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Sample records for breast x-ray ct

  1. Toward optimal X-ray flux utilization in breast CT

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Heide; Hansen, Per Christian; Sidky, Emil Y.

    2011-01-01

    A realistic computer-simulation of a breast computed tomography (CT) system and subject is constructed. The model is used to investigate the optimal number of views for the scan given a fixed total X-ray fluence. The reconstruction algorithm is based on accurate solution to a constrained......, TVminimization problem, which has received much interest recently for sparse-view CT data....

  2. Library based x-ray scatter correction for dedicated cone beam breast CT

    International Nuclear Information System (INIS)

    Shi, Linxi; Zhu, Lei; Vedantham, Srinivasan; Karellas, Andrew

    2016-01-01

    Purpose: The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose a library-based software approach to suppress scatter on CBBCT images with high efficiency, accuracy, and reliability. Methods: The authors precompute a scatter library on simplified breast models with different sizes using the GEANT4-based Monte Carlo (MC) toolkit. The breast is approximated as a semiellipsoid with homogeneous glandular/adipose tissue mixture. For scatter correction on real clinical data, the authors estimate the breast size from a first-pass breast CT reconstruction and then select the corresponding scatter distribution from the library. The selected scatter distribution from simplified breast models is spatially translated to match the projection data from the clinical scan and is subtracted from the measured projection for effective scatter correction. The method performance was evaluated using 15 sets of patient data, with a wide range of breast sizes representing about 95% of general population. Spatial nonuniformity (SNU) and contrast to signal deviation ratio (CDR) were used as metrics for evaluation. Results: Since the time-consuming MC simulation for library generation is precomputed, the authors’ method efficiently corrects for scatter with minimal processing time. Furthermore, the authors find that a scatter library on a simple breast model with only one input parameter, i.e., the breast diameter, sufficiently guarantees improvements in SNU and CDR. For the 15 clinical datasets, the authors’ method reduces the average SNU from 7.14% to 2.47% in coronal views and from 10.14% to 3.02% in sagittal views. On average, the CDR is improved by a factor of 1.49 in coronal views and 2.12 in sagittal

  3. Library based x-ray scatter correction for dedicated cone beam breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Linxi; Zhu, Lei, E-mail: leizhu@gatech.edu [Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Vedantham, Srinivasan; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2016-08-15

    Purpose: The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose a library-based software approach to suppress scatter on CBBCT images with high efficiency, accuracy, and reliability. Methods: The authors precompute a scatter library on simplified breast models with different sizes using the GEANT4-based Monte Carlo (MC) toolkit. The breast is approximated as a semiellipsoid with homogeneous glandular/adipose tissue mixture. For scatter correction on real clinical data, the authors estimate the breast size from a first-pass breast CT reconstruction and then select the corresponding scatter distribution from the library. The selected scatter distribution from simplified breast models is spatially translated to match the projection data from the clinical scan and is subtracted from the measured projection for effective scatter correction. The method performance was evaluated using 15 sets of patient data, with a wide range of breast sizes representing about 95% of general population. Spatial nonuniformity (SNU) and contrast to signal deviation ratio (CDR) were used as metrics for evaluation. Results: Since the time-consuming MC simulation for library generation is precomputed, the authors’ method efficiently corrects for scatter with minimal processing time. Furthermore, the authors find that a scatter library on a simple breast model with only one input parameter, i.e., the breast diameter, sufficiently guarantees improvements in SNU and CDR. For the 15 clinical datasets, the authors’ method reduces the average SNU from 7.14% to 2.47% in coronal views and from 10.14% to 3.02% in sagittal views. On average, the CDR is improved by a factor of 1.49 in coronal views and 2.12 in sagittal

  4. Phase-contrast X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi [Hitachi Ltd., Saitama (Japan). Advanced Research Laboratory; Takeda, Tohoru; Itai, Yuji

    1995-12-01

    Phase-contrast X-ray computed tomography (CT) enabling the observation of biological soft tissues without contrast enhancement has been developed. The X-ray phase shift caused by an object is measured and input to a standard CT reconstruction algorithm. A thousand times increase in the image sensitivity to soft tissues is achieved compared with the conventional CT using absorption contrast. This is because the X-ray phase shift cross section of light elements is about a thousand times larger than the absorption cross section. The phase shift is detected using an X-ray interferometer and computer analyses of interference patterns. Experiments were performed using a synchrotron X-ray source. Excellent image sensitivity is demonstrated in the observation of cancerous rabbit liver. The CT images distinguish cancer lesion from normal liver tissue and, moreover, visualize the pathological condition in the lesion. Although the X-ray energy employed and the present observation area size are not suitable for medical applications as they are, phase-contrast X-ray CT is promising for investigating the internal structure of soft tissue which is almost transparent for X-rays. The high sensitivity also provides the advantage of reducing X-ray doses. (author).

  5. Reconstructing misaligned x-ray CT data

    Energy Technology Data Exchange (ETDEWEB)

    Divin, C. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-24

    Misalignment errors for x-ray computed tomography (CT) systems can manifest as artifacts and a loss of spatial and contrast resolution. To mitigate artifacts, significant effort is taken to determine the system geometry and minimizing any residual error in the system alignment. This project improved our ability to post-correct data which was acquired on a misaligned CT system.

  6. TU-F-18C-03: X-Ray Scatter Correction in Breast CT: Advances and Patient Testing

    International Nuclear Information System (INIS)

    Ramamurthy, S; Sechopoulos, I

    2014-01-01

    Purpose: To further develop and perform patient testing of an x-ray scatter correction algorithm for dedicated breast computed tomography (BCT). Methods: A previously proposed algorithm for x-ray scatter signal reduction in BCT imaging was modified and tested with a phantom and on patients. A wireless electronic positioner system was designed and added to the BCT system that positions a tungsten plate in and out of the x-ray beam. The interpolation used by the algorithm was replaced with a radial basis function-based algorithm, with automated exclusion of non-valid sampled points due to patient motion or other factors. A 3D adaptive noise reduction filter was also introduced to reduce the impact of scatter quantum noise post-reconstruction. The impact on image quality of the improved algorithm was evaluated using a breast phantom and seven patient breasts, using quantitative metrics such signal difference (SD) and signal difference-to-noise ratios (SDNR) and qualitatively using image profiles. Results: The improvements in the algorithm resulted in a more robust interpolation step, with no introduction of image artifacts, especially at the imaged object boundaries, which was an issue in the previous implementation. Qualitative evaluation of the reconstructed slices and corresponding profiles show excellent homogeneity of both the background and the higher density features throughout the whole imaged object, as well as increased accuracy in the Hounsfield Units (HU) values of the tissues. Profiles also demonstrate substantial increase in both SD and SDNR between glandular and adipose regions compared to both the uncorrected and system-corrected images. Conclusion: The improved scatter correction algorithm can be reliably used during patient BCT acquisitions with no introduction of artifacts, resulting in substantial improvement in image quality. Its impact on actual clinical performance needs to be evaluated in the future. Research Agreement, Koning Corp., Hologic

  7. X-ray examination for breast cancer: Benefit versus risk

    International Nuclear Information System (INIS)

    Dalrymple, G.V.; Baker, M.L.

    1984-01-01

    Cancer of the breast is the most common malignancy afflicting American women. According to the American Cancer Society, one of 11 women (9 percent) born in the United States today, will develop breast cancer in her lifetime. Twenty-seven percent of all cancers in women and 19 percent of all cancer deaths in women are attributable to breast cancer. In 1982, 112,000 women were found to have cancer of the breast, and 37,000 women died from breast cancer. X-ray examinations of the breast are of considerable value in the diagnosis of breast cancer. This may be especially true in the asymptomatic patient who does not have a palpable mass. These x-ray examinations, however, are associated with both a finite though small risk of induction of cancer of the breasts and even smaller risk of death from cancer of the breast. This chapter presents a brief review of cancer of the breast and discusses the value of diagnostic studies, including x-ray mammography; the benefits and risks associated with x-ray examinations; and the future potential of computed tomography (CT) and ultrasound as imaging modalities in the detection of breast cancer

  8. Attenuation correction of myocardial SPECT images with X-ray CT. Effects of registration errors between X-ray CT and SPECT

    International Nuclear Information System (INIS)

    Takahashi, Yasuyuki; Murase, Kenya; Mochizuki, Teruhito; Motomura, Nobutoku

    2002-01-01

    Attenuation correction with an X-ray CT image is a new method to correct attenuation on SPECT imaging, but the effect of the registration errors between CT and SPECT images is unclear. In this study, we investigated the effects of the registration errors on myocardial SPECT, analyzing data from a phantom and a human volunteer. Registerion (fusion) of the X-ray CT and SPECT images was done with standard packaged software in three dimensional fashion, by using linked transaxial, coronal and sagittal images. In the phantom study, and X-ray CT image was shifted 1 to 3 pixels on the x, y and z axes, and rotated 6 degrees clockwise. Attenuation correction maps generated from each misaligned X-ray CT image were used to reconstruct misaligned SPECT images of the phantom filled with 201 Tl. In a human volunteer, X-ray CT was acquired in different conditions (during inspiration vs. expiration). CT values were transferred to an attenuation constant by using straight lines; an attenuation constant of 0/cm in the air (CT value=-1,000 HU) and that of 0.150/cm in water (CT value=0 HU). For comparison, attenuation correction with transmission CT (TCT) data and an external γ-ray source ( 99m Tc) was also applied to reconstruct SPECT images. Simulated breast attenuation with a breast attachment, and inferior wall attenuation were properly corrected by means of the attenuation correction map generated from X-ray CT. As pixel shift increased, deviation of the SPECT images increased in misaligned images in the phantom study. In the human study, SPECT images were affected by the scan conditions of the X-ray CT. Attenuation correction of myocardial SPECT with an X-ray CT image is a simple and potentially beneficial method for clinical use, but accurate registration of the X-ray CT to SPECT image is essential for satisfactory attenuation correction. (author)

  9. Is there any advantage of CT based 3-dimensional conformal planning over conventional orthogonal x-ray based planning in HDR brachytherapy in breast cancer

    International Nuclear Information System (INIS)

    Biswal, B.M.; Idris, N.R.; Zakaria, A.B.; Khairul, N.

    2003-01-01

    The conventional brachytherapy dose calculation is based on a particular brachytherapy rule or individual dosimetry based on the reconstruction of the sources from the orthogonal films. In the recent years many centers are using CT based 3D conformal brachytherapy in order to improve the dosimetric outcome of a given plan. Here we would like to present our experience on the use of both techniques to deliver HDR interstitial brachytherapy as boost in early breast cancer. From January 2001 to January 2003, we treated 4 breast cancer patients using conventional orthogonal x-rays and CT scan in 3 cases for the treatment plan. All patients received an external beam radiotherapy dose of 46 Gy in 23 fractions over 4.5 weeks to the whole breast using 6 MV photon beam. Subsequently the primary lesion was supplimented with HDR brachytherapy to a dose of 2.5 Gy BID for 3 consecutive days using a (192)Ir microSelectronHDR. The dose prescription was individualized to encompass the tumor volume with a 10 mm margin. The differences of the dosimetric outcome were compared. All patients completed above schedule of radiotherapy. The primary was implanted with single plane in 3 patients and multiplane implant in 4 patients. Orthogonal x-ray based localization was performed in 4 patients and CT scan based localization in 3 cases. Three patients were implanted single plane and 4 patients with multiplane implants with a median catheter number of 9 (range 6-14). The 3D conformal dose optimization was performed using Nucletron planning system (Plato). The mean 100% and 150% isodose volume was 67.3 cm 3 and 31.25cm 3 respectively. The identification of primary tumor volume, organ at risk, and identification of afterloading catheters were superior in CT based plan than conventional planning. CT scan based 3D conformal brachytherapy planning give better identification of tumor volume and its curvature, decrease the time to identify the sources and evaluate the radiation dose to organs at

  10. Noise variance analysis using a flat panel x-ray detector: A method for additive noise assessment with application to breast CT applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang Kai; Huang, Shih-Ying; Packard, Nathan J.; Boone, John M. [Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, Davis, California, 95616 (United States)

    2010-07-15

    Purpose: A simplified linear model approach was proposed to accurately model the response of a flat panel detector used for breast CT (bCT). Methods: Individual detector pixel mean and variance were measured from bCT projection images acquired both in air and with a polyethylene cylinder, with the detector operating in both fixed low gain and dynamic gain mode. Once the coefficients of the linear model are determined, the fractional additive noise can be used as a quantitative metric to evaluate the system's efficiency in utilizing x-ray photons, including the performance of different gain modes of the detector. Results: Fractional additive noise increases as the object thickness increases or as the radiation dose to the detector decreases. For bCT scan techniques on the UC Davis prototype scanner (80 kVp, 500 views total, 30 frames/s), in the low gain mode, additive noise contributes 21% of the total pixel noise variance for a 10 cm object and 44% for a 17 cm object. With the dynamic gain mode, additive noise only represents approximately 2.6% of the total pixel noise variance for a 10 cm object and 7.3% for a 17 cm object. Conclusions: The existence of the signal-independent additive noise is the primary cause for a quadratic relationship between bCT noise variance and the inverse of radiation dose at the detector. With the knowledge of the additive noise contribution to experimentally acquired images, system modifications can be made to reduce the impact of additive noise and improve the quantum noise efficiency of the bCT system.

  11. X-ray and CT findings of costal eosinophilic granuloma

    International Nuclear Information System (INIS)

    Tu Zhanhai; Lin Zhengyu; Chen Yiguang

    2010-01-01

    Objective: To study the X-ray and CT features of costal eosinophilic granuloma for a better understanding. Methods: Eight patients with costal eosinophilic granuloma proved by surgery or biopsy were analyzed retrospectively. All patients had X-ray plain film, 6 patients had CT examination, including a case of enhanced CT scan. Results: All 8 lesions were solitary. Six lesions were in the anterior rib and 2 in the posterior rib. On X-ray, all case showed single cavity and oval lesion with clear boundary. On CT images, 5 lesions demonstrated expansile destruction of bone with cortical bone thinning, and 3 were osteolystic destruction with soft tissue mass around. On the patient with enhanced CT scan, the lesions showed a moderate and uniform enhancement. Conclusion: The X-ray and CT findings of costal eosinophilic granuloma are characteristic. (authors)

  12. Material Discriminated X-Ray CT System by Using New X-Ray Imager with Energy Discriminate Function

    Directory of Open Access Journals (Sweden)

    Toru Aoki

    2008-04-01

    Full Text Available Material discriminated X-ray CT system has been constructed by using conventional X-ray tube (white X-ray source and photon-counting X-ray imager as an application with energy band detection. We have already reported material identify X-ray CT using K-shell edge method elsewhere. In this report the principle of material discrimination was adapted the separation of electron-density and atomic number from attenuation coefficient mapping in X-ray CT reconstructed image in two wavelength X-ray CT method using white X-ray source and energy discriminated X-ray imager by using two monochrome X-ray source method. The measurement phantom was prepared as four kinds material rods (Carbon(C, Iron(Fe, Copper(Cu, Titanium(Ti rods of 3mm-diameter inside an aluminum(Al rod of 20mm-diameter. We could observed material discriminated X-ray CT reconstructed image, however, the discrimination properties were not good than two monochrome X-ray CT method. This results was could be explained because X-ray scattering, beam-hardening and so on based on white X-ray source, which could not observe in two monochrome X-ray CT method. However, since our developed CdTe imager can be detect five energy-bands at the same time, we can use multi-band analysis to decrease the least square error margin. We will be able to obtain more high separation in atomic number mapping in X-ray CT reconstructed image by using this system.

  13. Hard X-ray Microscopic Imaging Of Human Breast Tissues

    Science.gov (United States)

    Park, Sung H.; Kim, Hong T.; Kim, Jong K.; Jheon, Sang H.; Youn, Hwa S.

    2007-01-01

    X-ray microscopy with synchrotron radiation will be a useful tool for innovation of x-ray imaging in clinical and laboratory settings. It helps us observe detailed internal structure of material samples non-invasively in air. And, it also has the potential to solve some tough problems of conventional breast imaging if it could evaluate various conditions of breast tissue effectively. A new hard x-ray microscope with a spatial resolution better than 100 nm was installed at Pohang Light Source, a third generation synchrotron radiation facility in Pohang, Korea. The x-ray energy was set at 6.95 keV, and the x-ray beam was monochromatized by W/B4C monochromator. Condenser and objective zone plates were used as x-ray lenses. Zernike phase plate next to condenser zone plate was introduced for improved contrast imaging. The image of a sample was magnified 30 times by objective zone plate and 20 times by microscope objective, respectively. After additional 10 times digital magnification, the total magnifying power was up to 6000 times in the end. Phase contrast synchrotron images of 10-μm-thick female breast tissue of the normal, fibroadenoma, fibrocystic change and carcinoma cases were obtained. By phase contrast imaging, hard x-rays enable us to observe many structures of breast tissue without sample preparations such as staining or fixation.

  14. Hard X-ray Microscopic Imaging Of Human Breast Tissues

    International Nuclear Information System (INIS)

    Park, Sung H.; Kim, Hong T.; Kim, Jong K.; Jheon, Sang H.; Youn, Hwa S.

    2007-01-01

    X-ray microscopy with synchrotron radiation will be a useful tool for innovation of x-ray imaging in clinical and laboratory settings. It helps us observe detailed internal structure of material samples non-invasively in air. And, it also has the potential to solve some tough problems of conventional breast imaging if it could evaluate various conditions of breast tissue effectively. A new hard x-ray microscope with a spatial resolution better than 100 nm was installed at Pohang Light Source, a third generation synchrotron radiation facility in Pohang, Korea. The x-ray energy was set at 6.95 keV, and the x-ray beam was monochromatized by W/B4C monochromator. Condenser and objective zone plates were used as x-ray lenses. Zernike phase plate next to condenser zone plate was introduced for improved contrast imaging. The image of a sample was magnified 30 times by objective zone plate and 20 times by microscope objective, respectively. After additional 10 times digital magnification, the total magnifying power was up to 6000 times in the end. Phase contrast synchrotron images of 10-μm-thick female breast tissue of the normal, fibroadenoma, fibrocystic change and carcinoma cases were obtained. By phase contrast imaging, hard x-rays enable us to observe many structures of breast tissue without sample preparations such as staining or fixation

  15. Three-dimensional monochromatic x-ray CT

    Science.gov (United States)

    Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Ktsuyuki; Uyama, Chikao

    1995-08-01

    In this paper, we describe a 3D computed tomography (3D CT) using monochromatic x-rays generated by synchrotron radiation, which performs a direct reconstruction of 3D volume image of an object from its cone-beam projections. For the develpment of 3D CT, scanning orbit of x-ray source to obtain complete 3D information about an object and corresponding 3D image reconstruction algorithm are considered. Computer simulation studies demonstrate the validities of proposed scanning method and reconstruction algorithm. A prototype experimental system of 3D CT was constructed. Basic phantom examinations and specific material CT image by energy subtraction obtained in this experimental system are shown.

  16. SCT-4800T whole body X-ray CT scanner

    International Nuclear Information System (INIS)

    Okumura, Yoshitaka; Sato, Yukio; Kuwahara, Hiroshi

    1994-01-01

    A whole body X-ray CT scanner, the SCT-4800T (trade name: INTELLECT series), has been developed. This system is the first CT scanner that is combined with general radiographic functions. The general radiographic functions include a patient couch with film casette and several tube support systems along with the CT scanner. This newly designed CT scanner also features a compact and light-weight gantry with a 700 mm diameter apperture and user-friendly operater's console. The SCT-4800T brings a new level of patient and operator comfort to the emergency radiology examination site. (author)

  17. X-ray CT in the detection of palm weevils

    International Nuclear Information System (INIS)

    Ma, A.K.W.; Alghamdi, A.A.; Spyrou, N.M.

    2012-01-01

    Early detection of the red palm weevils (RPW) is a major challenge in agriculture among all kinds of palm trees due to the nature of the insect and the difficulty to trace them through their life stages associated with the tree life. Many methods have been applied for the weevil detection such as X-ray diffraction techniques, fluoroscopy and ultrasound. On the other hand, the idea of tomography has been used for other purposes such as the determination of the age of the tree and for applied environmental studies. Such technology can also reveal the weevil in principle. In this study, we explore the use of X-ray CT for weevil detection with the Monte Carlo method. A model of the stem of a palm tree is developed for simulations. MCNPX is chosen to carry out the simulations for the radiography tally in the code. The tally records the 2D data of the X-ray beams irradiating the tree model. An iterative reconstruction method for cone beam CT is applied to obtain the 3D slices of the tree model. We are exploring the minimum number of projection angles and the detectability of the weevil. We shall also report the sensitivity of weevil detection using X-ray CT with a large set of simulations with different weevil sizes and tree diameters. (author)

  18. The value of X-ray CT in orbital fractures

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Myung Hee; Lee, Jae Mun; Kim, Choon Yul; Bahk, Yong Whee [Catholic Medical College, Seoul (Korea, Republic of)

    1986-08-15

    On the pulse from the trauma transiting to posterior side of the orbit, orbital fractures are occurred through the weak point of the orbital wall. Invagination of soft tissue or entrapment of muscles may be associated with orbital fracture. In condition of inaccurate diagnosis, appropriate surgical repairment is impossible and complication such as diplopia or enophthalmia are developed. CT scan is diagnostic procedure which demonstrates accurately the site and state of orbital fracture, and its associated findings. The authors has been studied in 21 orbital CT scan to evaluate the relative value of plain X rays and CT scans in the diagnosis of orbital fractures during the period from January 1982 to September 1985. The conclusions were as follows: 1. Diagnostic rate was 100% by CT, 40% by initial and 80% by retrospective interpretation of conventional X-ray films. 2. Low X-ray diagnostic rate of medical wall fractures (26.7%) was due to thinness of the bone. 3. Medial wall fractures were associated with floor fractures in 46%. 4. Orbital soft tissue injuries and abnormalities of PNS were precisely evaluated by CT scan.

  19. Multi-modality PET-CT imaging of breast cancer in an animal model using nanoparticle x-ray contrast agent and 18F-FDG

    Science.gov (United States)

    Badea, C. T.; Ghaghada, K.; Espinosa, G.; Strong, L.; Annapragada, A.

    2011-03-01

    Multi-modality PET-CT imaging is playing an important role in the field of oncology. While PET imaging facilitates functional interrogation of tumor status, the use of CT imaging is primarily limited to anatomical reference. In an attempt to extract comprehensive information about tumor cells and its microenvironment, we used a nanoparticle xray contrast agent to image tumor vasculature and vessel 'leakiness' and 18F-FDG to investigate the metabolic status of tumor cells. In vivo PET/CT studies were performed in mice implanted with 4T1 mammary breast cancer cells.Early-phase micro-CT imaging enabled visualization 3D vascular architecture of the tumors whereas delayedphase micro-CT demonstrated highly permeable vessels as evident by nanoparticle accumulation within the tumor. Both imaging modalities demonstrated the presence of a necrotic core as indicated by a hypo-enhanced region in the center of the tumor. At early time-points, the CT-derived fractional blood volume did not correlate with 18F-FDG uptake. At delayed time-points, the tumor enhancement in 18F-FDG micro-PET images correlated with the delayed signal enhanced due to nanoparticle extravasation seen in CT images. The proposed hybrid imaging approach could be used to better understand tumor angiogenesis and to be the basis for monitoring and evaluating anti-angiogenic and nano-chemotherapies.

  20. A survey on coordinate metrology using dimensional X-ray CT

    International Nuclear Information System (INIS)

    Matsuzaki, Kazuya

    2016-01-01

    X-ray computed tomography (X-ray CT) has been occupying indispensable position in geometrical and dimensional measurements in industry, which is capable of measuring both external and internal dimensions of industrial products. Since dimensional X-ray CT has problems about ensuring traceability and estimating uncertainty, requirement of developing measurement standard for dimensional X-ray CT is increasing. Some of national metrology institutes (NMIs) including NMIJ have been working on developing measurement standard. In this report, the background of coordinate metrology using dimensional X-ray CT is reviewed. Then, measurement error sources are discussed. Finally, the plan to develop high accuracy dimensional X-ray CT is presented. (author)

  1. WE-DE-207B-10: Library-Based X-Ray Scatter Correction for Dedicated Cone-Beam Breast CT: Clinical Validation

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L; Zhu, L [Georgia Institute of Technology, Atlanta, GA (Georgia); Vedantham, S; Karellas, A [University of Massachusetts Medical School, Worcester, MA (United States)

    2016-06-15

    Purpose: Scatter contamination is detrimental to image quality in dedicated cone-beam breast CT (CBBCT), resulting in cupping artifacts and loss of contrast in reconstructed images. Such effects impede visualization of breast lesions and the quantitative accuracy. Previously, we proposed a library-based software approach to suppress scatter on CBBCT images. In this work, we quantify the efficacy and stability of this approach using datasets from 15 human subjects. Methods: A pre-computed scatter library is generated using Monte Carlo simulations for semi-ellipsoid breast models and homogeneous fibroglandular/adipose tissue mixture encompassing the range reported in literature. Projection datasets from 15 human subjects that cover 95 percentile of breast dimensions and fibroglandular volume fraction were included in the analysis. Our investigations indicate that it is sufficient to consider the breast dimensions alone and variation in fibroglandular fraction does not significantly affect the scatter-to-primary ratio. The breast diameter is measured from a first-pass reconstruction; the appropriate scatter distribution is selected from the library; and, deformed by considering the discrepancy in total projection intensity between the clinical dataset and the simulated semi-ellipsoidal breast. The deformed scatter-distribution is subtracted from the measured projections for scatter correction. Spatial non-uniformity (SNU) and contrast-to-noise ratio (CNR) were used as quantitative metrics to evaluate the results. Results: On the 15 patient cases, our method reduced the overall image spatial non-uniformity (SNU) from 7.14%±2.94% (mean ± standard deviation) to 2.47%±0.68% in coronal view and from 10.14%±4.1% to 3.02% ±1.26% in sagittal view. The average contrast to noise ratio (CNR) improved by a factor of 1.49±0.40 in coronal view and by 2.12±1.54 in sagittal view. Conclusion: We demonstrate the robustness and effectiveness of a library-based scatter correction

  2. X-ray scatter signatures for enhanced breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kidane, Ghirmay; Speller, Robert; Royle, Gary [Medical Physics and Bioengineering Department, University College Landon, 11-20 Capper Street, London WC1E 6JA (United Kingdom)

    1999-12-31

    Conventional mammographic imaging suffers from a low specificity. The main cause is the small difference in the x-ray attenuation properties of healthy and diseased tissue leading to poor contrast in the image. It has been observed that additional information on breast tissue type can be obtained from x-ray diffraction effects. A study of excised normal and neoplastic breast tissue samples using x-ray diffraction apparatus has been observed that significant differences exist in the measured spectra between carcinoma and healthy tissue adjacent to the carcinoma. Such a difference allows tissue type to be characterised according to is diseased state. Furthermore the information can be applied to improve diagnosis. It is proposed that collection and analysis of the scattered x-rays present during a mammographic procedure can supply the additional information and be used to improve the image contrast. The ultimate aim of the project is to improve the specificity of x-ray mammography. (authors) 10 refs., 3 figs.

