowered, more MOSFET measurements are needed to estimate ED with the same precision and confidence.« less

Comparison of dosimetric properties among four commercial multi-detector computed tomography scanners.

PubMed

Ohno, Takeshi; Araki, Fujio; Onizuka, Ryota; Hatemura, Masahiro; Shimonobou, Toshiaki; Sakamoto, Takashi; Okumura, Shuichiro; Ideguchi, Daichi; Honda, Keiichi; Kawata, Kenji

2017-03-01

This study compared dosimetric properties among four commercial multi-detector CT (MDCT) scanners. The X-ray beam characteristics were obtained from photon intensity attenuation curves of aluminum and off-center ratio (OCR) profiles in air, which were measured with four commercial MDCT scanners. The absorbed dose for MDCT scanners was evaluated with Farmer ionization chamber measurements at the center and four peripheral points in the body- and head-type cylindrical water phantoms. Measured collected charge was converted to absorbed dose using a 60 Co absorbed dose-to-water calibration factor and Monte Carlo (MC)-calculated correction factors. Four MDCT scanners were modeled to correspond with measured X-ray beam characteristics using GMctdospp (IMPS, Germany) software. Al half-value layers (Al-HVLs) with a body-bowtie filter determined from measured Al-attenuation curves ranged 7.2‒9.1mm at 120kVp and 6.1‒8.0mm at 100kVp. MC-calculated Al-HVLs and OCRs in air were in acceptable agreement within 0.5mm and 5% of measured values, respectively. The percentage difference between nominal and actual beam width was greater with decreasing collimation width. The absorbed doses for MDCT scanners at 120kVp ranged 5.1‒7.1mGy and 10.8‒17.5mGy per 100mAs at the center in the body- and head-type water phantoms, respectively. Measured doses at four peripheral points were within 5% agreement of MC-calculated values. The absorbed dose at the center in both water phantoms increased with decreasing Al-HVL for the same charge on the focus. In this study the X-ray beam characteristics and the absorbed dose were measured and compared with calculated values for four MDCT scanners. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

SU-E-I-25: Determining Tube Current, Tube Voltage and Pitch Suitable for Low- Dose Lung Screening CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, K; Matthews, K

2014-06-01

Purpose: The quality of a computed tomography (CT) image and the dose delivered during its acquisition depend upon the acquisition parameters used. Tube current, tube voltage, and pitch are acquisition parameters that potentially affect image quality and dose. This study investigated physicians' abilities to characterize small, solid nodules in low-dose CT images for combinations of current, voltage and pitch, for three CT scanner models. Methods: Lung CT images was acquired of a Data Spectrum anthropomorphic torso phantom with various combinations of pitch, tube current, and tube voltage; this phantom was used because acrylic beads of various sizes could be placedmore » within the lung compartments to simulate nodules. The phantom was imaged on two 16-slice scanners and a 64-slice scanner. The acquisition parameters spanned a range of estimated CTDI levels; the CTDI estimates from the acquisition software were verified by measurement. Several experienced radiologists viewed the phantom lung CT images and noted nodule location, size and shape, as well as the acceptability of overall image quality. Results: Image quality for assessment of nodules was deemed unsatisfactory for all scanners at 80 kV (any tube current) and at 35 mA (any tube voltage). Tube current of 50 mA or more at 120 kV resulted in similar assessments from all three scanners. Physician-measured sphere diameters were closer to actual diameters for larger spheres, higher tube current, and higher kV. Pitch influenced size measurements less for larger spheres than for smaller spheres. CTDI was typically overestimated by the scanner software compared to measurement. Conclusion: Based on this survey of acquisition parameters, a low-dose CT protocol of 120 kV, 50 mA, and pitch of 1.4 is recommended to balance patient dose and acceptable image quality. For three models of scanners, this protocol resulted in estimated CTDIs from 2.9–3.6 mGy.« less

CT protocol management: simplifying the process by using a master protocol concept.

PubMed

Szczykutowicz, Timothy P; Bour, Robert K; Rubert, Nicholas; Wendt, Gary; Pozniak, Myron; Ranallo, Frank N

2015-07-08

This article explains a method for creating CT protocols for a wide range of patient body sizes and clinical indications, using detailed tube current information from a small set of commonly used protocols. Analytical expressions were created relating CT technical acquisition parameters which can be used to create new CT protocols on a given scanner or customize protocols from one scanner to another. Plots of mA as a function of patient size for specific anatomical regions were generated and used to identify the tube output needs for patients as a function of size for a single master protocol. Tube output data were obtained from the DICOM header of clinical images from our PACS and patient size was measured from CT localizer radiographs under IRB approval. This master protocol was then used to create 11 additional master protocols. The 12 master protocols were further combined to create 39 single and multiphase clinical protocols. Radiologist acceptance rate of exams scanned using the clinical protocols was monitored for 12,857 patients to analyze the effectiveness of the presented protocol management methods using a two-tailed Fisher's exact test. A single routine adult abdominal protocol was used as the master protocol to create 11 additional master abdominal protocols of varying dose and beam energy. Situations in which the maximum tube current would have been exceeded are presented, and the trade-offs between increasing the effective tube output via 1) decreasing pitch, 2) increasing the scan time, or 3) increasing the kV are discussed. Out of 12 master protocols customized across three different scanners, only one had a statistically significant acceptance rate that differed from the scanner it was customized from. The difference, however, was only 1% and was judged to be negligible. All other master protocols differed in acceptance rate insignificantly between scanners. The methodology described in this paper allows a small set of master protocols to be adapted among different clinical indications on a single scanner and among different CT scanners.

Temporal resolution improvement using PICCS in MDCT cardiac imaging

PubMed Central

Chen, Guang-Hong; Tang, Jie; Hsieh, Jiang

2009-01-01

The current paradigm for temporal resolution improvement is to add more source-detector units and∕or increase the gantry rotation speed. The purpose of this article is to present an innovative alternative method to potentially improve temporal resolution by approximately a factor of 2 for all MDCT scanners without requiring hardware modification. The central enabling technology is a most recently developed image reconstruction method: Prior image constrained compressed sensing (PICCS). Using the method, cardiac CT images can be accurately reconstructed using the projection data acquired in an angular range of about 120°, which is roughly 50% of the standard short-scan angular range (∼240° for an MDCT scanner). As a result, the temporal resolution of MDCT cardiac imaging can be universally improved by approximately a factor of 2. In order to validate the proposed method, two in vivo animal experiments were conducted using a state-of-the-art 64-slice CT scanner (GE Healthcare, Waukesha, WI) at different gantry rotation times and different heart rates. One animal was scanned at heart rate of 83 beats per minute (bpm) using 400 ms gantry rotation time and the second animal was scanned at 94 bpm using 350 ms gantry rotation time, respectively. Cardiac coronary CT imaging can be successfully performed at high heart rates using a single-source MDCT scanner and projection data from a single heart beat with gantry rotation times of 400 and 350 ms. Using the proposed PICCS method, the temporal resolution of cardiac CT imaging can be effectively improved by approximately a factor of 2 without modifying any scanner hardware. This potentially provides a new method for single-source MDCT scanners to achieve reliable coronary CT imaging for patients at higher heart rates than the current heart rate limit of 70 bpm without using the well-known multisegment FBP reconstruction algorithm. This method also enables dual-source MDCT scanner to achieve higher temporal resolution without further hardware modifications. PMID:19610302

Temporal resolution improvement using PICCS in MDCT cardiac imaging.

PubMed

Chen, Guang-Hong; Tang, Jie; Hsieh, Jiang

2009-06-01

The current paradigm for temporal resolution improvement is to add more source-detector units and/or increase the gantry rotation speed. The purpose of this article is to present an innovative alternative method to potentially improve temporal resolution by approximately a factor of 2 for all MDCT scanners without requiring hardware modification. The central enabling technology is a most recently developed image reconstruction method: Prior image constrained compressed sensing (PICCS). Using the method, cardiac CT images can be accurately reconstructed using the projection data acquired in an angular range of about 120 degrees, which is roughly 50% of the standard short-scan angular range (approximately 240 degrees for an MDCT scanner). As a result, the temporal resolution of MDCT cardiac imaging can be universally improved by approximately a factor of 2. In order to validate the proposed method, two in vivo animal experiments were conducted using a state-of-the-art 64-slice CT scanner (GE Healthcare, Waukesha, WI) at different gantry rotation times and different heart rates. One animal was scanned at heart rate of 83 beats per minute (bpm) using 400 ms gantry rotation time and the second animal was scanned at 94 bpm using 350 ms gantry rotation time, respectively. Cardiac coronary CT imaging can be successfully performed at high heart rates using a single-source MDCT scanner and projection data from a single heart beat with gantry rotation times of 400 and 350 ms. Using the proposed PICCS method, the temporal resolution of cardiac CT imaging can be effectively improved by approximately a factor of 2 without modifying any scanner hardware. This potentially provides a new method for single-source MDCT scanners to achieve reliable coronary CT imaging for patients at higher heart rates than the current heart rate limit of 70 bpm without using the well-known multisegment FBP reconstruction algorithm. This method also enables dual-source MDCT scanner to achieve higher temporal resolution without further hardware modifications.

SU-E-I-19: CTDI Values for All Protocols: Using the Ratio of the DLP Measured in CTDI Phantoms to the Measured Air Exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raterman, G; Gauntt, D

2014-06-01

Purpose: To propose a method other than CTDI phantom measurements for routine CT dosimetry QA. This consists of taking a series of air exposure measurements and calculating a factor for converting from this exposure measurement to the protocol's associated head or body CTDI value using DLP. The data presented are the ratios of phantom DLP to air exposure ratios for different scanners, as well as error in the displayed CTDI. Methods: For each scanner, the CTDI is measured at all available tube voltages using both the head and body phantoms. Then, the exposure is measured using a pencil chamber inmore » air at isocenter. A ratio of phantom DLP to exposure in air for a given protocol may be calculated and used for converting a simple air dose measurement to a head or body CTDI value. For our routine QA, the exposure in air for different collimations, mAs, and kVp is measured, and displayed CTDI is recorded. Therefore, the ratio calculated may convert these exposures to CTDI values that may then be compared to the displayed CTDI for a large range of acquisition parameter combinations. Results: It was found that all scanners tend to have a ratio factor that slightly increases with kVp. Also, Philips scanners appear to have less of a dependence on kVp; whereas, GE scanners have a lower ratio at lower kVp. The use of air exposure times the DLP conversion yielded CTDI values that were less than 10% different from the displayed CTDI on several scanners. Conclusion: This method may be used as a primary method for CT dosimetry QA. As a result of the ease of measurement, a dosimetry metric specific to that scanner may be calculated for a wide variety of CT protocols, which could also be used to monitor display CTDI value accuracy.« less

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols.

PubMed

Tan, Sock Keow; Yeong, Chai Hong; Ng, Kwan Hoong; Abdul Aziz, Yang Faridah; Sun, Zhonghua

2016-01-01

This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE). Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region. Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor. The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners.

SU-G-206-11: The Effect of Table Height On CTDIvol and SSDE in CT Scanning: A Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsh, R; Silosky, M

2016-06-15

Purpose: Localizer projection radiographs acquired prior to CT scans are used to estimate patient size, affecting the function of Automatic Tube Current Modulation (ATCM) and calculation of the Size Specific Dose Estimate (SSDE). Due to geometric effects, the projected patient size varies with scanner table height and with the orientation of the localizer (AP versus PA). Consequently, variations in scanner table height may affect both CTDIvol and the calculated size-corrected dose index (SSDE). This study sought to characterize these effects. Methods: An anthropomorphic phantom was imaged using an AP localizer, followed by a diagnostic scan using ATCM and our institution’smore » routine abdomen protocol. This was repeated at various scanner table heights, recording the scanner-reported CTDIvol for each diagnostic scan. The width of the phantom was measured from the localizer and diagnostic images using in-house software. The measured phantom width and scanner-reported CTDIvol were used to calculate SSDE. This was repeated using PA localizers followed by diagnostic scans. Results: 1) The localizer-based phantom width varied by up to 54% of the nominal phantom width between minimum and maximum table heights. 2) Changing the table height caused a variation in scanner-reported CTDIvol of a factor greater than 4.6 when using a PA localizer and almost 2 when using an AP localizer. 3) SSDE, calculated from measured phantom size and scanner-reported CTDIvol, varied by a factor of more than 2.8 when using a PA localizer and almost 1.5 when using an AP localizer. Conclusion: Our study demonstrates that off-center patient positioning affects the efficacy of ATCM, more severely when localizers are acquired in the PA rather than AP projection. Further, patient positioning errors can cause a large variation in the calculated SSDE. This hinders interpretation of SSDE for individual patients and aggregate SSDE data when evaluating CT protocols and clinical practices.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, H; UT Southwestern Medical Center, Dallas, TX; Hilts, M

Purpose: To commission a multislice computed tomography (CT) scanner for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD). Methods: Commissioning was performed for a 16-slice CT scanner using images acquired through a 1L cylinder filled with water. Additional images were collected using a single slice machine for comparison purposes. The variability in CT number associated with the anode heel effect was evaluated and used to define a new slice-by-slice background image subtraction technique. Image quality was assessed for the multislice system by comparing image noise and uniformity to that of the singlemore » slice machine. The consistency in CT number across slices acquired simultaneously using the multislice detector array was also evaluated. Finally, the variability in CT number due to increasing x-ray tube load was measured for the multislice scanner and compared to the tube load effects observed on the single slice machine. Results: Slice-by-slice background subtraction effectively removes the variability in CT number across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image quality for the multislice machine was found to be comparable to that of the single slice scanner. Further study showed CT number was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thickness examined. In addition, the multislice system was found to eliminate variations in CT number due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to imaging a large volume using a single slice scanner. Conclusion: A multislice CT scanner has been commissioning for CT PGD, allowing images of an entire dose distribution to be acquired in a matter of minutes. Funding support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC)« less

SU-E-I-48: The Behavior of AEC in Scan Regions Outside the Localizer Radiograph FOV: An In Phantom Study of CT Systems From Four Vendors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Supanich, M; Bevins, N

Purpose: This review of scanners from 4 major manufacturers examines the clinical impact of performing CT scans that extend into areas of the body that were not acquired in the CT localizer radiograph. Methods: Anthropomorphic chest and abdomen phantoms were positioned together on the tables of CT scanners from 4 different vendors. All of the scanners offered an Automatic Exposure Control (AEC) option with both lateral and axial tube current modulation. A localizer radiograph was taken covering the entire extent of both phantoms and then the scanner's Chest-Abdomen-Pelvis (CAP) study was performed with the clinical AEC settings employed and themore » scan and reconstruction range extending from the superior portion of the chest phantom through the inferior portion of the abdomen phantom. A new study was then initiated with a localizer radiograph extending the length of the chest phantom (not covering the abdomen phantom). The same CAP protocol and AEC settings were then used to scan and reconstruct the entire length of both phantoms. Scan parameters at specific locations in the abdomen phantom from both studies were investigated using the information contained in the DICOM metadata of the reconstructed images. Results: The AEC systems on all scanners utilized different tube current settings in the abdomen phantom for the scan completed without the full localizer radiograph. The AEC system behavior was also scanner dependent with the default manual tube current, the maximum tube current and the tube current at the last known position observed as outcomes. Conclusion: The behavior of the AEC systems of CT scanners in regions not covered by the localizer radiograph is vendor dependent. To ensure optimal image quality and radiation exposure it is important to include the entire planned scan region in the localizer radiograph.« less

Accuracy and precision of 3 intraoral scanners and accuracy of conventional impressions: A novel in vivo analysis method.

PubMed

Nedelcu, R; Olsson, P; Nyström, I; Rydén, J; Thor, A

2018-02-01

To evaluate a novel methodology using industrial scanners as a reference, and assess in vivo accuracy of 3 intraoral scanners (IOS) and conventional impressions. Further, to evaluate IOS precision in vivo. Four reference-bodies were bonded to the buccal surfaces of upper premolars and incisors in five subjects. After three reference-scans, ATOS Core 80 (ATOS), subjects were scanned three times with three IOS systems: 3M True Definition (3M), CEREC Omnicam (OMNI) and Trios 3 (TRIOS). One conventional impression (IMPR) was taken, 3M Impregum Penta Soft, and poured models were digitized with laboratory scanner 3shape D1000 (D1000). Best-fit alignment of reference-bodies and 3D Compare Analysis was performed. Precision of ATOS and D1000 was assessed for quantitative evaluation and comparison. Accuracy of IOS and IMPR were analyzed using ATOS as reference. Precision of IOS was evaluated through intra-system comparison. Precision of ATOS reference scanner (mean 0.6 μm) and D1000 (mean 0.5 μm) was high. Pairwise multiple comparisons of reference-bodies located in different tooth positions displayed a statistically significant difference of accuracy between two scanner-groups: 3M and TRIOS, over OMNI (p value range 0.0001 to 0.0006). IMPR did not show any statistically significant difference to IOS. However, deviations of IOS and IMPR were within a similar magnitude. No statistical difference was found for IOS precision. The methodology can be used for assessing accuracy of IOS and IMPR in vivo in up to five units bilaterally from midline. 3M and TRIOS had a higher accuracy than OMNI. IMPR overlapped both groups. Intraoral scanners can be used as a replacement for conventional impressions when restoring up to ten units without extended edentulous spans. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The artefacts of radiochromic film dosimetry with flatbed scanners and their causation by light scattering from radiation-induced polymers.

PubMed

Schoenfeld, Andreas A; Poppinga, Daniela; Harder, Dietrich; Doerner, Karl-Joachim; Poppe, Bjoern

2014-07-07

Optical experiments and theoretical considerations have been undertaken in order to understand the causes of the 'orientation effect' and the 'parabola effect', the artefacts impairing the desired light absorption measurement on radiochromic EBT3 films with flatbed scanners. EBT3 films exposed to doses up to 20.9 Gy were scanned with an Epson Expression 10000XL flatbed scanner in landscape and portrait orientation. The horizontally and vertically polarized light components of the scanner were determined, and another Epson Expression 10000XL flatbed scanner was disassembled to examine its optical components. The optical properties of exposed and unexposed EBT3 films were studied with incident polarized and unpolarized white light, and the transmitted red light was investigated for its polarization and scattering properties including the distribution of the scattering angles. Neutral density filters were studied for comparison. Guidance was sought from the theory of light scattering from rod-like macromolecular structures. The drastic dose-dependent variation of the transmitted total light current as function of the orientation of front and rear polarizers, interpreted by light scattering theory, shows that the radiation-induced polymerization of the monomers of EBT3 films produces light scattering oscillators preferably polarized at right angles with the coating direction of the film. The directional distribution of the scattered light is partly anisotropic, with a preferred scattering plane at right angles with the coating direction, indicating light scattering from stacks of coherently vibrating oscillators piled up along the monomer crystals. The polyester carrier film also participates in these effects. The 'orientation' and 'parabola' artefacts due to flatbed scanning of radiochromic films can be explained by the interaction of the polarization-dependent and anisotropic light scattering from exposed and unexposed EBT3 films with the quantitative difference between the scanner's horizontally and vertically polarized light supply and with the limited directional acceptance of the scanner's light recording system.