  3. WE-EF-207-06: Dedicated Cone-Beam Breast CT with Laterally-Shifted Detector: Monte Carlo Evaluation of X-Ray Scatter Distribution and Scatter-To-Primary Ratio

    International Nuclear Information System (INIS)

    Shi, L; Vedantham, S; Karellas, A

    2015-01-01

    Purpose: To determine the spatial distribution of x-ray scatter and scatter-to-primary ratio (SPR) in projections during cone-beam breast CT (CBBCT) with laterally-shifted detector that results in coronal (fan-angle) truncation. Methods: We hypothesized that CBBCT with coronal truncation would lower SPR due to reduction in irradiated breast volume, and that the location of maximum x-ray scatter fluence (scatter-peak) in the detector plane can be determined from the ratio of irradiated-to-total breast volume, breast dimensions and system geometry. Monte Carlo simulations (GEANT4) reflecting a prototype CBBCT system were used to record the position-dependent primary and scatter x-ray photon fluence incident on the detector without coronal truncation (full fan-angle, 2f=24-degrees) and with coronal truncation (fan-angle, f+ f=12+2.7-degrees). Semi-ellipsoidal breasts (10/14/18-cm diameter, chest-wall to nipple length: 0.75xdiameter, 2%/14%/100% fibroglandular content) aligned with the axis-of-rotation (AOR) were modeled. Mono-energy photons were simulated and weighted for 2 spectra (49kVp, 1.4-mm Al HVL; 60kVp, 3.76-mm Al HVL). In addition to SPR, the scatter maps were analyzed to identify the location of the scatter-peak. Results: For CBBCT without fan-angle truncation, the scatter-peaks were aligned with the projection of the AOR onto the detector for all breasts. With truncated fan-beam, the scatter-peaks were laterally-shifted from the projection of the AOR along the fan-angle direction by 14/38/70-pixels for 10/14/18-cm diameter breasts. The corresponding theoretical shifts were 14.8/39.7/68-pixels (p=0.47, 2-tailed paired-ratio t-test). Along the cone-angle, the shift in scatter-peaks between truncated and full-fan angle CBBCT were 2/2/4 -pixels for 10/14/18-cm diameter breasts. CBBCT with fan-angle truncation reduced SPR by 14/22/28% for 10/14/18-cm diameter breasts. 60kVp reduced SPR by 21–25% compared to 49kVp. Peak SPR for CBBCT with fan-angle truncation

  4. Patient size and x-ray transmission in body CT.

    Science.gov (United States)

    Ogden, Kent; Huda, Walter; Scalzetti, Ernest M; Roskopf, Marsha L

    2004-04-01

    Physical characteristics were obtained for 196 patients undergoing chest and abdomen computed tomography (CT) examinations. Computed tomography sections for these patients having no evident pathology were analyzed to determine patient dimensions (AP and lateral), together with the average attenuation coefficient. Patient weights ranged from approximately 3 kg to about 120 kg. For chest CT, the mean Hounsfield unit (HU) fell from about -120 HU for newborns to about -300 HU for adults. For abdominal CT, the mean HU for children and normal-sized adults was about 20 HU, but decreased to below -50 HU for adults weighing more than 100 kg. The effective photon energy and percent energy fluence transmitted through a given patient size and composition was calculated for representative x-ray spectra at 80, 100, 120, and 140 kV tube potentials. A 70-kg adult scanned at 120 kVp transmits 2.6% of the energy fluence for chest and 0.7% for abdomen CT examinations. Reducing the patient size to 10 kg increases transmission by an order of magnitude. For 70 kg patients, effective energies in body CT range from approximately 50 keV at 80 kVp to approximately 67 keV at 140 kVp; increasing patient size from 10 to 120 kg resulted in an increase in effective photon energy of approximately 4 keV. The x-ray transmission data and effective photon energy data can be used to determine CT image noise and image contrast, respectively, and information on patient size and composition can be used to determine patient doses.

  5. X-ray CT evaluation of pulmonary involvements of sarcoidosis

    International Nuclear Information System (INIS)

    Nishimura, Koichi; Izumi, Takateru; Kitaichi, Masanori

    1987-01-01

    We evaluated high resolution CT in 60 patients with histologically diagnosed pulmonary sarcoidosis and, also, studied the relationship between CT and findings in open lung biopsy specimens in 2 cases. The CT findings were as follows: (1) thickening of bronchial wall shadows (27 out of 60 cases, 45.0 %), (2) irregular enlargement of pulmonary vascular shadows (39 cases, 65.0 %), (3) small or large nodular shadows (24 cases, 40.0 %), (4) local volume loss (14 cases, 23.3 %), (5) slightly increased density of localized lung field areas (24 cases, 40.0 %), (6) pleural or subpleural involvement (27 cases, 45.0 %), (7) lymph node enlargement (59 cases, 98.3 %). X-ray CT in 7 patients revealed no evidence of lung field involvement in patients with histologicall confirmed epithelioid cell granuloma in transbronchial lung biopsy specimens. Lesions located within vessels or in the vascular wall, perivascular sheath or alveoli surrounding blood vessels might cause pulmonary vascular shadows to appear swollen on CT. In a comparative study, we found irregular dilatation of pulmonary vascular shadows corresponding to granulomas in the connective tissue sheath of blood vessels. Also, thickening of bronchial wall shadows corresponded to granulomas in and around the bronchial wall. From the point of histopathological view epithelioid cell granulomas in the bronchovascular sheath were most marked in sarcoidosis, and they apperaed on CT as an irregular enlargement of pulmonary vascular shadows and thickening of the bronchial wall. On the other hand, we reported that collapse of alveoli and fibrosis surrounding blood vessels could cause irregular enlargement of pulmonary vascular shadows on CT in idiopathic pulmonary fibrosis (IPF). Such shadows were seen on CT in both sarcoidosis and IPF but the mechanism of their appearance differed. (J.P.N.)

  6. Performance evaluation of X-ray CT using visible scintillation light

    International Nuclear Information System (INIS)

    Kodama, Kiyoyuki; Hamada, Minoru; Suzuki, Tamotsu; Hashimoto, Masatoshi; Hanada, Takashi; Ide, Tatsuya; Maruyama, Koichi

    2004-01-01

    We proposed a new method of performance evaluation for X-ray CT using visible scintillation light and examined its usefulness in this study. When we scanned a plastic scintillator disk in a gantry opening of the X-ray CT, we could observe visible scintillation light. The rotation of the light-emitting area of the disk corresponded to that of the X-ray tube. We were able to record the scintillation light by digital video camera. By analyzing the area of visible scintillation light, the rotation speed of the X-ray tube, angular spread of the X-ray beam, uniformity of the incident X-rays, and change in X-ray energy were measured. No other method is available to obtain the above parameters of X-ray CT during a single CT scan. In the measurements of the uniformity of incident X-rays and change of X-ray energy, our method showed good accuracy in detecting the attenuation caused by the couch between the X-ray tube and the plastic scintillator disc. The proposed method is inexpensive and easy-to-use. We conclude that the method is a useful tool for performance evaluation as well as a maintenance tool for X-ray CT. (author)

  7. An X-Ray computed tomography/positron emission tomography system designed specifically for breast imaging.

    Science.gov (United States)

    Boone, John M; Yang, Kai; Burkett, George W; Packard, Nathan J; Huang, Shih-ying; Bowen, Spencer; Badawi, Ramsey D; Lindfors, Karen K

    2010-02-01

    Mammography has served the population of women who are at-risk for breast cancer well over the past 30 years. While mammography has undergone a number of changes as digital detector technology has advanced, other modalities such as computed tomography have experienced technological sophistication over this same time frame as well. The advent of large field of view flat panel detector systems enable the development of breast CT and several other niche CT applications, which rely on cone beam geometry. The breast, it turns out, is well suited to cone beam CT imaging because the lack of bones reduces artifacts, and the natural tapering of the breast anteriorly reduces the x-ray path lengths through the breast at large cone angle, reducing cone beam artifacts as well. We are in the process of designing a third prototype system which will enable the use of breast CT for image guided interventional procedures. This system will have several copies fabricated so that several breast CT scanners can be used in a multi-institutional clinical trial to better understand the role that this technology can bring to breast imaging.

  8. Development of high resolution x-ray CT technique for irradiated fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Ishimi, Akihiro; Katsuyama, Kozo; Maeda, Koji; Asaga, Takeo [Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki (Japan)

    2012-03-15

    High X-ray CT technique was developed to observe the irradiation performance of FBR fuel assembly and MOX fuel. In this technique, the high energy X-ray pulse (12MeV) was used synchronizing detection system with the X-ray pulse to reduce the effect of the gamma ray emissions from the irradiated fuel assembly. In this study, this technique was upgraded to obtain high resolution X-ray CT image. In this upgrading, the collimator which had slit width of 0.1 mm and X-ray detector of a highly sensitive silicon semiconductor detector (100 channels) was introduced in the X-ray CT system. As a result of these developments, high resolution X-ray CT images could be obtained on the transverse cross section of irradiated fuel assembly. (author)

  9. X-ray CT analysis on archaeological iron based artifacts

    International Nuclear Information System (INIS)

    Honda, Takashi; Gunji, Eiichi

    2005-01-01

    Corrosion analysis was carried out on twenty iron-plates, which had been dug out at the 6th Yamato ancient tomb (Nara-shi). It was evaluated through the inner-structural analysis by X-ray CT and the XRD and chemical analysis of the rusts that the most iron-plates had been buried in a slightly oxidizing environment and the maximum corrosion depth was 1.6 mm for about 1500 years. The analysis result of the extreme-value data indicates that the maximum depth of an overpack is estimated to be 2.5-2.7 mm. A part of small iron-plates were supposed to have been buried in an oxidizing environment, and about 1 mm-thick rust layers with cavities existed and the corrosion amount was figured out to be about 0.3 mm. (author)

  10. Odontogenic maxillary sinusitis diagnosed using conebeam x-ray CT

    International Nuclear Information System (INIS)

    Sato, Kiminori

    2007-01-01

    We evaluated the usefulness of conebeam x-ray CT in the diagnosis of odontogenic maxillary sinusitis in 21 patients. Among teeth causing odontogenic maxillary sinusitis, 95% had apical lesions after root canal treatment. Most root canals were filled with filling materials incompletely. Apical lesions in inappropriately treated teeth thus caused odontogenic maxillary sinusitis. Conebeam CT involves 3-dimensional isotropic voxel image date in up to 512 frames for transaxial, coronal, and sagittal planes, so resolution in imaging on the body axis was especially high. Multiplanar reconstruction and volume rendering images at any optional plane could be obtained without interpolation. The relationship between causative teeth and the maxillary sinus could be observed and measured, and odontogenic maxillary sinusitis accurately diagnosed. In addition to the accurate diagnosis of apical lesions, maxilla, and maxillary sinus, periodontal ligament space, lamina dura, pulp cavity, root canal, canal-treated root, apical periodontitis, alveolar ostitis, marginal periodontitis of causative teeth could be observed. Metal artifacts were minimized, making conebeam CT useful in the diagnosis of periodontal tissue and causative teeth, including root-canal-treated and crown-restored teeth. (author)

  11. Positron emission CT and X-ray CT findings in chronic obstructive pulmonary diseases

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yoshikazu; Murata, Kiyoshi; Ito, Harumi; Senda, Michio; Yonekura, Yoshiharu; Konishi, Junji; Nishimura, Koichi; Izumi, Takahide; Oshima, Shunsaku

    1987-08-01

    Positron emission CT and X-ray CT were performed in fifteen patients with emphysema confirmed SAB and twelve patients with clinical DPB. In patients with emphysema, 20 of 36 areas showed a central pattern and their perfusion scintigrams showed stripe-signs. On the other hand, the patients with DPB showed outer layer progression of the disease.

  12. Magnetic resonance imaging of the central nervous system. Comparison with X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Kajima, Toshio; Kagawa, Yoshihiro; Katsuta, Shizutomo.

    1987-06-01

    Magnetic resonance imaging (MRI) and X-ray computed tomography (X-ray CT) have been performed in 169 consecutive patients with central nervous system diseases. The findings from the two methods were compared for the capacity to defect lesions. Magnetic resonance imaging was more sensitive than or equivalent to X-ray CT in detecting lesions - especially detecting. Arnold-Chiari malformation, syringomyelia, spinal cord injury, and pituitary adenoma - in 158 patients (94 %). In six patients (10 %), lesion detection was possible only by MRI. Magnetic resonance imaging was inferior to X-ray CT in 11 patients (7 %) in detecting calcified lesions, meningioma, and cavernous hemangioma. (Namekawa, K.).

  13. X- Ray marking of breast cancer in Mongolia

    International Nuclear Information System (INIS)

    Ranish, A.; Tugsjargal, P.; Tuvshinjargal, D.; Nyamdavaa, N.; Gonchigsuren, D.

    2007-01-01

    Full text: Mammography and other breast imaging techniques such as ultrasound are useful in the evaluation of women who have a sign or symptom that may suggest breast cancer. Physical examination evaluates different tissue characteristics than mammography. We have evaluated mammograms of 1286 patients with breast diseases and detected 107 patients with breast cancer. 25 patients underwent surgery and approved all of mammography diagnosis. In all 122 patients with diagnosed breast cancer, the normal breast X-ray markings have been changed; in 107 cases there were single nodular foci, in 15 patients infiltrative cancer was observed. In 9 cases with absence of cancer lesion on mammography, its secondary signs diagnosed the breast cancer. In 50,8% (62) of cases the visible lesion of the breast cancer was star-shaped, 25.4% (31)- lobed, 16,4% (20)- ovoid, 7,4% (9)- round. The lesion contrast varied differently due to its size; in 58,1%- the lesion was intensive, in 11%- poorly intensive, in 4.7% of all cases the cancer lesion was very vague. In mammography, we observed sprinkled-salt like calcification (7,3%), linear calcification (3,2%) and also irregular calcifications (1,6%). Mammography showed its effectiveness in the early diagnosis of breast cancer. In many cases, the radiographic differentiation between benign and malignant circumscribed masses was difficult or sometimes impossible and we have used other diagnostic modalities like mammography guided biopsy. In many cases, the radiographic differentiation between benign and malignant circumscribed masses was difficult or sometimes impossible and we have used other diagnostic modalities like mammography guided biopsy. (author)

  14. X-ray scatter correction method for dedicated breast computed tomography: improvements and initial patient testing

    International Nuclear Information System (INIS)

    Ramamurthy, Senthil; D’Orsi, Carl J; Sechopoulos, Ioannis

    2016-01-01

    A previously proposed x-ray scatter correction method for dedicated breast computed tomography was further developed and implemented so as to allow for initial patient testing. The method involves the acquisition of a complete second set of breast CT projections covering 360° with a perforated tungsten plate in the path of the x-ray beam. To make patient testing feasible, a wirelessly controlled electronic positioner for the tungsten plate was designed and added to a breast CT system. Other improvements to the algorithm were implemented, including automated exclusion of non-valid primary estimate points and the use of a different approximation method to estimate the full scatter signal. To evaluate the effectiveness of the algorithm, evaluation of the resulting image quality was performed with a breast phantom and with nine patient images. The improvements in the algorithm resulted in the avoidance of introduction of artifacts, especially at the object borders, which was an issue in the previous implementation in some cases. Both contrast, in terms of signal difference and signal difference-to-noise ratio were improved with the proposed method, as opposed to with the correction algorithm incorporated in the system, which does not recover contrast. Patient image evaluation also showed enhanced contrast, better cupping correction, and more consistent voxel values for the different tissues. The algorithm also reduces artifacts present in reconstructions of non-regularly shaped breasts. With the implemented hardware and software improvements, the proposed method can be reliably used during patient breast CT imaging, resulting in improvement of image quality, no introduction of artifacts, and in some cases reduction of artifacts already present. The impact of the algorithm on actual clinical performance for detection, diagnosis and other clinical tasks in breast imaging remains to be evaluated. (paper)

  15. Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging

    Science.gov (United States)

    Willner, M.; Herzen, J.; Grandl, S.; Auweter, S.; Mayr, D.; Hipp, A.; Chabior, M.; Sarapata, A.; Achterhold, K.; Zanette, I.; Weitkamp, T.; Sztrókay, A.; Hellerhoff, K.; Reiser, M.; Pfeiffer, F.

    2014-04-01

    X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method’s prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.

  16. X-ray CT analysis of pore structure in sand

    Science.gov (United States)

    Mukunoki, Toshifumi; Miyata, Yoshihisa; Mikami, Kazuaki; Shiota, Erika

    2016-06-01

    The development of microfocused X-ray computed tomography (CT) devices enables digital imaging analysis at the pore scale. The applications of these devices are diverse in soil mechanics, geotechnical and geoenvironmental engineering, petroleum engineering, and agricultural engineering. In particular, the imaging of the pore space in porous media has contributed to numerical simulations for single-phase and multiphase flows or contaminant transport through the pore structure as three-dimensional image data. These obtained results are affected by the pore diameter; therefore, it is necessary to verify the image preprocessing for the image analysis and to validate the pore diameters obtained from the CT image data. Moreover, it is meaningful to produce the physical parameters in a representative element volume (REV) and significant to define the dimension of the REV. This paper describes the underlying method of image processing and analysis and discusses the physical properties of Toyoura sand for the verification of the image analysis based on the definition of the REV. On the basis of the obtained verification results, a pore-diameter analysis can be conducted and validated by a comparison with the experimental work and image analysis. The pore diameter is deduced from Young-Laplace's law and a water retention test for the drainage process. The results from previous study and perforated-pore diameter originally proposed in this study, called the voxel-percolation method (VPM), are compared in this paper. In addition, the limitations of the REV, the definition of the pore diameter, and the effectiveness of the VPM for an assessment of the pore diameter are discussed.

  17. The upper limits of the SNR in radiography and CT with polyenergetic x-rays

    International Nuclear Information System (INIS)

    Shikhaliev, Polad M

    2010-01-01

    The aim of the study is to determine the upper limits of the signal-to-noise ratio (SNR) in radiography and computed tomography (CT) with polyenergetic x-ray sources. In x-ray imaging, monoenergetic x-rays provide a higher SNR compared to polyenergetic x-rays. However, the SNR in polyenergetic x-ray imaging can be increased when a photon-counting detector is used and x-rays are optimally weighted according to their energies. For a particular contrast/background combination and at a fixed x-ray entrance skin exposure, the SNR in energy-weighting x-ray imaging depends on tube voltage and can be maximized by selecting the optimal tube voltage. The SNR in energy-weighted x-ray images acquired at this optimal tube voltage is the highest SNR that can be achieved with polyenergetic x-ray sources. The optimal tube voltages and the highest SNR were calculated and compared to the SNR of monoenergetic x-ray imaging. Monoenergetic, energy-weighting polyenergetic and energy-integrating polyenergetic x-ray imagings were simulated at a fixed entrance skin exposure of 20 mR. The tube voltages varied in the range of 30-140 kVp with 10 kV steps. Contrast elements of CaCO 3 , iodine, adipose and tumor with thicknesses of 280 mg cm -2 , 15 mg cm -2 , 1 g cm -2 and 1 g cm -2 , respectively, inserted in a soft tissue background with 10 cm and 20 cm thicknesses, were used. The energy weighting also improves the contrast-to-noise ratio (CNR) in CT when monoenergetic CT projections are optimally weighted prior to CT reconstruction (projection-based weighting). Alternatively, monoenergetic CT images are reconstructed, optimally weighted and composed to yield a final CT image (image-based weighting). Both projection-based and image-based weighting methods improve the CNR in CT. An analytical approach was used to determine which of these two weighting methods provides the upper limit of the CNR in CT. The energy-weighting method was generalized and expanded as a weighting method applicable in

  18. Assessing the registration of CT-scan data to intraoperative x rays by fusing x rays and preoperative information

    Science.gov (United States)

    Gueziec, Andre P.

    1999-05-01

    This paper addresses a key issue of providing clinicians with visual feedback to validate a computer-generated registration of pre-operative and intra-operative data. With this feedback information, the clinician may decide to proceed with a computer-assisted intervention, revert to a manual intervention, or potentially provide information to the computer system to improve the registration. The paper focuses on total hip replacement (THR) surgery, but similar techniques could be applied to other types of interventions or therapy, including orthopedics, neurosurgery, and radiation therapy. Pre-operative CT data is used to plane the surgery (select an implant type, size and precise position), and is registered to intra-operative X-ray images, allowing to execute the plan: mill a cavity with the implant's shape. (Intra-operative X-ray images must be calibrated with respect to the surgical device executing the plan). One novel technique presented in this paper consists of simulating a post-operative X-ray image of the tissue of interest before doing the procedure, by projecting the registered implant onto an intra-operative X- ray image (corrected for distortion or not), providing clinicians with familiar and easy to interpret images. As an additional benefit, this method provides new means for comparing various strategies for registering pre-operative data to the physical space of the operating room.

  19. Power spectrum analysis of the x-ray scatter signal in mammography and breast tomosynthesis projections.

    Science.gov (United States)

    Sechopoulos, Ioannis; Bliznakova, Kristina; Fei, Baowei

    2013-10-01

    To analyze the frequency domain characteristics of the signal in mammography images and breast tomosynthesis projections with patient tissue texture due to detected scattered x-rays. Acquisitions of x-ray projection images of 19 different patient breasts were simulated using previously acquired volumetric patient images. Acquisition of these images was performed with a dedicated breast CT prototype system, and the images were classified into voxels representing skin, adipose, and glandular tissue with a previously validated automated algorithm. The classified three dimensional images then underwent simulated mechanical compression representing that which is performed during acquisition of mammography and breast tomosynthesis images. The acquisition of projection images of each patient breast was simulated using Monte Carlo methods with each simulation resulting in two images: one of the primary (non-scattered) signal and one of the scatter signal. To analyze the scatter signal for both mammography and breast tomosynthesis, two projections images of each patient breast were simulated, one with the x-ray source positioned at 0° (mammography and central tomosynthesis projection) and at 30° (wide tomosynthesis projection). The noise power spectra (NPS) for both the scatter signal alone and the total signal (primary + scatter) for all images were obtained and the combined results of all patients analyzed. The total NPS was fit to the expected power-law relationship NPS(f) = k/f β and the results were compared with those previously published on the power spectrum characteristics of mammographic texture. The scatter signal alone was analyzed qualitatively and a power-law fit was also performed. The mammography and tomosynthesis projections of three patient breasts were too small to analyze, so a total of 16 patient breasts were analyzed. The values of β for the total signal of the 0° projections agreed well with previously published results. As expected, the scatter

  20. Gas scintillation glass GEM detector for high-resolution X-ray imaging and CT

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, T., E-mail: fujiwara-t@aist.go.jp [Research Institute for Measurement and Analytical Instrumentation, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Mitsuya, Y. [Nuclear Professional School, The University of Tokyo, Tokai, Naka, Ibaraki 319-1188 (Japan); Fushie, T. [Radiment Lab. Inc., Setagaya, Tokyo 156-0044 (Japan); Murata, K.; Kawamura, A.; Koishikawa, A. [XIT Co., Naruse, Machida, Tokyo 194-0045 (Japan); Toyokawa, H. [Research Institute for Measurement and Analytical Instrumentation, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Takahashi, H. [Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8654 (Japan)

    2017-04-01

    A high-spatial-resolution X-ray-imaging gaseous detector has been developed with a single high-gas-gain glass gas electron multiplier (G-GEM), scintillation gas, and optical camera. High-resolution X-ray imaging of soft elements is performed with a spatial resolution of 281 µm rms and an effective area of 100×100 mm. In addition, high-resolution X-ray 3D computed tomography (CT) is successfully demonstrated with the gaseous detector. It shows high sensitivity to low-energy X-rays, which results in high-contrast radiographs of objects containing elements with low atomic numbers. In addition, the high yield of scintillation light enables fast X-ray imaging, which is an advantage for constructing CT images with low-energy X-rays.

  1. Cranial x-ray CT and MRI in congenital muscular dystrophy

    International Nuclear Information System (INIS)

    Horikawa, Hirosei; Konishi, Toshihiko; Konagaya, Masaaki; Mano, Yukio; Takayanagi, Tetsuya

    1988-01-01

    The involvements of central nervous system in those cases of congenital muscular dystrophy (CMD), especially in Fukuyama type CMD, have been observed both radiologically and pathologically. The recent development of MRI made it easier to detect fine structural changes in brain matter than the X-ray CT. Then, we tried to evaluate the central nervous system abnormalities of six cases of CMD by both X-ray CT and MRI. In one case, X-ray CT revealed diffuse hypodensity of cerebral white matter, and MRI showed high intensity on long spin-echo image and low intensity on inversion-recovery image. In another case, X-ray CT showed no abnormal findings, but long spin-echo image revealed two high intensity spots in cerebral white matter. In other four cases, brain atrophy was demonstrated by X-ray CT and/or MRI, one case of these patients had bilateral congenital arachnoid cysts in the middle cranial fossa and hypogenesis of temporal lobes. Although we could not demonstrate polymicrogyria and agyria in all cases by MRI, white matter changes and structural changes were revealed more clearly than X-ray CT. The combination of X-ray CT and MRI seems to make a noteworthy contribution to estimate the central nervous system abnormalities in CMD. (author)

  2. Integrated image presentation of transmission and fluorescent X-ray CT using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zeniya, T.; Takeda, T. E-mail: ttakeda@md.tsukuba.ac.jp; Yu, Q.; Hasegawa, Y.; Hyodo, K.; Yuasa, T.; Hiranaka, Y.; Itai, Y.; Akatsuka, T

    2001-07-21

    We have developed a computed tomography (CT) system with synchrotron radiation (SR) to detect fluorescent X-rays and transmitted X-rays simultaneously. Both SR transmission X-ray CT (SR-TXCT) and SR fluorescent X-ray CT (SR-FXCT) can describe cross-sectional images with high spatial and contrast resolutions as compared to conventional CT. TXCT gives morphological information and FXCT gives functional information of organs. So, superposed display system for SR-FXCT and SR-TXCT images has been developed for clinical diagnosis with higher reliability. Preliminary experiment with brain phantom was carried out and the superposition of both images was performed. The superposed SR-CT image gave us both functional and morphological information easily with high reliability, thus demonstrating the usefulness of this system.

  3. Integrated image presentation of transmission and fluorescent X-ray CT using synchrotron radiation

    Science.gov (United States)

    Zeniya, T.; Takeda, T.; Yu, Q.; Hasegawa, Y.; Hyodo, K.; Yuasa, T.; Hiranaka, Y.; Itai, Y.; Akatsuka, T.

    2001-07-01

    We have developed a computed tomography (CT) system with synchrotron radiation (SR) to detect fluorescent X-rays and transmitted X-rays simultaneously. Both SR transmission X-ray CT (SR-TXCT) and SR fluorescent X-ray CT (SR-FXCT) can describe cross-sectional images with high spatial and contrast resolutions as compared to conventional CT. TXCT gives morphological information and FXCT gives functional information of organs. So, superposed display system for SR-FXCT and SR-TXCT images has been developed for clinical diagnosis with higher reliability. Preliminary experiment with brain phantom was carried out and the superposition of both images was performed. The superposed SR-CT image gave us both functional and morphological information easily with high reliability, thus demonstrating the usefulness of this system.

  4. Introduction of X-ray CT application in geotechnical engineering - theory and practice

    International Nuclear Information System (INIS)

    Otani, J; Watanabe, Y; Chevalier, B

    2010-01-01

    In this paper, fundamental issues on the use of X-ray CT to geomaterials were discussed, which were the contents of what you have to know about the use of X-ray CT, especially for geomaterials or granular materials. Then, two of our recent studies were introduced, which are 1) the use of X-ray CT data to quantitative measurements such as deformation and strains and 2) comparison of X-ray CT results with numerical analysis. Here, the triaxial compression test on sand was conducted and the image analysis technique called 'Digital Image Correlation' was used to measure displacement and strain fields in the soils using a large number of CT images. For the second topic, one of the advantages on the use of X-ray CT is to investigate the behavior in three dimensions. Here, so called trap door test was conducted with the materials of glass beads and the shape of the square door. DEM analysis was also conducted for the simulation of this behaviour and both results were compared. Based on all the results in this paper, the effectiveness of the use of X-ray CT in geomechanics and geotechnical engineering was revealed.

  5. Bone Mechanical Strength Estimation from Micro X-ray CT Image

    National Research Council Canada - National Science Library

    Matani, A

    2001-01-01

    ... (Bone Mineral Density), an index to evaluate the mechanical strength of the bone, does not always reflect the strength, On the other hand, micro X-ray CT has revealed the inner structure of bone, Under such circumstances...

  6. X-ray CT core imaging of Oman Drilling Project on D/V CHIKYU

    Science.gov (United States)

    Michibayashi, K.; Okazaki, K.; Leong, J. A. M.; Kelemen, P. B.; Johnson, K. T. M.; Greenberger, R. N.; Manning, C. E.; Harris, M.; de Obeso, J. C.; Abe, N.; Hatakeyama, K.; Ildefonse, B.; Takazawa, E.; Teagle, D. A. H.; Coggon, J. A.

    2017-12-01

    We obtained X-ray computed tomography (X-ray CT) images for all cores (GT1A, GT2A, GT3A and BT1A) in Oman Drilling Project Phase 1 (OmanDP cores), since X-ray CT scanning is a routine measurement of the IODP measurement plan onboard Chikyu, which enables the non-destructive observation of the internal structure of core samples. X-ray CT images provide information about chemical compositions and densities of the cores and is useful for assessing sample locations and the quality of the whole-round samples. The X-ray CT scanner (Discovery CT 750HD, GE Medical Systems) on Chikyu scans and reconstructs the image of a 1.4 m section in 10 minutes and produces a series of scan images, each 0.625 mm thick. The X-ray tube (as an X-ray source) and the X-ray detector are installed inside of the gantry at an opposing position to each other. The core sample is scanned in the gantry with the scanning rate of 20 mm/sec. The distribution of attenuation values mapped to an individual slice comprises the raw data that are used for subsequent image processing. Successive two-dimensional (2-D) slices of 512 x 512 pixels yield a representation of attenuation values in three-dimensional (3-D) voxels of 512 x 512 by 1600 in length. Data generated for each core consist of core-axis-normal planes (XY planes) of X-ray attenuation values with dimensions of 512 × 512 pixels in 9 cm × 9 cm cross-section, meaning at the dimensions of a core section, the resolution is 0.176 mm/pixel. X-ray intensity varies as a function of X-ray path length and the linear attenuation coefficient (LAC) of the target material is a function of the chemical composition and density of the target material. The basic measure of attenuation, or radiodensity, is the CT number given in Hounsfield units (HU). CT numbers of air and water are -1000 and 0, respectively. Our preliminary results show that CT numbers of OmanDP cores are well correlated to gamma ray attenuation density (GRA density) as a function of chemical

  7. Estimation of effective dose from limited cone beam X-ray CT examination

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Kazuo; Arai, Yoshinori; Hashimoto, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Nishizawa, Kanae

    2000-12-01

    The limited cone beam X-ray CT (Ortho-CT) was developed on the basis of multi-functional panoramic apparatus, SCANORA (Soredex Co. Helsinki Finland). The imaging intensifier (I.I.) was built in this apparatus as a X-ray detection device instead of X-ray film. The signal provided from I.I. was converted from analog into digital by an analog-digital converter and image reconstitution was done as a three-directional image of the dimensions 3.8 cm of width, 3.0 cm height and 3.8 cm depth with the personal computer. The 3DX Multi image micro CT'' (3DX) was developed along similar lines by MORITA Co., Ltd. (Kyoto, JAPAN). In this study, the stochastic effect on organ and tissue caused by examinations using Ortho-CT and 3DX was measured. The effective dose was estimated according to the recommendation of ICRP60 and was compared with those of panoramic radiography and computed tomography. The irradiation conditions were as follows: 85 kV, 10 mA with the filtration of 3 mmAl and added 1 mmCu for Ortho-CT, and 80 kV, 2 mA and the filtration of 3.1 mmAL for 3DX. The measurement of organ and tissue dose was performed using an anthropomorphic Rando woman phantom (Alderson Research Laboratories Co., Stanfora, CN), as well as by using two different type of thermoluminescent dosimeter (TLD); Panasonic UD-170A (BeO) and UD-110S (CaSO{sub 4}: Tm). The UD-170A was for dose measurement of the inner useful X-ray beams, while the UD-110S was for outer beams. The measured organ and tissue were those recommended with ICRP60 (gonad, breast, bone marrow, lung, thyroid gland, esophagus, stomach, colon, liver, bladder, skin, brain, thymus, adrenal, kidney, spleen, pancrease, upper large intestine, uterus, eyes and major salivary gland). The imaging by Orhto-CT was made in the left maxillary 1st molar, left mandibular 1st molar and temporomandibular joint. 3DX measurement was made in the maxillary incisor region and middle ear regions other than the regions mentioned above. The skin

  8. A framework for breast cancer visualization using augmented reality x-ray vision technique in mobile technology

    Science.gov (United States)

    Rahman, Hameedur; Arshad, Haslina; Mahmud, Rozi; Mahayuddin, Zainal Rasyid

    2017-10-01

    Breast Cancer patients who require breast biopsy has increased over the past years. Augmented Reality guided core biopsy of breast has become the method of choice for researchers. However, this cancer visualization has limitations to the extent of superimposing the 3D imaging data only. In this paper, we are introducing an Augmented Reality visualization framework that enables breast cancer biopsy image guidance by using X-Ray vision technique on a mobile display. This framework consists of 4 phases where it initially acquires the image from CT/MRI and process the medical images into 3D slices, secondly it will purify these 3D grayscale slices into 3D breast tumor model using 3D modeling reconstruction technique. Further, in visualization processing this virtual 3D breast tumor model has been enhanced using X-ray vision technique to see through the skin of the phantom and the final composition of it is displayed on handheld device to optimize the accuracy of the visualization in six degree of freedom. The framework is perceived as an improved visualization experience because the Augmented Reality x-ray vision allowed direct understanding of the breast tumor beyond the visible surface and direct guidance towards accurate biopsy targets.

  9. A new cone-beam X-ray CT system with a reduced size planar detector

    International Nuclear Information System (INIS)

    Li Liang; Chen Zhiqiang; Zhang Li; Xing Yuxiang; Kang Kejun

    2006-01-01

    In a traditional cone-beam CT system, the cost of product and computation is very high. The authors propose a transversely truncated cone-beam X-ray CT system with a reduced size detector positioned off-center, in which X-ray beams only cover half of the object. The reduced detector size cuts the cost and the X-ray dose of the CT system. The existing CT reconstruction algorithms are not directly applicable in this new CT system. Hence, the authors develop a BPF-type direct backprojection algorithm. Different from the traditional rebinding methods, our algorithm directly backprojects the pretreated projection data without rebinding. This makes the algorithm compact and computationally more efficient. Finally, some numerical simulations and practical experiments are done to validate the proposed algorithm. (authors)

  10. Frameless image registration of X-ray CT and SPECT by volume matching

    International Nuclear Information System (INIS)

    Tanaka, Yuko; Kihara, Tomohiko; Yui, Nobuharu; Kinoshita, Fujimi; Kamimura, Yoshitsugu; Yamada, Yoshifumi.

    1998-01-01

    Image registration of functional (SPECT) and morphological (X-ray CT/MRI) images is studied in order to improve the accuracy and the quantity of the image diagnosis. We have developed a new frameless registration method of X-ray CT and SPECT image using transmission CT image acquired for absorption correction of SPECT images. This is the automated registration method and calculates the transformation matrix between the two coordinate systems of image data by the optimization method. This registration method is based on the similar physical property of X-ray CT and transmission CT image. The three-dimensional overlap of the bone region is used for image matching. We verified by a phantom test that it can provide a good result of within two millimeters error. We also evaluated visually the accuracy of the registration method by the application study of SPECT, X-ray CT, and transmission CT head images. This method can be carried out accurately without any frames. We expect this registration method becomes an efficient tool to improve image diagnosis and medical treatment. (author)

  11. Analysis of local concentration in stomach fold pattern by using abdominal X-ray CT image

    International Nuclear Information System (INIS)

    Watanabe, Shigeto; Hasegawa, Jun-ichi; Mekada, Yoshito; Mori, Kensaku; Nawano, Shigeru

    2004-01-01

    The paper presents a method for analysis of stomach folds pattern in abdominal X-ray CT images. Many stomach cancers have local concentration of folds at cancer lesions. Therefore, in stomach diagnosis, it is very important to evaluate quantitatively such fold concentration. In this paper, a method for calculation of concentration index for line figure on a curved surface is proposed first. Then, using this method a processing procedure for detection of stomach cancer from an abdominal X-ray CT image is developed. In the experiment using practical X-ray CT images, it is shown that by the proposed procedure, higher values of concentration index are obtained at cancer area. (author)

  12. Development and application of an educational 3D X-ray CT instrument

    International Nuclear Information System (INIS)

    Arakawa, Etsuo; Iwami, Ryutaro; Motohisa, Yasuko; Kamezawa, Chika; Kamogawa, Masashi; Voegeli, Wolfgang

    2016-01-01

    A three-dimensional (3D) X-ray computed tomography (CT) instrument for radiation education was developed. The structure of the instrument is such that the main parts, i.e. the X-ray source, specimen rotation stage, and two-dimensional detector can be easily observed. An experiment using a fruit of green pepper as a specimen was performed. CT images and intermediate steps for obtaining them, i.e. radiographs, sinograms after Radon transform, and real and imaginary parts of Fourier components in reciprocal space during inverse Radon transform are shown. We propose that these images will help students to understand the principle and mechanism of X-ray CT instruments visually. (author)

  13. Polymer gel dosimeters with enhanced sensitivity for use in x-ray CT polymer gel dosimetry

    International Nuclear Information System (INIS)

    Jirasek, A; Hilts, M; McAuley, K B

    2010-01-01

    A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. The low contrast is largely due to the low-dose sensitivity of current formulations of polymer gel for x-ray CT imaging. This study reports on the investigation of new dosimeter formulations with improved dose sensitivity for x-ray CT polymer gel dosimetry. We incorporate an isopropanol co-solvent into an N-isopropylacrylamide-based gel formulation in order to increase the total monomer/crosslinker concentration (%T) within the formulation. It is shown that gels of high %T exhibit enhanced dose sensitivity and dose resolutions over traditional formulations. The gels are shown to be temporally stable and reproducible. A single formulation (16%T) is used to demonstrate the capabilities of the x-ray CT polymer gel dosimetry system in measuring known dose distributions. A 1 L gel volume is exposed to three separate irradiations: a single-field percent depth dose, a two-field 'cross' and a three-field 'test case'. The first two irradiations are used to generate a dose calibration curve by which images are calibrated. The calibrated images are compared with treatment planning predictions and it is shown that the x-ray CT polymer gel dosimetry system is capable of capturing spatial and dose information accurately. The proposed new gel formulation is shown to be sensitive, stable and to improve the dose resolution over current formulations so as to provide a feasible gel for clinical applications of x-ray CT polymer gel dosimetry.

  14. Polymer gel dosimeters with enhanced sensitivity for use in x-ray CT polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria BC V8W 3P6 (Canada); Hilts, M [Medical Physics, BC Cancer Agency-Vancouver Island Centre, Victoria BC V6R 2B6 (Canada); McAuley, K B, E-mail: jirasek@uvic.c [Department of Chemical Engineering, Queens University, Kingston, ON K7 L 3N6 (Canada)

    2010-09-21

    A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. The low contrast is largely due to the low-dose sensitivity of current formulations of polymer gel for x-ray CT imaging. This study reports on the investigation of new dosimeter formulations with improved dose sensitivity for x-ray CT polymer gel dosimetry. We incorporate an isopropanol co-solvent into an N-isopropylacrylamide-based gel formulation in order to increase the total monomer/crosslinker concentration (%T) within the formulation. It is shown that gels of high %T exhibit enhanced dose sensitivity and dose resolutions over traditional formulations. The gels are shown to be temporally stable and reproducible. A single formulation (16%T) is used to demonstrate the capabilities of the x-ray CT polymer gel dosimetry system in measuring known dose distributions. A 1 L gel volume is exposed to three separate irradiations: a single-field percent depth dose, a two-field 'cross' and a three-field 'test case'. The first two irradiations are used to generate a dose calibration curve by which images are calibrated. The calibrated images are compared with treatment planning predictions and it is shown that the x-ray CT polymer gel dosimetry system is capable of capturing spatial and dose information accurately. The proposed new gel formulation is shown to be sensitive, stable and to improve the dose resolution over current formulations so as to provide a feasible gel for clinical applications of x-ray CT polymer gel dosimetry.

  15. TU-EF-207-03: Advances in Stationary Breast Tomosynthesis Using Distributed X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, O. [The University of North Carolina at Chapel Hill (United States)

    2015-06-15

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation.

  16. TU-EF-207-03: Advances in Stationary Breast Tomosynthesis Using Distributed X-Ray Sources

    International Nuclear Information System (INIS)

    Zhou, O.

    2015-01-01

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation

  17. Micron-CT using quasi-monochromatic x-rays produced in micro-PIXE

    International Nuclear Information System (INIS)

    Ishii, K.

    2009-01-01

    In ion-atom collision, characteristic X-rays are intensively produced and can be considered as a monochromatic X-ray source. We apply this feature to X-ray CT. By using micro-beams, cross sectional images can be provided with a spatial resolution of about 1 μm. On the basis of this idea, we developed a micron-CT consisting of a micro-beam system and an X-ray CCD camera. A tube holding samples was rotated by a stepping motor and the transmission images of the sample were taken with characteristic K-X-rays of Ti (4.558 keV) produced by 3 MeV proton micro-beams. After image reconstruction, images of cross sections of small objects were obtained with a spatial resolution of 3 μm. Using an absorption edge, we can identify an element in a sample. It is expected that our micron-CT can provide cross sectional images of in-vivo cellular samples and can be applied to a wide range of researches in biology and medicine. (author)

  18. X-ray and CT diagnosis of intraosseous ganglion

    International Nuclear Information System (INIS)

    Gong Xiangyang; Zhang Weimin; Yan Shigui

    2002-01-01

    Objective: To investigate the pathogenesis, clinical manifestations, imaging features, and differential diagnosis of intraosseous ganglion. Methods: Clinical and imaging features of 15 cases (5 men, 10 women; mean age 39.7 years) with intraosseous ganglia were retrospectively analyzed. There were 17 lesions, including 6 acetabular, 4 lunate, 3 proximal ends of tibia, 1 major tuberculum of humeral, 1 femoral head, 1 scaphoid, and 1 phalange. Results: ( 1 ) Common radiological features included a unilocular or multilocular cyst surrounded by a full and thin rim of sclerotic: bone in the subchondral epiphysis without any signs of degenerative joint disease. (2) Lesions were displayed as well-defined round radiolucent defect or multi-cystic changes with surrounding bony sclerosis or cystic and expansile change with irregular shape on CT scans. (3) CT showed an intraosseous ganglion communicating with adjacent joint in 1 patient. (4) CT values of the lesions were between 15 - 80 HU. (5) Gas in the cyst could be seen in 3 cases. Conclusion: Combined with patient's age, lesion distribution, clinical manifestations, and imaging features, it is possible to make a correct diagnosis of intraosseous ganglion

  19. A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Round, A R [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Wilkinson, S J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Hall, C J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Rogers, K D [Department of Materials and Medical Sciences, Cranfield University, Swindon, SN6 8LA (United Kingdom); Glatter, O [Department of Chemistry, University of Graz (Austria); Wess, T [School of Optometry and Vision Sciences, Cardiff University, Cardiff CF10 3NB, Wales (United Kingdom); Ellis, I O [Nottingham City Hospital, Nottingham (United Kingdom)

    2005-09-07

    Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.

  20. A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

    International Nuclear Information System (INIS)

    Round, A R; Wilkinson, S J; Hall, C J; Rogers, K D; Glatter, O; Wess, T; Ellis, I O

    2005-01-01

    Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique

  1. A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

    Science.gov (United States)

    Round, A. R.; Wilkinson, S. J.; Hall, C. J.; Rogers, K. D.; Glatter, O.; Wess, T.; Ellis, I. O.

    2005-09-01

    Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.

  2. The CT Scanner Facility at Stellenbosch University: An open access X-ray computed tomography laboratory

    Science.gov (United States)

    du Plessis, Anton; le Roux, Stephan Gerhard; Guelpa, Anina

    2016-10-01

    The Stellenbosch University CT Scanner Facility is an open access laboratory providing non-destructive X-ray computed tomography (CT) and a high performance image analysis services as part of the Central Analytical Facilities (CAF) of the university. Based in Stellenbosch, South Africa, this facility offers open access to the general user community, including local researchers, companies and also remote users (both local and international, via sample shipment and data transfer). The laboratory hosts two CT instruments, i.e. a micro-CT system, as well as a nano-CT system. A workstation-based Image Analysis Centre is equipped with numerous computers with data analysis software packages, which are to the disposal of the facility users, along with expert supervision, if required. All research disciplines are accommodated at the X-ray CT laboratory, provided that non-destructive analysis will be beneficial. During its first four years, the facility has accommodated more than 400 unique users (33 in 2012; 86 in 2013; 154 in 2014; 140 in 2015; 75 in first half of 2016), with diverse industrial and research applications using X-ray CT as means. This paper summarises the existence of the laboratory's first four years by way of selected examples, both from published and unpublished projects. In the process a detailed description of the capabilities and facilities available to users is presented.

  3. The CT Scanner Facility at Stellenbosch University: An open access X-ray computed tomography laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, Anton du, E-mail: anton2@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa); Physics Department, Stellenbosch University, Stellenbosch (South Africa); Roux, Stephan Gerhard le, E-mail: lerouxsg@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa); Guelpa, Anina, E-mail: aninag@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa)

    2016-10-01

    The Stellenbosch University CT Scanner Facility is an open access laboratory providing non-destructive X-ray computed tomography (CT) and a high performance image analysis services as part of the Central Analytical Facilities (CAF) of the university. Based in Stellenbosch, South Africa, this facility offers open access to the general user community, including local researchers, companies and also remote users (both local and international, via sample shipment and data transfer). The laboratory hosts two CT instruments, i.e. a micro-CT system, as well as a nano-CT system. A workstation-based Image Analysis Centre is equipped with numerous computers with data analysis software packages, which are to the disposal of the facility users, along with expert supervision, if required. All research disciplines are accommodated at the X-ray CT laboratory, provided that non-destructive analysis will be beneficial. During its first four years, the facility has accommodated more than 400 unique users (33 in 2012; 86 in 2013; 154 in 2014; 140 in 2015; 75 in first half of 2016), with diverse industrial and research applications using X-ray CT as means. This paper summarises the existence of the laboratory’s first four years by way of selected examples, both from published and unpublished projects. In the process a detailed description of the capabilities and facilities available to users is presented.

  4. X-ray, CT and MRI findings of synovial tuberculosis in joints

    International Nuclear Information System (INIS)

    Yu Jinghong; Tao Meili; You Zhuangzhi; Yu Huazhi

    2006-01-01

    Objective: To analyze the X-ray, CT and MRI findings of synovial tuberculosis, and to evaluate the role of MRI in diagnosing synovial tuberculosis. Methods: Fourteen cases of synovial tuberculosis comfirmed by operation and pathology were retrospectively analyzed and summarized. All patients were examined by MRI and X-ray, and CT scans were performed in 3 cases. Results: X-ray showed joint swelling (8 cases), articular space narrowing (7 cases), marginal joint erosions (4 cases), and periarticular osteoporosis (9 cases). The joint swelling was detected on CT in all 3 cases, and bony erosion and speckled sequestra were seen in 2 cases. MRI in all of patients showed joint swelling and synovial proliferation in different drgees, demonstrated as heterogeneously low signal on T 1 WI and slight high signal (7 cases) and obvious high signal (6 cases) on T 2 WI, and diffuse synovial proliferation was demonstrated as massive and nodular signal in 8 cases. Joint effusion was present in 7 cases as low signal on T 1 WI and high signal on T 2 WI. Osseous erosion lesions were seen in 7 cases, and intra-articular cartilage thinned, partly or mostly disappeared in 11 cases. Periarticular bone marrow edema was found in 7 cases. Conclusion: MRI was superior to X-ray and CT in the diagnosis and differential diagnosis of synovial tuberculosis. (authors)

  5. Head injury in childhood: comparison of sonography with the conventional X-ray and CT

    International Nuclear Information System (INIS)

    Steiner, S.; Riebel, T.; Nazarenko, O.; Bassir, C.; Steger, W.; Vogl, T.; Felix, R.

    1996-01-01

    Purpose: The purpose of our study was to compare the value of ultrasound, conventional X-ray diagnosis and CT in detecting skull fractures and intracranial haemorrhage in children suffering from a head injury. Material and methods: We examined 210 children who had a head injury. In all cases the calvarium was investigated by ultrasound using a 7.0 MHz linear transducer. In children with an open fontanel (n=190) the cerebrum was screened additionally by ultrasound following a standard protocol. The sonographic findings were correlated to the X-ray examination (n=21) and CT (n=13). Results: Ultrasound enabled diagnosis of linear calvarial fractures (n=29), depressed fratures (n=6) and intracranial haemorrhage (n=8). X-Ray and XT examination confirmed the diagnosis of linear calvarial fractures in 16 cases, of depressed fractures in 6 cases. CT confirmed the sonographic diagnosis of intracranial haemorrhage in 8 cases. Conclusion: Ultrasound as a primary method can replace the conventional X-ray in detecting calvarial fracture and posttraumatic sequelae. Additional CT examination depends on the sonographic and neurological status. (orig.) [de

  6. X-ray CT high-density artefact suppression in cryosurgery

    International Nuclear Information System (INIS)

    Wei Jikun; Sandison, George A; Chen Laigao; Liang Yun; Xu, Lisa X

    2002-01-01

    Advantages of x-ray CT for imaging guidance of cryosurgery include 3D visualization of frozen and unfrozen tissue and calibration of temperature in the tissue water-ice interface (0-10 deg. C) to Hounsfield units. However, use of x-ray CT images and their thermal calibration can be compromised by the cryoprobes generating high-density streak artefacts. A new subtraction technique for artefact suppression is proposed and tested in prostate cryosurgery simulations. By subtracting the measured CT x-ray projection profile without cryoprobes from the profile with cryoprobes plus iceballs, one obtains the combined profile of the cryoprobes and a low value background. Polynomial interpolation to obtain the background profile allows its addition to the original profile without probes. The result may then be fed to a conventional filtered back-projection routine to reconstruct the probe-free image. Finally the cryoprobe pixels in the originally constructed image with probes and iceballs are added back to the probe-free image to get the final artefact-suppressed image. The major advantage of this subtraction technique is that it can successfully suppress the high-density artefacts in bone-abundant body regions such as the pelvis. X-ray CT images of cryoprobe arrays in a homogeneous gelatin phantom and the pelvic region of an anthropomorphic Rando phantom containing a human skeleton were generated. After suppression, cryoprobe metal artefact streaks are reduced and visualization of the positions and dimensions of the cryoprobes are well preserved. (note)

  7. Grating Oriented Line-Wise Filtration (GOLF) for Dual-Energy X-ray CT

    Science.gov (United States)

    Xi, Yan; Cong, Wenxiang; Harrison, Daniel; Wang, Ge

    2017-12-01

    In medical X-ray Computed Tomography (CT), the use of two distinct X-ray source spectra (energies) allows dose-reduction and material discrimination relative to that achieved with only one source spectrum. Existing dual-energy CT methods include source kVp-switching, double-layer detection, dual-source gantry, and two-pass scanning. Each method suffers either from strong spectral correlation or patient-motion artifacts. To simultaneously address these problems, we propose to improve CT data acquisition with the Grating Oriented Line-wise Filtration (GOLF) method, a novel X-ray filter that is placed between the source and patient. GOLF uses a combination of absorption and filtering gratings that are moved relative to each other and in synchronization with the X-ray tube kVp-switching process and/or the detector view-sampling process. Simulation results show that GOLF can improve the spectral performance of kVp-switching to match that of dual-source CT while avoiding patient motion artifacts and dual imaging chains. Although significant flux is absorbed by this pre-patient filter, the proposed GOLF method is a novel path for cost-effectively extracting dual-energy or multi-energy data and reducing radiation dose with or without kVp switching.

  8. Study on optical properties of ceramics scintillator for X-ray CT equipment. (Pt. 2)

    International Nuclear Information System (INIS)

    Nakamura, Ryouhei; Tsukuda, Yasuo; Nitanda, Humio

    1993-01-01

    The scintillator elements in X-ray CT equipment of the third generation type require high uniformity of distribution of light output as well as quality response characteristic. Parameters responsible for the distribution of light output were studied using the Monte Carlo method. Although the scattering coefficient was neglected, close agreement was obtained between calculated and experimental results. Calculated results indicated that relative output drop at both ends decreased with increasing optical absorption coefficient and was constant for X-ray absorption factor. (author)

  9. Development of high-resolution x-ray CT system using parallel beam geometry

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Akio, E-mail: akio.yoneyama.bu@hitachi.com; Baba, Rika [Central Research Laboratory, Hitachi Ltd., Hatoyama, Saitama (Japan); Hyodo, Kazuyuki [Institute of Materials Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Takeda, Tohoru [School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa (Japan); Nakano, Haruhisa; Maki, Koutaro [Department of Orthodontics, School of Dentistry Showa University, Ota-ku, Tokyo (Japan); Sumitani, Kazushi; Hirai, Yasuharu [Kyushu Synchrotron Light Research Center, Tosu, Saga (Japan)

    2016-01-28

    For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

  10. Use of a priori information in incomplete data x-ray CT imaging

    International Nuclear Information System (INIS)

    Eberhard, J.W.; Hedengren, K.H.