How flatbed scanners upset accurate film dosimetry

NASA Astrophysics Data System (ADS)

van Battum, L. J.; Huizenga, H.; Verdaasdonk, R. M.; Heukelom, S.

2016-01-01

Film is an excellent dosimeter for verification of dose distributions due to its high spatial resolution. Irradiated film can be digitized with low-cost, transmission, flatbed scanners. However, a disadvantage is their lateral scan effect (LSE): a scanner readout change over its lateral scan axis. Although anisotropic light scattering was presented as the origin of the LSE, this paper presents an alternative cause. Hereto, LSE for two flatbed scanners (Epson 1680 Expression Pro and Epson 10000XL), and Gafchromic film (EBT, EBT2, EBT3) was investigated, focused on three effects: cross talk, optical path length and polarization. Cross talk was examined using triangular sheets of various optical densities. The optical path length effect was studied using absorptive and reflective neutral density filters with well-defined optical characteristics (OD range 0.2-2.0). Linear polarizer sheets were used to investigate light polarization on the CCD signal in absence and presence of (un)irradiated Gafchromic film. Film dose values ranged between 0.2 to 9 Gy, i.e. an optical density range between 0.25 to 1.1. Measurements were performed in the scanner’s transmission mode, with red-green-blue channels. LSE was found to depend on scanner construction and film type. Its magnitude depends on dose: for 9 Gy increasing up to 14% at maximum lateral position. Cross talk was only significant in high contrast regions, up to 2% for very small fields. The optical path length effect introduced by film on the scanner causes 3% for pixels in the extreme lateral position. Light polarization due to film and the scanner’s optical mirror system is the main contributor, different in magnitude for the red, green and blue channel. We concluded that any Gafchromic EBT type film scanned with a flatbed scanner will face these optical effects. Accurate dosimetry requires correction of LSE, therefore, determination of the LSE per color channel and dose delivered to the film.

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols

PubMed Central

Tan, Sock Keow; Yeong, Chai Hong; Ng, Kwan Hoong; Abdul Aziz, Yang Faridah; Sun, Zhonghua

2016-01-01

Objectives This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE). Materials and Methods Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region. Results Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor. Conclusion The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners. PMID:27552224

Effect of mixing scanner types and reconstruction kernels on the characterization of lung parenchymal pathologies: emphysema, interstitial pulmonary fibrosis and normal non-smokers

NASA Astrophysics Data System (ADS)

Xu, Ye; van Beek, Edwin J.; McLennan, Geoffrey; Guo, Junfeng; Sonka, Milan; Hoffman, Eric

2006-03-01

In this study we utilize our texture characterization software (3-D AMFM) to characterize interstitial lung diseases (including emphysema) based on MDCT generated volumetric data using 3-dimensional texture features. We have sought to test whether the scanner and reconstruction filter (kernel) type affect the classification of lung diseases using the 3-D AMFM. We collected MDCT images in three subject groups: emphysema (n=9), interstitial pulmonary fibrosis (IPF) (n=10), and normal non-smokers (n=9). In each group, images were scanned either on a Siemens Sensation 16 or 64-slice scanner, (B50f or B30 recon. kernel) or a Philips 4-slice scanner (B recon. kernel). A total of 1516 volumes of interest (VOIs; 21x21 pixels in plane) were marked by two chest imaging experts using the Iowa Pulmonary Analysis Software Suite (PASS). We calculated 24 volumetric features. Bayesian methods were used for classification. Images from different scanners/kernels were combined in all possible combinations to test how robust the tissue classification was relative to the differences in image characteristics. We used 10-fold cross validation for testing the result. Sensitivity, specificity and accuracy were calculated. One-way Analysis of Variances (ANOVA) was used to compare the classification result between the various combinations of scanner and reconstruction kernel types. This study yielded a sensitivity of 94%, 91%, 97%, and 93% for emphysema, ground-glass, honeycombing, and normal non-smoker patterns respectively using a mixture of all three subject groups. The specificity for these characterizations was 97%, 99%, 99%, and 98%, respectively. The F test result of ANOVA shows there is no significant difference (p <0.05) between different combinations of data with respect to scanner and convolution kernel type. Since different MDCT and reconstruction kernel types did not show significant differences in regards to the classification result, this study suggests that the 3-D AMFM can be generally introduced.

Pediatric radiation dose and risk from bone density measurements using a GE Lunar Prodigy scanner.

PubMed

Damilakis, J; Solomou, G; Manios, G E; Karantanas, A

2013-07-01

Effective radiation doses associated with bone mineral density examinations performed on children using a GE Lunar Prodigy fan-beam dual-energy X-ray absorptiometry (DXA) scanner were found to be comparable to doses from pencil-beam DXA devices, i.e., lower than 1 μSv. Cancer risks associated with acquisitions obtained in this study are negligible. No data were found in the literature on radiation doses and potential risks following pediatric DXA performed on GE Lunar DXA scanners. This study aimed to estimate effective doses and associated cancer risks involved in pediatric examinations performed on a GE Lunar Prodigy scanner. Four physical anthropomorphic phantoms representing newborn, 1-, 5-, and 10-year-old patients were employed to simulate DXA exposures. All acquisitions were carried out using the Prodigy scanner. Dose measurements were performed for spine and dual femur using the phantoms simulating the 5- and 10-year-old child. Moreover, doses associated with whole-body examinations were measured for the four phantoms used in the current study. The gender-average effective dose for spine and hip examinations were 0.65 and 0.36 μSv, respectively, for the phantom representing the 5-year-old child and 0.93 and 0.205 μSv, respectively, for the phantom representing the 10-year-old child. Effective doses for whole-body examinations were 0.25, 0.22, 0.19, and 0.15 μSv for the neonate, 1-, 5-, and 10-year old child, respectively. The estimated lifetime cancer risks were negligible, i.e., 0.02-0.25 per million, depending on the sex, age, and type of DXA examination. A formula is presented for the estimation of effective dose from examinations performed on GE Lunar Prodigy scanners installed in other institutions. The effective doses and potential cancer risks associated with pediatric DXA examinations performed on a GE Lunar Prodigy fan-beam scanner were found to be comparable to doses and risks reported from pencil-beam DXA devices.

Sample size requirements for estimating effective dose from computed tomography using solid-state metal-oxide-semiconductor field-effect transistor dosimetry

PubMed Central

Trattner, Sigal; Cheng, Bin; Pieniazek, Radoslaw L.; Hoffmann, Udo; Douglas, Pamela S.; Einstein, Andrew J.

2014-01-01

Purpose: Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (MOSFET) solid-state dosimeters have been placed to enable organ dose measurements. Here a statistical framework is established to determine the sample size (number of scans) needed for estimating ED to a desired precision and confidence, for a particular scanner and scan protocol, subject to practical limitations. Methods: The statistical scheme involves solving equations which minimize the sample size required for estimating ED to desired precision and confidence. It is subject to a constrained variation of the estimated ED and solved using the Lagrange multiplier method. The scheme incorporates measurement variation introduced both by MOSFET calibration, and by variation in MOSFET readings between repeated CT scans. Sample size requirements are illustrated on cardiac, chest, and abdomen–pelvis CT scans performed on a 320-row scanner and chest CT performed on a 16-row scanner. Results: Sample sizes for estimating ED vary considerably between scanners and protocols. Sample size increases as the required precision or confidence is higher and also as the anticipated ED is lower. For example, for a helical chest protocol, for 95% confidence and 5% precision for the ED, 30 measurements are required on the 320-row scanner and 11 on the 16-row scanner when the anticipated ED is 4 mSv; these sample sizes are 5 and 2, respectively, when the anticipated ED is 10 mSv. Conclusions: Applying the suggested scheme, it was found that even at modest sample sizes, it is feasible to estimate ED with high precision and a high degree of confidence. As CT technology develops enabling ED to be lowered, more MOSFET measurements are needed to estimate ED with the same precision and confidence. PMID:24694150

Effect of different CT scanners and settings on femoral failure loads calculated by finite element models.

PubMed

Eggermont, Florieke; Derikx, Loes C; Free, Jeffrey; van Leeuwen, Ruud; van der Linden, Yvette M; Verdonschot, Nico; Tanck, Esther

2018-03-06

In a multi-center patient study, using different CT scanners, CT-based finite element (FE) models are utilized to calculate failure loads of femora with metastases. Previous studies showed that using different CT scanners can result in different outcomes. This study aims to quantify the effects of (i) different CT scanners; (ii) different CT protocols with variations in slice thickness, field of view (FOV), and reconstruction kernel; and (iii) air between calibration phantom and patient, on Hounsfield Units (HU), bone mineral density (BMD), and FE failure load. Six cadaveric femora were scanned on four CT scanners. Scans were made with multiple CT protocols and with or without an air gap between the body model and calibration phantom. HU and calibrated BMD were determined in cortical and trabecular regions of interest. Non-linear isotropic FE models were constructed to calculate failure load. Mean differences between CT scanners varied up to 7% in cortical HU, 6% in trabecular HU, 6% in cortical BMD, 12% in trabecular BMD, and 17% in failure load. Changes in slice thickness and FOV had little effect (≤4%), while reconstruction kernels had a larger effect on HU (16%), BMD (17%), and failure load (9%). Air between the body model and calibration phantom slightly decreased the HU, BMD, and failure loads (≤8%). In conclusion, this study showed that quantitative analysis of CT images acquired with different CT scanners, and particularly reconstruction kernels, can induce relatively large differences in HU, BMD, and failure loads. Additionally, if possible, air artifacts should be avoided. © 2018 Orthopaedic Research Society. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society.

Optical Automatic Car Identification (OACI) : Volume 1. Advanced System Specification.

DOT National Transportation Integrated Search

1978-12-01

A performance specification is provided in this report for an Optical Automatic Car Identification (OACI) scanner system which features 6% improved readability over existing industry scanner systems. It also includes the analysis and rationale which ...

Which satellites were used?

Atmospheric Science Data Center

2014-12-08

... instrument packages (Scanner and NonScanner) were used. The NASA Goddard Space Flight Center built the Earth Radiation Budget Satellite ... which the first ERBE instruments were launched by the Space Shuttle Challenger in 1984. ERBE instruments were also launched on two ...

Determining density of maize canopy. 2: Airborne multispectral scanner data

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F.; Cipra, J. E.

1971-01-01

Multispectral scanner data were collected in two flights over a light colored soil background cover plot at an altitude of 305 m. Energy in eleven reflective wavelength band from 0.45 to 2.6 microns was recorded. Four growth stages of maize (Zea mays L.) gave a wide range of canopy densities for each flight date. Leaf area index measurements were taken from the twelve subplots and were used as a measure of canopy density. Ratio techniques were used to relate uncalibrated scanner response to leaf area index. The ratios of scanner data values for the 0.72 to 0.92 micron wavelength band over the 0.61 to 0.70 micron wavelength band were calculated for each plot. The ratios related very well to leaf area index for a given flight date. The results indicated that spectral data from maize canopies could be of value in determining canopy density.

Dental impressions using 3D digital scanners: virtual becomes reality.

PubMed

Birnbaum, Nathan S; Aaronson, Heidi B

2008-10-01

The technologies that have made the use of three-dimensional (3D) digital scanners an integral part of many industries for decades have been improved and refined for application to dentistry. Since the introduction of the first dental impressioning digital scanner in the 1980s, development engineers at a number of companies have enhanced the technologies and created in-office scanners that are increasingly user-friendly and able to produce precisely fitting dental restorations. These systems are capable of capturing 3D virtual images of tooth preparations, from which restorations may be fabricated directly (ie, CAD/CAM systems) or fabricated indirectly (ie, dedicated impression scanning systems for the creation of accurate master models). The use of these products is increasing rapidly around the world and presents a paradigm shift in the way in which dental impressions are made. Several of the leading 3D dental digital scanning systems are presented and discussed in this article.

A coherent light scanner for optical processing of large format transparencies

NASA Technical Reports Server (NTRS)

Callen, W. R.; Weaver, J. E.; Shackelford, R. G.; Walsh, J. R.

1975-01-01

A laser scanner is discussed in which the scanning beam is random-access addressable and perpendicular to the image input plane and the irradiance of the scanned beam is controlled so that a constant average irradiance is maintained after passage through the image plane. The scanner's optical system and design are described, and its performance is evaluated. It is noted that with this scanner, data in the form of large-format transparencies can be processed without the expense, space, maintenance, and precautions attendant to the operation of a high-power laser with large-aperture collimating optics. It is shown that the scanned format as well as the diameter of the scanning beam may be increased by simple design modifications and that higher scan rates can be achieved at the expense of resolution by employing acousto-optic deflectors with different relay optics.

Development of Great Lakes algorithms for the Nimbus-G coastal zone color scanner

NASA Technical Reports Server (NTRS)

Tanis, F. J.; Lyzenga, D. R.

1981-01-01

A series of experiments in the Great Lakes designed to evaluate the application of the Nimbus G satellite Coastal Zone Color Scanner (CZCS) were conducted. Absorption and scattering measurement data were reduced to obtain a preliminary optical model for the Great Lakes. Available optical models were used in turn to calculate subsurface reflectances for expected concentrations of chlorophyll-a pigment and suspended minerals. Multiple nonlinear regression techniques were used to derive CZCS water quality prediction equations from Great Lakes simulation data. An existing atmospheric model was combined with a water model to provide the necessary simulation data for evaluation of the preliminary CZCS algorithms. A CZCS scanner model was developed which accounts for image distorting scanner and satellite motions. This model was used in turn to generate mapping polynomials that define the transformation from the original image to one configured in a polyconic projection. Four computer programs (FORTRAN IV) for image transformation are presented.

Risks of exposure to ionizing and millimeter-wave radiation from airport whole-body scanners.

PubMed

Moulder, John E

2012-06-01

Considerable public concern has been expressed around the world about the radiation risks posed by the backscatter (ionizing radiation) and millimeter-wave (nonionizing radiation) whole-body scanners that have been deployed at many airports. The backscatter and millimeter-wave scanners currently deployed in the U.S. almost certainly pose negligible radiation risks if used as intended, but their safety is difficult-to-impossible to prove using publicly accessible data. The scanners are widely disliked and often feared, which is a problem made worse by what appears to be a veil of secrecy that covers their specifications and dosimetry. Therefore, for these and future similar technologies to gain wide acceptance, more openness is needed, as is independent review and regulation. Publicly accessible, and preferably peer-reviewed evidence is needed that the deployed units (not just the prototypes) meet widely-accepted safety standards. It is also critical that risk-perception issues be handled more competently.

Modeling And Simulation Of Bar Code Scanners Using Computer Aided Design Software

NASA Astrophysics Data System (ADS)

Hellekson, Ron; Campbell, Scott

1988-06-01

Many optical systems have demanding requirements to package the system in a small 3 dimensional space. The use of computer graphic tools can be a tremendous aid to the designer in analyzing the optical problems created by smaller and less costly systems. The Spectra Physics grocery store bar code scanner employs an especially complex 3 dimensional scan pattern to read bar code labels. By using a specially written program which interfaces with a computer aided design system, we have simulated many of the functions of this complex optical system. In this paper we will illustrate how a recent version of the scanner has been designed. We will discuss the use of computer graphics in the design process including interactive tweaking of the scan pattern, analysis of collected light, analysis of the scan pattern density, and analysis of the manufacturing tolerances used to build the scanner.

Comparison of solid shapes geometry derived by a laser scanner and a total station

NASA Astrophysics Data System (ADS)

Sidiropoulos, Andreas; Lakakis, Konstantinos

2016-08-01

The laser scanning technology has become a common method for the daily applications of a large variety of scientists and professionals. Even for more sophisticated projects, laser scanners have been proved a very useful tool at researchers' and engineers' disposal. In this paper, we investigated the ability of a laser scanner compared to the ability of a total station to provide the geometry of solids. The tests were made in the laboratory facilities of the Aristotle University of Thessaloniki, in a variety of distances between the measuring instrument and the object. The solids that were used differ in shape, material and color. The objects are a wooden cube, a metal cube and a wooden pyramid. The absolute dimensions of the solid shapes were provided by the use of a caliper and were compared to the dimensions that were calculated by the coordinates produced by the total station and laser scanner measurements.

A flexible and wearable terahertz scanner

NASA Astrophysics Data System (ADS)

Suzuki, D.; Oda, S.; Kawano, Y.

2016-12-01

Imaging technologies based on terahertz (THz) waves have great potential for use in powerful non-invasive inspection methods. However, most real objects have various three-dimensional curvatures and existing THz technologies often encounter difficulties in imaging such configurations, which limits the useful range of THz imaging applications. Here, we report the development of a flexible and wearable THz scanner based on carbon nanotubes. We achieved room-temperature THz detection over a broad frequency band ranging from 0.14 to 39 THz and developed a portable THz scanner. Using this scanner, we performed THz imaging of samples concealed behind opaque objects, breakages and metal impurities of a bent film and multi-view scans of a syringe. We demonstrated a passive biometric THz scan of a human hand. Our results are expected to have considerable implications for non-destructive and non-contact inspections, such as medical examinations for the continuous monitoring of health conditions.

Conceptual study of Earth observation missions with a space-borne laser scanner

NASA Astrophysics Data System (ADS)

Kobayashi, Takashi; Sato, Yohei; Yamakawa, Shiro

2017-11-01

The Japan Aerospace Exploration Agency (JAXA) has started a conceptual study of earth observation missions with a space-borne laser scanner (GLS, as Global Laser Scanner). Laser scanners are systems which transmit intense pulsed laser light to the ground from an airplane or a satellite, receive the scattered light, and measure the distance to the surface from the round-trip delay time of the pulse. With scanning mechanisms, GLS can obtain high-accuracy three-dimensional (3D) information from all over the world. High-accuracy 3D information is quite useful in various areas. Currently, following applications are considered. 1. Observation of tree heights to estimate the biomass quantity. 2. Making the global elevation map with high resolution. 3. Observation of ice-sheets. This paper aims at reporting the present state of our conceptual study of the GLS. A prospective performance of the GLS for earth observation missions mentioned above.

Nodular melanoma serendipitously detected by airport full body scanners.

PubMed

Mayer, Jonathan E; Adams, Brian B

2015-01-01

Nodular melanoma is the most dangerous form of melanoma and often evades early detection. We present a frequently traveling businessman whose nodular melanoma was detected by airport full body scanners. For about 20 flights over 2 months, the airport full body scanners singled out an area on his left lower leg for a pat-down. Dermatologic examination discovered a nodular melanoma in this area, and after surgical excision, the man traveled without incident. This case raises the possibility of using full body imaging in the detection of melanomas, especially of the nodular subtype. In its current form, full body scanning would most likely not be sensitive or specific enough to become a recommended screening tool. Nonetheless, for travelers with areas repeatedly singled out by the machines without a known justification, airport scanners could serve as incidental free screening for suspicious nodular lesions that should prompt dermatologist referral. © 2014 S. Karger AG, Basel.