    1988-01-01

    A new technique for utilizing a priori information is presented which uses CAD electronic part models to make use of effectively all the information which is available in the blueprint of a selected industrial part. Significant improvements in x-ray image quality are demonstrated using the technique in the image enhancement of the model of an exhaust nozzle actuation ring for the F110 aircraft. Three approaches were evaluated: a projection data approach, an iterative reconstruction approach, and an image processing and analysis approach. Results for these approaches are included. X-ray CT images of the simulated part image reconstructed with several choices of available angular range are shown

  11. High energy X-ray CT system using a linear accelerator for automobile parts inspection

    International Nuclear Information System (INIS)

    Kanamori, T.; Sukita, T.

    1995-01-01

    A high energy X-ray CT system (maximum photon energy: 0.95 MeV) has been developed for industrial use. This system employs a linear accelerator as an X-ray source. It is able to image the cross section of automobile parts and can be applied to a solidification analysis study of the cylinder head in an automobile. This paper describes the features of the system and application results which can be related to solidification analysis of the cylinder head when fabricated from an aluminum casting. Some cross-sectional images are also presented as evidence for nondestructive inspection of automobile parts. (orig.)

  12. Interferometric phase-contrast X-ray CT imaging of VX2 rabbit cancer at 35keV X-ray energy

    Science.gov (United States)

    Takeda, Tohoru; Wu, Jin; Tsuchiya, Yoshinori; Yoneyama, Akio; Lwin, Thet-Thet; Hyodo, Kazuyuki; Itai, Yuji

    2004-05-01

    Imaging of large objects at 17.7-keV low x-ray energy causes huge x-ray exposure to the objects even using interferometric phase-contrast x-ray CT (PCCT). Thus, we tried to obtain PCCT images at high x-ray energy of 35keV and examined the image quality using a formalin-fixed VX2 rabbit cancer specimen with 15-mm in diameter. The PCCT system consisted of an asymmetrically cut silicon (220) crystal, a monolithic x-ray interferometer, a phase-shifter, an object cell and an x-ray CCD camera. The PCCT at 35 keV clearly visualized various inner structures of VX2 rabbit cancer such as necrosis, cancer, the surrounding tumor vessels, and normal liver tissue. Besides, image-contrast was not degraded significantly. These results suggest that the PCCT at 35 KeV is sufficient to clearly depict the histopathological morphology of VX2 rabbit cancer specimen.

  13. Application of small-angle X-ray scattering for differentiation among breast tumors

    International Nuclear Information System (INIS)

    Changizi, V.; Kheradmand, A. Arab; Oghabian, M.A.

    2008-01-01

    Small-angle X-ray scattering (SAXS) is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe) detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6 deg scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer) of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 ), mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 ), fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 ) and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 ). We were able to differentiate between normal, fibrocystic changes (benign) and carcinoma (malignant) breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma. (author)

  14. Application of small-angle X-ray scattering for differentiation among breast tumors

    Directory of Open Access Journals (Sweden)

    Changizi V

    2008-01-01

    Full Text Available Small-angle X-ray scattering (SAXS is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6° scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 , mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 , fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 . We were able to differentiate between normal, fibrocystic changes (benign and carcinoma (malignant breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma.

  15. The methods for detecting multiple small nodules from 3D chest X-ray CT images

    International Nuclear Information System (INIS)

    Hayase, Yosuke; Mekada, Yoshito; Mori, Kensaku; Toriwaki, Jun-ichiro; Natori, Hiroshi

    2004-01-01

    This paper describes a method for detecting small nodules, whose CT values and diameters are more than -600 Hounsfield unit (H.U.) and 2 mm, from three-dimensional chest X-ray CT images. The proposed method roughly consists of two submodules: initial detection of nodule candidates by discriminating between nodule regions and other regions such as blood vessels or bronchi using a shape feature computed from distance values inside the regions and reduction of false positive (FP) regions by using a minimum directional difference filter called minimum directional difference filter (Min-DD) changing its radius suit to the size of the initial candidates. The performance of the proposed method was evaluated by using seven cases of chest X-ray CT images including six abnormal cases where multiple lung cancers are observed. The experimental results for nodules (361 regions in total) showed that sensitivity and FP regions are 71% and 7.4 regions in average per case. (author)

  16. High-energy x-ray CT and its application for digital engineering

    International Nuclear Information System (INIS)

    Kamimura, H.; Sadaoka, N.

    2005-01-01

    A high-energy x-ray computed tomography system and x-ray CT data handling software have been developed for digital engineering; internal dimension measurement, density analysis, actual and designed shape comparison, STL file generation, and support for reverse engineering and rapid prototyping. The system is designed to collect accurate images in short scanning time (10 s per section) using a MeV-energy electron linear accelerator and highly sensitive semiconductor detectors in order to scan large objects made of aluminum and/or iron. An excellent environment in digital engineering is provided by the software products; 'StereoCooker' for 3D bitmap CAD (rendering, feature extraction, dimensional measurement, and shape comparison, etc.), 'FeatureMaker' for translating bitmap CT data to CAD data including feature information, and 'Wingware' for realizing an Windows PC cluster system 'WINGluster' to apply CT data analysis. (author)

  17. Dosimetric comparison between CT and X-ray simulation of radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Kali Ayguli, Zhang Jinrong; Wang Juwu; Ge Feng; Wang Haifeng; Xu Suling

    2007-01-01

    Objective: To compare radiotherapy plan of conventional X-ray simulation with CT simulation by 3D-TPS for lung cancer. Methods: Thirty-three patients were allotted to receive both conventional X-ray simulation and CT simulation in the same treatment position. 3D-TPS was used to design 4-field conventional plan of X-ray simulation (RT), 4-field two dimensional plan(2D)and three dimensional conformal radiation plan(3DCRT) of CT simulation for all patients. The total dose was 50 Gy. Dose volume histogram(DVH) was applied to evaluate the difference of target coverage, dose distribution and normal tissue protection among the three plans. Results: 3DCRT and 2D based on CT simulation were superior to RT in the target coverage, target conformity index (TCI) and target homogeneity (TH) (P 20 , V 30 and mean lung dose were similar among 3DCRT, 2D and RT plans. Moreover, the maximum doses of spinal cord were significantly different among the three plans. No statistical differences of doses to 30% of the heart and esophagus volume among the three plans were observed. Conclusions: There is significantly better tumour volume coverage in CT simulation when compared with X-ray conventional simulation. Target volume delineation by CT simulation is improved significantly. The dose distribution is improved by using three dimensional treatment planning system. 3DCRT plan is superior to 2D plans in target conformity index and target homogeneity. Doses delivered to organs surrounding the target such as lung and heart were reduced significantly in 3DCRT. (authors)

  18. Quantitative measurement of lung density with x-ray CT and positron CT, (2). Diseased subjects

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kengo; Ito, Masatoshi; Kubota, Kazuo

    1985-05-01

    Lung density was quantitatively measured on six diseased patients with X-ray CT (XCT) and Positron CT(PCT). The findings are as follows: In the silicosis, extravascular lung density was found to be remarkably increased compared to normals (0.29gcm/sup 3/), but blood volume was in normal range. In the post-irradiated lung cancers, extravascular lung density increased in the irradiated sites compared to the non-irradiated opposite sites, and blood volume varied in each case. In a patient with chronic heart failure, blood volume decreased (0.11mlcm/sup 3/) with increased extravascular lung density (0.23gcm/sup 3/). In the chronic obstructive pulmonary disease, both extravascular lung density and blood volume decreased (0.11gcm/sup 3/ and 0.10mlcm/sup 3/ respectively). Lung density measured with XCT was constantly lower than that with PCT in all cases. But changes in the values of lung density measured, correlated well with each other. In conclusion, the method presented here may clarify the etiology of the diffuse pulmonary diseases, and be used to differentiate and grade the diseases.

  19. Quantitative measurement of lung density with x-ray CT and positron CT, (2)

    International Nuclear Information System (INIS)

    Ito, Kengo; Ito, Masatoshi; Kubota, Kazuo

    1985-01-01

    Lung density was quantitatively measured on six diseased patients with X-ray CT (XCT) and Positron CT(PCT). The findings are as follows: In the silicosis, extravascular lung density was found to be remarkably increased compared to normals (0.29gcm -3 ), but blood volume was in normal range. In the post-irradiated lung cancers, extravascular lung density increased in the irradiated sites compared to the non-irradiated opposite sites, and blood volume varied in each case. In a patient with chronic heart failure, blood volume decreased (0.11mlcm -3 ) with increased extravascular lung density (0.23gcm -3 ). In the chronic obstructive pulmonary disease, both extravascular lung density and blood volume decreased (0.11gcm -3 and 0.10mlcm -3 respectively). Lung density measured with XCT was constantly lower than that with PCT in all cases. But changes in the values of lung density measured, correlated well with each other. In conclusion, the method presented here may clarify the etiology of the diffuse pulmonary diseases, and be used to differentiate and grade the diseases. (author)

  20. Synchrotron X-ray CT of rose peduncles. Evaluation of tissue damage by radiation

    International Nuclear Information System (INIS)

    Herppich, Werner B.; Zabler, Simon; Dawson, Martin; Choinka, Gerard; Manke, Ingo

    2015-01-01

    ''Bent-neck'' syndrome, an important postharvest problem of cut roses, is probably caused by water supply limitations and/or the structural weakness of vascular bundles of the peduncle tissue. For this reason, advanced knowledge about the microstructures of rose peduncles and their cultivar specific variations may lead to a better understanding of the underlying mechanisms. Synchrotron X-ray computed tomography (SXCT), especially phase-based CT, is a highly suitable technique to nondestructively investigate plants' micro anatomy. SXCT with monochromatic X-ray beams of 30, 40 and 50 keV photon energy was used to evaluate the three-dimensional inner structures of the peduncles of 3 rose cultivars that differ greatly in their bent-neck susceptibility. Results indicated that this technique achieves sufficiently high spatial resolution to investigate complex tissues. However, further investigations with chlorophyll fluorescence analysis (CFA) and optical microscope imagery reveal different kinds of heavy damage of the irradiated regions induced by synchrotron X-rays; in a cultivar-specific manner, partial destruction of cell walls occurred a few hours after X-ray irradiation. Furthermore, a delayed inhibition of photosynthesis accompanied by the degradation of chlorophyll was obvious from CFA within hours and days after the end of CT measurements. Although SXCT is certainly well suited for three-dimensional anatomical analysis of rose peduncles, the applied technique is not nondestructive.

  1. Synchrotron X-ray CT of rose peduncles. Evaluation of tissue damage by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Herppich, Werner B. [Leibniz-Institut fuer Agrartechnik Potsdam-Bornim e.V., Potsdam (Germany). Abt. Technik im Gartenbau; Matsushima, Uzuki [Iwate Univ., Morioka (Japan). Faculty of Agriculture; Graf, Wolfgang [Association for Technology and Structures in Agriculture (KTBL), Darmstadt (Germany); Zabler, Simon [Fraunhofer-Institut fuer Integrierte Schaltungen (IIS), Wuerzburg (Germany). Project group NanoCT Systems (NCTS); Dawson, Martin [Salford Univ., Greater Manchester (United Kingdom); Choinka, Gerard; Manke, Ingo [Helmholtz Center Berlin for Materials and Energy (HZB), Berlin (Germany)

    2015-02-01

    ''Bent-neck'' syndrome, an important postharvest problem of cut roses, is probably caused by water supply limitations and/or the structural weakness of vascular bundles of the peduncle tissue. For this reason, advanced knowledge about the microstructures of rose peduncles and their cultivar specific variations may lead to a better understanding of the underlying mechanisms. Synchrotron X-ray computed tomography (SXCT), especially phase-based CT, is a highly suitable technique to nondestructively investigate plants' micro anatomy. SXCT with monochromatic X-ray beams of 30, 40 and 50 keV photon energy was used to evaluate the three-dimensional inner structures of the peduncles of 3 rose cultivars that differ greatly in their bent-neck susceptibility. Results indicated that this technique achieves sufficiently high spatial resolution to investigate complex tissues. However, further investigations with chlorophyll fluorescence analysis (CFA) and optical microscope imagery reveal different kinds of heavy damage of the irradiated regions induced by synchrotron X-rays; in a cultivar-specific manner, partial destruction of cell walls occurred a few hours after X-ray irradiation. Furthermore, a delayed inhibition of photosynthesis accompanied by the degradation of chlorophyll was obvious from CFA within hours and days after the end of CT measurements. Although SXCT is certainly well suited for three-dimensional anatomical analysis of rose peduncles, the applied technique is not nondestructive.

  2. Status of X-ray CT photography in the radiology department of our school of dentistry

    International Nuclear Information System (INIS)

    Hokari, Seishi; Takahashi, Nobutoshi; Tsutsumi, Hiroyuki; Shirai, Yoshihiro; Inoue, Hiroshi; Inoue, Nobuyuki; Yamada, Hidehiko; Okumura, Yasuhiko

    1999-01-01

    Aided by the significant increase in its performance and reduction in cost, the X-ray CT, which originated from the EMI scanner of the 1970's, has become an essential tool in the field of diagnostic X-ray images in medicine. To comprehend in detail the status of X-ray CT photography used in a special diagnostic situation of an adjust hospital of a school of dentistry is beneficial for evaluating the use of exploratory X-ray photography to obtain useful diagnostic information as well as routine photography format. Also, knowledge of its status is necessary to address the issues of justification and optimization of X-ray examinations. Therefore, we conducted research and evaluation on various items, such as the number of cases photographed, number of contrast enhanced, and male to female ratio, over a six-years period to assess the status of photography conducted with a Toshiba CT Scanner TCT-700S, which was introduced to the Radiology Department of our school in September 1991. The following are part of our findings; 1. Status of photography in total. 1) The total number of cases photographed was 5,346 cases. 2) The number of cases contrast enhanced was 903 cases. 3) Contrast enhanced cases ratio was 16.9%. 4) Male to female ratio was 55.4: 44.6%. 2. Status of case photography by different department was: dentistry, 73.3%; medicine, 26.7%. In order to descending case frequency was oral surgery, 53.0%; internal medicine, 19.4%; and radiology 15.0%. 3. Status of case photography by age was, in order of descending frequency, 50s, 40s, and 60s. (author)

  3. MRI features of myositis ossificans with X-ray and CT findings

    International Nuclear Information System (INIS)

    Gu Xiang; Bai Rongjie; Qu Hui; Cheng Xiaoguang; Li Yuang

    2009-01-01

    Objective: To investigate the MRI features of myositis ossificans, and to address the correlation with X-ray radiography and CT findings. Methods: X-ray films, CT and MRI of 36 documented cases of myositis ossificans were retrospectively analyzed, and the literatures were reviewed. Results: Of the 36 cases, 4 cases occurred in the elbow joint, 4 in the shoulder joint, 15 in the hip joint, 6 in the tibiofibula, 5 in the femur, 1 in the metatarsal bones, and 1 in the ilium, respectively. Irregular patchy or lamellar high density calcification or ossification could be seen in the soft tissue parenchym on X-ray films and CT scan. Cortical bone integrity was preserved in diaphysis. CT enhanced scan showed that the swollen parenchyma was not enhanced and there was no parenchyma mass. On the early and middle stages, MR T 1 WI and T 2 WI showed slice-shaped low signal in the peripheral parenchyma, but patchy high signal was found around the low signal on T 2 WI. STIR showed mixed high and low signals in the swollen parenchyma with unclear demarcation. The lesions showed low signal on MR T 1 WI and T 2 WI in the late stage, and there was no edema in peripheral parenehyma. MRI enhanced scan found that the swollen parenchyma showed no enhancement in all stages. Conclusions: The imaging features of myositis ossificans have some characteristics. Misdiagnosis could be avoided when the disease was evaluated with the course. (authors)

  4. MRI of atlantoaxial subluxation; Correlating with plain X-ray films and CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Saikawa, Yuko; Nishi, Naoko; Saitoh, Yoko; Akimura, Rumiko; Sasaki, Taisuke; Yodono, Hiraku; Takekawa, Shoichi; Harata, Seikou; Sannohe, Akio (Hirosaki Univ., Aomori (Japan). School of Medicine)

    1991-04-01

    Twenty-three patients with atlantoaxial subluxation (14 with rheumatoid arthritis, one each with rheumatoid arthritis and Arnold-Chiari malformation, os odontoideum, Klippel-Feil syndrome, trauma, and 5 with unknown causes) were evaluated with MRI. We used 0.5 T MRI unit (RESONA; Yokogawa Medical Systems, Japan) and 1.5 T MRI unit (SMT 150; Shimazu, Japan) with head or flexible coils. We compared the usefulness of MRI with those of plain X-ray films and CT regarding several points. MRI provided better image of the soft tissue mass around the odontoid process, compression of cord or subarachnoid space than plain X-ray films and CT. Atlanto-odontoid distance on MRI is nearer to that on plain X-ray films than CT. MRI is useful in analyzing the anatomic details such as transverse ligament, alar ligament, tectorial membrane and thickened synovium. Both MRI and CT provided detailed bony changes. High correlation was observed between MRI grading of cord compression and the degree of myelopathy. (author).

  5. Geometric calibration of a stationary digital breast tomosynthesis system based on distributed carbon nanotube X-ray source arrays.

    Directory of Open Access Journals (Sweden)

    Changhui Jiang

    Full Text Available Stationary digital breast tomosynthesis (sDBT with distributed X-ray sources based on carbon nanotube (CNT field emission cathodes has been recently proposed as an approach that can prevent motion blur produced by traditional DBT systems. In this paper, we simulate a geometric calibration method based on a proposed multi-source CNT X-ray sDBT system. This method is a projection matrix-based approach with seven geometric parameters, all of which can be obtained from only one projection datum of the phantom. To our knowledge, this study reports the first application of this approach in a CNT-based multi-beam X-ray sDBT system. The simulation results showed that the extracted geometric parameters from the calculated projection matrix are extremely close to the input values and that the proposed method is effective and reliable for a square sDBT system. In addition, a traditional cone-beam computed tomography (CT system was also simulated, and the uncalibrated and calibrated geometric parameters were used in image reconstruction based on the filtered back-projection (FBP method. The results indicated that the images reconstructed with calibrated geometric parameters have fewer artifacts and are closer to the reference image. All the simulation tests showed that this geometric calibration method is optimized for sDBT systems but can also be applied to other application-specific CT imaging systems.

  6. Geometric calibration of a stationary digital breast tomosynthesis system based on distributed carbon nanotube X-ray source arrays.

    Science.gov (United States)

    Jiang, Changhui; Zhang, Na; Gao, Juan; Hu, Zhanli

    2017-01-01

    Stationary digital breast tomosynthesis (sDBT) with distributed X-ray sources based on carbon nanotube (CNT) field emission cathodes has been recently proposed as an approach that can prevent motion blur produced by traditional DBT systems. In this paper, we simulate a geometric calibration method based on a proposed multi-source CNT X-ray sDBT system. This method is a projection matrix-based approach with seven geometric parameters, all of which can be obtained from only one projection datum of the phantom. To our knowledge, this study reports the first application of this approach in a CNT-based multi-beam X-ray sDBT system. The simulation results showed that the extracted geometric parameters from the calculated projection matrix are extremely close to the input values and that the proposed method is effective and reliable for a square sDBT system. In addition, a traditional cone-beam computed tomography (CT) system was also simulated, and the uncalibrated and calibrated geometric parameters were used in image reconstruction based on the filtered back-projection (FBP) method. The results indicated that the images reconstructed with calibrated geometric parameters have fewer artifacts and are closer to the reference image. All the simulation tests showed that this geometric calibration method is optimized for sDBT systems but can also be applied to other application-specific CT imaging systems.

  7. Design of scanning motion control system for high-energy X-ray industrial CT

    International Nuclear Information System (INIS)

    Duan Liming

    2008-01-01

    A scanning motion control system was developed for the high-energy X-ray industrial computerized tomography (CT). The system consists of an industrial control computer, a counter card, a control card, servo drivers, servo motors, working platforms, gratings and control software. Based on windows driver model(WDM) mode, the composition of the driver pro- gram for the system was studied. Took the motor control card as an example, the method to develop the driver program was researched, and the intercourse process between the device driver program and the user-program was analyzed. The real-time control of the system was implemented using the WDM driver. The real-time performance and reliability of the system can satisfy the requirement of high-energy X-ray industrial CT. (authors)

  8. Transference of surface markers in X-ray, CT- and MR-imaging

    International Nuclear Information System (INIS)

    Grevelhoerster, T.; Poetter, R.; Prott, F.J.; Dittrich, M.

    1995-01-01

    By using pharmacological capsules and plastic tubes filled with oily contrast medium contraining iodine (Lipiodol; Byk Gulden), marking aids were developed which can be seen in similar definite limits within the framework of MRI-, CT- and conventional X-ray-Imaging. A method to view these new, artificial markers in combination with individual, anatomical landmarks is introduced. The marking aid/surface marker, fixed on anatomical reference structures on the skin, does not result in an additional burden for the patient. The new, artificial markers are also useful for making other structures recognizable, such as anatomical relation lines, center of the portal and edges in planning imaging for radiotherapy treatments and are used as leading and reference structures to compare localisation and extent of lesions in X-ray-, CT- and MRI. Marking aids/surface markers do not have to be changed in different imaging methods. (orig./MG) [de

  9. Determination of x-ray spectra incident on and transmitted through whole excised breast for improved mammographic exposing technique

    International Nuclear Information System (INIS)

    Haus, A.G.; Metz, C.E.; Doi, K.; Bernstein, J.

    1976-01-01

    Measurements were made of x-ray spectra incident on and transmitted through whole excised fresh breast tissue. The spectra and corresponding radiographs show that hardening of the x-ray beam from a molybdenum anode x-ray tube by a 0.5 mm Al filter instead of the conventional 0.03 mm Mo filter allows shorter exposure times and reduces patient radiation exposure. With the Al filter, acceptable image contrast is preserved in mammography of thick or dense breasts

  10. Three dimensional analysis of coelacanth body structure by computer graphics and X-ray CT images

    International Nuclear Information System (INIS)

    Suzuki, Naoki; Hamada, Takashi.

    1990-01-01

    Three dimensional imaging processes were applied for the structural and functional analyses of the modern coelacanth (Latimeria chalumnae). Visualization of the obtained images is performed with computer graphics on the basis of serial images by an X-ray CT scanning method. Reconstruction of three dimensional images of the body structure of coelacanth using the volume rendering and surface rendering methods provides us various information about external and internal shapes of this exquisite fish. (author)

  11. Registration of SPECT, PET and/or X-ray CT images in patients with lung cancer

    International Nuclear Information System (INIS)

    Uemura, K.; Toyama, H.; Miyamoto, T.; Yoshikawa, K.; Mori, Y.

    2002-01-01

    Aim: In order to evaluate the therapeutic gain of heavy ion therapy performed on patients with lung cancer, the regional pulmonary functions and the amount of radio tracer accumulation to the tumor, we are investigated by using the region of interest based on anatomical information obtained from X-ray CT. There are many registration techniques for brain images, but not so much for the other organ images that we have studied registration of chest SPECT, PET and/or X-ray CT images. Materials and Methods: Perfusion, ventilation and blood pool images with Tc 99m labeled radiopharmaceuticals and SPECT, tumor images with 11 C-methionine and PET and X-ray CT scans were performed on several patients with lung cancer before and after heavy ion therapy. The registrations of SPECT-CT, PET-CT and CT-CT were performed by using AMIR (Automatic Multimodality Image Registration), which was developed by Babak et al. for registration of brain images. In a case of SPECT-CT registration, each of the three functional images was registered to the X-ray CT image, and the accuracy of each registration was compared. In the studies of PET-CT registration, the transmission images and X-ray CT images were registered at first, because the 11 C-methionine PET images bear little resemblance to the underlying anatomical images. Next, the emission images were realigned by using the same registration parameters. The X-ray CT images obtained from a single subject at the different time were registered to the first X-ray CT images, respectively. Results: In the SPECT-CT registration, the blood pool-CT registration is the best among three SPECT images in visual inspection by radiologists. In the PET-CT registration, the Transmission-CT registrations got good results. Therefore, Emission-CT registrations also got good results. In the CT-CT registration, the X-ray CT images obtained from a single subject at the different time were superimposed well each other except for lower lobe. As the results, it was

  12. Optimizing abdominal CT dose and image quality with respect to x-ray tube voltage

    Science.gov (United States)

    Huda, Walter; Ogden, Kent M.

    2004-05-01

    The objective of this study was to identify the x-ray tube voltage that results in optimum performance for abdominal CT imaging for a range of imaging tasks and patient sizes. Theoretical calculations were performed of the contrast to noise ratio (CNR) for disk shaped lesions of muscle, fat, bone and iodine embedded in a uniform water background. Lesion contrast was the mean Hounsfield Unit value at the effective photon energy, and image noise was determined from the total radiation intensity incident on the CT x-ray detector. Patient size ranging from young infants (10 kg) to oversized adults (120 kg), with CNR values obtained for x-ray tube voltages ranging from 80 to 140 kV. Patients of varying sizes were modeled as an equivalent cylinder of water, and the mean section dose (D) was determined for each selected x-ray tube kV value at a constant mAs. For each patient size and lesion type, we identified an optimal kV as the x-ray tube voltage that yields a maximum value of the figure of merit (CNR2/D). Increasing the x-ray tube voltage from 80 to 140 kV reduced lesion contrast by 11% for muscle, 21% for fat, 35% for bone and 52% for iodine, and these reductions were approximately independent of patient size. Increasing the x-ray tube voltage from 80 to 140 kV increased a muscle lesion CNR relative to a uniform water background by a factor of 2.6, with similar trends observed for fat (2.3), bone (1.9) and iodine (1.4). The improvement in lesion CNR with increasing x-ray tube voltage was highest for the largest sized patients. Increasing the x-ray tube voltage from 80 to 140 kV increased the patient dose by a factor of between 5.0 and 6.2 depending on the patient size. For small sized patients (10 and 30 kg) and muscle lesions, best performance is obtained at 80 kV; however, for adults (70 kg) and oversized adults (120 kg), the best performance would be obtained at 140 kV. Imaging fat lesions was best performed at 80 kV for all patients except for oversized adults

  13. Fatigue damage observed non-destructively in fibre composite coupon test specimens by X-ray CT

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Mikkelsen, Lars Pilgaard

    2016-01-01

    This study presents a method for monitoring the 3D fatigue damage progression on a micro-structural level in a glass fibre/polymer coupon test specimen by means of laboratory X-ray Computed Tomography (CT). A modified mount and holder made for the standard test samples to fit into the X-ray CT...... scanner along with a tension clamp solution is presented. Initially, the same location of the test specimen is inspected by ex-situ X-ray CT during the fatigue loading history, which shows the damage progression on a micro-structural level. The openings of individual uni-directional (UD) fibre fractures...

  14. Incoherent-scatter computed tomography with monochromatic synchrotron x ray: feasibility of multi-CT imaging system for simultaneous measurement-of fluorescent and incoherent scatter x rays

    Science.gov (United States)

    Yuasa, T.; Akiba, M.; Takeda, T.; Kazama, M.; Hoshino, A.; Watanabe, Y.; Hyodo, K.; Dilmanian, F. A.; Akatsuka, T.; Itai, Y.

    1997-10-01

    We describe a new system of incoherent scatter computed tomography (ISCT) using monochromatic synchrotron X rays, and we discuss its potential to be used in in vivo imaging for medical use. The system operates on the basis of computed tomography (CT) of the first generation. The reconstruction method for ISCT uses the least squares method with singular value decomposition. The research was carried out at the BLNE-5A bending magnet beam line of the Tristan Accumulation Ring in KEK, Japan. An acrylic cylindrical phantom of 20-mm diameter containing a cross-shaped channel was imaged. The channel was filled with a diluted iodine solution with a concentration of 200 /spl mu/gI/ml. Spectra obtained with the system's high purity germanium (HPGe) detector separated the incoherent X-ray line from the other notable peaks, i.e., the iK/sub /spl alpha// and K/sub /spl beta/1/ X-ray fluorescent lines and the coherent scattering peak. CT images were reconstructed from projections generated by integrating the counts In the energy window centering around the incoherent scattering peak and whose width was approximately 2 keV. The reconstruction routine employed an X-ray attenuation correction algorithm. The resulting image showed more homogeneity than one without the attenuation correction.

  15. Early Detection of Amyloid Plaque in Alzheimer’s Disease via X-ray Phase CT

    Science.gov (United States)

    2016-08-01

    Geraghty, J. A. Seibert, and S. L. Wootton-Gorges, “Dose reduction in pediatric CT : A rational approach,” Radiology 228, 352–360 (2003). Medical...improvement in image quality can be quantified as large as 450 [Fig. 6(c)] and 350 [Fig. 6(d)] Hounsfield units (HUs), where the Hounsfield unit is defined...AWARD NUMBER: W81XWH-12-1-0138 TITLE: Early Detection of Amyloid Plaque in Alzheimer’s Disease via X-ray Phase CT PRINCIPAL INVESTIGATOR

  16. Multisource inverse-geometry CT. Part II. X-ray source design and prototype

    Energy Technology Data Exchange (ETDEWEB)

    Neculaes, V. Bogdan, E-mail: neculaes@ge.com; Caiafa, Antonio; Cao, Yang; De Man, Bruno; Edic, Peter M.; Frutschy, Kristopher; Gunturi, Satish; Inzinna, Lou; Reynolds, Joseph; Vermilyea, Mark; Wagner, David; Zhang, Xi; Zou, Yun [GE Global Research, Niskayuna, New York 12309 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Lounsberry, Brian [Healthcare Science Technology, GE Healthcare, West Milwaukee, Wisconsin 53219 (United States)

    2016-08-15

    Purpose: This paper summarizes the development of a high-power distributed x-ray source, or “multisource,” designed for inverse-geometry computed tomography (CT) applications [see B. De Man et al., “Multisource inverse-geometry CT. Part I. System concept and development,” Med. Phys. 43, 4607–4616 (2016)]. The paper presents the evolution of the source architecture, component design (anode, emitter, beam optics, control electronics, high voltage insulator), and experimental validation. Methods: Dispenser cathode emitters were chosen as electron sources. A modular design was adopted, with eight electron emitters (two rows of four emitters) per module, wherein tungsten targets were brazed onto copper anode blocks—one anode block per module. A specialized ceramic connector provided high voltage standoff capability and cooling oil flow to the anode. A matrix topology and low-noise electronic controls provided switching of the emitters. Results: Four modules (32 x-ray sources in two rows of 16) have been successfully integrated into a single vacuum vessel and operated on an inverse-geometry computed tomography system. Dispenser cathodes provided high beam current (>1000 mA) in pulse mode, and the electrostatic lenses focused the current beam to a small optical focal spot size (0.5 × 1.4 mm). Controlled emitter grid voltage allowed the beam current to be varied for each source, providing the ability to modulate beam current across the fan of the x-ray beam, denoted as a virtual bowtie filter. The custom designed controls achieved x-ray source switching in <1 μs. The cathode-grounded source was operated successfully up to 120 kV. Conclusions: A high-power, distributed x-ray source for inverse-geometry CT applications was successfully designed, fabricated, and operated. Future embodiments may increase the number of spots and utilize fast read out detectors to increase the x-ray flux magnitude further, while still staying within the stationary target inherent

  17. Study on Compression Induced Contrast in X-ray Mammograms Using Breast Mimicking Phantoms

    Directory of Open Access Journals (Sweden)

    A. B. M. Aowlad Hossain

    2015-09-01

    Full Text Available X-ray mammography is commonly used to scan cancer or tumors in breast using low dose x-rays. But mammograms suffer from low contrast problem. The breast is compressed in mammography to reduce x-ray scattering effects. As tumors are stiffer than normal tissues, they undergo smaller deformation under compression. Therefore, image intensity at tumor region may change less than the background tissues. In this study, we try to find out compression induced contrast from multiple mammographic images of tumorous breast phantoms taken with different compressions. This is an extended work of our previous simulation study with experiment and more analysis. We have used FEM models for synthetic phantom and constructed a phantom using agar and n-propanol for simulation and experiment. The x-ray images of deformed phantoms have been obtained under three compression steps and a non-rigid registration technique has been applied to register these images. It is noticeably observed that the image intensity changes at tumor are less than those at surrounding which induce a detectable contrast. Addition of this compression induced contrast to the simulated and experimental images has improved their original contrast by a factor of about 1.4

  18. Diagnostic modalities x-ray and CT chest differ in the management of thoracic injury

    Directory of Open Access Journals (Sweden)

    D Chapagain

    2015-06-01

    Full Text Available Objective: To observe difference in the management of blunt trauma to the chest on the basis of conventional xray and computerised tomography of the chest. Methods: This prospective study was conducted between December 2011 to October 2012 in COMS in Bharatpur,a tertiary referral centre in central Nepal . Clinically stable thoracic injury patients were first evaluated with chest x-ray and the management on this basis was recorded. The findings of the CT chest were assessed and the type of management on the basis of CT was also recorded. Outcome was assessed in terms of mortality, morbidity, hospital and ICU stay with respect to the management on the basis of chest x-ray and CT scan. Results: Of the 129 patients, 74.4% were male and 25.6% were female with the patients ranging in age from 7 to 87 years (mean = 40.41 years. The most common mechanism of trauma to the chest was as a result of a motor vehicle accident (69.8%, followed by fall injury (20.2%. X-ray chest diagnosed rib fracture in 62%, haemothorax in 37%, pneumothorax in 27%, lung contusion in 10% and haemopneumothorax in 21% patients. Similarly CT chest diagnosed rib fracture in 86%, haemothorax in 54%, pneumothorax in 36%, lung contusion in 30% and haemopneumothorax in 30% patients. Mean hospital stay was 9.5 days in the group of patients having management on the basis of x-ray chest relative to mean stay of 10.2 days in the CT- chest group. In the management on the basis of xray group, there was a mean ICU stay of 2.8days compared to mean stays of 3.2 days in CT chest group. Conclusion: Though CT scan of the chest is more informative and differs the management of the blunt chest trauma, one should not forget to advise the cost effective, easily available and initial guiding agent, xray chest for early management of the chest injury patient. DOI: http://dx.doi.org/10.3126/jcmsn.v10i1.12764 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(1; 22-31

  19. Monte Carlo evaluation of glandular dose in cone-beam X-ray computed tomography dedicated to the breast: Homogeneous and heterogeneous breast models.

    Science.gov (United States)

    Sarno, Antonio; Mettivier, Giovanni; Tucciariello, Raffaele M; Bliznakova, Kristina; Boone, John M; Sechopoulos, Ioannis; Di Lillo, Francesca; Russo, Paolo

    2018-06-07

    In cone-beam computed tomography dedicated to the breast (BCT), the mean glandular dose (MGD) is the dose metric of reference, evaluated from the measured air kerma by means of normalized glandular dose coefficients (DgN CT ). This work aimed at computing, for a simple breast model, a set of DgN CT values for monoenergetic and polyenergetic X-ray beams, and at validating the results vs. those for patient specific digital phantoms from BCT scans. We developed a Monte Carlo code for calculation of monoenergetic DgN CT coefficients (energy range 4.25-82.25 keV). The pendant breast was modelled as a cylinder of a homogeneous mixture of adipose and glandular tissue with glandular fractions by mass of 0.1%, 14.3%, 25%, 50% or 100%, enveloped by a 1.45 mm-thick skin layer. The breast diameter ranged between 8 cm and 18 cm. Then, polyenergetic DgN CT coefficients were analytically derived for 49-kVp W-anode spectra (half value layer 1.25-1.50 mm Al), as in a commercial BCT scanner. We compared the homogeneous models to 20 digital phantoms produced from classified 3D breast images. Polyenergetic DgN CT resulted 13% lower than most recent published data. The comparison vs. patient specific breast phantoms showed that the homogeneous cylindrical model leads to a DgN CT percentage difference between -15% and +27%, with an average overestimation of 8%. A dataset of monoenergetic and polyenergetic DgN CT coefficients for BCT was provided. Patient specific breast models showed a different volume distribution of glandular dose and determined a DgN CT 8% lower, on average, than homogeneous breast model. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  20. Role of X-ray CT in the evaluation of extension of ovarian cancer

    International Nuclear Information System (INIS)

    Saito, Takashi

    1991-01-01

    To evaluate the utility of X-ray computed tomography (CT) in the management of malignant ovarian tumor, preoperative CT of 89 patients with ovarian cancer were analyzed on the basis of their surgically confirmed findings. Relationships between CT findings and clinical factors such as actual tumor spread, stage, and accomplished surgery were studied. The results obtained were as follows. The rates of correct diagnosis in tumor spread were 79.8% for tumor growth on the external surface of the ovary, 77.6% for involvement of both ovaries, 79.8% for ascites, 78.2% for metastasis to the uterus, 68.2% for peritoneal metastasis, 77.0% for metastasis to the intestine, and 79.3% for the metastasis to the omentum. Comparing the stage suggested by CT (CT stage) and the stage revealed by surgery (surgical stage), the stages coincided in 57 patients (64.0%). CT stages were overestimated in 9 caces and underestimated in 23 caces. As for the practicability of surgery, either complete or standard operation was performed in 31 of 33 caces (93.9%) of CT stage I, 21 of 28 (75.0%) of CT stage II, and 11 of 28 (39.3%) of CT stage III. The possibility of accomplishing surgery was very low when CT indicated stage III disease. (author)

  1. X-ray and CT findings of soft tissue and bone infections secondary to acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Jiang Songfeng; Liu Jinxin; Chen Bihua; Zhang Lieguang; Gan Qingxin; Huang Deyang

    2011-01-01

    Objective: To summarize X-ray and CT findings of soft tissue and bone infections secondary to acquired immunodeficiency syndrome (AIDS). Methods: The data of X-ray and CT findings of soft tissue and bone infections in 18 patients with AIDS were retrospectively collected and analyzed. Results: Of 18 patients with AIDS, the CT features of soft tissue demonstrated that subcutaneous patchy high density in 1 case which considered as cellulitis, round low density lesions with ring enhancement in 6 cases which considered as soft tissue abscesses, heterogeneous density lesions with peripheral enhancement in 1 case which considered as pyomyositis. Of 18 patients with AIDS, septic arthritis was found in 4 cases involving knee lesion in 3 cases and hip lesion. In the 4 case, the X-ray films showed bony destruction in 2 cases and the CT showed bone destruction in 3 cases and arthroedema in 4 cases. Of 18 patients with AIDS, osteomyelitis was found in 9 cases of which tuberculosis was considered in. 8 cases and vertebral involvement in 6 cases. In the 9 cases, the X-ray films and CT displayed bony destruction, hyperostosis, small sequestra, and intervertebral space narrowing. Of 18 patients with AIDS, costal lesions were found in 3 cases in which the CT showed expandable bony destruction. Of 18 patients with AIDS, ilium and sacroiliac joint lesions were found in 1 case in which the X-ray films and CT showed bony destruction, sequestra, and joint widening. Of 18 patients with AIDS, chronic pyogenic osteomyelitis of femur was found in 1 case in which the X-ray films showed bony destruction, hyperostosis osteosclerosis, and periosteal reaction. Conclusion: The X-ray and CT features of soft tissue and bone infections secondary to AIDS are characterized. The X-ray and CT are useful tools to early diagnose soft tissue and bone infections secondary to AIDS. (authors)

  2. Using x-ray mammograms to assist in microwave breast image interpretation.

    Science.gov (United States)

    Curtis, Charlotte; Frayne, Richard; Fear, Elise

    2012-01-01

    Current clinical breast imaging modalities include ultrasound, magnetic resonance (MR) imaging, and the ubiquitous X-ray mammography. Microwave imaging, which takes advantage of differing electromagnetic properties to obtain image contrast, shows potential as a complementary imaging technique. As an emerging modality, interpretation of 3D microwave images poses a significant challenge. MR images are often used to assist in this task, and X-ray mammograms are readily available. However, X-ray mammograms provide 2D images of a breast under compression, resulting in significant geometric distortion. This paper presents a method to estimate the 3D shape of the breast and locations of regions of interest from standard clinical mammograms. The technique was developed using MR images as the reference 3D shape with the future intention of using microwave images. Twelve breast shapes were estimated and compared to ground truth MR images, resulting in a skin surface estimation accurate to within an average Euclidean distance of 10 mm. The 3D locations of regions of interest were estimated to be within the same clinical area of the breast as corresponding regions seen on MR imaging. These results encourage investigation into the use of mammography as a source of information to assist with microwave image interpretation as well as validation of microwave imaging techniques.

  3. Using X-Ray Mammograms to Assist in Microwave Breast Image Interpretation

    Directory of Open Access Journals (Sweden)

    Charlotte Curtis

    2012-01-01

    Full Text Available Current clinical breast imaging modalities include ultrasound, magnetic resonance (MR imaging, and the ubiquitous X-ray mammography. Microwave imaging, which takes advantage of differing electromagnetic properties to obtain image contrast, shows potential as a complementary imaging technique. As an emerging modality, interpretation of 3D microwave images poses a significant challenge. MR images are often used to assist in this task, and X-ray mammograms are readily available. However, X-ray mammograms provide 2D images of a breast under compression, resulting in significant geometric distortion. This paper presents a method to estimate the 3D shape of the breast and locations of regions of interest from standard clinical mammograms. The technique was developed using MR images as the reference 3D shape with the future intention of using microwave images. Twelve breast shapes were estimated and compared to ground truth MR images, resulting in a skin surface estimation accurate to within an average Euclidean distance of 10 mm. The 3D locations of regions of interest were estimated to be within the same clinical area of the breast as corresponding regions seen on MR imaging. These results encourage investigation into the use of mammography as a source of information to assist with microwave image interpretation as well as validation of microwave imaging techniques.

  4. Combined X-ray CT and mass spectrometry for biomedical imaging applications

    Science.gov (United States)

    Schioppa, E., Jr.; Ellis, S.; Bruinen, A. L.; Visser, J.; Heeren, R. M. A.; Uher, J.; Koffeman, E.

    2014-04-01

    Imaging technologies play a key role in many branches of science, especially in biology and medicine. They provide an invaluable insight into both internal structure and processes within a broad range of samples. There are many techniques that allow one to obtain images of an object. Different techniques are based on the analysis of a particular sample property by means of a dedicated imaging system, and as such, each imaging modality provides the researcher with different information. The use of multimodal imaging (imaging with several different techniques) can provide additional and complementary information that is not possible when employing a single imaging technique alone. In this study, we present for the first time a multi-modal imaging technique where X-ray computerized tomography (CT) is combined with mass spectrometry imaging (MSI). While X-ray CT provides 3-dimensional information regarding the internal structure of the sample based on X-ray absorption coefficients, MSI of thin sections acquired from the same sample allows the spatial distribution of many elements/molecules, each distinguished by its unique mass-to-charge ratio (m/z), to be determined within a single measurement and with a spatial resolution as low as 1 μm or even less. The aim of the work is to demonstrate how molecular information from MSI can be spatially correlated with 3D structural information acquired from X-ray CT. In these experiments, frozen samples are imaged in an X-ray CT setup using Medipix based detectors equipped with a CO2 cooled sample holder. Single projections are pre-processed before tomographic reconstruction using a signal-to-thickness calibration. In the second step, the object is sliced into thin sections (circa 20 μm) that are then imaged using both matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and secondary ion (SIMS) mass spectrometry, where the spatial distribution of specific molecules within the sample is determined. The

  5. Fourier domain image fusion for differential X-ray phase-contrast breast imaging

    International Nuclear Information System (INIS)

    Coello, Eduardo; Sperl, Jonathan I.; Bequé, Dirk; Benz, Tobias; Scherer, Kai; Herzen, Julia; Sztrókay-Gaul, Anikó; Hellerhoff, Karin; Pfeiffer, Franz; Cozzini, Cristina; Grandl, Susanne

    2017-01-01

    X-Ray Phase-Contrast (XPC) imaging is a novel technology with a great potential for applications in clinical practice, with breast imaging being of special interest. This work introduces an intuitive methodology to combine and visualize relevant diagnostic features, present in the X-ray attenuation, phase shift and scattering information retrieved in XPC imaging, using a Fourier domain fusion algorithm. The method allows to present complementary information from the three acquired signals in one single image, minimizing the noise component and maintaining visual similarity to a conventional X-ray image, but with noticeable enhancement in diagnostic features, details and resolution. Radiologists experienced in mammography applied the image fusion method to XPC measurements of mastectomy samples and evaluated the feature content of each input and the fused image. This assessment validated that the combination of all the relevant diagnostic features, contained in the XPC images, was present in the fused image as well.

  6. Fourier domain image fusion for differential X-ray phase-contrast breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Coello, Eduardo, E-mail: eduardo.coello@tum.de [GE Global Research, Garching (Germany); Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality, Institut für Informatik, Technische Universität München, Garching (Germany); Sperl, Jonathan I.; Bequé, Dirk [GE Global Research, Garching (Germany); Benz, Tobias [Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality, Institut für Informatik, Technische Universität München, Garching (Germany); Scherer, Kai; Herzen, Julia [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching (Germany); Sztrókay-Gaul, Anikó; Hellerhoff, Karin [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich (Germany); Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching (Germany); Cozzini, Cristina [GE Global Research, Garching (Germany); Grandl, Susanne [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich (Germany)

    2017-04-15

    X-Ray Phase-Contrast (XPC) imaging is a novel technology with a great potential for applications in clinical practice, with breast imaging being of special interest. This work introduces an intuitive methodology to combine and visualize relevant diagnostic features, present in the X-ray attenuation, phase shift and scattering information retrieved in XPC imaging, using a Fourier domain fusion algorithm. The method allows to present complementary information from the three acquired signals in one single image, minimizing the noise component and maintaining visual similarity to a conventional X-ray image, but with noticeable enhancement in diagnostic features, details and resolution. Radiologists experienced in mammography applied the image fusion method to XPC measurements of mastectomy samples and evaluated the feature content of each input and the fused image. This assessment validated that the combination of all the relevant diagnostic features, contained in the XPC images, was present in the fused image as well.

  7. Early experience with a picture archiving and communication system for X-ray CT

    International Nuclear Information System (INIS)

    Nakano, Y.; Komori, M.; Minato, K.

    1987-01-01

    A network using fiberoptic ring architecture has been implemented to connect an x-ray CT unit with an image work station and optical disk storage unit. The work station has three noninterlaced cathode-ray tube (CRT) monitors of 1,024 X 1,024 pixels. The optical disk system stores 32 optical disk cartridges (2.6 Gbytes per cartridge). A general-purpose interface bus is used for communication between the CT unit and the network interface unit. Transfer time from CT to interface unit is 40 kbyte/second, 5 seconds per image. On-line data acquisition, long-term archiving, and CT interpretation using CRTs have been tested and the system has been working for 3 months in a clinical environment

  8. Elastographic versus x-ray CT imaging of radio frequency ablation coagulations: An in vitro study

    International Nuclear Information System (INIS)

    Liu Wu; Techavipoo, Udomchai; Varghese, Tomy; Zagzebski, James A.; Chen, Quan; Lee, Fred T. Jr.

    2004-01-01

    Techniques to image elasticity parameters (i.e., elastography) have recently become of great interest to researchers. In this paper we use conventional ultrasound elastography and x-ray CT to image radio frequency (RF) ablation sites of excised canine liver enclosed in gelatin. Thermal coagulations of different sizes were produced by applying the RF procedure for various times and end point temperatures. Dimensions, areas and volumes computed from CT and elastography were compared with those on whole mount pathology specimens. Ultrasound elastography exhibited high contrast for the thermal coagulations and performed better than CT. The correlation between pathology and elastography for this sample set of 40 thermal coagulations (r=0.94 for volume estimation, r=0.87 for area estimation) is better than the correlation between pathology and CT (r=0.89 for volume estimation, r=0.82 for area estimation)

  9. Three dimensional reconstruction of fossils with X-ray CT and computer graphics

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Takashi; Tateno, Satoko (Tokyo Univ. (Japan). Coll. of Arts and Sciences); Suzuki, Naoki

    1991-12-01

    We have developed a method for three dimensional (3D) visualization of fossils such as trilobites and ammonites by non-destructive measurement and computer graphics. The imaging techniques in the medical sciences are applied for fossils by us to have quantitative data analyses on the structural and functional features of some extinct creatures. These methods are composed of a high resolutional X-ray computed tomography (X-ray CT) and computer graphics. We are able to observe not only outer shape but also inner structure of fossils as a 3D image by this method. Consequently, the shape and volume are measurable on these 3D image quantitatively. In addition to that, it is able to reconstruct an ideal figure from the deformed fossils by graphical treatments of the data. Such a 3D reconstruction method is useful to obtain a new information from the paleontological standpoint. (author).

  10. Three dimensional reconstruction of fossils with X-ray CT and computer graphics

    International Nuclear Information System (INIS)

    Hamada, Takashi; Tateno, Satoko; Suzuki, Naoki.

    1991-01-01

    We have developed a method for three dimensional (3D) visualization of fossils such as trilobites and ammonites by non-destructive measurement and computer graphics. The imaging techniques in the medical sciences are applied for fossils by us to have quantitative data analyses on the structural and functional features of some extinct creatures. These methods are composed of a high resolutional X-ray computed tomography (X-ray CT) and computer graphics. We are able to observe not only outer shape but also inner structure of fossils as a 3D image by this method. Consequently, the shape and volume are measurable on these 3D image quantitatively. In addition to that, it is able to reconstruct an ideal figure from the deformed fossils by graphical treatments of the data. Such a 3D reconstruction method is useful to obtain a new information from the paleontological standpoint. (author)

  11. Incorporating multislice imaging into x-ray CT polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H., E-mail: holly.johnston@utsw.edu [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2 (Canada); Hilts, M. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada and Medical Physics, BC Cancer Agency, Vancouver Island Centre, Victoria, British Columbia V8R 6V5 (Canada); Jirasek, A. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada and Department of Physics, University of British Columbia—Okanagan Campus, Kelowna, British Columbia V1V 1V7 (Canada)

    2015-04-15

    Purpose: To evaluate multislice computed tomography (CT) scanning for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD) and to establish a baseline assessment of image noise and uniformity in an unirradiated gel dosimeter. Methods: A 16-slice CT scanner was used to acquire images through a 1 L cylinder filled with water. Additional images were collected using a single slice machine. The variability in CT number (N{sub CT}) associated with the anode heel effect was evaluated and used to define a new slice-by-slice background subtraction artifact removal technique for CT PGD. Image quality was assessed for the multislice system by evaluating image noise and uniformity. The agreement in N{sub CT} for slices acquired simultaneously using the multislice detector array was also examined. Further study was performed to assess the effects of increasing x-ray tube load on the constancy of measured N{sub CT} and overall scan time. In all cases, results were compared to the single slice machine. Finally, images were collected throughout the volume of an unirradiated gel dosimeter to quantify image noise and uniformity before radiation is delivered. Results: Slice-by-slice background subtraction effectively removes the variability in N{sub CT} observed across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image noise was higher for the multislice system compared to the single slice scanner, but overall image quality was comparable between the two systems. Further study showed N{sub CT} was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thicknesses examined. In addition, the multislice system was found to eliminate variations in N{sub CT} due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to

  12. Patient dose simulation in X-ray CT using a radiation treatment-planning system

    International Nuclear Information System (INIS)

    Nakae, Yasuo; Oda, Masahiko; Minamoto, Takahiro

    2003-01-01

    Medical irradiation dosage has been increasing with the development of new radiological equipment and new techniques like interventional radiology. It is fair to say that patient dose has been increased as a result of the development of multi-slice CT. A number of studies on the irradiation dose of CT have been reported, and the computed tomography dose index (CTDI) is now used as a general means of determining CT dose. However, patient dose distribution in the body varies with the patient's constitution, bowel gas in the body, and conditions of exposure. In this study, patient dose was analyzed from the viewpoint of dose distribution, using a radiation treatment-planning computer. Percent depth dose (PDD) and the off-center ratio (OCR) of the CT beam are needed to calculate dose distribution by the planning computer. Therefore, X-ray CT data were measured with various apparatuses, and beam data were sent to the planning computer. Measurement and simulation doses in the elliptical phantom (Mix-Dp: water equivalent material) were collated, and the CT irradiation dose was determined for patient dose simulation. The rotational radiation treatment technique was used to obtain the patient dose distribution of CT, and patient dose was evaluated through simulation of the dose distribution. CT images of the thorax were sent to the planning computer and simulated. The result was that the patient dose distribution of the thorax was obtained for CT examination. (author)

  13. Methods of X-ray CT image reconstruction from few projections

    International Nuclear Information System (INIS)

    Wang, H.