Galileo Attitude Determination: Experiences with a Rotating Star Scanner

NASA Technical Reports Server (NTRS)

Merken, L.; Singh, G.

1991-01-01

The Galileo experience with a rotating star scanner is discussed in terms of problems encountered in flight, solutions implemented, and lessons learned. An overview of the Galileo project and the attitude and articulation control subsystem is given and the star scanner hardware and relevant software algorithms are detailed. The star scanner is the sole source of inertial attitude reference for this spacecraft. Problem symptoms observed in flight are discussed in terms of effects on spacecraft performance and safety. Sources of thse problems include contributions from flight software idiosyncrasies and inadequate validation of the ground procedures used to identify target stars for use by the autonomous on-board star identification algorithm. Problem fixes (some already implemented and some only proposed) are discussed. A general conclusion is drawn regarding the inherent difficulty of performing simulation tests to validate algorithms which are highly sensitive to external inputs of statistically 'rare' events.

Comparative Performance Analysis of Different Fingerprint Biometric Scanners for Patient Matching.

PubMed

Kasiiti, Noah; Wawira, Judy; Purkayastha, Saptarshi; Were, Martin C

2017-01-01

Unique patient identification within health services is an operational challenge in healthcare settings. Use of key identifiers, such as patient names, hospital identification numbers, national ID, and birth date are often inadequate for ensuring unique patient identification. In addition approximate string comparator algorithms, such as distance-based algorithms, have proven suboptimal for improving patient matching, especially in low-resource settings. Biometric approaches may improve unique patient identification. However, before implementing the technology in a given setting, such as health care, the right scanners should be rigorously tested to identify an optimal package for the implementation. This study aimed to investigate the effects of factors such as resolution, template size, and scan capture area on the matching performance of different fingerprint scanners for use within health care settings. Performance analysis of eight different scanners was tested using the demo application distributed as part of the Neurotech Verifinger SDK 6.0.

Centimeter-scale MEMS scanning mirrors for high power laser application

NASA Astrophysics Data System (ADS)

Senger, F.; Hofmann, U.; v. Wantoch, T.; Mallas, C.; Janes, J.; Benecke, W.; Herwig, Patrick; Gawlitza, P.; Ortega-Delgado, M.; Grune, C.; Hannweber, J.; Wetzig, A.

2015-02-01

A higher achievable scan speed and the capability to integrate two scan axes in a very compact device are fundamental advantages of MEMS scanning mirrors over conventional galvanometric scanners. There is a growing demand for biaxial high speed scanning systems complementing the rapid progress of high power lasers for enabling the development of new high throughput manufacturing processes. This paper presents concept, design, fabrication and test of biaxial large aperture MEMS scanning mirrors (LAMM) with aperture sizes up to 20 mm for use in high-power laser applications. To keep static and dynamic deformation of the mirror acceptably low all MEMS mirrors exhibit full substrate thickness of 725 μm. The LAMM-scanners are being vacuum packaged on wafer-level based on a stack of 4 wafers. Scanners with aperture sizes up to 12 mm are designed as a 4-DOF-oscillator with amplitude magnification applying electrostatic actuation for driving a motor-frame. As an example a 7-mm-scanner is presented that achieves an optical scan angle of 32 degrees at 3.2 kHz. LAMM-scanners with apertures sizes of 20 mm are designed as passive high-Q-resonators to be externally excited by low-cost electromagnetic or piezoelectric drives. Multi-layer dielectric coatings with a reflectivity higher than 99.9 % have enabled to apply cw-laser power loads of more than 600 W without damaging the MEMS mirror. Finally, a new excitation concept for resonant scanners is presented providing advantageous shaping of intensity profiles of projected laser patterns without modulating the laser. This is of interest in lighting applications such as automotive laser headlights.

Peak skin and eye lens radiation dose from brain perfusion CT based on Monte Carlo simulation.

PubMed

Zhang, Di; Cagnon, Chris H; Villablanca, J Pablo; McCollough, Cynthia H; Cody, Dianna D; Stevens, Donna M; Zankl, Maria; Demarco, John J; Turner, Adam C; Khatonabadi, Maryam; McNitt-Gray, Michael F

2012-02-01

The purpose of our study was to accurately estimate the radiation dose to skin and the eye lens from clinical CT brain perfusion studies, investigate how well scanner output (expressed as volume CT dose index [CTDI(vol)]) matches these estimated doses, and investigate the efficacy of eye lens dose reduction techniques. Peak skin dose and eye lens dose were estimated using Monte Carlo simulation methods on a voxelized patient model and 64-MDCT scanners from four major manufacturers. A range of clinical protocols was evaluated. CTDI(vol) for each scanner was obtained from the scanner console. Dose reduction to the eye lens was evaluated for various gantry tilt angles as well as scan locations. Peak skin dose and eye lens dose ranged from 81 mGy to 348 mGy, depending on the scanner and protocol used. Peak skin dose and eye lens dose were observed to be 66-79% and 59-63%, respectively, of the CTDI(vol) values reported by the scanners. The eye lens dose was significantly reduced when the eye lenses were not directly irradiated. CTDI(vol) should not be interpreted as patient dose; this study has shown it to overestimate dose to the skin or eye lens. These results may be used to provide more accurate estimates of actual dose to ensure that protocols are operated safely below thresholds. Tilting the gantry or moving the scanning region further away from the eyes are effective for reducing lens dose in clinical practice. These actions should be considered when they are consistent with the clinical task and patient anatomy.

Comparative dose levels between CT-scanner and slot-scanning device (EOS system) in pregnant women pelvimetry.

PubMed

Ben Abdennebi, A; Aubry, S; Ounalli, L; Fayache, M S; Delabrousse, E; Petegnief, Y

2017-01-01

To estimate fetal absorbed doses for pregnant women pelvimetry, a comparative study between EOS imaging system and low-dose spiral CT-scanner was carried out. For this purpose three different studies were investigated: in vivo, in vitro and Monte Carlo calculations. In vivo dosimetry was performed, using OSL NanoDot dosimeters, to determine the dose to the skin of twenty pregnant women. In vitro studies were established by using a cubic phantom of water, in order to estimate the out of field doses. In the latter study, OSLDs were placed at depths corresponding to the lowest, average and highest position of the uterus. Monte Carlo calculations of effective doses to high radio-sensitive organs were established, using PCXMC and CTExpo software suites for EOS imaging system and CT-scanner, respectively. The EOS imaging system reduces radiation exposure 4 to 8 times compared to the CT-scanner. The entrance skin doses were 74% (p-values <0.01) higher with the CT-scanner than with the EOS system. In the out of field region, the measured doses of the EOS system were reduced by 80% (p-values <0.02). Monte Carlo calculations confirmed that effective doses to organs are less accentuated for EOS than for CT pelvimetry. The EOS system is less irradiating than the CT exam. The out-of-field dose which is significant, is lower in the EOS than in the CT-scanner and could be reduced even further by optimizing the time used for image acquisition. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Design and experimental validation of novel 3D optical scanner with zoom lens unit

NASA Astrophysics Data System (ADS)

Huang, Jyun-Cheng; Liu, Chien-Sheng; Chiang, Pei-Ju; Hsu, Wei-Yan; Liu, Jian-Liang; Huang, Bai-Hao; Lin, Shao-Ru

2017-10-01

Optical scanners play a key role in many three-dimensional (3D) printing and CAD/CAM applications. However, existing optical scanners are generally designed to provide either a wide scanning area or a high 3D reconstruction accuracy from a lens with a fixed focal length. In the former case, the scanning area is increased at the expense of the reconstruction accuracy, while in the latter case, the reconstruction performance is improved at the expense of a more limited scanning range. In other words, existing optical scanners compromise between the scanning area and the reconstruction accuracy. Accordingly, the present study proposes a new scanning system including a zoom-lens unit, which combines both a wide scanning area and a high 3D reconstruction accuracy. In the proposed approach, the object is scanned initially under a suitable low-magnification setting for the object size (setting 1), resulting in a wide scanning area but a poor reconstruction resolution in complicated regions of the object. The complicated regions of the object are then rescanned under a high-magnification setting (setting 2) in order to improve the accuracy of the original reconstruction results. Finally, the models reconstructed after each scanning pass are combined to obtain the final reconstructed 3D shape of the object. The feasibility of the proposed method is demonstrated experimentally using a laboratory-built prototype. It is shown that the scanner has a high reconstruction accuracy over a large scanning area. In other words, the proposed optical scanner has significant potential for 3D engineering applications.

A simulation study of a dual-plate in-room PET system for dose verification in carbon ion therapy

NASA Astrophysics Data System (ADS)

Chen, Ze; Hu, Zheng-Guo; Chen, Jin-Da; Zhang, Xiu-Ling; Guo, Zhong-Yan; Xiao, Guo-Qing; Sun, Zhi-Yu; Huang, Wen-Xue; Wang, Jian-Song

2014-08-01

During carbon ion therapy, lots of positron emitters such as 11C, 15O, 10C are generated in irradiated tissues by nuclear reactions, and can be used to track the carbon beam in the tissue by a positron emission tomography (PET) scanner. In this study, an dual-plate in-room PET scanner has been designed and evaluated based on the GATE simulation platform to monitor patient dose in carbon ion therapy. The dual-plate PET is designed to avoid interference with the carbon beamline and with patient positioning. Its performance was compared with that of four-head and full-ring PET scanners. The dual-plate, four-head and full-ring PET scanners consisted of 30, 60, 60 detector modules, respectively, with a 36 cm distance between directly opposite detector modules for dose deposition measurements. Each detector module consisted of a 24×24 array of 2 mm×2 mm×18 mm LYSO pixels coupled to a Hamamatsu H8500 PMT. To estimate the production yield of positron emitters, a 10 cm×15 cm×15 cm cuboid PMMA phantom was irradiated with 172, 200, 250 MeV/u 12C beams. 3D images of the activity distribution measured by the three types of scanner are produced by an iterative reconstruction algorithm. By comparing the longitudinal profile of positron emitters along the carbon beam path, it is indicated that use of the dual-plate PET scanner is feasible for monitoring the dose distribution in carbon ion therapy.

Spectral performance of a whole-body research photon counting detector CT: quantitative accuracy in derived image sets

NASA Astrophysics Data System (ADS)

Leng, Shuai; Zhou, Wei; Yu, Zhicong; Halaweish, Ahmed; Krauss, Bernhard; Schmidt, Bernhard; Yu, Lifeng; Kappler, Steffen; McCollough, Cynthia

2017-09-01

Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI). Vials containing iodine with five known concentrations were scanned on the PCCT scanner after being placed in phantoms representing the attenuation of different size patients. For comparison, the same vials and phantoms were also scanned on 2nd and 3rd generation dual-source, dual-energy scanners. After material decomposition, iodine maps were generated, from which iodine concentration was measured for each vial and phantom size and compared with the known concentration. Additionally, VMIs were generated and CT number accuracy was compared to the reference standard, which was calculated based on known iodine concentration and attenuation coefficients at each keV obtained from the U.S. National Institute of Standards and Technology (NIST). Results showed accurate iodine quantification (root mean square error of 0.5 mgI/cc) and accurate CT number of VMIs (percentage error of 8.9%) using the PCCT scanner. The overall performance of the PCCT scanner, in terms of iodine quantification and VMI CT number accuracy, was comparable to that of EID-based dual-source, dual-energy scanners.

Workflow efficiency of two 1.5 T MR scanners with and without an automated user interface for head examinations.

PubMed

Moenninghoff, Christoph; Umutlu, Lale; Kloeters, Christian; Ringelstein, Adrian; Ladd, Mark E; Sombetzki, Antje; Lauenstein, Thomas C; Forsting, Michael; Schlamann, Marc

2013-06-01

Workflow efficiency and workload of radiological technologists (RTs) were compared in head examinations performed with two 1.5 T magnetic resonance (MR) scanners equipped with or without an automated user interface called "day optimizing throughput" (Dot) workflow engine. Thirty-four patients with known intracranial pathology were examined with a 1.5 T MR scanner with Dot workflow engine (Siemens MAGNETOM Aera) and with a 1.5 T MR scanner with conventional user interface (Siemens MAGNETOM Avanto) using four standardized examination protocols. The elapsed time for all necessary work steps, which were performed by 11 RTs within the total examination time, was compared for each examination at both MR scanners. The RTs evaluated the user-friendliness of both scanners by a questionnaire. Normality of distribution was checked for all continuous variables by use of the Shapiro-Wilk test. Normally distributed variables were analyzed by Student's paired t-test, otherwise Wilcoxon signed-rank test was used to compare means. Total examination time of MR examinations performed with Dot engine was reduced from 24:53 to 20:01 minutes (P < .001) and the necessary RT intervention decreased by 61% (P < .001). The Dot engine's automated choice of MR protocols was significantly better assessed by the RTs than the conventional user interface (P = .001). According to this preliminary study, the Dot workflow engine is a time-saving user assistance software, which decreases the RTs' effort significantly and may help to automate neuroradiological examinations for a higher workflow efficiency. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

The design of the CMOS wireless bar code scanner applying optical system based on ZigBee

NASA Astrophysics Data System (ADS)

Chen, Yuelin; Peng, Jian

2008-03-01

The traditional bar code scanner is influenced by the length of data line, but the farthest distance of the wireless bar code scanner of wireless communication is generally between 30m and 100m on the market. By rebuilding the traditional CCD optical bar code scanner, a CMOS code scanner is designed based on the ZigBee to meet the demands of market. The scan system consists of the CMOS image sensor and embedded chip S3C2401X, when the two dimensional bar code is read, the results show the inaccurate and wrong code bar, resulted from image defile, disturber, reads image condition badness, signal interference, unstable system voltage. So we put forward the method which uses the matrix evaluation and Read-Solomon arithmetic to solve them. In order to construct the whole wireless optics of bar code system and to ensure its ability of transmitting bar code image signals digitally with long distances, ZigBee is used to transmit data to the base station, and this module is designed based on image acquisition system, and at last the wireless transmitting/receiving CC2430 module circuit linking chart is established. And by transplanting the embedded RTOS system LINUX to the MCU, an applying wireless CMOS optics bar code scanner and multi-task system is constructed. Finally, performance of communication is tested by evaluation software Smart RF. In broad space, every ZIGBEE node can realize 50m transmission with high reliability. When adding more ZigBee nodes, the transmission distance can be several thousands of meters long.

Comparing the accuracy of terrestrial laser scanner in measuring forest inventory variables to enhance better decision making for potential fire hazards

NASA Astrophysics Data System (ADS)

Ghimire, Suman; Xystrakis, Fotios; Koutsias, Nikos

2017-04-01

Forest inventory variables are essential in accessing the potential of wildfire hazard, obtaining above ground biomass and carbon sequestration which helps developing strategies for sustainable management of forests. Effective management of forest resources relies on the accuracy of such inventory variables. This study aims to compare the accuracy in obtaining the forest inventory variables like diameter at breast height (DBH) and tree height from Terrestrial Laser Scanner (Faro Focus 3D X 330) with that from the traditional forest inventory techniques in the Mediterranean forests of Greece. The data acquisition was carried out on an area of 9,539.8 m2 with six plots each of radius 6 m. Computree algorithm was applied for automatic detection of DBH from terrestrial laser scanner data. Similarly, tree height was estimated manually using CloudCompare software for the terrestrial laser scanner data. The field estimates of DBH and tree height was carried out using calipers and Nikon Forestry 550 Laser Rangefinder. The comparison of DBH measured between field estimates and Terrestrial Laser Scanner (TLS), resulted in R squared values ranging from 0.75 to 0.96 at the plot level. An average R2 and RMSE value of 0.80 and 1.07 m respectively was obtained when comparing the tree height between TLS and field data. Our results confirm that terrestrial laser scanner can provide nondestructive, high-resolution, and precise determination of forest inventory for better decision making in sustainable forest management and assessing potential of forest fire hazards.

Electrical continuity scanner facilitates identification of wires for soldering to connectors

NASA Technical Reports Server (NTRS)

Boulton, H. C.; Diclemente, R. A.

1966-01-01

Electrical continuity scanner automatically scans 50 wires in 2 seconds to correlate all wires in a circuit with their respective known ends. Modifications made to the basic plan provide circuitry for scanning up to 250 wires.

Impact of topographic mask models on scanner matching solutions

NASA Astrophysics Data System (ADS)

Tyminski, Jacek K.; Pomplun, Jan; Renwick, Stephen P.

2014-03-01

Of keen interest to the IC industry are advanced computational lithography applications such as Optical Proximity Correction of IC layouts (OPC), scanner matching by optical proximity effect matching (OPEM), and Source Optimization (SO) and Source-Mask Optimization (SMO) used as advanced reticle enhancement techniques. The success of these tasks is strongly dependent on the integrity of the lithographic simulators used in computational lithography (CL) optimizers. Lithographic mask models used by these simulators are key drivers impacting the accuracy of the image predications, and as a consequence, determine the validity of these CL solutions. Much of the CL work involves Kirchhoff mask models, a.k.a. thin masks approximation, simplifying the treatment of the mask near-field images. On the other hand, imaging models for hyper-NA scanner require that the interactions of the illumination fields with the mask topography be rigorously accounted for, by numerically solving Maxwell's Equations. The simulators used to predict the image formation in the hyper-NA scanners must rigorously treat the masks topography and its interaction with the scanner illuminators. Such imaging models come at a high computational cost and pose challenging accuracy vs. compute time tradeoffs. Additional complication comes from the fact that the performance metrics used in computational lithography tasks show highly non-linear response to the optimization parameters. Finally, the number of patterns used for tasks such as OPC, OPEM, SO, or SMO range from tens to hundreds. These requirements determine the complexity and the workload of the lithography optimization tasks. The tools to build rigorous imaging optimizers based on first-principles governing imaging in scanners are available, but the quantifiable benefits they might provide are not very well understood. To quantify the performance of OPE matching solutions, we have compared the results of various imaging optimization trials obtained with Kirchhoff mask models to those obtained with rigorous models involving solutions of Maxwell's Equations. In both sets of trials, we used sets of large numbers of patterns, with specifications representative of CL tasks commonly encountered in hyper-NA imaging. In this report we present OPEM solutions based on various mask models and discuss the models' impact on hyper- NA scanner matching accuracy. We draw conclusions on the accuracy of results obtained with thin mask models vs. the topographic OPEM solutions. We present various examples representative of the scanner image matching for patterns representative of the current generation of IC designs.

Correcting scan-to-scan response variability for a radiochromic film-based reference dosimetry system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, David, E-mail: rcfilmconsulting@gmail.com; Devic, Slobodan

Purpose: In radiochromic film dosimetry systems, measurements are usually obtained from film images acquired on a CCD-based flatbed scanner. The authors investigated factors affecting scan-to-scan response variability leading to increased dose measurement uncertainty. Methods: The authors used flatbed document scanners to repetitively scan EBT3 radiochromic films exposed to doses 0–1000 cGy, together with three neutral density filters and three blue optical filters. Scanning was performed under two conditions: scanner lid closed and scanner lid opened/closed between scans. The authors also placed a scanner in a cold room at 9 °C and later in a room at 22 °C and scanned EBT3 filmsmore » to explore temperature effects. Finally, the authors investigated the effect of altering the distance between the film and the scanner’s light source. Results: Using a measurement protocol to isolate the contribution of the CCD and electronic circuitry of the scanners, the authors found that the standard deviation of response measurements for the EBT3 film model was about 0.17% for one scanner and 0.09% for the second. When the lid of the first scanner was opened and closed between scans, the average scan-to-scan difference of responses increased from 0.12% to 0.27%. Increasing the sample temperature during scanning changed the RGB response values by about −0.17, −0.14, and −0.05%/°C, respectively. Reducing the film-to-light source distance increased the RBG response values about 1.1, 1.3, and 1.4%/mm, respectively. The authors observed that films and film samples were often not flat with some areas up to 8 mm away from the scanner’s glass window. Conclusions: In the absence of measures to deal with the response irregularities, each factor the authors investigated could lead to dose uncertainty >2%. Those factors related to the film-to-light source distance could be particularly impactful since the authors observed many instances where the curl of film samples had the potential to cause dose uncertainty in excess of 5%. Two expedients will eliminate the uncertainties: a transparent sheet (preferably glass) placed over the scanned film keeps the film-to-light source distance constant, and an EBT3 reference film included in all scans provides correction factors for measured response values.« less

Optical fuel pin scanner

DOEpatents

Kirchner, Tommy L.; Powers, Hurshal G.

1983-01-01

An optical scanner for indicia arranged in a focal plane at a cylindrical outside surface by use of an optical system including a rotatable dove prism. The dove prism transmits a rotating image of an encircled cylindrical surface area to a stationary photodiode array.

What Scanner products are available?

Atmospheric Science Data Center

2014-12-08

... not provide the full diurnal coverage, which can affect the quality of the shortwave and longwave estimate. ERBS covers all 24-hour local ... algorithm. Because of these differences, it is best to work with these two data sets separately. ERBE/ERBS scanner operated ...

Cardiac multidetector computed tomography: basic physics of image acquisition and clinical applications.

PubMed

Bardo, Dianna M E; Brown, Paul

2008-08-01

Cardiac MDCT is here to stay. And, it is more than just imaging coronary arteries. Understanding the differences in and the benefits of one CT scanner from another will help you to optimize the capabilities of the scanner, but requires a basic understanding of the MDCT imaging physics.This review provides key information needed to understand the differences in the types of MDCT scanners, from 64 - 320 detectors, flat panels, single and dual source configurations, step and shoot prospective and retrospective gating, and how each factor influences radiation dose, spatial and temporal resolution, and image noise.

Design and development of the coaxial scanner as a compact high-performance thermal imager

NASA Astrophysics Data System (ADS)

Lettington, Alan H.

1994-09-01

This paper describes the original requirement of a light weight, high performance, low cost thermal imager which resulted in the design of the novel coaxial scanner. The early form of imager used a dedicated display to match the original cyclic scan sequence. With the advent of fast digital scan converters and the desire to use standard TV monitors the imager was redesigned and new TV compatible scan sequences devised. A version of this scanner is currently being manufactured by GEC Marconi Avionics, UK, and the paper concludes with examples of its application.

Laser Scanner Technology, Ground-Penetrating Radar and Augmented Reality for the Survey and Recovery of Artistic, Archaeological and Cultural Heritage

NASA Astrophysics Data System (ADS)

Barrile, V.; Bilotta, G.; Meduri, G. M.; De Carlo, D.; Nunnari, A.

2017-11-01

In this study, using technologies such as laser scanner and GPR it was desired to see their potential in the cultural heritage. Also with regard to the processing part we are compared the results obtained by the various commercial software and algorithms developed and implemented in Matlab. Moreover, Virtual Reality and Augmented Reality allow integrating the real world with historical-artistic information, laser scanners and georadar (GPR) data and virtual objects, virtually enriching it with multimedia elements, graphic and textual information accessible through smartphones and tablets.

Localization of a mobile laser scanner via dimensional reduction

NASA Astrophysics Data System (ADS)

Lehtola, Ville V.; Virtanen, Juho-Pekka; Vaaja, Matti T.; Hyyppä, Hannu; Nüchter, Andreas

2016-11-01

We extend the concept of intrinsic localization from a theoretical one-dimensional (1D) solution onto a 2D manifold that is embedded in a 3D space, and then recover the full six degrees of freedom for a mobile laser scanner with a simultaneous localization and mapping algorithm (SLAM). By intrinsic localization, we mean that no reference coordinate system, such as global navigation satellite system (GNSS), nor inertial measurement unit (IMU) are used. Experiments are conducted with a 2D laser scanner mounted on a rolling prototype platform, VILMA. The concept offers potential in being extendable to other wheeled platforms.

Miniature rotating transmissive optical drum scanner

NASA Technical Reports Server (NTRS)

Lewis, Robert (Inventor); Parrington, Lawrence (Inventor); Rutberg, Michael (Inventor)

2013-01-01

A miniature rotating transmissive optical scanner system employs a drum of small size having an interior defined by a circumferential wall rotatable on a drum axis, an optical element positioned within the interior of the drum, and a light-transmissive lens aperture provided at an angular position in the circumferential wall of the drum for scanning a light beam to or from the optical element in the drum along a beam azimuth angle as the drum is rotated. The miniature optical drum scanner configuration obtains a wide scanning field-of-view (FOV) and large effective aperture is achieved within a physically small size.

Scanner baseliner monitoring and control in high volume manufacturing

NASA Astrophysics Data System (ADS)

Samudrala, Pavan; Chung, Woong Jae; Aung, Nyan; Subramany, Lokesh; Gao, Haiyong; Gomez, Juan-Manuel

2016-03-01

We analyze performance of different customized models on baseliner overlay data and demonstrate the reduction in overlay residuals by ~10%. Smart Sampling sets were assessed and compared with the full wafer measurements. We found that performance of the grid can still be maintained by going to one-third of total sampling points, while reducing metrology time by 60%. We also demonstrate the feasibility of achieving time to time matching using scanner fleet manager and thus identify the tool drifts even when the tool monitoring controls are within spec limits. We also explore the scanner feedback constant variation with illumination sources.

Determination of noise equivalent reflectance for a multispectral scanner: A scanner sensitivity study

NASA Technical Reports Server (NTRS)

Gibbons, D. E.; Richard, R. R.

1979-01-01

The methods used to calculate the sensitivity parameter noise equivalent reflectance of a remote-sensing scanner are explored, and the results are compared with values measured over calibrated test sites. Data were acquired on four occasions covering a span of 4 years and providing various atmospheric conditions. One of the calculated values was based on assumed atmospheric conditions, whereas two others were based on atmospheric models. Results indicate that the assumed atmospheric conditions provide useful answers adequate for many purposes. A nomograph was developed to indicate sensitivity variations due to geographic location, time of day, and season.

Performance comparison of two commercial BGO-based PET/CT scanners using NEMA NU 2-2001.

PubMed

Bolard, Grégory; Prior, John O; Modolo, Luca; Delaloye, Angelika Bischof; Kosinski, Marek; Wastiel, Claude; Malterre, Jérôme; Bulling, Shelley; Bochud, François; Verdun, Francis R

2007-07-01

Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than 18F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards. At the time of publication of the latest version of the standards (NU 2-2001) that have been adapted for whole-body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery-ST (D-ST) and Discovery-STE (D-STE), were commercially available. We report on the full characterization both in the two- and three-dimensional acquisition mode of the D-LS according to latest NEMA NU 2-2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D-ST widely used and whose characteristics are already published.

High speed micro scanner for 3D in-volume laser micro processing

NASA Astrophysics Data System (ADS)

Schaefer, D.; Gottmann, J.; Hermans, M.; Ortmann, J.; Kelbassa, I.

2013-03-01

Using an in-house developed micro scanner three-dimensional micro components and micro fluidic devices in fused silica are realized using the ISLE process (in-volume selective laser-induced etching). With the micro scanner system the potential of high average power femtosecond lasers (P > 100 W) is exploited by the fabrication of components with micrometer precision at scan speeds of several meters per second. A commercially available galvanometer scanner is combined with an acousto-optical and/or electro-optical beam deflector and translation stages. For focusing laser radiation high numerical aperture microscope objectives (NA > 0.3) are used generating a focal volume of a few cubic micrometers. After laser exposure the materials are chemically wet etched in aqueous solution. The laser-exposed material is etched whereas the unexposed material remains nearly unchanged. Using the described technique called ISLE the fabrication of three-dimensional micro components, micro holes, cuts and channels is possible with high average power femtosecond lasers resulting in a reduced processing time for exposure. By developing the high speed micro scanner up-scaling of the ISLE process is demonstrated. The fabricated components made out of glass can be applied in various markets like biological and medical diagnostics as well as in micro mechanics.

The Function Biomedical Informatics Research Network Data Repository.

PubMed

Keator, David B; van Erp, Theo G M; Turner, Jessica A; Glover, Gary H; Mueller, Bryon A; Liu, Thomas T; Voyvodic, James T; Rasmussen, Jerod; Calhoun, Vince D; Lee, Hyo Jong; Toga, Arthur W; McEwen, Sarah; Ford, Judith M; Mathalon, Daniel H; Diaz, Michele; O'Leary, Daniel S; Jeremy Bockholt, H; Gadde, Syam; Preda, Adrian; Wible, Cynthia G; Stern, Hal S; Belger, Aysenil; McCarthy, Gregory; Ozyurt, Burak; Potkin, Steven G

2016-01-01

The Function Biomedical Informatics Research Network (FBIRN) developed methods and tools for conducting multi-scanner functional magnetic resonance imaging (fMRI) studies. Method and tool development were based on two major goals: 1) to assess the major sources of variation in fMRI studies conducted across scanners, including instrumentation, acquisition protocols, challenge tasks, and analysis methods, and 2) to provide a distributed network infrastructure and an associated federated database to host and query large, multi-site, fMRI and clinical data sets. In the process of achieving these goals the FBIRN test bed generated several multi-scanner brain imaging data sets to be shared with the wider scientific community via the BIRN Data Repository (BDR). The FBIRN Phase 1 data set consists of a traveling subject study of 5 healthy subjects, each scanned on 10 different 1.5 to 4 T scanners. The FBIRN Phase 2 and Phase 3 data sets consist of subjects with schizophrenia or schizoaffective disorder along with healthy comparison subjects scanned at multiple sites. In this paper, we provide concise descriptions of FBIRN's multi-scanner brain imaging data sets and details about the BIRN Data Repository instance of the Human Imaging Database (HID) used to publicly share the data. Copyright © 2015 Elsevier Inc. All rights reserved.

Performance comparison of two commercial BGO-based PET/CT scanners using NEMA NU 2-2001

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolard, Gregory; Prior, John O.; Modolo, Luca

2007-07-15

Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than {sup 18}F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards. At the time of publication ofmore » the latest version of the standards (NU 2-2001) that have been adapted for whole-body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery-ST (D-ST) and Discovery-STE (D-STE), were commercially available. We report on the full characterization both in the two- and three-dimensional acquisition mode of the D-LS according to latest NEMA NU 2-2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D-ST widely used and whose characteristics are already published.« less

Implementation of fast macromolecular proton fraction mapping on 1.5 and 3 Tesla clinical MRI scanners: preliminary experience

NASA Astrophysics Data System (ADS)

Yarnykh, V.; Korostyshevskaya, A.

2017-08-01

Macromolecular proton fraction (MPF) is a biophysical parameter describing the amount of macromolecular protons involved into magnetization exchange with water protons in tissues. MPF represents a significant interest as a magnetic resonance imaging (MRI) biomarker of myelin for clinical applications. A recent fast MPF mapping method enabled clinical translation of MPF measurements due to time-efficient acquisition based on the single-point constrained fit algorithm. However, previous MPF mapping applications utilized only 3 Tesla MRI scanners and modified pulse sequences, which are not commonly available. This study aimed to test the feasibility of MPF mapping implementation on a 1.5 Tesla clinical scanner using standard manufacturer’s sequences and compare the performance of this method between 1.5 and 3 Tesla scanners. MPF mapping was implemented on 1.5 and 3 Tesla MRI units of one manufacturer with either optimized custom-written or standard product pulse sequences. Whole-brain three-dimensional MPF maps obtained from a single volunteer were compared between field strengths and implementation options. MPF maps demonstrated similar quality at both field strengths. MPF values in segmented brain tissues and specific anatomic regions appeared in close agreement. This experiment demonstrates the feasibility of fast MPF mapping using standard sequences on 1.5 T and 3 T clinical scanners.

Lack of CT scanner in a rural emergency department increases inter-facility transfers: a pilot study.

PubMed

Bergeron, Catherine; Fleet, Richard; Tounkara, Fatoumata Korika; Lavallée-Bourget, Isabelle; Turgeon-Pelchat, Catherine

2017-12-28

Rural emergency departments (EDs) are an important gateway to care for the 20% of Canadians who reside in rural areas. Less than 15% of Canadian rural EDs have access to a computed tomography (CT) scanner. We hypothesized that a significant proportion of inter-facility transfers from rural hospitals without CT scanners are for CT imaging. Our objective was to assess inter-facility transfers for CT imaging in a rural ED without a CT scanner. We selected a rural ED that offers 24/7 medical care with admission beds but no CT scanner. Descriptive statistics were collected from 2010 to 2015 on total ED visits and inter-facility transfers. Data was accessible through hospital and government databases. Between 2010 and 2014, there were respectively 13,531, 13,524, 13,827, 12,883, and 12,942 ED visits, with an average of 444 inter-facility transfers. An average of 33% (148/444) of inter-facility transfers were to a rural referral centre with a CT scan, with 84% being for CT scan. Inter-facility transfers incur costs and potential delays in patient diagnosis and management, yet current databases could not capture transfer times. Acquiring a CT scan may represent a reasonable opportunity for the selected rural hospital considering the number of required transfers.

Extracting atomic numbers and electron densities from a dual source dual energy CT scanner: experiments and a simulation model.

PubMed

Landry, Guillaume; Reniers, Brigitte; Granton, Patrick Vincent; van Rooijen, Bart; Beaulieu, Luc; Wildberger, Joachim E; Verhaegen, Frank

2011-09-01

Dual energy CT (DECT) imaging can provide both the electron density ρ(e) and effective atomic number Z(eff), thus facilitating tissue type identification. This paper investigates the accuracy of a dual source DECT scanner by means of measurements and simulations. Previous simulation work suggested improved Monte Carlo dose calculation accuracy when compared to single energy CT for low energy photon brachytherapy, but lacked validation. As such, we aim to validate our DECT simulation model in this work. A cylindrical phantom containing tissue mimicking inserts was scanned with a second generation dual source scanner (SOMATOM Definition FLASH) to obtain Z(eff) and ρ(e). A model of the scanner was designed in ImaSim, a CT simulation program, and was used to simulate the experiment. Accuracy of measured Z(eff) (labelled Z) was found to vary from -10% to 10% from low to high Z tissue substitutes while the accuracy on ρ(e) from DECT was about 2.5%. Our simulation reproduced the experiments within ±5% for both Z and ρ(e). A clinical DECT scanner was able to extract Z and ρ(e) of tissue substitutes. Our simulation tool replicates the experiments within a reasonable accuracy. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A PC-based multispectral scanner data evaluation workstation: Application to Daedalus scanners

NASA Technical Reports Server (NTRS)

Jedlovec, Gary J.; James, Mark W.; Smith, Matthew R.; Atkinson, Robert J.

1991-01-01

In late 1989, a personal computer (PC)-based data evaluation workstation was developed to support post flight processing of Multispectral Atmospheric Mapping Sensor (MAMS) data. The MAMS Quick View System (QVS) is an image analysis and display system designed to provide the capability to evaluate Daedalus scanner data immediately after an aircraft flight. Even in its original form, the QVS offered the portability of a personal computer with the advanced analysis and display features of a mainframe image analysis system. It was recognized, however, that the original QVS had its limitations, both in speed and processing of MAMS data. Recent efforts are presented that focus on overcoming earlier limitations and adapting the system to a new data tape structure. In doing so, the enhanced Quick View System (QVS2) will accommodate data from any of the four spectrometers used with the Daedalus scanner on the NASA ER2 platform. The QVS2 is designed around the AST 486/33 MHz CPU personal computer and comes with 10 EISA expansion slots, keyboard, and 4.0 mbytes of memory. Specialized PC-McIDAS software provides the main image analysis and display capability for the system. Image analysis and display of the digital scanner data is accomplished with PC-McIDAS software.

Improved reliability in skeletal age assessment using a pediatric hand MR scanner with a 0.3T permanent magnet.

PubMed

Terada, Yasuhiko; Kono, Saki; Uchiumi, Tomomi; Kose, Katsumi; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; Yoshioka, Hiroshi

2014-01-01

The purpose of this study was to improve the reliability and validity of skeletal age assessment using an open and compact pediatric hand magnetic resonance (MR) imaging scanner. We used such a scanner with 0.3-tesla permanent magnet to image the left hands of 88 healthy children (aged 3.4 to 15.7 years, mean 8.8 years), and 3 raters (2 orthopedic specialists and a radiologist) assessed skeletal age using those images. We measured the strength of agreement in ratings by values of weighted Cohen's κ and the proportion of cases excluded from rating because of motion artifact and inappropriate positioning. We compared the current results with those of a previous study in which 93 healthy children (aged 4.1 to 16.4 years, mean 9.7 years) were examined with an adult hand scanner. The κ values between raters exceeded 0.80, which indicates almost perfect agreement, and most were higher than those of the previous study. The proportion of cases excluded from rating because of motion artifact or inappropriate positioning was also reduced. The results indicate that use of the compact pediatric hand scanner improved the reliability and validity of skeletal age assessments.

Development of a compact optical MEMS scanner with integrated VCSEL light source and diffractive optics

NASA Astrophysics Data System (ADS)

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven; Smith, James H.; Warren, Mial E.; Sweatt, William C.; Blum-Spahn, Olga; Wendt, Joel R.; Asbill, Randolph E.

1999-09-01

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOE's) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysilicon gold- coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 50 micrometer X 1000 micrometer shuttle is extremely low, with a maximum deflection of only 0.18 micrometer over an 800 micrometer span for an unmetallized case and a deflection of 0.56 micrometer for the metallized case. A conservative estimate for the scan range is approximately plus or minus 4 degrees, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.

Multicenter study of quantitative computed tomography analysis using a computer-aided three-dimensional system in patients with idiopathic pulmonary fibrosis.