    2011-01-01

    To improve the safety (low dose) and the productivity (fast acquisition) of a X-ray CT system, we want to reconstruct a high quality image from a small number of projections. The classical reconstruction algorithms generally fail since the reconstruction procedure is unstable and suffers from artifacts. A new approach based on the recently developed 'Compressed Sensing' (CS) theory assumes that the unknown image is in some sense 'sparse' or 'compressible', and the reconstruction is formulated through a non linear optimization problem (TV/l1 minimization) by enhancing the sparsity. Using the pixel (or voxel in 3D) as basis, to apply the CS framework in CT one usually needs a 'sparsifying' transform, and combines it with the 'X-ray projector' which applies on the pixel image. In this thesis, we have adapted a 'CT-friendly' radial basis of Gaussian family called 'blob' to the CS-CT framework. The blob has better space-frequency localization properties than the pixel, and many operations, such as the X-ray transform, can be evaluated analytically and are highly parallelizable (on GPU platform). Compared to the classical Kaisser-Bessel blob, the new basis has a multi-scale structure: an image is the sum of dilated and translated radial Mexican hat functions. The typical medical objects are compressible under this basis, so the sparse representation system used in the ordinary CS algorithms is no more needed. 2D simulations show that the existing TV and l1 algorithms are more efficient and the reconstructions have better visual quality than the equivalent approach based on the pixel or wavelet basis. The new approach has also been validated on 2D experimental data, where we have observed that in general the number of projections can be reduced to about 50%, without compromising the image quality. (author) [fr

  14. X-ray phase-contrast CT of a pancreatic ductal adenocarcinoma mouse model.

    Directory of Open Access Journals (Sweden)

    Arne Tapfer

    Full Text Available To explore the potential of grating-based x-ray phase-contrast computed tomography (CT for preclinical research, a genetically engineered mouse model of pancreatic ductal adenocarcinoma (PDAC was investigated. One ex-vivo mouse specimen was scanned with different grating-based phase-contrast CT imaging setups covering two different settings: i high-resolution synchrotron radiation (SR imaging and ii dose-reduced imaging using either synchrotron radiation or a conventional x-ray tube source. These experimental settings were chosen to assess the potential of phase-contrast imaging for two different types of application: i high-performance imaging for virtual microscopy applications and ii biomedical imaging with increased soft-tissue contrast for in-vivo applications. For validation and as a reference, histological slicing and magnetic resonance imaging (MRI were performed on the same mouse specimen. For each x-ray imaging setup, attenuation and phase-contrast images were compared visually with regard to contrast in general, and specifically concerning the recognizability of lesions and cancerous tissue. To quantitatively assess contrast, the contrast-to-noise ratios (CNR of selected regions of interest (ROI in the attenuation images and the phase images were analyzed and compared. It was found that both for virtual microscopy and for in-vivo applications, there is great potential for phase-contrast imaging: in the SR-based benchmarking data, fine details about tissue composition are accessible in the phase images and the visibility of solid tumor tissue under dose-reduced conditions is markedly superior in the phase images. The present study hence demonstrates improved diagnostic value with phase-contrast CT in a mouse model of a complex endogenous cancer, promoting the use and further development of grating-based phase-contrast CT for biomedical imaging applications.

  15. Development of a fast multi-line x-ray CT detector for NDT

    International Nuclear Information System (INIS)

    Hofmann, T.; Nachtrab, F.; Schlechter, T.; Mühlbauer, J.; Schröpfer, S.; Firsching, M.; Uhlmann, N.; Neubauer, H.; Ernst, J.; Schweiger, T.; Oberst, M.; Meyer, A.

    2015-01-01

    Typical X-ray detectors for non-destructive testing (NDT) are line detectors or area detectors, like e.g. flat panel detectors. Multi-line detectors are currently only available in medical Computed Tomography (CT) scanners. Compared to flat panel detectors, line and multi-line detectors can achieve much higher frame rates. This allows time-resolved 3D CT scans of an object under investigation. Also, an improved image quality can be achieved due to reduced scattered radiation from object and detector themselves. Another benefit of line and multi-line detectors is that very wide detectors can be assembled easily, while flat panel detectors are usually limited to an imaging field with a size of approx. 40 × 40 cm 2 at maximum. The big disadvantage of line detectors is the limited number of object slices that can be scanned simultaneously. This leads to long scan times for large objects. Volume scans with a multi-line detector are much faster, but with almost similar image quality. Due to the promising properties of multi-line detectors their application outside of medical CT would also be very interesting for NDT. However, medical CT multi-line detectors are optimized for the scanning of human bodies. Many non-medical applications require higher spatial resolutions and/or higher X-ray energies. For those non-medical applications we are developing a fast multi-line X-ray detector.In the scope of this work, we present the current state of the development of the novel detector, which includes several outstanding properties like an adjustable curved design for variable focus-detector-distances, conserving nearly uniform perpendicular irradiation over the entire detector width. Basis of the detector is a specifically designed, radiation hard CMOS imaging sensor with a pixel pitch of 200 μ m. Each pixel has an automatic in-pixel gain adjustment, which allows for both: a very high sensitivity and a wide dynamic range. The final detector is planned to have 256 lines of

  16. Variance analysis of x-ray CT sinograms in the presence of electronic noise background.

    Science.gov (United States)

    Ma, Jianhua; Liang, Zhengrong; Fan, Yi; Liu, Yan; Huang, Jing; Chen, Wufan; Lu, Hongbing

    2012-07-01

    Low-dose x-ray computed tomography (CT) is clinically desired. Accurate noise modeling is a fundamental issue for low-dose CT image reconstruction via statistics-based sinogram restoration or statistical iterative image reconstruction. In this paper, the authors analyzed the statistical moments of low-dose CT data in the presence of electronic noise background. The authors first studied the statistical moment properties of detected signals in CT transmission domain, where the noise of detected signals is considered as quanta fluctuation upon electronic noise background. Then the authors derived, via the Taylor expansion, a new formula for the mean-variance relationship of the detected signals in CT sinogram domain, wherein the image formation becomes a linear operation between the sinogram data and the unknown image, rather than a nonlinear operation in the CT transmission domain. To get insight into the derived new formula by experiments, an anthropomorphic torso phantom was scanned repeatedly by a commercial CT scanner at five different mAs levels from 100 down to 17. The results demonstrated that the electronic noise background is significant when low-mAs (or low-dose) scan is performed. The influence of the electronic noise background should be considered in low-dose CT imaging.

  17. SU-E-T-70: Commissioning a Multislice CT Scanner for X-Ray CT Polymer Gel Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H [University of Victoria, Victoria, BC (Australia); UT Southwestern Medical Center, Dallas, TX (United States); Hilts, M [University of Victoria, Victoria, BC (Australia); BC Cancer Agency, Kelowna, BC (Australia); Jirasek, A [University of Victoria, Victoria, BC (Australia)

    2014-06-01

    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 single 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

  18. Empirical average-case relation between undersampling and sparsity in X-ray CT

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Sauer; Sidky, Emil Y.; Hansen, Per Christian

    2015-01-01

    In X-ray computed tomography (CT) it is generally acknowledged that reconstruction methods exploiting image sparsity allow reconstruction from a significantly reduced number of projections. The use of such reconstruction methods is inspired by recent progress in compressed sensing (CS). However......, the CS framework provides neither guarantees of accurate CT reconstruction, nor any relation between sparsity and a sufficient number of measurements for recovery, i.e., perfect reconstruction from noise-free data. We consider reconstruction through 1-norm minimization, as proposed in CS, from data...... obtained using a standard CT fan-beam sampling pattern. In empirical simulation studies we establish quantitatively a relation between the image sparsity and the sufficient number of measurements for recovery within image classes motivated by tomographic applications. We show empirically that the specific...

  19. Patellofemoral joint dysfunction. Combined diagnostic imaging evaluation (X-rays, 3D helical CT and MRI)

    International Nuclear Information System (INIS)

    Carrascosa, P.; Sanchez, F.; Mazzucco, J.; Capanay, C.; Carrascosa, J.

    2000-01-01

    The comprehensive study including 3D helical CT, Magnetic Resonance (MR) and X-ray exams provide a more complete diagnosis than those obtained through the conventional CT. We studied 43 patients with presumptive or certain diagnosis of patellofemoral instability. All the patients were studied by: a) Radiological pair; b) Tomography under extension and flexion, without and with contraction, using a helical CT equipment; and c) MRI STIR sequence in axial plane. The findings were classified as muscular lesion, cartilage lesion, bone and associated lesions (e.g. synovitis), statistically comparing both studies (comprehensive vs. conventional). The results allow us to accept the hypothesis that the comprehensive study provides a more complete diagnosis about the origin of the patellofemoral dysfunction. In 65% of the patients, the conventional study gave a negative result. Only in 35% of the cases the result was positive, but incomplete, showing only 35.3% of the pathological findings detected by the comprehensive study. (author)

  20. Low-dose x-ray phase-contrast and absorption CT using equally sloped tomography

    International Nuclear Information System (INIS)

    Fahimian, Benjamin P; Miao Jianwei; Mao Yu; Cloetens, Peter

    2010-01-01

    Tomographic reconstruction from undersampled and noisy projections is often desirable in transmission CT modalities for purposes of low-dose tomography and fast acquisition imaging. However under such conditions, due to the violation of the Nyquist sampling criteria and the presence of noise, reconstructions with acceptable accuracy may not be possible. Recent experiments in transmission electron tomography and coherent diffraction microscopy have shown that the technique of equally sloped tomography (EST), an exact tomographic method utilizing an oversampling iterative Fourier-based reconstruction, provides more accurate image reconstructions when the number of projections is significantly undersampled relative to filtered back projection and algebraic iterative methods. Here we extend this technique by developing new reconstruction algorithms which allow for the incorporation of advanced mathematical regularization constraints, such as the nonlocal means total variational model, in a manner that is consistent with experimental projections. We then evaluate the resulting image quality of the developed algorithm through simulations and experiments at the European Synchrotron Radiation Facility on image quality phantoms using the x-ray absorption and phase contrast CT modalities. Both our simulation and experimental results have indicated that the method can reduce the number of projections by 60-75% in parallel beam modalities, while achieving comparable or better image quality than the conventional reconstructions. As large-scale and compact synchrotron radiation facilities are currently under rapid development worldwide, the implementation of low-dose x-ray absorption and phase-contrast CT can find broad applications in biology and medicine using these advanced x-ray sources.

  1. A simple, direct method for x-ray scatter estimation and correction in digital radiography and cone-beam CT

    International Nuclear Information System (INIS)

    Siewerdsen, J.H.; Daly, M.J.; Bakhtiar, B.

    2006-01-01

    X-ray scatter poses a significant limitation to image quality in cone-beam CT (CBCT), resulting in contrast reduction, image artifacts, and lack of CT number accuracy. We report the performance of a simple scatter correction method in which scatter fluence is estimated directly in each projection from pixel values near the edge of the detector behind the collimator leaves. The algorithm operates on the simple assumption that signal in the collimator shadow is attributable to x-ray scatter, and the 2D scatter fluence is estimated by interpolating between pixel values measured along the top and bottom edges of the detector behind the collimator leaves. The resulting scatter fluence estimate is subtracted from each projection to yield an estimate of the primary-only images for CBCT reconstruction. Performance was investigated in phantom experiments on an experimental CBCT benchtop, and the effect on image quality was demonstrated in patient images (head, abdomen, and pelvis sites) obtained on a preclinical system for CBCT-guided radiation therapy. The algorithm provides significant reduction in scatter artifacts without compromise in contrast-to-noise ratio (CNR). For example, in a head phantom, cupping artifact was essentially eliminated, CT number accuracy was restored to within 3%, and CNR (breast-to-water) was improved by up to 50%. Similarly in a body phantom, cupping artifact was reduced by at least a factor of 2 without loss in CNR. Patient images demonstrate significantly increased uniformity, accuracy, and contrast, with an overall improvement in image quality in all sites investigated. Qualitative evaluation illustrates that soft-tissue structures that are otherwise undetectable are clearly delineated in scatter-corrected reconstructions. Since scatter is estimated directly in each projection, the algorithm is robust with respect to system geometry, patient size and heterogeneity, patient motion, etc. Operating without prior information, analytical modeling

  2. Characterization of breast tissue using energy-dispersive X-ray diffraction computed tomography

    International Nuclear Information System (INIS)

    Pani, S.; Cook, E.J.; Horrocks, J.A.; Jones, J.L.; Speller, R.D.

    2010-01-01

    A method for sample characterization using energy-dispersive X-ray diffraction computed tomography (EDXRDCT) is presented. The procedures for extracting diffraction patterns from the data and the corrections applied are discussed. The procedures were applied to the characterization of breast tissue samples, 6 mm in diameter. Comparison with histological sections of the samples confirmed the possibility of grouping the patterns into five families, corresponding to adipose tissue, fibrosis, poorly differentiated cancer, well differentiated cancer and benign tumour.

  3. Breast neoplasms in women treated with x-rays for acute postpartum mastitis

    International Nuclear Information System (INIS)

    Shore, R.E.; Hempelmann, L.H.; Kowaluk, E.; Mansur, P.S.; Pasternack, B.S.; Albert, R.E.; Haughie, G.E.

    1977-01-01

    Breast cancer has been studied by mail survey up to 34 years in 571 of 606 women treated with x-rays for acute postpartum mastitis. The incidence of neoplasms was compared with that of three nonirradiated control groups--nonirradiated sisters of the treated women, women with acute postpartum mastitis not treated with X-rays, and their nonirradiated sisters. For the irradiated group, with a mean dose of 247 rads to both breasts, the overall relative risk of breast cancer was 2.2 for years 10 to 34 post irradiation and 3.6 for 20 to 34. The dose response for malignant and benign breast neoplasms was compatible with a linear fit. For comparable total doses, fractionation of exposure did not reduce carcinogenic action. Women over age 30 years at radiation treatment had as great an excess risk of breast cancer as did younger women. The overall excess risk of developing breast cancer was about 8 to 10 cases per million women per rad per year, an increase of about 0.5% per rad

  4. X-ray scattering for the characterization of lyophilized breast tissue samples

    International Nuclear Information System (INIS)

    Elshemey, Wael M.; Mohamed, Fayrouz S.; Khater, Ibrahim M.

    2013-01-01

    This work investigates the possibility of characterizing breast cancer by measuring the X-ray scattering profiles of lyophilized excised breast tissue samples. Since X-ray scattering from water-rich tissue is dominated by scattering from water, the removal of water by lyophilization would enhance the characterization process. In the present study, X-ray scattering profiles of 22 normal, 22 malignant and 10 benign breast tissue samples are measured. The cut-offs of scatter diagrams, sensitivity, specificity and diagnostic accuracy of three characterization parameters (full width at half maximum (FWHM) for the peak at 1.1 nm −1 , area under curve (AUC), and ratio of 1st to 2nd scattering peak intensities (I 1 /I 2 %)) are calculated and compared to the data from non-lyophilized samples. Results show increased sensitivity (up to 100%) of the present data on lyophilized breast tissue samples compared to previously reported data for non-lyophilized samples while the specificity (up to 95.4%), diagnostic accuracy (up to 95.4%) and receiver operating characteristic (ROC) curve values (up to 0.9979) for both sets of data are comparable. The present study shows significant differences between normal samples and each of malignant and benign samples. Only subtle differences exist between malignant and benign lyophilized breast tissue samples where FWHM=0.7±0.1 and 0.8±0.3, AUC=1.3±0.2 and 1.4±0.2 and I 1 /I 2 %=44.9±11.0 and 52.4±7.6 for malignant and benign samples respectively. - Highlights: • X-ray scattering profiles of breast tissue samples are acquired. • Three X-ray profile characterization parameters are calculated. • The cut-offs, sensitivity, specificity and diagnostic accuracy are calculated. • They are compared to the data from non-lyophilized samples. • Results show increased sensitivity in case of lyophilized samples

  5. Low-Dose X-ray CT Reconstruction via Dictionary Learning

    Science.gov (United States)

    Xu, Qiong; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2013-01-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures. PMID:22542666

  6. Low-dose X-ray CT reconstruction via dictionary learning.

    Science.gov (United States)

    Xu, Qiong; Yu, Hengyong; Mou, Xuanqin; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2012-09-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures.

  7. High resolution stationary digital breast tomosynthesis using distributed carbon nanotube x-ray source array.

    Science.gov (United States)

    Qian, Xin; Tucker, Andrew; Gidcumb, Emily; Shan, Jing; Yang, Guang; Calderon-Colon, Xiomara; Sultana, Shabana; Lu, Jianping; Zhou, Otto; Spronk, Derrek; Sprenger, Frank; Zhang, Yiheng; Kennedy, Don; Farbizio, Tom; Jing, Zhenxue

    2012-04-01

    The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array, which generates all the projection images needed for tomosynthesis reconstruction by electronically activating individual x-ray sources without any mechanical motion. The stationary digital breast tomosynthesis (s-DBT) design aims to (i) increase the system spatial resolution by eliminating image blurring due to x-ray tube motion and (ii) reduce the scanning time. Low spatial resolution and long scanning time are the two main technical limitations of current DBT technology. A CNT x-ray source array was designed and evaluated against a set of targeted system performance parameters. Simulations were performed to determine the maximum anode heat load at the desired focal spot size and to design the electron focusing optics. Field emission current from CNT cathode was measured for an extended period of time to determine the stable life time of CNT cathode for an expected clinical operation scenario. The source array was manufactured, tested, and integrated with a Selenia scanner. An electronic control unit was developed to interface the source array with the detection system and to scan and regulate x-ray beams. The performance of the s-DBT system was evaluated using physical phantoms. The spatially distributed CNT x-ray source array comprised 31 individually addressable x-ray sources covering a 30 angular span with 1 pitch and an isotropic focal spot size of 0.6 mm at full width at half-maximum. Stable operation at 28 kV(peak) anode voltage and 38 mA tube current was demonstrated with extended lifetime and good source-to-source consistency. For the standard imaging protocol of 15 views over 14, 100 mAs dose, and 2 × 2 detector binning, the projection

  8. Matching methods evaluation framework for stereoscopic breast x-ray images.

    Science.gov (United States)

    Rousson, Johanna; Naudin, Mathieu; Marchessoux, Cédric

    2016-01-01

    Three-dimensional (3-D) imaging has been intensively studied in the past few decades. Depth information is an important added value of 3-D systems over two-dimensional systems. Special focuses were devoted to the development of stereo matching methods for the generation of disparity maps (i.e., depth information within a 3-D scene). Dedicated frameworks were designed to evaluate and rank the performance of different stereo matching methods but never considering x-ray medical images. Yet, 3-D x-ray acquisition systems and 3-D medical displays have already been introduced into the diagnostic market. To access the depth information within x-ray stereoscopic images, computing accurate disparity maps is essential. We aimed at developing a framework dedicated to x-ray stereoscopic breast images used to evaluate and rank several stereo matching methods. A multiresolution pyramid optimization approach was integrated to the framework to increase the accuracy and the efficiency of the stereo matching techniques. Finally, a metric was designed to score the results of the stereo matching compared with the ground truth. Eight methods were evaluated and four of them [locally scaled sum of absolute differences (LSAD), zero mean sum of absolute differences, zero mean sum of squared differences, and locally scaled mean sum of squared differences] appeared to perform equally good with an average error score of 0.04 (0 is the perfect matching). LSAD was selected for generating the disparity maps.

  9. X-ray CT high-density artefact suppression in the presence of bones

    Energy Technology Data Exchange (ETDEWEB)

    Wei Jikun [School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051 (United States); Chen Laigao [BioImaging Center of Emphasis, Pfizer Global Research and Development, 2800 Plymouth RD, Ann Arbor, MI 48105 (United States); Sandison, George A [School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051 (United States); Liang Yun [Department of Radiology, Indiana University Medical School, Indianapolis, IN 46202 (United States); Xu, Lisa X [School of Mechanical Engineering, 585 Purdue Mall, West Lafayette, IN 47907-2040 (United States)

    2004-12-21

    This paper presents a novel method of reducing x-ray CT high-density artefacts generated by metal objects when abundant bone structures are present in the region of interest. This method has an advantage over previously proposed methods since it heavily suppresses the metal artefacts without introducing extra bone artefacts. The method of suppression requires that bone pixels are isolated and segmented by thresholding. Then artificial CT numbers are assigned to the bone pixels so that their projection profiles are smooth and thus can be properly simulated by a polynomial interpolation. The projection profile of the metal object is then removed to fully suppress the artefacts. The resulting processed profile is fed to a reconstruction routine and the previously preserved bone pixels added back. The new method utilizes two important features of the CT image with metal artefacts: (a) metal and bone pixels are not severely affected by the high-density artefacts and (b) the high-density artefacts can be located in specific projection channels in the profile domain, although they are spread out in the image domain. This suppression method solves the problem of CT image artefacts arising from metal objects in the body. It has the potential to greatly improve diagnostic CT imaging in the presence of these objects and treatment planning that utilizes CT for patients with metal applicators (e.g., brachytherapy for cervix cancer and prostate cryotherapy)

  10. Diagnosis of ovarian tumors by ultrasonography and x-ray CT

    International Nuclear Information System (INIS)

    Watanabe, Hiromu

    1986-01-01

    A drawback in ultrasonography, an indispensable technique in imaging ovarian malignancies, is that it sometimes shows false positive for benign tumors including dermoid cyst and ovarian endometriosis. To overcome this, the concurrent use of X-Ray CT seems warrantable and this led us to carry out the study summarized below. CT was carried out on 268 of 322 ovarian disease cases which had undergone ultrasonography. The results obtained were as follows. Sensitivity of ultrasonography and CT in ovarian malignancies were 82 % and 88 % respectively. Of the cases subjected to both techniques, those who were deemed false positive were 39 in ultrasonography and 12 in CT. Ultrasonographic imagings of dermoid cyst and ovarian endometriosis were classified on the basis of their patterns. The results obtained revealed that those in which it was difficult to discriminate the image from ovarian malignancy were types V and VI in dermoid cyst and type III-C in ovarian endometriosis. In both dermoid cyst and ovarian endometriosis, nearly a 100 % accuracy rate was obtainable with CT for diagnosis of benign tumors. This strongly suggested that concurrent use of CT was required, in diagnosing ovarian diseases with the V or VI and III-C patterns referred to above. (author)

  11. X-ray CT high-density artefact suppression in the presence of bones

    International Nuclear Information System (INIS)

    Wei Jikun; Chen Laigao; Sandison, George A; Liang Yun; Xu, Lisa X

    2004-01-01

    This paper presents a novel method of reducing x-ray CT high-density artefacts generated by metal objects when abundant bone structures are present in the region of interest. This method has an advantage over previously proposed methods since it heavily suppresses the metal artefacts without introducing extra bone artefacts. The method of suppression requires that bone pixels are isolated and segmented by thresholding. Then artificial CT numbers are assigned to the bone pixels so that their projection profiles are smooth and thus can be properly simulated by a polynomial interpolation. The projection profile of the metal object is then removed to fully suppress the artefacts. The resulting processed profile is fed to a reconstruction routine and the previously preserved bone pixels added back. The new method utilizes two important features of the CT image with metal artefacts: (a) metal and bone pixels are not severely affected by the high-density artefacts and (b) the high-density artefacts can be located in specific projection channels in the profile domain, although they are spread out in the image domain. This suppression method solves the problem of CT image artefacts arising from metal objects in the body. It has the potential to greatly improve diagnostic CT imaging in the presence of these objects and treatment planning that utilizes CT for patients with metal applicators (e.g., brachytherapy for cervix cancer and prostate cryotherapy)

  12. Sparse signal reconstruction from polychromatic X-ray CT measurements via mass attenuation discretization

    International Nuclear Information System (INIS)

    Gu, Renliang; Dogandžić, Aleksandar

    2014-01-01

    We propose a method for reconstructing sparse images from polychromatic x-ray computed tomography (ct) measurements via mass attenuation coefficient discretization. The material of the inspected object and the incident spectrum are assumed to be unknown. We rewrite the Lambert-Beer’s law in terms of integral expressions of mass attenuation and discretize the resulting integrals. We then present a penalized constrained least-squares optimization approach for reconstructing the underlying object from log-domain measurements, where an active set approach is employed to estimate incident energy density parameters and the nonnegativity and sparsity of the image density map are imposed using negative-energy and smooth ℓ 1 -norm penalty terms. We propose a two-step scheme for refining the mass attenuation discretization grid by using higher sampling rate over the range with higher photon energy, and eliminating the discretization points that have little effect on accuracy of the forward projection model. This refinement allows us to successfully handle the characteristic lines (Dirac impulses) in the incident energy density spectrum. We compare the proposed method with the standard filtered backprojection, which ignores the polychromatic nature of the measurements and sparsity of the image density map. Numerical simulations using both realistic simulated and real x-ray ct data are presented

  13. Application of 3D X-ray CT data sets to finite element analysis

    International Nuclear Information System (INIS)

    Bossart, P.L.; Martz, H.E.; Brand, H.R.; Hollerbach, K.

    1995-01-01

    Finite Element Modeling (FEM) is becoming more important as industry drives toward concurrent engineering. A fundamental hindrance to fully exploiting the power of FEM is the human effort required to acquire complex part geometry, particularly as-built geometry, as a FEM mesh. Many Quantitative Non Destructive Evaluation (QNDE) techniques that produce three-dimensional (3D) data sets provide a substantial reduction in the effort required to apply FEM to as-built parts. This paper describes progress at LLNL on the application of 3D X-ray computed tomography (CT) data sets to more rapidly produce high-quality FEM meshes of complex, as-built geometries. Issues related to the volume segmentation of the 3D CT data as well as the use of this segmented data to tailor generic hexahedral FEM meshes to part specific geometries are discussed. The application of these techniques to FEM analysis in the medical field is reported here

  14. Differential diagnosis of benign and malignant breast tumors by high frequency molybdenum-target X-ray photography

    International Nuclear Information System (INIS)

    Mai Yuanqi; Wang Maosheng; Huang Jian; Cui Guoru; Liang Zhicong; Lu Yingying

    2008-01-01

    Objective: To explore the X-ray Image of benign and malignant breast lesions (tumors) in order to improve their differcatial diagnostic level. Methods: X-ray image changes of 63 malignant breast neoplasms were described by the mammography and in comparision with those of 43 benign masses. Results: The accordance percentages between the X-ray and histological examinations for the benign and malignant neoplasms were shown as 85% and 90.6% respectively. Spiculated mass, calcification granules in clusters and other images were found to be indication of benign or malignant breast lesion. Conclusion: The High Frequency Molybdenum-target X-ray Photography can provide effective imaging data for diagnosis and distinguish between the benign and malignant breast lesions. (authors)

  15. Dual-energy X-ray micro-CT imaging of hybrid Ni/Al open-cell foam

    Czech Academy of Sciences Publication Activity Database

    Fíla, T.; Kumpová, Ivana; Koudelka_ml., P.; Zlámal, P.; Vavřík, Daniel; Jiroušek, O.; Jung, A.