PubMed

Iwasawa, Tae; Kanauchi, Tetsu; Hoshi, Toshiko; Ogura, Takashi; Baba, Tomohisa; Gotoh, Toshiyuki; Oba, Mari S

2016-01-01

To evaluate the feasibility of automated quantitative analysis with a three-dimensional (3D) computer-aided system (i.e., Gaussian histogram normalized correlation, GHNC) of computed tomography (CT) images from different scanners. Each institution's review board approved the research protocol. Informed patient consent was not required. The participants in this multicenter prospective study were 80 patients (65 men, 15 women) with idiopathic pulmonary fibrosis. Their mean age was 70.6 years. Computed tomography (CT) images were obtained by four different scanners set at different exposures. We measured the extent of fibrosis using GHNC, and used Pearson's correlation analysis, Bland-Altman plots, and kappa analysis to directly compare the GHNC results with manual scoring by radiologists. Multiple linear regression analysis was performed to determine the association between the CT data and forced vital capacity (FVC). For each scanner, the extent of fibrosis as determined by GHNC was significantly correlated with the radiologists' score. In multivariate analysis, the extent of fibrosis as determined by GHNC was significantly correlated with FVC (p < 0.001). There was no significant difference between the results obtained using different CT scanners. Gaussian histogram normalized correlation was feasible, irrespective of the type of CT scanner used.

Prediction of cervical cancer recurrence using textural features extracted from 18F-FDG PET images acquired with different scanners.

PubMed

Reuzé, Sylvain; Orlhac, Fanny; Chargari, Cyrus; Nioche, Christophe; Limkin, Elaine; Riet, François; Escande, Alexandre; Haie-Meder, Christine; Dercle, Laurent; Gouy, Sébastien; Buvat, Irène; Deutsch, Eric; Robert, Charlotte

2017-06-27

To identify an imaging signature predicting local recurrence for locally advanced cervical cancer (LACC) treated by chemoradiation and brachytherapy from baseline 18F-FDG PET images, and to evaluate the possibility of gathering images from two different PET scanners in a radiomic study. 118 patients were included retrospectively. Two groups (G1, G2) were defined according to the PET scanner used for image acquisition. Eleven radiomic features were extracted from delineated cervical tumors to evaluate: (i) the predictive value of features for local recurrence of LACC, (ii) their reproducibility as a function of the scanner within a hepatic reference volume, (iii) the impact of voxel size on feature values. Eight features were statistically significant predictors of local recurrence in G1 (p < 0.05). The multivariate signature trained in G2 was validated in G1 (AUC=0.76, p<0.001) and identified local recurrence more accurately than SUVmax (p=0.022). Four features were significantly different between G1 and G2 in the liver. Spatial resampling was not sufficient to explain the stratification effect. This study showed that radiomic features could predict local recurrence of LACC better than SUVmax. Further investigation is needed before applying a model designed using data from one PET scanner to another.

Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results

NASA Astrophysics Data System (ADS)

Xu, Y.; Wuu, Cheng-Shie

2013-02-01

The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub-millimeter accuracy of the phantom positioning between the reference scan and the actual scan is demonstrated to be essential. The fast scanner is shown to be able to scan gel phantoms with a wider field of view (5 mm from the edge of the scanned dosimeters) and at a speed 10 to 20 times faster than the OCTOPUS™ scanner. A large uncertainty of 5% (defined as the ratio of the standard deviation to the mean) is typically observed in the reconstructed images, owing to the inaccuracy in the phantom positioning process. Methods for further improvement of the accuracy of the in-house modified OCTOPUS™-10× scanner are discussed.

Vacuum compatible, high-speed, 2-D mirror tilt stage

DOEpatents

Denham; Paul E.

2007-09-25

A compact and vacuum compatible magnetic-coil driven tiltable stage that is equipped with a high efficiency reflective coating can be employed as a scanner in EUV applications. The drive electronics for the scanner is fully in situ programmable and rapidly switchable.

What is Scanner and NonScanner?

Atmospheric Science Data Center

2014-12-08

... instruments specifically designed by a team of electronic, thermal, and mechanical experts, built and integrated with the ERBS and NOAA ... of three co-planar detectors (longwave, shortwave and total energy), all of which scan from one limb of the Earth to the other, across the ...

Algorithms for Coastal-Zone Color-Scanner Data

NASA Technical Reports Server (NTRS)

1986-01-01

Software for Nimbus-7 Coastal-Zone Color-Scanner (CZCS) derived products consists of set of scientific algorithms for extracting information from CZCS-gathered data. Software uses CZCS-generated Calibrated RadianceTemperature (CRT) tape as input and outputs computer-compatible tape and film product.

Miniature 'Wearable' PET Scanner Ready for Use

ScienceCinema

Vaska, Paul

2017-12-27

Scientists from BNL, Stony Brook University, and collaborators have demonstrated the efficacy of a "wearable" portable PET scanner they've developed for rats. The device will give neuroscientists a new tool for simultaneously studying brain function and behavior in fully awake, moving animals.

Accuracy, reliability, and efficiency of intraoral scanners for full-arch impressions: a systematic review of the clinical evidence.

PubMed

Goracci, Cecilia; Franchi, Lorenzo; Vichi, Alessandro; Ferrari, Marco

2016-08-01

The interest on intraoral scanners for digital impressions has been growing and new devices are continuously introduced on the market. It is timely to verify whether the several scanners proposed for full-arch digital impressions have been tested under clinical conditions for validity, repeatability, reproducibility, as well as for time efficiency, and patient acceptance. An electronic search of the literature was conducted through PubMed, Scopus, Cochrane Library, Web of Science, and Embase, entering the query terms 'digital impression', 'intraoral digital impression', 'intraoral scanning', 'intraoral scanner', 'intraoral digital scanner', combined by the Boolean operator 'OR'. No language or time limitation was applied. Only studies where digital full-arch impressions had been recorded intraorally were considered. In only eight studies full-arch scans had been performed intraorally. Only four studies reported data on validity, repeatability, reproducibility of digital measurements and their samples were limited to subjects in complete permanent dentition. Only two intraoral scanners, Lava COS and iTero, were tested. Scanning times were measured in six studies and varied largely. Patients' acceptance of intraoral scanning was evaluated in four studies, but it was not specifically assessed for children. The scientific evidence so far collected on intraoral scanning is neither exhaustive, nor up-to-date. Data from full-arch scans performed in children should be collected. For a meaningful assessment of time efficiency, agreement should be reached on the procedural steps to be included in the computation of scanning time. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Performance comparison of two resolution modeling PET reconstruction algorithms in terms of physical figures of merit used in quantitative imaging.

PubMed

Matheoud, R; Ferrando, O; Valzano, S; Lizio, D; Sacchetti, G; Ciarmiello, A; Foppiano, F; Brambilla, M

2015-07-01

Resolution modeling (RM) of PET systems has been introduced in iterative reconstruction algorithms for oncologic PET. The RM recovers the loss of resolution and reduces the associated partial volume effect. While these methods improved the observer performance, particularly in the detection of small and faint lesions, their impact on quantification accuracy still requires thorough investigation. The aim of this study was to characterize the performances of the RM algorithms under controlled conditions simulating a typical (18)F-FDG oncologic study, using an anthropomorphic phantom and selected physical figures of merit, used for image quantification. Measurements were performed on Biograph HiREZ (B_HiREZ) and Discovery 710 (D_710) PET/CT scanners and reconstructions were performed using the standard iterative reconstructions and the RM algorithms associated to each scanner: TrueX and SharpIR, respectively. RM determined a significant improvement in contrast recovery for small targets (≤17 mm diameter) only for the D_710 scanner. The maximum standardized uptake value (SUVmax) increased when RM was applied using both scanners. The SUVmax of small targets was on average lower with the B_HiREZ than with the D_710. Sharp IR improved the accuracy of SUVmax determination, whilst TrueX showed an overestimation of SUVmax for sphere dimensions greater than 22 mm. The goodness of fit of adaptive threshold algorithms worsened significantly when RM algorithms were employed for both scanners. Differences in general quantitative performance were observed for the PET scanners analyzed. Segmentation of PET images using adaptive threshold algorithms should not be undertaken in conjunction with RM reconstructions. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Computed gray levels in multislice and cone-beam computed tomography.

PubMed

Azeredo, Fabiane; de Menezes, Luciane Macedo; Enciso, Reyes; Weissheimer, Andre; de Oliveira, Rogério Belle

2013-07-01

Gray level is the range of shades of gray in the pixels, representing the x-ray attenuation coefficient that allows for tissue density assessments in computed tomography (CT). An in-vitro study was performed to investigate the relationship between computed gray levels in 3 cone-beam CT (CBCT) scanners and 1 multislice spiral CT device using 5 software programs. Six materials (air, water, wax, acrylic, plaster, and gutta-percha) were scanned with the CBCT and CT scanners, and the computed gray levels for each material at predetermined points were measured with OsiriX Medical Imaging software (Geneva, Switzerland), OnDemand3D (CyberMed International, Seoul, Korea), E-Film (Merge Healthcare, Milwaukee, Wis), Dolphin Imaging (Dolphin Imaging & Management Solutions, Chatsworth, Calif), and InVivo Dental Software (Anatomage, San Jose, Calif). The repeatability of these measurements was calculated with intraclass correlation coefficients, and the gray levels were averaged to represent each material. Repeated analysis of variance tests were used to assess the differences in gray levels among scanners and materials. There were no differences in mean gray levels with the different software programs. There were significant differences in gray levels between scanners for each material evaluated (P <0.001). The software programs were reliable and had no influence on the CT and CBCT gray level measurements. However, the gray levels might have discrepancies when different CT and CBCT scanners are used. Therefore, caution is essential when interpreting or evaluating CBCT images because of the significant differences in gray levels between different CBCT scanners, and between CBCT and CT values. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Quantifying brain volumes for Multiple Sclerosis patients follow-up in clinical practice - comparison of 1.5 and 3 Tesla magnetic resonance imaging.

PubMed

Lysandropoulos, Andreas P; Absil, Julie; Metens, Thierry; Mavroudakis, Nicolas; Guisset, François; Van Vlierberghe, Eline; Smeets, Dirk; David, Philippe; Maertens, Anke; Van Hecke, Wim

2016-02-01

There is emerging evidence that brain atrophy is a part of the pathophysiology of Multiple Sclerosis (MS) and correlates with several clinical outcomes of the disease, both physical and cognitive. Consequently, brain atrophy is becoming an important parameter in patients' follow-up. Since in clinical practice both 1.5Tesla (T) and 3T magnetic resonance imaging (MRI) systems are used for MS patients follow-up, questions arise regarding compatibility and a possible need for standardization. Therefore, in this study 18 MS patients were scanned on the same day on a 1.5T and a 3T scanner. For each scanner, a 3D T1 and a 3D FLAIR were acquired. As no atrophy is expected within 1 day, these datasets can be used to evaluate the median percentage error of the brain volume measurement for gray matter (GM) volume and parenchymal volume (PV) between 1.5T and 3T scanners. The results are obtained with MSmetrix, which is developed especially for use in the MS clinical care path, and compared to Siena (FSL), a widely used software for research purposes. The MSmetrix median percentage error of the brain volume measurement between a 1.5T and a 3T scanner is 0.52% for GM and 0.35% for PV. For Siena this error equals 2.99%. When data of the same scanner are compared, the error is in the order of 0.06-0.08% for both MSmetrix and Siena. MSmetrix appears robust on both the 1.5T and 3T systems and the measurement error becomes an order of magnitude higher between scanners with different field strength.

Limitations of Airway Dimension Measurement on Images Obtained Using Multi-Detector Row Computed Tomography

PubMed Central

Oguma, Tsuyoshi; Hirai, Toyohiro; Niimi, Akio; Matsumoto, Hisako; Muro, Shigeo; Shigematsu, Michio; Nishimura, Takashi; Kubo, Yoshiro; Mishima, Michiaki

2013-01-01

Objectives (a) To assess the effects of computed tomography (CT) scanners, scanning conditions, airway size, and phantom composition on airway dimension measurement and (b) to investigate the limitations of accurate quantitative assessment of small airways using CT images. Methods An airway phantom, which was constructed using various types of material and with various tube sizes, was scanned using four CT scanner types under different conditions to calculate airway dimensions, luminal area (Ai), and the wall area percentage (WA%). To investigate the limitations of accurate airway dimension measurement, we then developed a second airway phantom with a thinner tube wall, and compared the clinical CT images of healthy subjects with the phantom images scanned using the same CT scanner. The study using clinical CT images was approved by the local ethics committee, and written informed consent was obtained from all subjects. Data were statistically analyzed using one-way ANOVA. Results Errors noted in airway dimension measurement were greater in the tube of small inner radius made of material with a high CT density and on images reconstructed by body algorithm (p<0.001), and there was some variation in error among CT scanners under different fields of view. Airway wall thickness had the maximum effect on the accuracy of measurements with all CT scanners under all scanning conditions, and the magnitude of errors for WA% and Ai varied depending on wall thickness when airways of <1.0-mm wall thickness were measured. Conclusions The parameters of airway dimensions measured were affected by airway size, reconstruction algorithm, composition of the airway phantom, and CT scanner types. In dimension measurement of small airways with wall thickness of <1.0 mm, the accuracy of measurement according to quantitative CT parameters can decrease as the walls become thinner. PMID:24116105

Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner.

PubMed

Arabi, Hossein; Kamali Asl, Ali Reza; Ay, Mohammad Reza; Zaidi, Habib

2015-07-01

The purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner. A realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-to-primary ratio of the scanner were estimated for both fixed and optimum object magnification at each detector rotation angle. Comparison and inference between these performance parameters were performed angle by angle to determine appropriate object position at each opening half angle. Optimization of magnification resulted in a trade-off between spatial resolution and FOV of the scanner at opening half angles of 90°-12°, where the spatial resolution increased up to 50% and the scatter-to-primary ratio decreased from 4.8% to 3.8% at a detector angle of about 90° for the same FOV and X-ray energy spectrum. The disadvantage of magnification optimization at these angles is the significant reduction of the FOV (up to 50%). Moreover, magnification optimization was definitely beneficial for opening half angles below 12° improving the spatial resolution from 7.5 cy/mm to 20 cy/mm. Meanwhile, the FOV increased by more than 50% at these angles. It can be concluded that optimization of magnification is essential for opening half angles below 12°. For opening half angles between 90° and 12°, the VRX CT scanner magnification should be set according to the desired spatial resolution and FOV. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Occupational exposure of healthcare and research staff to static magnetic stray fields from 1.5–7 Tesla MRI scanners is associated with reporting of transient symptoms

PubMed Central

Schaap, Kristel; Christopher-de Vries, Yvette; Mason, Catherine K; de Vocht, Frank; Portengen, Lützen; Kromhout, Hans

2014-01-01

Objectives Limited data is available about incidence of acute transient symptoms associated with occupational exposure to static magnetic stray fields from MRI scanners. We aimed to assess the incidence of these symptoms among healthcare and research staff working with MRI scanners, and their association with static magnetic field exposure. Methods We performed an observational study among 361 employees of 14 clinical and research MRI facilities in The Netherlands. Each participant completed a diary during one or more work shifts inside and/or outside the MRI facility, reporting work activities and symptoms (from a list of potentially MRI-related symptoms, complemented with unrelated symptoms) experienced during a working day. We analysed 633 diaries. Exposure categories were defined by strength and type of MRI scanner, using non-MRI shifts as the reference category for statistical analysis. Non-MRI shifts originated from MRI staff who also participated on MRI days, as well as CT radiographers who never worked with MRI. Results Varying per exposure category, symptoms were reported during 16–39% of the MRI work shifts. We observed a positive association between scanner strength and reported symptoms among healthcare and research staff working with closed-bore MRI scanners of 1.5 Tesla (T) and higher (1.5 T OR=1.88; 3.0 T OR=2.14; 7.0 T OR=4.17). This finding was mainly driven by reporting of vertigo and metallic taste. Conclusions The results suggest an exposure-response association between exposure to strong static magnetic fields (and associated motion-induced time-varying magnetic fields) and reporting of transient symptoms on the same day of exposure. Trial registration number 11-032/C PMID:24714654

Direct determination of geometric alignment parameters for cone-beam scanners

PubMed Central

Mennessier, C; Clackdoyle, R; Noo, F

2009-01-01

This paper describes a comprehensive method for determining the geometric alignment parameters for cone-beam scanners (often called calibrating the scanners or performing geometric calibration). The method is applicable to x-ray scanners using area detectors, or to SPECT systems using pinholes or cone-beam converging collimators. Images of an alignment test object (calibration phantom) fixed in the field of view of the scanner are processed to determine the nine geometric parameters for each view. The parameter values are found directly using formulae applied to the projected positions of the test object marker points onto the detector. Each view is treated independently, and no restrictions are made on the position of the cone vertex, or on the position or orientation of the detector. The proposed test object consists of 14 small point-like objects arranged with four points on each of three orthogonal lines, and two points on a diagonal line. This test object is shown to provide unique solutions for all possible scanner geometries, even when partial measurement information is lost by points superimposing in the calibration scan. For the many situations where the cone vertex stays reasonably close to a central plane (for circular, planar, or near-planar trajectories), a simpler version of the test object is appropriate. The simpler object consists of six points, two per orthogonal line, but with some restrictions on the positioning of the test object. This paper focuses on the principles and mathematical justifications for the method. Numerical simulations of the calibration process and reconstructions using estimated parameters are also presented to validate the method and to provide evidence of the robustness of the technique. PMID:19242049

In vivo cellular imaging with microscopes enabled by MEMS scanners

NASA Astrophysics Data System (ADS)

Ra, Hyejun

High-resolution optical imaging plays an important role in medical diagnosis and biomedical research. Confocal microscopy is a widely used imaging method for obtaining cellular and sub-cellular images of biological tissue in reflectance and fluorescence modes. Its characteristic optical sectioning capability also enables three-dimensional (3-D) image reconstruction. However, its use has mostly been limited to excised tissues due to the requirement of high numerical aperture (NA) lenses for cellular resolution. Microscope miniaturization can enable in vivo imaging to make possible early cancer diagnosis and biological studies in the innate environment. In this dissertation, microscope miniaturization for in vivo cellular imaging is presented. The dual-axes confocal (DAC) architecture overcomes limitations of the conventional single-axis confocal (SAC) architecture to allow for miniaturization with high resolution. A microelectromechanical systems (MEMS) scanner is the central imaging component that is key in miniaturization of the DAC architecture. The design, fabrication, and characterization of the two-dimensional (2-D) MEMS scanner are presented. The gimbaled MEMS scanner is fabricated on a double silicon-on-insulator (SOI) wafer and is actuated by self-aligned vertical electrostatic combdrives. The imaging performance of the MEMS scanner in a DAC configuration is shown in a breadboard microscope setup, where reflectance and fluorescence imaging is demonstrated. Then, the MEMS scanner is integrated into a miniature DAC microscope. The whole imaging system is integrated into a portable unit for research in small animal models of human biology and disease. In vivo 3-D imaging is demonstrated on mouse skin models showing gene transfer and siRNA silencing. The siRNA silencing process is sequentially imaged in one mouse over time.