    2016-01-01

    Roč. 11, č. 1 (2016), C01005 ISSN 1748-0221. [International Workshop on Radiation Imaging Detectors (IWORID2015) /17./. Hamburg, 28.06.2015-02.07.2015] Institutional support: RVO:68378297 Keywords : computerized tomography (CT) * computed radiography (CR) * X-ray radiography and digital radiography (DR) * inspection with x-rays Subject RIV: JJ - Other Materials Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/11/01/C01005/pdf

  16. Coherent scattering X-ray imaging at the Brazilian National Synchrotron Laboratory: Preliminary breast images

    Energy Technology Data Exchange (ETDEWEB)

    Castro, C.R.F. [Nuclear Instrumentation Laboratory-COPPE/UFRJ, P.O. Box 68509, Rio de Janeiro 21945-970 (Brazil); Barroso, R.C. [Physics Institute-University of Rio de Janeiro State, Rio de Janeiro 20559-900 (Brazil)]. E-mail: cely@uerij.br; Oliveira, L.F. de [Physics Institute-University of Rio de Janeiro State, Rio de Janeiro 20559-900 (Brazil); Lopes, R.T. [Nuclear Instrumentation Laboratory-COPPE/UFRJ, P.O. Box 68509, Rio de Janeiro 21945-970 (Brazil)

    2005-08-11

    The angular distribution of coherent scatter (low-momentum transfer) carries information about atomic structures, resulting in a pattern, which can be used to reconstruct a series of images. Coherent-scatter computed tomography is a novel imaging method developed to produce cross-sectional images based on the X-ray diffraction properties of an object. A different approach to coherent X-ray imaging is possible by fixing the detector at a given scatter angle {theta}, which produces an interference peak and then, carried out a tomography in the standard way. The cross-sectional images obtained allow determining the spatial dependence of coherent scatter cross-section of selected volume elements of inhomogeneous, extend objects for a single predetermined value of {theta} of interest, leading to a simplification of the data processing and the complexity of the apparatus. This work presents preliminary coherent scattering images carried out at the X-ray Diffraction beamline of the National Synchrotron Light Laboratory in Campinas, Brazil. The specimens were excised human breast tissues fixed in formaline. No frozen procedure was used in order to minimize preferred orientation during sample preparation. About 1mm thick slices cut from each of the fresh samples were mounted in frames without windows and placed on a translator to allow acquisition of scattering spectra. Cylinders containing healthy and cancerous (infiltrating ductal carcinoma) breast tissues were imagined at the characteristic angle for adipose tissue. Transmission and coherent scatter images are compared.

  17. Optimized control of X-ray exposure and image noise using a particular multislice CT scanner

    International Nuclear Information System (INIS)

    Yamamoto, Shuji; Suzuki, Masahiro; Kakinuma, Ryutaro; Moriyama, Noriyuki; Koyama, Yoshihiro; Nagasawa, Hirofumi

    2008-01-01

    Patient dose reduction in computed tomography (CT) always results in a trade off between radiation exposure and image quality. There are few reports that estimate the relationship between image quality and X-ray exposure in CT examinations as one optimal index. The purpose of this study was to determine the optimal parameter settings enabling a low radiation exposure without compromising image quality using a particular 4-row multislice CT (MSCT) scanner (Aquilion VZ 4-slice CT scanner, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan). Normalized dose divided by image noise for helical pitches (nDNR: normalized dose to noise ratio) were calculated in consideration of beam collimation and tube current-time product. Optimal tube current-time product was calculated using the nDNR for the helical pitches based on user-defined standards of quality of the CT image. As a result, the nDNR proved to be well-supported to decrease the patient exposure in various exposure conditions of MSCT scans; however, the dose and image noise did not show a linear relation to the helical pitch. In conclusion, nDNR can be applied to patient dose reduction while keeping an acceptable image quality using a particular 4-row MSCT scanner. (author)

  18. Automated analysis for early signs of cerebral infarctions on brain X-ray CT images

    International Nuclear Information System (INIS)

    Oshima, Kazuki; Hara, Takeshi; Zhou, X.; Muramatsu, Chisako; Fujita, Hiroshi; Sakashita, Keiji

    2010-01-01

    t-PA (tissue plasminogen activator) thrombolysis is an effective clinical treatment for the acute cerebral infarction by breakdown to blood clots. However there is a risk of hemorrhage with its use. The guideline of the treatment is denying cerebral hemorrhage and widespread Early CT sign (ECS) on CT images. In this study, we analyzed the CT value of normal brain and ECS with normal brain model by comparing patient brain CT scan with a statistical normal model. Our method has constructed normal brain models consisted of 60 normal brain X-ray CT images. We calculated Z-score based on statistical model for 16 cases of cerebral infarction with ECS, 3 cases of cerebral infarction without ECS, and 25 cases of normal brain. The results of statistical analysis showed that there was a statistically significant difference between control and abnormal groups. This result implied that the automated detection scheme for ECS by using Z-score would be a possible application for brain computer-aided diagnosis (CAD). (author)

  19. Analysis on breast X-ray of chronic schizophrenia and Iiterature review

    International Nuclear Information System (INIS)

    Dang Lianrong; Wang Xuqiang; Xie Junwei; Pei Genxiang

    2008-01-01

    Objective: To research the symptom of breast X-ray of chronic schizophrenia and the influence of its clinical features. Methods: Take 50 patients who have been under treatment in our hospital for over 5 years as sample of psychotic group and same number of healthy people as control group. Analyze their X-ray films, using statistics to deal with their lung area of both before and after 5 years. Evaluation Criteria of X-ray: (1) Double layer rise; (2)Single or double lung base subsegmental atelectasis; (3)Heart drown; (4)Heart turing with the heart apex extending to the left; (5)The double lung bottom have gathering stripes; (6)The upper layer have wider shadow. Results: The lung lobes of the patient group become smaller than they were 5 years ago. Data show great difference between two years (t=6.7099, P<0.01). The lung lobes of psychotic group become bigger than the control group in the first X-ray films (t=2.025, P<0.05), but smaller in the last X-ray films (t=5.512, P<0.01). Among them, 37 cases show double layer rise; 19 cases show single or double lung base subsegmental atelectasis; 24 cases show heart drown; 19 cases show heart turing and heart apex extending to the left; 37 cases show double lung bottom gathering stripes; 17 cases show wider shadow. Conclusion: Morphology and pathology changes of schizophrenia patients are related to the side effect of anti-schizophrenia medicine and endocrine disorders. (authors)

  20. A spectral X-ray CT simulation study for quantitative determination of iron

    Science.gov (United States)

    Su, Ting; Kaftandjian, Valérie; Duvauchelle, Philippe; Zhu, Yuemin

    2018-06-01

    Iron is an essential element in the human body and disorders in iron such as iron deficiency or overload can cause serious diseases. This paper aims to explore the ability of spectral X-ray CT to quantitatively separate iron from calcium and potassium and to investigate the influence of different acquisition parameters on material decomposition performance. We simulated spectral X-ray CT imaging of a PMMA phantom filled with iron, calcium, and potassium solutions at various concentrations (15-200 mg/cc). Different acquisition parameters were considered, such as the number of energy bins (6, 10, 15, 20, 30, 60) and exposure factor per projection (0.025, 0.1, 1, 10, 100 mA s). Based on the simulation data, we investigated the performance of two regularized material decomposition approaches: projection domain method and image domain method. It was found that the former method discriminated iron from calcium, potassium and water in all cases and tended to benefit from lower number of energy bins for lower exposure factor acquisition. The latter method succeeded in iron determination only when the number of energy bins equals 60, and in this case, the contrast-to-noise ratios of the decomposed iron images are higher than those obtained using the projection domain method. The results demonstrate that both methods are able to discriminate and quantify iron from calcium, potassium and water under certain conditions. Their performances vary with the acquisition parameters of spectral CT. One can use one method or the other to benefit better performance according to the data available.

  1. Introduction of a deformable x-ray CT polymer gel dosimetry system

    Science.gov (United States)

    Maynard, E.; Heath, E.; Hilts, M.; Jirasek, A.

    2018-04-01

    This study introduces the first 3D deformable dosimetry system based on x-ray computed tomography (CT) polymer gel dosimetry and establishes the setup reproducibility, deformation characteristics and dose response of the system. A N-isopropylacrylamide (NIPAM)-based gel formulation optimized for x-ray CT gel dosimetry was used, with a latex balloon serving as the deformable container and low-density polyethylene and polyvinyl alcohol providing additional oxygen barrier. Deformable gels were irradiated with a 6 MV calibration pattern to determine dosimetric response and a dosimetrically uniform plan to determine the spatial uniformity of the response. Wax beads were added to each gel as fiducial markers to track the deformation and setup of the gel dosimeters. From positions of the beads on CT images the setup reproducibility and the limits and reproducibility of gel deformation were determined. Comparison of gel measurements with Monte Carlo dose calculations found excellent dosimetric accuracy, comparable to that of an established non-deformable dosimetry system, with a mean dose discrepancy of 1.5% in the low-dose gradient region and a gamma pass rate of 97.9% using a 3%/3 mm criterion. The deformable dosimeter also showed good overall spatial dose uniformity throughout the dosimeter with some discrepancies within 20 mm of the edge of the container. Tracking of the beads within the dosimeter found that sub-millimetre setup accuracy is achievable with this system. The dosimeter was able to deform and relax when externally compressed by up to 30 mm without sustaining any permanent damage. Internal deformations in 3D produced average marker movements of up to 12 mm along the direction of compression. These deformations were also shown to be reproducible over 100 consecutive deformations. This work has established several important characteristics of a new deformable dosimetry system which shows promise for future clinical applications, including the

  2. Structural changes of green roof growing substrate layer studied by X-ray CT

    Science.gov (United States)

    Jelinkova, Vladimira; Sacha, Jan; Dohnal, Michal; Snehota, Michal

    2017-04-01

    Increasing interest in green infrastructure linked with newly implemented legislation/rules/laws worldwide opens up research potential for field of soil hydrology. A better understanding of function of engineered soils involved in green infrastructure solutions such as green roofs or rain garden is needed. A soil layer is considered as a highly significant component of the aforesaid systems. In comparison with a natural soil, the engineered soil is assumed to be the more challenging case due to rapid structure changes early stages after its build-up. The green infrastructure efficiency depends on the physical and chemical properties of the soil, which are, in the case of engineered soils, a function of its initial composition and subsequent soil formation processes. The project presented in this paper is focused on fundamental processes in the relatively thick layer of engineered soil. The initial structure development, during which the pore geometry is altered by the growth of plant roots, water influx, solid particles translocation and other soil formation processes, is investigated with the help of noninvasive imaging technique  X-ray computed tomography. The soil development has been studied on undisturbed soil samples taken periodically from green roof test system during early stages of its life cycle. Two approaches and sample sizes were employed. In the first approach, undisturbed samples (volume of about 63 cm3) were taken each time from the test site and scanned by X-ray CT. In the second approach, samples (volume of about 630 cm3) were permanently installed at the test site and has been repeatedly removed to perform X-ray CT imaging. CT-derived macroporosity profiles reveal significant temporal changes of soil structure. Clogging of pores by fine particles and fissures development are two most significant changes that would affect the green roof system efficiency. This work has been supported by the Ministry of Education, Youth and Sports within

  3. Water equivalence of NIPAM based polymer gel dosimeters with enhanced sensitivity for x-ray CT

    Science.gov (United States)

    Gorjiara, Tina; Hill, Robin; Bosi, Stephen; Kuncic, Zdenka; Baldock, Clive

    2013-10-01

    Two new formulations of N-isopropylacrylamide (NIPAM) based three dimensional (3D) gel dosimeters have recently been developed with improved sensitivity to x-ray CT readout, one without any co-solvent and the other one with isopropanol co-solvent. The water equivalence of the NIPAM gel dosimeters was investigated using different methods to calculate their radiological properties including: density, electron density, number of electrons per grams, effective atomic number, photon interaction probabilities, mass attenuation and energy absorption coefficients, electron collisional, radiative and total mass stopping powers and electron mass scattering power. Monte Carlo modelling was also used to compare the dose response of these gel dosimeters with water for kilovoltage and megavoltage x-ray beams and for megavoltage electron beams. We found that the density and electron density of the co-solvent free gel dosimeter are more water equivalent with less than a 2.6% difference compared to a 5.7% difference for the isopropanol gel dosimeter. Both the co-solvent free and isopropanol solvent gel dosimeters have lower effective atomic numbers than water, differing by 2.2% and 6.5%, respectively. As a result, their photoelectric absorption interaction probabilities are up to 6% and 19% different from water, respectively. Compton scattering and pair production interaction probabilities of NIPAM gel with isopropanol differ by up to 10% from water while for the co-solvent free gel, the differences are 3%. Mass attenuation and energy absorption coefficients of the co-solvent free gel dosimeter and the isopropanol gel dosimeter are up to 7% and 19% lower than water, respectively. Collisional and total mass stopping powers of both gel dosimeters differ by less than 2% from those of water. The dose response of the co-solvent free gel dosimeter is water equivalent (with x-ray beams over the energy range 180 keV-18 MV, both gel dosimeters have less than 2% discrepancy with water. For

  4. Direct 3-D morphological measurements of silicone rubber impression using micro-focus X-ray CT.

    Science.gov (United States)

    Kamegawa, Masayuki; Nakamura, Masayuki; Fukui, Yu; Tsutsumi, Sadami; Hojo, Masaki

    2010-01-01

    Three-dimensional computer models of dental arches play a significant role in prosthetic dentistry. The microfocus X-ray CT scanner has the advantage of capturing precise 3D shapes of deep fossa, and we propose a new method of measuring the three-dimensional morphology of a dental impression directly, which will eliminate the conversion process to dental casts. Measurement precision and accuracy were evaluated using a standard gage comprised of steel balls which simulate the dental arch. Measurement accuracy, standard deviation of distance distribution of superimposed models, was determined as +/-0.050 mm in comparison with a CAD model. Impressions and casts of an actual dental arch were scanned by microfocus X-ray CT and three-dimensional models were compared. The impression model had finer morphology, especially around the cervical margins of teeth. Within the limitations of the current study, direct three-dimensional impression modeling was successfully demonstrated using microfocus X-ray CT.

  5. Visualization of soil particulate organic matter by means of X-ray CT?

    Science.gov (United States)

    Sleutel, Steven; Van Loo, Denis; Maenhout, Peter; Van Hoorebeke, Luc; Cnudde, Veerle; De Neve, Stefaan

    2014-05-01

    The role of soil structure in organic matter (OM) stabilization has been primarily investigated through physical fractionation studies operative at the scale of aggregates and smaller organo-mineral particles. By narrowing down soil structure to an arrangement of mineral and organic particles, the majority of studies did not explore the spatial organization of the soil pore network, the actual habitat of microorganisms. The pore structure of soil can have a significant impact on soil processes like OM decomposition by excluding OM from micro-organisms in small pores, by regulating the diffusion of substrates and metabolites and by regulating aeration and presence of moisture. Because of its ability to visualize the 3D architecture of soil non-destructively, X-ray Computed Tomography (CT) is becoming a widespread tool for studying soil pore network structure. However, phase determination of pore space, soil OM, soil mineral matter (MM) and water is often limited even with the latest technological and software advances, allowing high resolution and better quality imaging. Contrast agents commonly used in histology enable enhancement of X-ray attenuation of targeted structures or compounds. Here we report on the first systematic investigation of the use of such X-ray contrast agents for soil research. An evaluation procedure as well as a method to apply the agents to soil samples was developed and applied on reference soil samples. The effectiveness and selectivity of the contrast agents was evaluated for soil organic matter (SOM), MM and water. Several products were found to selectively increase the attenuation of water or SOM. The four agents with the best OM-staining capabilities (Phosphomolybdenic acid (PMA), silver nitrate, lead nitrate and lead acetate) were further tested on an OM-MM mixture. Observed differences in reactivity of the staining agents with MM components were apparent, suggesting that contrasting agents may have to be selected for the specific

  6. Radiation dose reduction in medical x-ray CT via Fourier-based iterative reconstruction.

    Science.gov (United States)

    Fahimian, Benjamin P; Zhao, Yunzhe; Huang, Zhifeng; Fung, Russell; Mao, Yu; Zhu, Chun; Khatonabadi, Maryam; DeMarco, John J; Osher, Stanley J; McNitt-Gray, Michael F; Miao, Jianwei

    2013-03-01

    A Fourier-based iterative reconstruction technique, termed Equally Sloped Tomography (EST), is developed in conjunction with advanced mathematical regularization to investigate radiation dose reduction in x-ray CT. The method is experimentally implemented on fan-beam CT and evaluated as a function of imaging dose on a series of image quality phantoms and anonymous pediatric patient data sets. Numerical simulation experiments are also performed to explore the extension of EST to helical cone-beam geometry. EST is a Fourier based iterative algorithm, which iterates back and forth between real and Fourier space utilizing the algebraically exact pseudopolar fast Fourier transform (PPFFT). In each iteration, physical constraints and mathematical regularization are applied in real space, while the measured data are enforced in Fourier space. The algorithm is automatically terminated when a proposed termination criterion is met. Experimentally, fan-beam projections were acquired by the Siemens z-flying focal spot technology, and subsequently interleaved and rebinned to a pseudopolar grid. Image quality phantoms were scanned at systematically varied mAs settings, reconstructed by EST and conventional reconstruction methods such as filtered back projection (FBP), and quantified using metrics including resolution, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs). Pediatric data sets were reconstructed at their original acquisition settings and additionally simulated to lower dose settings for comparison and evaluation of the potential for radiation dose reduction. Numerical experiments were conducted to quantify EST and other iterative methods in terms of image quality and computation time. The extension of EST to helical cone-beam CT was implemented by using the advanced single-slice rebinning (ASSR) method. Based on the phantom and pediatric patient fan-beam CT data, it is demonstrated that EST reconstructions with the lowest scanner flux setting of 39 m

  7. Radiation dose reduction in medical x-ray CT via Fourier-based iterative reconstruction

    International Nuclear Information System (INIS)

    Fahimian, Benjamin P.; Zhao Yunzhe; Huang Zhifeng; Fung, Russell; Zhu Chun; Miao Jianwei; Mao Yu; Khatonabadi, Maryam; DeMarco, John J.; McNitt-Gray, Michael F.; Osher, Stanley J.

    2013-01-01

    Purpose: A Fourier-based iterative reconstruction technique, termed Equally Sloped Tomography (EST), is developed in conjunction with advanced mathematical regularization to investigate radiation dose reduction in x-ray CT. The method is experimentally implemented on fan-beam CT and evaluated as a function of imaging dose on a series of image quality phantoms and anonymous pediatric patient data sets. Numerical simulation experiments are also performed to explore the extension of EST to helical cone-beam geometry. Methods: EST is a Fourier based iterative algorithm, which iterates back and forth between real and Fourier space utilizing the algebraically exact pseudopolar fast Fourier transform (PPFFT). In each iteration, physical constraints and mathematical regularization are applied in real space, while the measured data are enforced in Fourier space. The algorithm is automatically terminated when a proposed termination criterion is met. Experimentally, fan-beam projections were acquired by the Siemens z-flying focal spot technology, and subsequently interleaved and rebinned to a pseudopolar grid. Image quality phantoms were scanned at systematically varied mAs settings, reconstructed by EST and conventional reconstruction methods such as filtered back projection (FBP), and quantified using metrics including resolution, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs). Pediatric data sets were reconstructed at their original acquisition settings and additionally simulated to lower dose settings for comparison and evaluation of the potential for radiation dose reduction. Numerical experiments were conducted to quantify EST and other iterative methods in terms of image quality and computation time. The extension of EST to helical cone-beam CT was implemented by using the advanced single-slice rebinning (ASSR) method. Results: Based on the phantom and pediatric patient fan-beam CT data, it is demonstrated that EST reconstructions with the lowest

  8. Characterization of metal additive manufacturing surfaces using synchrotron X-ray CT and micromechanical modeling

    Science.gov (United States)

    Kantzos, C. A.; Cunningham, R. W.; Tari, V.; Rollett, A. D.

    2018-05-01

    Characterizing complex surface topologies is necessary to understand stress concentrations created by rough surfaces, particularly those made via laser power-bed additive manufacturing (AM). Synchrotron-based X-ray microtomography (μ XCT) of AM surfaces was shown to provide high resolution detail of surface features and near-surface porosity. Using the CT reconstructions to instantiate a micromechanical model indicated that surface notches and near-surface porosity both act as stress concentrators, while adhered powder carried little to no load. Differences in powder size distribution had no direct effect on the relevant surface features, nor on stress concentrations. Conventional measurements of surface roughness, which are highly influenced by adhered powder, are therefore unlikely to contain the information relevant to damage accumulation and crack initiation.

  9. Summary of the dose assessment tool for diagnostic X-ray CT, WAZA-ARIv2

    International Nuclear Information System (INIS)

    Koba, Yosuke

    2016-01-01

    WAZA-ARIv2 is the web-based open system for the dose assessment for diagnostic X-ray CT. Amid growing interest about the dose assessment for medical exposure, WAZA-ARIv2 is opened to the public from January 2015 and attracts rising attention. Using WAZA-ARIv2 system, users can calculate exposure dose to consider patient's age and body shape, and can register the calculation results on WAZA-ARIv2 server for checking as histogram statistics. This paper reviews the background of development of WAZA-ARI system, the comparison of characteristics between WAZA-ARIv2 and other tools, and the calculation method of organ dose in WAZA-ARIv2. (author)

  10. Temporal dynamics for soil aggregates determined using X-ray CT scanning

    DEFF Research Database (Denmark)

    Garbout, Amin; Munkholm, Lars Juhl; Hansen, Søren Baarsgaard

    2013-01-01

    Soil structure plays a key role in the ability of soil to fulfil essential soil functions and services in relation to e.g. root growth, gas and water transport and organic matter turnover. However, soils are not a very easy object to study as they are highly complex and opaque to the human eye...... aggregate properties such as volume, surface area and sphericity based on 3D images. We tested the methods on aggregates from different treatments and quantified changes over time. A total of 32 collections of aggregates, enclosed in mesocosms, were incubated in soil to follow the structural changes over....... Traditionally, they have been studied using invasive or destructive techniques. The advantage of using X-ray computed tomography (CT) in soil morphology is that it enables non-destructive quantification of soil structure in three dimensions (3D). The prime objective of the present study was to characterize soil...

  11. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields.

    Science.gov (United States)

    Kelaranta, Anna; Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

    2016-01-01

    Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. The foetal dose levels without lead shielding were dental radiographic examination.

  12. Registration of pencil beam proton radiography data with X-ray CT.

    Science.gov (United States)

    Deffet, Sylvain; Macq, Benoît; Righetto, Roberto; Vander Stappen, François; Farace, Paolo

    2017-10-01

    Proton radiography seems to be a promising tool for assessing the quality of the stopping power computation in proton therapy. However, range error maps obtained on the basis of proton radiographs are very sensitive to small misalignment between the planning CT and the proton radiography acquisitions. In order to be able to mitigate misalignment in postprocessing, the authors implemented a fast method for registration between pencil proton radiography data obtained with a multilayer ionization chamber (MLIC) and an X-ray CT acquired on a head phantom. The registration was performed by optimizing a cost function which performs a comparison between the acquired data and simulated integral depth-dose curves. Two methodologies were considered, one based on dual orthogonal projections and the other one on a single projection. For each methodology, the robustness of the registration algorithm with respect to three confounding factors (measurement noise, CT calibration errors, and spot spacing) was investigated by testing the accuracy of the method through simulations based on a CT scan of a head phantom. The present registration method showed robust convergence towards the optimal solution. For the level of measurement noise and the uncertainty in the stopping power computation expected in proton radiography using a MLIC, the accuracy appeared to be better than 0.3° for angles and 0.3 mm for translations by use of the appropriate cost function. The spot spacing analysis showed that a spacing larger than the 5 mm used by other authors for the investigation of a MLIC for proton radiography led to results with absolute accuracy better than 0.3° for angles and 1 mm for translations when orthogonal proton radiographs were fed into the algorithm. In the case of a single projection, 6 mm was the largest spot spacing presenting an acceptable registration accuracy. For registration of proton radiography data with X-ray CT, the use of a direct ray-tracing algorithm to compute

  13. Rib necrosis after postoperative irradiation with 6MeV x-ray to breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Asakawa, H; Watarai, J; Otawa, H [Miyagi Prefectural Adult Disease Center, Natori (Japan)

    1975-04-01

    In order to examine quality of rays in radiation injury in the rib by high energy x-ray, radiation injury in the rib was roentgenologically followed up in the subjects that received postoperative irradiation only with 6 MeV x-ray to breast cancer. The subjects consisted of 79 patients with the age of 30 to 78 and were irradiated with 200 rads of 6 MeV x-ray 5 times a week delivered in 5 to 6 weeks postoperatively. Two fields were irradiated in a day and the total dose reached more than 5,000 rads. Roentgenologic follow up for more than 12 months revealed that rib necrosis occurred in 9 (11%) of 79 patients and that there was no relation to the age of patient. The necrosis was most likely to develop in the right second rib 10 to 23 months after the irradiation and the mean was 16 months. To the rib region where necrosis occurred, 1,880 to 2,230 ret were irradiated and the mean was 2,014 ret. There found no relation between the irradiation dose and occurrence of rib necrosis in the extent of 4,000 to 6,000 rads for tumor doses. Radiation injury in the lung was complicated in 8 (89%) of 9 patients with rib necrosis, indicating high incidence.

  14. X-ray CT monitoring of iceball growth and thermal distribution during cryosurgery

    International Nuclear Information System (INIS)

    Sandison, G.A.; Loye, M.P.; Rewcastle, J.C.; Hahn, L.J.; Saliken, J.C.; McKinnon, J.G.; Donnelly, B.J.