Toward Precision and Reproducibility of Diffusion Tensor Imaging: A Multicenter Diffusion Phantom and Traveling Volunteer Study.

PubMed

Palacios, E M; Martin, A J; Boss, M A; Ezekiel, F; Chang, Y S; Yuh, E L; Vassar, M J; Schnyer, D M; MacDonald, C L; Crawford, K L; Irimia, A; Toga, A W; Mukherjee, P

2017-03-01

Precision medicine is an approach to disease diagnosis, treatment, and prevention that relies on quantitative biomarkers that minimize the variability of individual patient measurements. The aim of this study was to assess the intersite variability after harmonization of a high-angular-resolution 3T diffusion tensor imaging protocol across 13 scanners at the 11 academic medical centers participating in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury multisite study. Diffusion MR imaging was acquired from a novel isotropic diffusion phantom developed at the National Institute of Standards and Technology and from the brain of a traveling volunteer on thirteen 3T MR imaging scanners representing 3 major vendors (GE Healthcare, Philips Healthcare, and Siemens). Means of the DTI parameters and their coefficients of variation across scanners were calculated for each DTI metric and white matter tract. For the National Institute of Standards and Technology diffusion phantom, the coefficients of variation of the apparent diffusion coefficient across the 13 scanners was <3.8% for a range of diffusivities from 0.4 to 1.1 × 10 -6 mm 2 /s. For the volunteer, the coefficients of variations across scanners of the 4 primary DTI metrics, each averaged over the entire white matter skeleton, were all <5%. In individual white matter tracts, large central pathways showed good reproducibility with the coefficients of variation consistently below 5%. However, smaller tracts showed more variability, with the coefficients of variation of some DTI metrics reaching 10%. The results suggest the feasibility of standardizing DTI across 3T scanners from different MR imaging vendors in a large-scale neuroimaging research study. © 2017 by American Journal of Neuroradiology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Battum, LJ van; Heukelom, S

Purpose This study investigates the origin of lateral optical density (OD) variation for Gafchromic film (EBT and EBT2) scanned in transmission mode with Epson flatbed scanners (1680 Expression Pro and 10000XL). Effects investigated are: cross talk, optical path length and polarization. Methods Cross talk has been examined with triangular shaped light-transmission sheets with OD ranging from 0 to opaque. Optical path length has been studied with absorptive and reflective OD-filters (OD range 0.2 to 2.0). Dependency on light-polarization on the scanner read out has been investigated using linear polarizer sheets. All experiments have been performed at centre scanner position (normmore » point) and at several lateral scan positions, without and with (un)irradiated EBT-film. Dose values used ranged between 0.2 to 9 Gy, yielding an OD-range between 0.25 to 1.1. Results The lateral OD variation is dose dependent and increases up to 14% at most lateral position for dose up to 9 Gy. Cross talk effect contributes to 0.5% in clinical used OD ranges but equals 2% for extreme high dose gradients. Film induced optical path length will effect the lateral OD variation up to 3% at most lateral points. Light polarization is inherent present in these scanners due to multiple reflection on mirrors. In addition film induced polarization is the most important effect generating the observed lateral OD variation. Both Gafchromic film base and sensitive layer have polarizing capabilities; for the sensitive layer its influence is dose dependent. Conclusions Lateral OD variation origins from optical physics (i.e. polarization and reflection) related to scanner and film construction. Cross talk can be ignored in film dosimetry for clinical used dose values and gradients. Therefore it is recommended to determine the lateral OD variation per film type and scanner.« less

[Technique of abdominal ultrasonography in newborn foals and normal findings].

PubMed

Behn, C; Bostedt, H

2000-09-01

Under field conditions, the diagnosis of foal's diseases relies almost exclusively on the physical examination. As the signs of illness in the equine neonate are frequently vage and non-localizing, the diagnosis of diseases may be problematic. This often causes misinterpretations and leads to ineffective prophylaxis and treatment. The purpose of this study was to evaluate the usefulness of diagnostic ultrasonography of the foal's abdomen under field conditions to provide an optimized technique and to describe the normal findings. Diagnostic ultrasonography of the abdomen was performed after obtaining clinical history and passing the physical examination of 25 foals without signs of abdominal problems. The foals were scanned in a stable box, being restrained by three persons in semi-lateral recumbency. Usually, sedation was not necessary. The ventral abdominal wall was clipped, a generous amount of ultrasound coupling gel was applied and massaged on the skin surface. The ultrasonographic examination was carried out using a portable sector scanner ("Microimager 2000", Ausonics) with 5.0 and 7.5-MHz transducers or a combined 5.0 and 7.5-MHz transrectal linear-array scanner ("450 Enhanced", Pie Medical). Employing the 5.0-MHz sector scanner first, the abdomen was explored from caudal to cranial in left and right semi-lateral recumbency. The 7.5-MHz scanner was used to attain higher resolution of certain structures. The sector scanner turned out to be suitable under field conditions and adequate to examine the abdominal organs. The transrectal linear-array scanner also provided the most important informations, although it was difficult to maintain a good contact area of the scan head. By ultrasonography it was possible to identify the urinary bladder, kidneys, spleen, liver and part of the gastrointestinal tract. Thus, application of ultrasound could successfully be performed on newborn foals under field conditions.

Teach Your Computer to Read: Scanners and Optical Character Recognition.

ERIC Educational Resources Information Center

Marsden, Jim

1993-01-01

Desktop scanners can be used with a software technology called optical character recognition (OCR) to convert the text on virtually any paper document into an electronic form. OCR offers educators new flexibility in incorporating text into tests, lesson plans, and other materials. (MLF)

OCR Scanners Facilitate WP Training in Business Schools and Colleges.

ERIC Educational Resources Information Center

School Business Affairs, 1983

1983-01-01

Optical Character Recognition Scanners (OCR) scan typed text and feed it directly into word processing systems, saving input time. OCRs are valuable in word processing training programs because they allow more students access to classes and more time for skill training. (MD)

21 CFR 892.1220 - Fluorescent scanner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fluorescent scanner. 892.1220 Section 892.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, component parts and accessories. (b...

21 CFR 892.1220 - Fluorescent scanner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fluorescent scanner. 892.1220 Section 892.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, component parts and accessories. (b...

21 CFR 892.1220 - Fluorescent scanner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fluorescent scanner. 892.1220 Section 892.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, component parts and accessories. (b...

21 CFR 892.1220 - Fluorescent scanner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fluorescent scanner. 892.1220 Section 892.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, component parts and accessories. (b...

21 CFR 892.1220 - Fluorescent scanner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fluorescent scanner. 892.1220 Section 892.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, component parts and accessories. (b...

Scanners, optical character readers, Cyrillic alphabet and Russian translations

NASA Technical Reports Server (NTRS)

Johnson, Gordon G.

1995-01-01

The writing of code for capture, in a uniform format, of bit maps of words and characters from scanner PICT files is presented. The coding of Dynamic Pattern Matched for the identification of the characters, words and sentences in preparation for translation is discussed.

Application of Mobile Laser Scanning for Lean and Rapid Highway Maintenance and Construction

DOT National Transportation Integrated Search

2015-08-28

Mobile Terrestrial Laser Scanning (MTLS) is an emerging technology that combines the use of a laser scanner(s), the Global Navigation Satellite System (GNSS), and an Inertial Measurement Unit (IMU) on a vehicle to collect geo-spatial data. The overal...

Qualification of the RSRM case membrane case-to-insulation bondline inspection using the Thiokol Corporation ultrasonic RSRM bondline inspection system

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Qualification testing of Combustion Engineering's AMDATA Intraspect/98 Data Acquisition and Imaging System that applies to the redesigned solid rocket motor (RSRM) case membrane case-to-insulation bondline inspection was performed. Testing was performed at M-67, the Thiokol Corp. RSRM Assembly Facility. The purpose of the inspection was to verify the integrity of the case membrane case-to-insulation bondline. The case membrane scanner was calibrated on the redesigned solid rocket motor case segment calibration standard, which had an intentional 1.0 by 1.0 in. case-to-insulation unbond. The case membrane scanner was then used to scan a 20 by 20 in. membrane area of the case segment. Calibration of the scanner was then rechecked on the calibration standard to ensure that the calibration settings did not change during the case membrane scan. This procedure was successfully performed five times to qualify the unbond detection capability of the case membrane scanner.

The impact of realistic source shape and flexibility on source mask optimization

NASA Astrophysics Data System (ADS)

Aoyama, Hajime; Mizuno, Yasushi; Hirayanagi, Noriyuki; Kita, Naonori; Matsui, Ryota; Izumi, Hirohiko; Tajima, Keiichi; Siebert, Joachim; Demmerle, Wolfgang; Matsuyama, Tomoyuki

2013-04-01

Source mask optimization (SMO) is widely used to make state-of-the-art semiconductor devices in high volume manufacturing. To realize mature SMO solutions in production, the Intelligent Illuminator, which is an illumination system on Nikon scanner, is useful because it can provide generation of freeform sources with high fidelity to the target. Proteus SMO, which employs co-optimization method and an insertion of validation with mask 3D effect and resist properties for an accurate prediction of wafer printing, can take into account the properties of Intelligent Illuminator. We investigate an impact of the source properties on the SMO to pattern of a static-random access memory. Quality of a source made on the scanner compared to the SMO target is evaluated with in-situ measurement and aerial image simulation using its measurement data. Furthermore we discuss an evaluation of a universality of the source to use it in multiple scanners with a validation with estimated value of scanner errors.

Incorporation of a two metre long PET scanner in STIR

NASA Astrophysics Data System (ADS)

Tsoumpas, C.; Brain, C.; Dyke, T.; Gold, D.

2015-09-01

The Explorer project aims to investigate the potential benefits of a total-body 2 metre long PET scanner. The following investigation incorporates this scanner in STIR library and demonstrates the capabilities and weaknesses of existing reconstruction (FBP and OSEM) and single scatter simulation algorithms. It was found that sensible images are reconstructed but at the expense of high memory and processing time demands. FBP requires 4 hours on a core; OSEM: 2 hours per iteration if ran in parallel on 15-cores of a high performance computer. The single scatter simulation algorithm shows that on a short scale, up to a fifth of the scanner length, the assumption that the scatter between direct rings is similar to the scatter between the oblique rings is approximately valid. However, for more extreme cases this assumption is not longer valid, which illustrates that consideration of the oblique rings within the single scatter simulation will be necessary, if this scatter correction is the method of choice.

Reduction of thoracic aorta motion artifact with high-pitch 128-slice dual-source computed tomographic angiography: a historical control study.

PubMed

Nakagawa, Junichiro; Tasaki, Osamu; Watanabe, Yoshiyuki; Azuma, Takeo; Ohnishi, Mitsuo; Ukai, Isao; Tahara, Kenichi; Ogura, Hiroshi; Kuwagata, Yasuyuki; Hamasaki, Toshimitsu; Shimazu, Takeshi

2013-01-01

Electrocardiogram-gated imaging combined with multi-detector row computed tomography (MDCT) has reduced cardiac motion artifacts, but it was not practical in the emergency setting. The purpose of this study was to evaluate the ability of a high-pitch, 128-slice dual-source CT (DSCT) scanner to reduce motion artifacts in patients admitted to the emergency room. This study comprised 100 patients suspected of having thoracic aorta lesions. We examined 47 patients with the 128-slice DSCT scanner (DSCT group), and 53 patients were examined with a 64-slice MDCT scanner (MDCT group). Six anatomic areas in the thoracic aorta were evaluated. Computed tomography images in the DSCT group were distinct, and significant differences were observed in images of all areas between the 2 groups except for the descending aorta. The high-pitch DSCT scanner can reduce motion artifacts of the thoracic aorta and enable radiological diagnosis even in patients with tachycardia and without breath hold.

A dedicated breast-PET/CT scanner: Evaluation of basic performance characteristics.

PubMed

Raylman, Raymond R; Van Kampen, Will; Stolin, Alexander V; Gong, Wenbo; Jaliparthi, Gangadhar; Martone, Peter F; Smith, Mark F; Sarment, David; Clinthorne, Neal H; Perna, Mark

2018-04-01

Application of advanced imaging techniques, such as PET and x ray CT, can potentially improve detection of breast cancer. Unfortunately, both modalities have challenges in the detection of some lesions. The combination of the two techniques, however, could potentially lead to an overall improvement in diagnostic breast imaging. The purpose of this investigation is to test the basic performance of a new dedicated breast-PET/CT. The PET component consists of a rotating pair of detectors. Its performance was evaluated using the NEMA NU4-2008 protocols. The CT component utilizes a pulsed x ray source and flat panel detector mounted on the same gantry as the PET scanner. Its performance was assessed using specialized phantoms. The radiation dose to a breast during CT imaging was explored by the measurement of free-in-air kerma and air kerma measured at the center of a 16 cm-diameter PMMA cylinder. Finally, the combined capabilities of the system were demonstrated by imaging of a micro-hot-rod phantom. Overall, performance of the PET component is comparable to many pre-clinical and other dedicated breast-PET scanners. Its spatial resolution is 2.2 mm, 5 mm from the center of the scanner using images created with the single-sliced-filtered-backprojection algorithm. Peak NECR is 24.6 kcps; peak sensitivity is 1.36%; the scatter fraction is 27%. Spatial resolution of the CT scanner is 1.1 lp/mm at 10% MTF. The free-in-air kerma is 2.33 mGy, while the PMMA-air kerma is 1.24 mGy. Finally, combined imaging of a micro-hot-rod phantom illustrated the potential utility of the dual-modality images produced by the system. The basic performance characteristics of a new dedicated breast-PET/CT scanner are good, demonstrating that its performance is similar to current dedicated PET and CT scanners. The potential value of this system is the capability to produce combined duality-modality images that could improve detection of breast disease. The next stage in development of this system is testing with more advanced phantoms and human subjects. © 2018 American Association of Physicists in Medicine.

CT protocol management: simplifying the process by using a master protocol concept

PubMed Central

Bour, Robert K.; Rubert, Nicholas; Wendt, Gary; Pozniak, Myron; Ranallo, Frank N.

2015-01-01

This article explains a method for creating CT protocols for a wide range of patient body sizes and clinical indications, using detailed tube current information from a small set of commonly used protocols. Analytical expressions were created relating CT technical acquisition parameters which can be used to create new CT protocols on a given scanner or customize protocols from one scanner to another. Plots of mA as a function of patient size for specific anatomical regions were generated and used to identify the tube output needs for patients as a function of size for a single master protocol. Tube output data were obtained from the DICOM header of clinical images from our PACS and patient size was measured from CT localizer radiographs under IRB approval. This master protocol was then used to create 11 additional master protocols. The 12 master protocols were further combined to create 39 single and multiphase clinical protocols. Radiologist acceptance rate of exams scanned using the clinical protocols was monitored for 12,857 patients to analyze the effectiveness of the presented protocol management methods using a two‐tailed Fisher's exact test. A single routine adult abdominal protocol was used as the master protocol to create 11 additional master abdominal protocols of varying dose and beam energy. Situations in which the maximum tube current would have been exceeded are presented, and the trade‐offs between increasing the effective tube output via 1) decreasing pitch, 2) increasing the scan time, or 3) increasing the kV are discussed. Out of 12 master protocols customized across three different scanners, only one had a statistically significant acceptance rate that differed from the scanner it was customized from. The difference, however, was only 1% and was judged to be negligible. All other master protocols differed in acceptance rate insignificantly between scanners. The methodology described in this paper allows a small set of master protocols to be adapted among different clinical indications on a single scanner and among different CT scanners. PACS number: 87.57.Q PMID:26219005

SU-E-T-135: Investigation of Commercial-Grade Flatbed Scanners and a Medical- Grade Scanner for Radiochromic EBT Film Dosimetry.

PubMed

Syh, J; Patel, B; Syh, J; Wu, H; Rosen, L; Durci, M; Katz, S; Sibata, C

2012-06-01

To evaluate the characteristics of commercial-grade flatbed scanners and medical-grade scanners for radiochromic EBT film dosimetry. Performance aspects of a Vidar Dosimetry Pro Advantage (Red), Epson 750 Pro, Microtek ArtixScan 1800f, and Microtek ScanMaker 8700 scanner for EBT2 Gafchromic film were evaluated in the categories of repeatability, maximum distinguishable optical density (OD) differentiation, OD variance, and dose curve characteristics. OD step film by Stouffer Industries containing 31 steps ranging from 0.05 to 3.62 OD was used. EBT films were irradiated with dose ranging from 20 to 600 cGy in 6×6 cm 2 field sizes and analyzed 24 hours later using RIT113 and Tomotherapy Film Analyzer software. Scans were performed in transmissive mode, landscape orientation, 16-bit image. The mean and standard deviation Analog to Digital (A/D) scanner value was measured by selecting a 3×3 mm 2 uniform area in the central region of each OD step from a total of 20 scans performed over several weeks. Repeatability was determined from the variance of OD step 0.38. Maximum distinguishable OD was defined as the last OD step whose range of A/D values does not overlap with its neighboring step. Repeatability uncertainty ranged from 0.1% for Vidar to 4% for Epson. Average standard deviation of OD steps ranged from 0.21% for Vidar to 6.4% for ArtixScan 1800f. Maximum distinguishable optical density ranged from 3.38 for Vidar to 1.32 for ScanMaker 8700. A/D range of each OD step corresponds to a dose range. Dose ranges of OD steps varied from 1% for Vidar to 20% for ScanMaker 8700. The Vidar exhibited a dose curve that utilized a broader range of OD values than the other scanners. Vidar exhibited higher maximum distinguishable OD, smaller variance in repeatability, smaller A/D value deviation per OD step, and a shallower dose curve with respect to OD. © 2012 American Association of Physicists in Medicine.

Evaluation and implementation of triple‐channel radiochromic film dosimetry in brachytherapy

PubMed Central

Bradley, David; Nisbet, Andrew

2014-01-01

The measurement of dose distributions in clinical brachytherapy, for the purpose of quality control, commissioning or dosimetric audit, is challenging and requires development. Radiochromic film dosimetry with a commercial flatbed scanner may be suitable, but careful methodologies are required to control various sources of uncertainty. Triple‐channel dosimetry has recently been utilized in external beam radiotherapy to improve the accuracy of film dosimetry, but its use in brachytherapy, with characteristic high maximum doses, steep dose gradients, and small scales, has been less well researched. We investigate the use of advanced film dosimetry techniques for brachytherapy dosimetry, evaluating uncertainties and assessing the mitigation afforded by triple‐channel dosimetry. We present results on postirradiation film darkening, lateral scanner effect, film surface perturbation, film active layer thickness, film curling, and examples of the measurement of clinical brachytherapy dose distributions. The lateral scanner effect in brachytherapy film dosimetry can be very significant, up to 23% dose increase at 14 Gy, at ± 9 cm lateral from the scanner axis for simple single‐channel dosimetry. Triple‐channel dosimetry mitigates the effect, but still limits the useable width of a typical scanner to less than 8 cm at high dose levels to give dose uncertainty to within 1%. Triple‐channel dosimetry separates dose and dose‐independent signal components, and effectively removes disturbances caused by film thickness variation and surface perturbations in the examples considered in this work. The use of reference dose films scanned simultaneously with brachytherapy test films is recommended to account for scanner variations from calibration conditions. Postirradiation darkening, which is a continual logarithmic function with time, must be taken into account between the reference and test films. Finally, films must be flat when scanned to avoid the Callier‐like effects and to provide reliable dosimetric results. We have demonstrated that radiochromic film dosimetry with GAFCHROMIC EBT3 film and a commercial flatbed scanner is a viable method for brachytherapy dose distribution measurement, and uncertainties may be reduced with triple‐channel dosimetry and specific film scan and evaluation methodologies. PACS numbers: 87.55.Qr, 87.56.bg, 87.55.km PMID:25207417

SU-F-T-578: Characterization of Vidar DosimetryPro Advantage RED Scanner with Application to SBRT and SRS QA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumas, M; Wen, N

Purpose: To use Gafchromic EBT3 film to quantify key dosimetric characteristics of the Vidar DosimetryPro Advantage RED film scanner for use in SBRT/SRS QA, by analyzing scanner uniformity and dose sensitivity. Method: Gafchromic EBT3 film was used in this study. Films were irradiated using 6MV FFF and 10MV FFF beams from a Varian Edge linear accelerator, with setup of 100cm SAD at depth 5 cm. Nine doses were delivered per film, with calibration dose ranges of 1–10 Gy and 3–24 Gy for 6MV FFF, and 3–27 Gy for 10MV FFF. Films were scanned with the long side of the filmmore » parallel to the detector array. Dose calibration curves were fitted to a 3rd degree polynomial. The derivative of a calibration curve was taken to determine the scanner’s sensitivity per dose delivered (OD/Gy). Scanner non-uniformity was calculated in 2 dimensions by taking the mean of standard deviation in each row and column. Absolute dose SRS/SBRT Gamma analyses were performed with passing criteria of 3% and 1mm DTA. For comparison, Gamma analyses were also performed using an Epson Expression 10000 XL. Results: Uniformity for the Vidar scanner was 0.37% +/− 0.03% in the perpendicular to scan direction and 0.67% +/− 0.05% in the parallel to scan direction, with an overall uniformity of 0.52% +/− 0.03%. Epson red channel uniformity was 0.85% +/− 0.05% and 0.88% +/− 0.08% for the green channel. The Vidar average dose sensitivity from 1–10 Gy was 0.112 OD/Gy and 0.061 OD/Gy for 3–24 Gy. SBRT/SRS Gamma pass rates were 97.8 +/− 1.4 for Vidar and 97.5 +/− 1.4 for Epson. Conclusion: The Vidar scanner has 41% less non-uniformity compared to Epson XL10000 green channel. The dose sensitivity is 2–3 time greater for the Vidar scanner compared to the Epson in the SRS/SBRT dose range of 5–24 Gy.« less

Calibration and assessment of channel-specific biases in microarray data with extended dynamical range.

PubMed

Bengtsson, Henrik; Jönsson, Göran; Vallon-Christersson, Johan

2004-11-12

Non-linearities in observed log-ratios of gene expressions, also known as intensity dependent log-ratios, can often be accounted for by global biases in the two channels being compared. Any step in a microarray process may introduce such offsets and in this article we study the biases introduced by the microarray scanner and the image analysis software. By scanning the same spotted oligonucleotide microarray at different photomultiplier tube (PMT) gains, we have identified a channel-specific bias present in two-channel microarray data. For the scanners analyzed it was in the range of 15-25 (out of 65,535). The observed bias was very stable between subsequent scans of the same array although the PMT gain was greatly adjusted. This indicates that the bias does not originate from a step preceding the scanner detector parts. The bias varies slightly between arrays. When comparing estimates based on data from the same array, but from different scanners, we have found that different scanners introduce different amounts of bias. So do various image analysis methods. We propose a scanning protocol and a constrained affine model that allows us to identify and estimate the bias in each channel. Backward transformation removes the bias and brings the channels to the same scale. The result is that systematic effects such as intensity dependent log-ratios are removed, but also that signal densities become much more similar. The average scan, which has a larger dynamical range and greater signal-to-noise ratio than individual scans, can then be obtained. The study shows that microarray scanners may introduce a significant bias in each channel. Such biases have to be calibrated for, otherwise systematic effects such as intensity dependent log-ratios will be observed. The proposed scanning protocol and calibration method is simple to use and is useful for evaluating scanner biases or for obtaining calibrated measurements with extended dynamical range and better precision. The cross-platform R package aroma, which implements all described methods, is available for free from http://www.maths.lth.se/bioinformatics/.

SU-E-I-17: Evaluation of Commercially Available Extension Plates for the ACR CT Accreditation Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene-Donnelly, K; Ogden, K

Purpose: To evaluate the impact of commercially available extension plates on Hounsfield Unit (HU) values in the ACR CT accreditation phantom (Model 464, Gammex Inc., Middleton, Wi). The extension plates are intended to improve water HU values in scanners where the traditional solution involves scanning the phantom with an adjacent water or CTDI phantom. Methods: The Model 464 phantom was scanned on 9 different CT scanners at 8 separate sites representing 16 and 64 slice MDCT technology from four CT manufacturers. The phantom was scanned with and without the extension plates (Gammex 464 EXTPLT-KIT) in helical and axial modes. Amore » water phantom was also scanned to verify water HU calibration. Technique was 120 kV tube potential, 350 mAs, and 210 mm display field of view. Slice thickness and reconstruction algorithm were based on site clinical protocols. The widest available beam collimation was used. Regions of interest were drawn on the HU test objects in Module 1 of the phantom and mean values recorded. Results: For all axial mode scans, water HU values were within limits with or without the extension plates. For two scanners (both Lightspeed VCT, GE Medical Systems, Waukesha WI), axial mode bone HU values were above the specified range both with and without the extension plates though they were closer to the specified range with the plates installed. In helical scan mode, two scanners (both GE Lightspeed VCT) had water HU values above the specified range without the plates installed. With the plates installed, the water HU values were within range for all scanners in all scan modes. Conclusion: Using the plates, the Lightspeed VCT scanners passed the water HU test when scanning in helical mode. The benefit of the extension plates was evident in helical mode scanning with GE scanners using a nominal 4 cm beam. Disclosure: The extension plates evaluated in this work were provided free of charge to the authors. The authors have no other financial interest in Gammex Inc.« less

Impact of detector design on imaging performance of a long axial field-of-view, whole-body PET scanner

NASA Astrophysics Data System (ADS)

Surti, S.; Karp, J. S.

2015-07-01

Current generation of commercial time-of-flight (TOF) PET scanners utilize 20-25 mm thick LSO or LYSO crystals and have an axial FOV (AFOV) in the range of 16-22 mm. Longer AFOV scanners would provide increased intrinsic sensitivity and require fewer bed positions for whole-body imaging. Recent simulation work has investigated the sensitivity gains that can be achieved with these long AFOV scanners, and has motivated new areas of investigation such as imaging with a very low dose of injected activity as well as providing whole-body dynamic imaging capability in one bed position. In this simulation work we model a 72 cm long scanner and prioritize the detector design choices in terms of timing resolution, crystal size (spatial resolution), crystal thickness (detector sensitivity), and depth-of-interaction (DOI) measurement capability. The generated list data are reconstructed with a list-mode OSEM algorithm using a Gaussian TOF kernel that depends on the timing resolution and blob basis functions for regularization. We use lesion phantoms and clinically relevant metrics for lesion detectability and contrast measurement. The scan time was fixed at 10 min for imaging a 100 cm long object assuming a 50% overlap between adjacent bed positions. Results show that a 72 cm long scanner can provide a factor of ten reduction in injected activity compared to an identical 18 cm long scanner to get equivalent lesion detectability. While improved timing resolution leads to further gains, using 3 mm (as opposed to 4 mm) wide crystals does not show any significant benefits for lesion detectability. A detector providing 2-level DOI information with equal crystal thickness also does not show significant gains. Finally, a 15 mm thick crystal leads to lower lesion detectability than a 20 mm thick crystal when keeping all other detector parameters (crystal width, timing resolution, and DOI capability) the same. However, improved timing performance with 15 mm thick crystals can provide similar or better performance than that achieved by a detector using 20 mm thick crystals.

Estimation of the weighted CTDI{sub {infinity}} for multislice CT examinations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Xinhua; Zhang Da; Liu, Bob

2012-02-15

Purpose: The aim of this study was to examine the variations of CT dose index (CTDI) efficiencies, {epsilon}(CTDI{sub 100})=CTDI{sub 100}/CTDI{sub {infinity}}, with bowtie filters and CT scanner types. Methods: This was an extension of our previous study [Li, Zhang, and Liu, Phys. Med. Biol. 56, 5789-5803 (2011)]. A validated Monte Carlo program was used to calculate {epsilon}(CTDI{sub 100}) on a Siemens Somatom Definition scanner. The {epsilon}(CTDI{sub 100}) dependencies on tube voltages and beam widths were tested in previous studies. The influences of different bowtie filters and CT scanner types were examined in this work. The authors tested the variations ofmore » {epsilon}(CTDI{sub 100}) with bowtie filters on the Siemens Definition scanner. The authors also analyzed the published CTDI measurements of four independent studies on five scanners of four models from three manufacturers. Results: On the Siemens Definition scanner, the difference in {epsilon}(CTDI{sub W}) between using the head and body bowtie filters was 2.5% (maximum) in the CT scans of the 32-cm phantom, and 1.7% (maximum) in the CT scans of the 16-cm phantom. Compared with CTDI{sub W}, the weighted CTDI{sub {infinity}} increased by 30.5% (on average) in the 32-cm phantom, and by 20.0% (on average) in the 16-cm phantom. These results were approximately the same for 80-140 kV and 1-40 mm beam widths (4.2% maximum deviation). The differences in {epsilon}(CTDI{sub 100}) between the simulations and the direct measurements of four previous studies were 1.3%-5.0% at the center/periphery of the 16-cm/32-cm phantom (on average). Conclusions: Compared with CTDI{sub vol}, the equilibrium dose for large scan lengths is 30.5% higher in the 32-cm phantom, and is 20.0% higher in the 16-cm phantom. The relative increases are practically independent of tube voltages (80-140 kV), beam widths (up to 4 cm), and the CT scanners covered in this study.« less

People counting and re-identification using fusion of video camera and laser scanner

NASA Astrophysics Data System (ADS)

Ling, Bo; Olivera, Santiago; Wagley, Raj

2016-05-01

We present a system for people counting and re-identification. It can be used by transit and homeland security agencies. Under FTA SBIR program, we have developed a preliminary system for transit passenger counting and re-identification using a laser scanner and video camera. The laser scanner is used to identify the locations of passenger's head and shoulder in an image, a challenging task in crowed environment. It can also estimate the passenger height without prior calibration. Various color models have been applied to form color signatures. Finally, using a statistical fusion and classification scheme, passengers are counted and re-identified.

Earth Radiation Budget Experiment (ERBE) scanner instrument anomaly investigation

NASA Technical Reports Server (NTRS)

Watson, N. D.; Miller, J. B.; Taylor, L. V.; Lovell, J. B.; Cox, J. W.; Fedors, J. C.; Kopia, L. P.; Holloway, R. M.; Bradley, O. H.

1985-01-01

The results of an ad-hoc committee investigation of in-Earth orbit operational anomalies noted on two identical Earth Radiation Budget Experiment (ERBE) Scanner instruments on two different spacecraft busses is presented. The anomalies are attributed to the bearings and the lubrication scheme for the bearings. A detailed discussion of the pertinent instrument operations, the approach of the investigation team and the current status of the instruments now in Earth orbit is included. The team considered operational changes for these instruments, rework possibilities for the one instrument which is waiting to be launched, and preferable lubrication considerations for specific space operational requirements similar to those for the ERBE scanner bearings.

Note: Low-temperature scanning tunneling microscope with detachable scanner and reliable transfer mechanism for tip and sample exchange

NASA Astrophysics Data System (ADS)

Ge, Weifeng; Wang, Jihao; Wang, Junting; Zhang, Jing; Hou, Yubin; Lu, Qingyou

2017-12-01

A homebuilt low-temperature scanning tunneling microscope (STM) featuring a detachable scanner based on a double slider design, along with a reliable transfer mechanism for tip and sample exchange, is present. The coarse motor is decoupled from the scanner, which prevents the motor instabilities including vibrations and drifts from entering the tip-sample loop and thus improves the performance of the STM. In addition, in situ exchange of tips and samples can be implemented easily and reliably using a winch-type transfer mechanism. Atomically resolved images on graphite are demonstrated to show the performance of the proposed STM.

X-ray imaging physics for nuclear medicine technologists. Part 2: X-ray interactions and image formation.

PubMed

Seibert, J Anthony; Boone, John M

2005-03-01

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. In part 1, the production and characteristics of x-rays were reviewed. In this article, the principles of x-ray interactions and image formation are discussed, in preparation for a general review of CT (part 3) and a more detailed investigation of PET/CT scanners in part 4.

The conical scanner evaluation system design

NASA Technical Reports Server (NTRS)

Cumella, K. E.; Bilanow, S.; Kulikov, I. B.

1982-01-01

The software design for the conical scanner evaluation system is presented. The purpose of this system is to support the performance analysis of the LANDSAT-D conical scanners, which are infrared horizon detection attitude sensors designed for improved accuracy. The system consists of six functionally independent subsystems and five interface data bases. The system structure and interfaces of each of the subsystems is described and the content, format, and file structure of each of the data bases is specified. For each subsystem, the functional logic, the control parameters, the baseline structure, and each of the subroutines are described. The subroutine descriptions include a procedure definition and the input and output parameters.

Providing Situational Awareness for Pipeline Control Operations

NASA Astrophysics Data System (ADS)

Butts, Jonathan; Kleinhans, Hugo; Chandia, Rodrigo; Papa, Mauricio; Shenoi, Sujeet

A SCADA system for a single 3,000-mile-long strand of oil or gas pipeline may employ several thousand field devices to measure process parameters and operate equipment. Because of the vital tasks performed by these sensors and actuators, pipeline operators need accurate and timely information about their status and integrity. This paper describes a realtime scanner that provides situational awareness about SCADA devices and control operations. The scanner, with the assistance of lightweight, distributed sensors, analyzes SCADA network traffic, verifies the operational status and integrity of field devices, and identifies anomalous activity. Experimental results obtained using real pipeline control traffic demonstrate the utility of the scanner in industrial settings.

A report on the use of thermal scanner data in an operational program for monitoring apparent rooftop temperatures

NASA Technical Reports Server (NTRS)

Bjorklund, J.; Schmer, F. A.; Isakson, R. E.

1975-01-01

CENGAS, a division of Central Telephone and Utilities Corporation in cooperation with the Remote Sensing Institute, South Dakota State University, is using airborne thermal scanner data to monitor relative rooftop temperatures. Four Nebraska communities and one South Dakota community were surveyed by the Remote Sensing Institute for CENGAS. Thermal scanner data were converted to a film format and the resultant imagery has been successfully employed by CENGAS. The program places emphasis on heat losses resulting from inadequate home insulation, offers CENGAS customers the opportunity to observe a thermogram of their rooftop, and assists homeowners in evaluating insulation needs.

Note: Low-temperature scanning tunneling microscope with detachable scanner and reliable transfer mechanism for tip and sample exchange.

PubMed

Ge, Weifeng; Wang, Jihao; Wang, Junting; Zhang, Jing; Hou, Yubin; Lu, Qingyou

2017-12-01

A homebuilt low-temperature scanning tunneling microscope (STM) featuring a detachable scanner based on a double slider design, along with a reliable transfer mechanism for tip and sample exchange, is present. The coarse motor is decoupled from the scanner, which prevents the motor instabilities including vibrations and drifts from entering the tip-sample loop and thus improves the performance of the STM. In addition, in situ exchange of tips and samples can be implemented easily and reliably using a winch-type transfer mechanism. Atomically resolved images on graphite are demonstrated to show the performance of the proposed STM.

21 CFR 882.1925 - Ultrasonic scanner calibration test block.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ultrasonic scanner calibration test block. 882.1925 Section 882.1925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1925...

Description of algorithms for processing Coastal Zone Color Scanner (CZCS) data

NASA Technical Reports Server (NTRS)

Zion, P. M.

1983-01-01

The algorithms for processing coastal zone color scanner (CZCS) data to geophysical units (pigment concentration) are described. Current public domain information for processing these data is summarized. Calibration, atmospheric correction, and bio-optical algorithms are presented. Three CZCS data processing implementations are compared.

Development and testing of laser Doppler system components for wake vortex monitoring. Volume 2: Scanner operations manual

NASA Technical Reports Server (NTRS)

Edwards, B. B.; Coffey, E. W.

1974-01-01

The theory and operation of the scanner portion of the laser Doppler system for detecting and monitoring aircraft trailing vortices in an airport environment are discussed. Schematics, wiring diagrams, component values, and operation and checkout procedures are included.

A Field Study of an Iris Identification System

DTIC Science & Technology

2008-05-01

conducted a field trial of a commercial iris identification scanner at the US Navy Fleet Numerical Meterology and Oceanography Center (FNMOC) in...identification scanner at the US Navy Fleet Numerical Meterology and Oceanography Center (FNMOC) in Mon- terey, CA. Scans were performed by US military guards

Survey of computed tomography scanners in Taiwan: Dose descriptors, dose guidance levels, and effective doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, H. Y.; Tung, C. J.; Yu, C. C.

2007-04-15

The IAEA and the ICRP recommended dose guidance levels for the most frequent computed tomography (CT) examinations to promote strategies for the optimization of radiation dose to CT patients. A national survey, including on-site measurements and questionnaires, was conducted in Taiwan in order to establish dose guidance levels and evaluate effective doses for CT. The beam quality and output and the phantom doses were measured for nine representative CT scanners. Questionnaire forms were completed by respondents from facilities of 146 CT scanners out of 285 total scanners. Information on patient, procedure, scanner, and technique for the head and body examinationsmore » was provided. The weighted computed tomography dose index (CTDI{sub w}), the dose length product (DLP), organ doses and effective dose were calculated using measured data, questionnaire information and Monte Carlo simulation results. A cost-effective analysis was applied to derive the dose guidance levels on CTDI{sub w} and DLP for several CT examinations. The mean effective dose{+-}standard deviation distributes from 1.6{+-}0.9 mSv for the routine head examination to 13{+-}11 mSv for the examination of liver, spleen, and pancreas. The surveyed results and the dose guidance levels were provided to the national authorities to develop quality control standards and protocols for CT examinations.« less

Development of a Compact Optical-MEMS Scanner with Integrated VCSEL Light Source and Diffractive Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven

1999-06-30

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOEs) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysiliconmore » gold-coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 500 {micro}m x 1000 {micro}m shuttle is extremely low, with a maximum deflection of only 0.18{micro}m over an 800 {micro}m span for an unmetallized case and a deflection of 0.56{micro}m for the metallized case. A conservative estimate for the scan range is {approximately}{+-}4{degree}, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.« less

Development of proton computed tomography detectors for applications in hadron therapy

NASA Astrophysics Data System (ADS)

Bashkirov, Vladimir A.; Johnson, Robert P.; Sadrozinski, Hartmut F.-W.; Schulte, Reinhard W.

2016-02-01

Radiation therapy with protons and heavier ions is an attractive form of cancer treatment that could enhance local control and survival of cancers that are currently difficult to cure and lead to less side effects due to sparing of normal tissues. However, particle therapy faces a significant technical challenge because one cannot accurately predict the particle range in the patient using data provided by existing imaging technologies. Proton computed tomography (pCT) is an emerging imaging modality capable of improving the accuracy of range prediction. In this paper, we describe the successive pCT scanners designed and built by our group with the goal to support particle therapy treatment planning and image guidance by reconstructing an accurate 3D map of the stopping power relative to water in patient tissues. The pCT scanners we have built to date consist of silicon telescopes, which track the proton before and after the object to be reconstructed, and an energy or range detector, which measures the residual energy and/or range of the protons used to evaluate the water equivalent path length (WEPL) of each proton in the object. An overview of a decade-long evolution of the conceptual design of pCT scanners and their calibration is given. Results of scanner performance tests are presented, which demonstrate that the latest pCT scanner approaches readiness for clinical applications in hadron therapy.

Ultrafast axial scanning for two-photon microscopy via a digital micromirror device and binary holography.

PubMed

Cheng, Jiyi; Gu, Chenglin; Zhang, Dapeng; Wang, Dien; Chen, Shih-Chi

2016-04-01

In this Letter, we present an ultrafast nonmechanical axial scanning method for two-photon excitation (TPE) microscopy based on binary holography using a digital micromirror device (DMD), achieving a scanning rate of 4.2 kHz, scanning range of ∼180  μm, and scanning resolution (minimum step size) of ∼270  nm. Axial scanning is achieved by projecting the femtosecond laser to a DMD programmed with binary holograms of spherical wavefronts of increasing/decreasing radii. To guide the scanner design, we have derived the parametric relationships between the DMD parameters (i.e., aperture and pixel size), and the axial scanning characteristics, including (1) maximum optical power, (2) minimum step size, and (3) scan range. To verify the results, the DMD scanner is integrated with a custom-built TPE microscope that operates at 60 frames per second. In the experiment, we scanned a pollen sample via both the DMD scanner and a precision z-stage. The results show the DMD scanner generates images of equal quality throughout the scanning range. The overall efficiency of the TPE system was measured to be ∼3%. With the high scanning rate, the DMD scanner may find important applications in random-access imaging or high-speed volumetric imaging that enables visualization of highly dynamic biological processes in 3D with submillisecond temporal resolution.

Enabling automated magnetic resonance imaging-based targeting assessment during dipole field navigation

NASA Astrophysics Data System (ADS)

Latulippe, Maxime; Felfoul, Ouajdi; Dupont, Pierre E.; Martel, Sylvain

2016-02-01

The magnetic navigation of drugs in the vascular network promises to increase the efficacy and reduce the secondary toxicity of cancer treatments by targeting tumors directly. Recently, dipole field navigation (DFN) was proposed as the first method achieving both high field and high navigation gradient strengths for whole-body interventions in deep tissues. This is achieved by introducing large ferromagnetic cores around the patient inside a magnetic resonance imaging (MRI) scanner. However, doing so distorts the static field inside the scanner, which prevents imaging during the intervention. This limitation constrains DFN to open-loop navigation, thus exposing the risk of a harmful toxicity in case of a navigation failure. Here, we are interested in periodically assessing drug targeting efficiency using MRI even in the presence of a core. We demonstrate, using a clinical scanner, that it is in fact possible to acquire, in specific regions around a core, images of sufficient quality to perform this task. We show that the core can be moved inside the scanner to a position minimizing the distortion effect in the region of interest for imaging. Moving the core can be done automatically using the gradient coils of the scanner, which then also enables the core to be repositioned to perform navigation to additional targets. The feasibility and potential of the approach are validated in an in vitro experiment demonstrating navigation and assessment at two targets.

Cross-calibration of Fuji TR image plate and RAR 2492 x-ray film to determine the response of a DITABIS Super Micron image plate scanner

NASA Astrophysics Data System (ADS)

Dunham, G.; Harding, E. C.; Loisel, G. P.; Lake, P. W.; Nielsen-Weber, L. B.

2016-11-01

Fuji TR image plate is frequently used as a replacement detector medium for x-ray imaging and spectroscopy diagnostics at NIF, Omega, and Z facilities. However, the familiar Fuji BAS line of image plate scanners is no longer supported by the industry, and so a replacement scanning system is needed. While the General Electric Typhoon line of scanners could replace the Fuji systems, the shift away from photo stimulated luminescence units to 16-bit grayscale Tag Image File Format (TIFF) leaves a discontinuity when comparing data collected from both systems. For the purposes of quantitative spectroscopy, a known unit of intensity applied to the grayscale values of the TIFF is needed. The DITABIS Super Micron image plate scanning system was tested and shown to potentially rival the resolution and dynamic range of Kodak RAR 2492 x-ray film. However, the absolute sensitivity of the scanner is unknown. In this work, a methodology to cross calibrate Fuji TR image plate and the absolutely calibrated Kodak RAR 2492 x-ray film is presented. Details of the experimental configurations used are included. An energy dependent scale factor to convert Fuji TR IP scanned on a DITABIS Super Micron scanner from 16-bit grayscale TIFF to intensity units (i.e., photons per square micron) is discussed.

Cross-calibration of Fuji TR image plate and RAR 2492 x-ray film to determine the response of a DITABIS Super Micron image plate scanner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunham, G., E-mail: gsdunha@sandia.gov; Harding, E. C.; Loisel, G. P.

Fuji TR image plate is frequently used as a replacement detector medium for x-ray imaging and spectroscopy diagnostics at NIF, Omega, and Z facilities. However, the familiar Fuji BAS line of image plate scanners is no longer supported by the industry, and so a replacement scanning system is needed. While the General Electric Typhoon line of scanners could replace the Fuji systems, the shift away from photo stimulated luminescence units to 16-bit grayscale Tag Image File Format (TIFF) leaves a discontinuity when comparing data collected from both systems. For the purposes of quantitative spectroscopy, a known unit of intensity appliedmore » to the grayscale values of the TIFF is needed. The DITABIS Super Micron image plate scanning system was tested and shown to potentially rival the resolution and dynamic range of Kodak RAR 2492 x-ray film. However, the absolute sensitivity of the scanner is unknown. In this work, a methodology to cross calibrate Fuji TR image plate and the absolutely calibrated Kodak RAR 2492 x-ray film is presented. Details of the experimental configurations used are included. An energy dependent scale factor to convert Fuji TR IP scanned on a DITABIS Super Micron scanner from 16-bit grayscale TIFF to intensity units (i.e., photons per square micron) is discussed.« less

21 CFR 862.2400 - Densitometer/scanner (integrating, reflectance, TLC, or radiochromatogram) for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., TLC, or radiochromatogram) for clinical use. 862.2400 Section 862.2400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2400 Densitometer/scanner (integrating...

A preliminary report of multispectral scanner data from the Cleveland harbor study

NASA Technical Reports Server (NTRS)

Shook, D.; Raquet, C.; Svehla, R.; Wachter, D.; Salzman, J.; Coney, T.; Gedney, D.

1975-01-01

Imagery obtained from an airborne multispectral scanner is presented. A synoptic view of the entire study area is shown for a number of time periods and for a number of spectral bands. Using several bands, sediment distributions, thermal plumes, and Rhodamine B dye distributions are shown.

Speech Perception in MRI Scanner Noise by Persons with Aphasia

ERIC Educational Resources Information Center

Healy, Eric W.; Moser, Dana C.; Morrow-Odom, K. Leigh; Hall, Deborah A.; Fridriksson, Julius

2007-01-01

Purpose: To examine reductions in performance on auditory tasks by aphasic and neurologically intact individuals as a result of concomitant magnetic resonance imaging (MRI) scanner noise. Method: Four tasks together forming a continuum of linguistic complexity were developed. They included complex-tone pitch discrimination, same-different…

Laser excited confocal microscope fluorescence scanner and method

DOEpatents

Mathies, Richard A.; Peck, Konan

1992-01-01

A fluorescent scanner for scanning the fluorescence from a fluorescence labeled separated sample on a sample carrier including a confocal microscope for illuminating a predetermined volume of the sample carrier and/or receiving and processing fluorescence emissions from said volume to provide a display of the separated sample.

21 CFR 892.1330 - Nuclear whole body scanner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear whole body scanner. 892.1330 Section 892.1330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... respect to the patient. This generic type of device may include signal analysis and display equipment...

21 CFR 892.1300 - Nuclear rectilinear scanner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear rectilinear scanner. 892.1300 Section 892.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... the patient. This generic type of device may include signal analysis and display equipment, patient...

21 CFR 892.1330 - Nuclear whole body scanner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear whole body scanner. 892.1330 Section 892.1330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... respect to the patient. This generic type of device may include signal analysis and display equipment...

21 CFR 892.1300 - Nuclear rectilinear scanner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear rectilinear scanner. 892.1300 Section 892.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... the patient. This generic type of device may include signal analysis and display equipment, patient...

21 CFR 892.1330 - Nuclear whole body scanner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear whole body scanner. 892.1330 Section 892.1330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... respect to the patient. This generic type of device may include signal analysis and display equipment...

21 CFR 892.1300 - Nuclear rectilinear scanner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear rectilinear scanner. 892.1300 Section 892.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... the patient. This generic type of device may include signal analysis and display equipment, patient...

Information content of data from the LANDSAT-4 Thematic Mapper (TM) and multispectral scanner (MSS)

NASA Technical Reports Server (NTRS)

Price, J. C.

1983-01-01

The progress of an investigation to quantify the increased information content of thematic mapper (TM) data as compared to that from the LANDSAT 4 multispectral scanner (MSS) is reported. Two night infrared images were examined and compared with Heat Capacity Mapping Mission data.

29 CFR 1918.1 - Scope and application.

Code of Federal Regulations, 2011 CFR

2011-07-01

... commercial vessel radar transmitters are considered hazardous under the following situations: (a) Where the radar is transmitting, the scanner is stationary, and the exposure distance is 19 feet (5.79 m) or less; or (b) where the radar is transmitting, the scanner is rotating, and the exposure distance is 5 feet...

29 CFR 1918.1 - Scope and application.

Code of Federal Regulations, 2012 CFR

2012-07-01

... commercial vessel radar transmitters are considered hazardous under the following situations: (a) Where the radar is transmitting, the scanner is stationary, and the exposure distance is 19 feet (5.79 m) or less; or (b) where the radar is transmitting, the scanner is rotating, and the exposure distance is 5 feet...

29 CFR 1918.1 - Scope and application.

Code of Federal Regulations, 2013 CFR

2013-07-01

... commercial vessel radar transmitters are considered hazardous under the following situations: (a) Where the radar is transmitting, the scanner is stationary, and the exposure distance is 19 feet (5.79 m) or less; or (b) where the radar is transmitting, the scanner is rotating, and the exposure distance is 5 feet...

29 CFR 1918.1 - Scope and application.

Code of Federal Regulations, 2014 CFR

2014-07-01

... commercial vessel radar transmitters are considered hazardous under the following situations: (a) Where the radar is transmitting, the scanner is stationary, and the exposure distance is 19 feet (5.79 m) or less; or (b) where the radar is transmitting, the scanner is rotating, and the exposure distance is 5 feet...

NREL Develops High-Speed Scanner to Monitor Fuel Cell Material Defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-09-01

This highlight describes results of recent work in which polymer electrolyte membrane fuel cell electrodes with intentionally introduced known defects were imaged and analyzed using a fuel cell scanner recently developed at NREL. The highlight is being developed for the September 2015 Alliance S&T Board meeting.

Quantitative imaging of peripheral trabecular bone microarchitecture using MDCT.

PubMed

Chen, Cheng; Zhang, Xiaoliu; Guo, Junfeng; Jin, Dakai; Letuchy, Elena M; Burns, Trudy L; Levy, Steven M; Hoffman, Eric A; Saha, Punam K

2018-01-01

Osteoporosis associated with reduced bone mineral density (BMD) and microarchitectural changes puts patients at an elevated risk of fracture. Modern multidetector row CT (MDCT) technology, producing high spatial resolution at increasingly lower dose radiation, is emerging as a viable modality for trabecular bone (Tb) imaging. Wide variation in CT scanners raises concerns of data uniformity in multisite and longitudinal studies. A comprehensive cadaveric study was performed to evaluate MDCT-derived Tb microarchitectural measures. A human pilot study was performed comparing continuity of Tb measures estimated from two MDCT scanners with significantly different image resolution features. Micro-CT imaging of cadaveric ankle specimens (n=25) was used to examine the validity of MDCT-derived Tb microarchitectural measures. Repeat scan reproducibility of MDCT-based Tb measures and their ability to predict mechanical properties were examined. To assess multiscanner data continuity of Tb measures, the distal tibias of 20 volunteers (age:26.2±4.5Y,10F) were scanned using the Siemens SOMATOM Definition Flash and the higher resolution Siemens SOMATOM Force scanners with an average 45-day time gap between scans. The correlation of Tb measures derived from the two scanners over 30% and 60% peel regions at the 4% to 8% of distal tibia was analyzed. MDCT-based Tb measures characterizing bone network area density, plate-rod microarchitecture, and transverse trabeculae showed good correlations (r∈0.85,0.92) with the gold standard micro-CT-derived values of matching Tb measures. However, other MDCT-derived Tb measures characterizing trabecular thickness and separation, erosion index, and structure model index produced weak correlation (r<0.8) with their micro-CT-derived values. Most MDCT Tb measures were found repeatable (ICC∈0.94,0.98). The Tb plate-width measure showed a strong correlation (r = 0.89) with experimental yield stress, while the transverse trabecular measure produced the highest correlation (r = 0.81) with Young's modulus. The data continuity experiment showed that, despite significant differences in image resolution between two scanners (10% MTF along xy-plane and z-direction - Flash: 16.2 and 17.9 lp/cm; Force: 24.8 and 21.0 lp/cm), most Tb measures had high Pearson correlations (r > 0.95) between values estimated from the two scanners. Relatively lower correlation coefficients were observed for the bone network area density (r = 0.91) and Tb separation (r = 0.93) measures. Most MDCT-derived Tb microarchitectural measures are reproducible and their values derived from two scanners strongly correlate with each other as well as with bone strength. This study has highlighted those MDCT-derived measures which show the greatest promise for characterization of bone network area density, plate-rod and transverse trabecular distributions with a good correlation (r ≥ 0.85) compared with their micro-CT-derived values. At the same time, other measures representing trabecular thickness and separation, erosion index, and structure model index produced weak correlations (r < 0.8) with their micro-CT-derived values, failing to accurately portray the projected trabecular microarchitectural features. Strong correlations of Tb measures estimated from two scanners suggest that image data from different scanners can be used successfully in multisite and longitudinal studies with linear calibration required for some measures. In summary, modern MDCT scanners are suitable for effective quantitative imaging of peripheral Tb microarchitecture if care is taken to focus on appropriate quantitative metrics. © 2017 American Association of Physicists in Medicine.

Standardizing CT lung density measure across scanner manufacturers.

PubMed

Chen-Mayer, Huaiyu Heather; Fuld, Matthew K; Hoppel, Bernice; Judy, Philip F; Sieren, Jered P; Guo, Junfeng; Lynch, David A; Possolo, Antonio; Fain, Sean B

2017-03-01

Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls. To reduce variability in the density metrics specified by CT attenuation, the Quantitative Imaging Biomarkers Alliance (QIBA) Lung Density Committee has organized efforts to conduct phantom studies in a variety of scanner models to establish a baseline for assessing the variations in patient studies that can be attributed to scanner calibration and measurement uncertainty. Data were obtained from a phantom study on CT scanners from four manufacturers with several protocols at various tube potential voltage (kVp) and exposure settings. Free from biological variation, these phantom studies provide an assessment of the accuracy and precision of the density metrics across platforms solely due to machine calibration and uncertainty of the reference materials. The phantom used in this study has three foam density references in the lung density region, which, after calibration against a suite of Standard Reference Materials (SRM) foams with certified physical density, establishes a HU-electron density relationship for each machine-protocol. We devised a 5-step calibration procedure combined with a simplified physical model that enabled the standardization of the CT numbers reported across a total of 22 scanner-protocol settings to a single energy (chosen at 80 keV). A standard deviation was calculated for overall CT numbers for each density, as well as by scanner and other variables, as a measure of the variability, before and after the standardization. In addition, a linear mixed-effects model was used to assess the heterogeneity across scanners, and the 95% confidence interval of the mean CT number was evaluated before and after the standardization. We show that after applying the standardization procedures to the phantom data, the instrumental reproducibility of the CT density measurement of the reference foams improved by more than 65%, as measured by the standard deviation of the overall mean CT number. Using the lung foam that did not participate in the calibration as a test case, a mixed effects model analysis shows that the 95% confidence intervals are [-862.0 HU, -851.3 HU] before standardization, and [-859.0 HU, -853.7 HU] after standardization to 80 keV. This is in general agreement with the expected CT number value at 80 keV of -855.9 HU with 95% CI of [-857.4 HU, -854.5 HU] based on the calibration and the uncertainty in the SRM certified density. This study provides a quantitative assessment of the variations expected in CT lung density measures attributed to non-biological sources such as scanner calibration and scanner x-ray spectrum and filtration. By removing scanner-protocol dependence from the measured CT numbers, higher accuracy and reproducibility of quantitative CT measures were attainable. The standardization procedures developed in study may be explored for possible application in CT lung density clinical data. © 2017 American Association of Physicists in Medicine.

Investigation of a high speed data handling system for use with multispectral aircraft scanners

NASA Technical Reports Server (NTRS)

Kelly, W. L.; Meredith, B. D.

1978-01-01

A buffer memory data handling technique for use with multispectral aircraft scanners is presented which allows digital data generated at high data rates to be recorded on magnetic tape. A digital memory is used to temporarily store the data for subsequent recording at slower rates during the passive time of the scan line, thereby increasing the maximum data rate recording capability over real-time recording. Three possible implementations are described and the maximum data rate capability is defined in terms of the speed capability of the key hardware components. The maximum data rates can be used to define the maximum ground resolution achievable by a multispectral aircraft scanner using conventional data handling techniques.