    1998-01-01

    X-ray CT is able to image the internal architecture of frozen tissue. Phantoms of distilled water, a saline-gelatin mixture, lard and a calf liver-gelatin suspension cooled by a plastic tube acting as a long liquid nitrogen cryoprobe were used to study the relationship between Hounsfield unit (HU) values and temperature. There is a signature change in HU value from unfrozen to completely frozen tissue. No discernible relation exists between temperature in a completely frozen tissue and its HU value for the temperature range achieved with commercial cryoprobes. However, such a relation does exist in the typically narrow region of phase change and it is this change in HU value that is the parameter of concern for quantitative monitoring of the freezing process. Calibration of temperature against change in HU value allows a limited set of isotherms to be generated in the phase change region for direct monitoring of iceball growth. The phase change temperature range, mid-phase change temperature and the absolute value of HU change from completely frozen to unfrozen tissue are shown to be sensitive to the medium. Modelling of the temperature distribution within the region of completely frozen phantom using the infinite cylinder solution to the Fourier heat equation allows the temperature history of the phantom to be predicted. A set of isotherms, generated using a combination of thermal modelling and calibrated HU values demonstrates the feasibility of routine x-ray CT assisted cryotherapy. Isotherm overlay will be a major aid to the cryosurgeon who adopts a fixed target temperature as the temperature below which there is a certainty of ablation of the diseased tissue. (author)

  15. X-ray CT monitoring of iceball growth and thermal distribution during cryosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Sandison, G.A.; Loye, M.P.; Rewcastle, J.C. [Departments of Oncology and Medical Physics, Tom Baker Cancer Centre, Calgary, Canada T2N 4N2 (Canada); Department of Physics and Astronomy, University of Calgary, Calgary, Canada T2N 2N4 (Canada); Hahn, L.J. [Department of Physics and Astronomy, University of Calgary, Calgary, Canada T2N 2N4 (Canada); Department of Diagnostic Imaging, Foothills Hospital, Calgary, Canada T2N 2T7 (Canada); Saliken, J.C. [Department of Diagnostic Imaging, Foothills Hospital, Calgary, Canada T2N 2T7 (Canada); Department of Surgery, Tom Baker Cancer Centre, Calgary, Canada T2N 4N2 (Canada); McKinnon, J.G. [Department of Surgery, Foothills Hospital, Calgary, Canada T2N 2T7 (Canada); Donnelly, B.J. [Department of Surgery, Tom Baker Cancer Centre, Calgary, Canada T2N 4N2 (Canada)

    1998-11-01

    X-ray CT is able to image the internal architecture of frozen tissue. Phantoms of distilled water, a saline-gelatin mixture, lard and a calf liver-gelatin suspension cooled by a plastic tube acting as a long liquid nitrogen cryoprobe were used to study the relationship between Hounsfield unit (HU) values and temperature. There is a signature change in HU value from unfrozen to completely frozen tissue. No discernible relation exists between temperature in a completely frozen tissue and its HU value for the temperature range achieved with commercial cryoprobes. However, such a relation does exist in the typically narrow region of phase change and it is this change in HU value that is the parameter of concern for quantitative monitoring of the freezing process. Calibration of temperature against change in HU value allows a limited set of isotherms to be generated in the phase change region for direct monitoring of iceball growth. The phase change temperature range, mid-phase change temperature and the absolute value of HU change from completely frozen to unfrozen tissue are shown to be sensitive to the medium. Modelling of the temperature distribution within the region of completely frozen phantom using the infinite cylinder solution to the Fourier heat equation allows the temperature history of the phantom to be predicted. A set of isotherms, generated using a combination of thermal modelling and calibrated HU values demonstrates the feasibility of routine x-ray CT assisted cryotherapy. Isotherm overlay will be a major aid to the cryosurgeon who adopts a fixed target temperature as the temperature below which there is a certainty of ablation of the diseased tissue. (author)

  16. X-ray strain tensor imaging: FEM simulation and experiments with a micro-CT.

    Science.gov (United States)

    Kim, Jae G; Park, So E; Lee, Soo Y

    2014-01-01

    In tissue elasticity imaging, measuring the strain tensor components is necessary to solve the inverse problem. However, it is impractical to measure all the tensor components in ultrasound or MRI elastography because of their anisotropic spatial resolution. The objective of this study is to compute 3D strain tensor maps from the 3D CT images of a tissue-mimicking phantom. We took 3D micro-CT images of the phantom twice with applying two different mechanical compressions to it. Applying the 3D image correlation technique to the CT images under different compression, we computed 3D displacement vectors and strain tensors at every pixel. To evaluate the accuracy of the strain tensor maps, we made a 3D FEM model of the phantom, and we computed strain tensor maps through FEM simulation. Experimentally obtained strain tensor maps showed similar patterns to the FEM-simulated ones in visual inspection. The correlation between the strain tensor maps obtained from the experiment and the FEM simulation ranges from 0.03 to 0.93. Even though the strain tensor maps suffer from high level noise, we expect the x-ray strain tensor imaging may find some biomedical applications such as malignant tissue characterization and stress analysis inside the tissues.

  17. Morphological and quantitative analyses on features of asymmetric mandible with X-ray CT images

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masaki; Isshiki, Yasushige; Nishikawa, Keiichi [Tokyo Dental Coll., Chiba (Japan)

    2001-09-01

    Biomechanical disproportion of the mandible causes morphological and quantitative changes in the bone and induces jaw deformities. The purpose of this study was to clarify the influence of the biomechanical disproportion on the structure and quality of the mandible, using spiral X-ray CT images. Subjects were 11 patients with mandibular asymmetry requiring orthognathic surgery. Lateral and vertical shift angles of the mandible against the maxilla were determined mathematically from the coordinates of structural reference points in 3-dimensional orthogonal coordinate systems as indices of the deformity degree. Several properties concerning thickness and CT value of mandibular cortical bone were measured as indices of the morphological and quantitative changes in mandibular cortical bone. Occlusal force was also measured using a pressure sensitive film as an index of biomechanical disproportion. Asymmetric indices of them were calculated from data of the left and right sides. The Pearson's correlation coefficients were obtained for these data. As a result, the mandible tended to shift laterally toward the side where the occlusal force at the second molar region was stronger and also to shift upward on that side. At the central incisor region of the laterally shifted side, CT values were relatively decreased. At the lateral incisor region, cortical bone density was relatively increased. At the first bicuspid region and the posterior tooth regions, cortical bone thickness was relatively decreased. (author)

  18. Morphological and quantitative analyses on features of asymmetric mandible with X-ray CT images

    International Nuclear Information System (INIS)

    Hayashi, Masaki; Isshiki, Yasushige; Nishikawa, Keiichi

    2001-01-01

    Biomechanical disproportion of the mandible causes morphological and quantitative changes in the bone and induces jaw deformities. The purpose of this study was to clarify the influence of the biomechanical disproportion on the structure and quality of the mandible, using spiral X-ray CT images. Subjects were 11 patients with mandibular asymmetry requiring orthognathic surgery. Lateral and vertical shift angles of the mandible against the maxilla were determined mathematically from the coordinates of structural reference points in 3-dimensional orthogonal coordinate systems as indices of the deformity degree. Several properties concerning thickness and CT value of mandibular cortical bone were measured as indices of the morphological and quantitative changes in mandibular cortical bone. Occlusal force was also measured using a pressure sensitive film as an index of biomechanical disproportion. Asymmetric indices of them were calculated from data of the left and right sides. The Pearson's correlation coefficients were obtained for these data. As a result, the mandible tended to shift laterally toward the side where the occlusal force at the second molar region was stronger and also to shift upward on that side. At the central incisor region of the laterally shifted side, CT values were relatively decreased. At the lateral incisor region, cortical bone density was relatively increased. At the first bicuspid region and the posterior tooth regions, cortical bone thickness was relatively decreased. (author)

  19. Evaluation of accelerated iterative x-ray CT image reconstruction using floating point graphics hardware

    International Nuclear Information System (INIS)

    Kole, J S; Beekman, F J

    2006-01-01

    Statistical reconstruction methods offer possibilities to improve image quality as compared with analytical methods, but current reconstruction times prohibit routine application in clinical and micro-CT. In particular, for cone-beam x-ray CT, the use of graphics hardware has been proposed to accelerate the forward and back-projection operations, in order to reduce reconstruction times. In the past, wide application of this texture hardware mapping approach was hampered owing to limited intrinsic accuracy. Recently, however, floating point precision has become available in the latest generation commodity graphics cards. In this paper, we utilize this feature to construct a graphics hardware accelerated version of the ordered subset convex reconstruction algorithm. The aims of this paper are (i) to study the impact of using graphics hardware acceleration for statistical reconstruction on the reconstructed image accuracy and (ii) to measure the speed increase one can obtain by using graphics hardware acceleration. We compare the unaccelerated algorithm with the graphics hardware accelerated version, and for the latter we consider two different interpolation techniques. A simulation study of a micro-CT scanner with a mathematical phantom shows that at almost preserved reconstructed image accuracy, speed-ups of a factor 40 to 222 can be achieved, compared with the unaccelerated algorithm, and depending on the phantom and detector sizes. Reconstruction from physical phantom data reconfirms the usability of the accelerated algorithm for practical cases

  20. Scatter correction method for x-ray CT using primary modulation: Phantom studies

    International Nuclear Information System (INIS)

    Gao Hewei; Fahrig, Rebecca; Bennett, N. Robert; Sun Mingshan; Star-Lack, Josh; Zhu Lei

    2010-01-01

    Purpose: Scatter correction is a major challenge in x-ray imaging using large area detectors. Recently, the authors proposed a promising scatter correction method for x-ray computed tomography (CT) using primary modulation. Proof of concept was previously illustrated by Monte Carlo simulations and physical experiments on a small phantom with a simple geometry. In this work, the authors provide a quantitative evaluation of the primary modulation technique and demonstrate its performance in applications where scatter correction is more challenging. Methods: The authors first analyze the potential errors of the estimated scatter in the primary modulation method. On two tabletop CT systems, the method is investigated using three phantoms: A Catphan(c)600 phantom, an anthropomorphic chest phantom, and the Catphan(c)600 phantom with two annuli. Two different primary modulators are also designed to show the impact of the modulator parameters on the scatter correction efficiency. The first is an aluminum modulator with a weak modulation and a low modulation frequency, and the second is a copper modulator with a strong modulation and a high modulation frequency. Results: On the Catphan(c)600 phantom in the first study, the method reduces the error of the CT number in the selected regions of interest (ROIs) from 371.4 to 21.9 Hounsfield units (HU); the contrast to noise ratio also increases from 10.9 to 19.2. On the anthropomorphic chest phantom in the second study, which represents a more difficult case due to the high scatter signals and object heterogeneity, the method reduces the error of the CT number from 327 to 19 HU in the selected ROIs and from 31.4% to 5.7% on the overall average. The third study is to investigate the impact of object size on the efficiency of our method. The scatter-to-primary ratio estimation error on the Catphan(c)600 phantom without any annulus (20 cm in diameter) is at the level of 0.04, it rises to 0.07 and 0.1 on the phantom with an

  1. A measurement-based X-ray source model characterization for CT dosimetry computations.

    Science.gov (United States)

    Sommerville, Mitchell; Poirier, Yannick; Tambasco, Mauro

    2015-11-08

    The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance beams were modeled for 90, 120, and 140 kVp tube settings. The GE Optima beams were modeled for 80, 100, 120, and 140 kVp tube settings. Relative doses measured using a Capintec Farmer-type ionization chamber (0.65 cc) placed in a cylindrical polymethyl methacrylate (PMMA) phantom and irradiated by the Philips Brilliance, were compared to those computed with kVDoseCalc. Relative doses in an anthropomorphic thorax phantom (E2E SBRT Phantom) irradiated by the GE Optima were measured using a (0.015 cc) PTW Freiburg ionization chamber and compared to computations from kVDoseCalc. The number of photons required to reduce the average statistical uncertainty in dose to measurement over all 12 PMMA phantom positions was found to be 1.44%, 1.47%, and 1.41% for 90, 120, and 140 kVp, respectively. The maximum percent difference between calculation and measurement for all energies, measurement positions, and phantoms was less than 3.50%. Thirty-five out of a total of 36 simulation conditions were

  2. X-ray and CT signs of connective tissue dysplasia in patients with primarily diagnosed infiltrative pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Sukhanova, L.A.; Sharmazanova, O.P.

    2009-01-01

    The x-ray signs of connective tissue systemic dysplasia (CTSD) in patients with primarily diagnosed pulmonary tuberculosis was investigated. Fifty-four patients (28 med and 26 women aged 18-70) with primarily diagnosed infiltrative pulmonary tuberculosis underwent x-ray study. In patients with infiltration pulmonary tuberculosis CTSD in the lungs manifests by their diminishing, deformity of the lung pattern, high position of the diaphragm cupola, mediastinum shift to the side of the pathology, which is better seen on CT. The degree of CTSD x-ray signs in the lungs depends on the number of phenotypical signs that is the degree of the disease manifestation. CT allows more accurate determining of the signs of connective tissue dysplasia in which tuberculosis develops

  3. Comparison of the efficacy of preoperative X-ray and thermoradiotherapy used for the treatment of breast cancer

    International Nuclear Information System (INIS)

    Muravskaya, G.V.; Pantyushenko, T.A.; Fradkin, S.Z.; Zhavrid, Eh.A.; Moiseenko, V.V.

    1984-01-01

    An experience of the first randomatized clinical investigation on the usage of different variants of preoperative X-ray (with simultaneous local UHF hyperthepmia and without it) action in the case of combined treatment of patients with breast cancer has been summarized. It has been shown that conventional values of preoperative X-ray therapy (about 30-45 G.) are optimum ones. An increase of complex thermoradiotherapy efficacy in the case of considered cancer forms may be achieved at the expense of a stre gthening of preoperative X-ray action by means of dose increase up to the cancerogenic level or preoperative irradiation under the conditions of local UHF-hyperthermia

  4. Refinement of clinical X-ray computed tomography (CT) scans containing metal implants.

    Science.gov (United States)

    Treece, Graham

    2017-03-01

    X-ray computed tomography (CT) data contains artefacts from many sources, with sufficient prominence to affect diagnostic utility when metal is present in the scans. These artefacts can be reduced, usually by the removal and in-filling of any sinogram data which has been affected by metal, and several such techniques have been proposed. Most of them are prone to introducing new artefacts into the CT data or may take a long time to correct the data. It is the purpose of this paper to introduce a new technique which is fast, yet can effectively remove most artefacts without introducing significant new ones. The new metal artefact reduction technique (RMAR) consists of an iterative refinement of the CT data by alternately forward- and back-projecting the part of the reconstruction near to metal. The forward-projection is corrected by making use of a prior derived from the reconstructed data which is independently estimated for each projection angle, and smoothed using a newly developed Bitonic filter. The new technique is compared with previously published (LI, NMAR, MDT) and commercial (O-MAR, IMAR) alternatives, quantitatively on phantom data, and qualitatively on a selection of clinical scans, mostly of the hip. The phantom data is from two recently published studies, enabling direct comparison with previous results. The results show an increased reduction of artefacts on the four phantom data sets tested. On two of the phantom data sets, RMAR is significantly better (pCT data, RMAR can correct each image in 3-8s, which is more than one hundred times faster than MDT. The new technique is demonstrated to have performance at least as good as MDT, with both out-performing other approaches. However, it is much faster then the latter technique, and shows better preservation of data very close to metal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. An angle-dependent estimation of CT x-ray spectrum from rotational transmission measurements

    International Nuclear Information System (INIS)

    Lin, Yuan; Samei, Ehsan; Ramirez-Giraldo, Juan Carlos; Gauthier, Daniel J.; Stierstorfer, Karl

    2014-01-01

    Purpose: Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors propose an angle-dependent estimation technique, where the incident spectra across a wide range of angular trajectories can be estimated accurately with only a single phantom and a single axial scan in the absence of the knowledge of the bowtie filter. Methods: The proposed technique uses a uniform cylindrical phantom, made of ultra-high-molecular-weight polyethylene and positioned in an off-centered geometry. The projection data acquired with an axial scan have a twofold purpose. First, they serve as a reflection of the transmission measurements across different angular trajectories. Second, they are used to reconstruct the cross sectional image of the phantom, which is then utilized to compute the intersection length of each transmission measurement. With each CT detector element recording a range of transmission measurements for a single angular trajectory, the spectrum is estimated for that trajectory. A data conditioning procedure is used to combine information from hundreds of collected transmission measurements to accelerate the estimation speed, to reduce noise, and to improve estimation stability. The proposed spectral estimation technique was validated experimentally using a clinical scanner (Somatom Definition Flash, Siemens Healthcare, Germany) with spectra provided by the manufacturer serving as the comparison standard. Results obtained with the proposed technique were compared against those obtained from a second conventional transmission measurement technique with two materials (i.e., Cu and Al). After validation, the proposed technique was applied to measure

  6. Water equivalence of NIPAM based polymer gel dosimeters with enhanced sensitivity for x-ray CT

    International Nuclear Information System (INIS)

    Gorjiara, Tina; Hill, Robin; Bosi, Stephen; Kuncic, Zdenka; Baldock, Clive

    2013-01-01

    Two new formulations of N-isopropylacrylamide (NIPAM) based three dimensional (3D) gel dosimeters have recently been developed with improved sensitivity to x-ray CT readout, one without any co-solvent and the other one with isopropanol co-solvent. The water equivalence of the NIPAM gel dosimeters was investigated using different methods to calculate their radiological properties including: density, electron density, number of electrons per grams, effective atomic number, photon interaction probabilities, mass attenuation and energy absorption coefficients, electron collisional, radiative and total mass stopping powers and electron mass scattering power. Monte Carlo modelling was also used to compare the dose response of these gel dosimeters with water for kilovoltage and megavoltage x-ray beams and for megavoltage electron beams. We found that the density and electron density of the co-solvent free gel dosimeter are more water equivalent with less than a 2.6% difference compared to a 5.7% difference for the isopropanol gel dosimeter. Both the co-solvent free and isopropanol solvent gel dosimeters have lower effective atomic numbers than water, differing by 2.2% and 6.5%, respectively. As a result, their photoelectric absorption interaction probabilities are up to 6% and 19% different from water, respectively. Compton scattering and pair production interaction probabilities of NIPAM gel with isopropanol differ by up to 10% from water while for the co-solvent free gel, the differences are 3%. Mass attenuation and energy absorption coefficients of the co-solvent free gel dosimeter and the isopropanol gel dosimeter are up to 7% and 19% lower than water, respectively. Collisional and total mass stopping powers of both gel dosimeters differ by less than 2% from those of water. The dose response of the co-solvent free gel dosimeter is water equivalent (with 100 keV, correction factor is required for the gels. • For MV electron, correction factor needed for the gels to

  7. Comparative analysis among X-ray mammographic findings, nuclear and histologic grading, and TNM staging of breast carcinoma

    International Nuclear Information System (INIS)

    Park, Jin Sook; Sung, Ki Joon; Cho, Mee Yon; Hong, In Soo; Kim, Myung Soon; Oh, Ki Keun

    1996-01-01

    The purpose of this study was to evaluate the prognosis of breast carcinoma by comparison with X-ray mammographic findings, nuclear and histologic grade, and TNM staging. We retrospectively reviewed 114 cases (113 patients) of breast carcinoma, analysing X-ray mammographic findings of all cases with regard to mass, calcification, and spiculation. In 80 cases of scirrhous invasive ductal breast carcinoma. Black's nuclear and Bloom-Richardson's histologic grade were also evaluated. Mammographic findings and nuclear and histologic grade were compared with TNM staging which might suggest the prognosis of breast carcinoma. X-ray mammographic findings (mass, calcification and spiculation) did not significantly correlate with T staging, but the clinical staging of the spiculation was advanced. These X-ray findings did not significantly correlate with the nuclear grading and the histologic grading. Nuclear grade did not correlate with T and M staging, but correlated significantly with N staging and clinical stage(p < 0.05). Histologic grade did not significantly correlate with TNM staging. The clinical staging of spiculation was advanced and nuclear grade correlated significantly with N stage and clinical staging. X-ray mammographic findings did not directly correlate with nuclear and histologic grading, but combined studies of the evaluation of mammographic findings and nuclear and histologic grade were useful for prognosing breast carcinoma

  8. Low-dose CT of the paranasal sinuses. Minimizing X-ray exposure with spectral shaping

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, Wolfgang [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany); Radiological Institute, Erlangen (Germany); May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany)

    2016-11-15

    Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192 x 0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 x 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDI{sub vol} 1.2 mGy vs. 4.4 mGy, p < 0.001). Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. (orig.)

  9. High speed imaging of dynamic processes with a switched source x-ray CT system

    International Nuclear Information System (INIS)

    Thompson, William M; Lionheart, William R B; Morton, Edward J; Cunningham, Mike; Luggar, Russell D

    2015-01-01

    Conventional x-ray computed tomography (CT) scanners are limited in their scanning speed by the mechanical constraints of their rotating gantries and as such do not provide the necessary temporal resolution for imaging of fast-moving dynamic processes, such as moving fluid flows. The Real Time Tomography (RTT) system is a family of fast cone beam CT scanners which instead use multiple fixed discrete sources and complete rings of detectors in an offset geometry. We demonstrate the potential of this system for use in the imaging of such high speed dynamic processes and give results using simulated and real experimental data. The unusual scanning geometry results in some challenges in image reconstruction, which are overcome using algebraic iterative reconstruction techniques and explicit regularisation. Through the use of a simple temporal regularisation term and by optimising the source firing pattern, we show that temporal resolution of the system may be increased at the expense of spatial resolution, which may be advantageous in some situations. Results are given showing temporal resolution of approximately 500 µs with simulated data and 3 ms with real experimental data. (paper)

  10. Accelerating statistical image reconstruction algorithms for fan-beam x-ray CT using cloud computing

    Science.gov (United States)

    Srivastava, Somesh; Rao, A. Ravishankar; Sheinin, Vadim

    2011-03-01

    Statistical image reconstruction algorithms potentially offer many advantages to x-ray computed tomography (CT), e.g. lower radiation dose. But, their adoption in practical CT scanners requires extra computation power, which is traditionally provided by incorporating additional computing hardware (e.g. CPU-clusters, GPUs, FPGAs etc.) into a scanner. An alternative solution is to access the required computation power over the internet from a cloud computing service, which is orders-of-magnitude more cost-effective. This is because users only pay a small pay-as-you-go fee for the computation resources used (i.e. CPU time, storage etc.), and completely avoid purchase, maintenance and upgrade costs. In this paper, we investigate the benefits and shortcomings of using cloud computing for statistical image reconstruction. We parallelized the most time-consuming parts of our application, the forward and back projectors, using MapReduce, the standard parallelization library on clouds. From preliminary investigations, we found that a large speedup is possible at a very low cost. But, communication overheads inside MapReduce can limit the maximum speedup, and a better MapReduce implementation might become necessary in the future. All the experiments for this paper, including development and testing, were completed on the Amazon Elastic Compute Cloud (EC2) for less than $20.

  11. Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Baissalov, R.; Sandison, G.A.; Rewcastle, J.C. [Department of Medical Physics, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 2 Department of Physics and Astronomy, University of Calgary, Calgary T2N 2N4 (Canada); Donnelly, B.J. [Department of Surgery, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 4 Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Saliken, J.C. [Department of Surgery, Tom Baker Cancer Center, Calgary T2N 4N2 (Canada); Department of Diagnostic Imaging, Foothills Hospital, Calgary T2N 2T7 (Canada); McKinnon, J.G. [Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Muldrew, K. [Department of Surgery, Faculty of Medicine, University of Calgary, Calgary T2N 2T7 (Canada)

    2000-05-01

    Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

  12. Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

    International Nuclear Information System (INIS)

    Baissalov, R.; Sandison, G.A.; Rewcastle, J.C.; Donnelly, B.J.; Saliken, J.C.; McKinnon, J.G.; Muldrew, K.

    2000-01-01

    Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

  13. Adaptive wiener filter based on Gaussian mixture distribution model for denoising chest X-ray CT image

    International Nuclear Information System (INIS)

    Tabuchi, Motohiro; Yamane, Nobumoto; Morikawa, Yoshitaka

    2008-01-01

    In recent decades, X-ray CT imaging has become more important as a result of its high-resolution performance. However, it is well known that the X-ray dose is insufficient in the techniques that use low-dose imaging in health screening or thin-slice imaging in work-up. Therefore, the degradation of CT images caused by the streak artifact frequently becomes problematic. In this study, we applied a Wiener filter (WF) using the universal Gaussian mixture distribution model (UNI-GMM) as a statistical model to remove streak artifact. In designing the WF, it is necessary to estimate the statistical model and the precise co-variances of the original image. In the proposed method, we obtained a variety of chest X-ray CT images using a phantom simulating a chest organ, and we estimated the statistical information using the images for training. The results of simulation showed that it is possible to fit the UNI-GMM to the chest X-ray CT images and reduce the specific noise. (author)

  14. 3d Finite Element Modelling of Non-Crimp Fabric Based Fibre Composite Based on X-Ray Ct Data

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Asp, Leif; Mikkelsen, Lars Pilgaard

    2017-01-01

    initiation and progression in the material. In the current study, the real bundle structure inside a non-crimp fabric based fibre composite is extracted from 3D X-ray CT images and imported into ABAQUS for numerical modelling.The local stress concentrations when loaded in tension caused by the fibre bundle...

  15. Correlation of conventional simulation x-ray films and CT images for HDR-brachytherapy catheters reconstruction

    International Nuclear Information System (INIS)

    Rajendran, M.; Reddy, K.D.; Reddy, R.M.; Reddy, J.M.; Reddy, B.V.N.; Kiran Kumar; Gopi, S.; Dharaniraj; Janardhanan

    2002-01-01

    In order to plan a brachytherapy implant, it is imperative that implant reconstruction is done accurately. The purpose of this paper is to evaluate whether implant reconstruction done with transverse CT images is comparable to reconstruction done with conventional x-ray films

  16. Non-destructive test for irradiated fuels using X-ray CT system in hot-laboratory

    International Nuclear Information System (INIS)

    Kim, Heemoon; Kim, Gil-Soo; Yoo, Boung-Ok; Tahk, Young-Wook; Cho, Moon-Sung; Ahn, Sang-Bok

    2015-01-01

    To inspect inside of irradiated fuel rod for PIE in hotcell, neutron beam and X-ray have been used. Many hot laboratories in the world have shown the results for NDT by 2-D film data. Currently, computed image processing technology instead of film has been developed and CT was applied to the X-ray and neutron beam system. In this trend, our facility needed to set up X-ray system for irradiated fuel inspection and installed in hotcell with consideration of radiation damage. In this study, X-ray system was tested to be operated with radioactive samples and was performed to inspect fuel rods and observe internal damage and dimensional change. 450kV X-ray CT system was installed in hotcell with modification and tested to check image resolution and radiation damage. The image data were analyzed by 3-D computer software. 8 fuel plates and VHTR rods were inspected and measured internal shape and dimension

  17. A deep convolutional neural network using directional wavelets for low-dose X-ray CT reconstruction.

    Science.gov (United States)

    Kang, Eunhee; Min, Junhong; Ye, Jong Chul

    2017-10-01

    Due to the potential risk of inducing cancer, radiation exposure by X-ray CT devices should be reduced for routine patient scanning. However, in low-dose X-ray CT, severe artifacts typically occur due to photon starvation, beam hardening, and other causes, all of which decrease the reliability of the diagnosis. Thus, a high-quality reconstruction method from low-dose X-ray CT data has become a major research topic in the CT community. Conventional model-based de-noising approaches are, however, computationally very expensive, and image-domain de-noising approaches cannot readily remove CT-specific noise patterns. To tackle these problems, we want to develop a new low-dose X-ray CT algorithm based on a deep-learning approach. We propose an algorithm which uses a deep convolutional neural network (CNN) which is applied to the wavelet transform coefficients of low-dose CT images. More specifically, using a directional wavelet transform to extract the directional component of artifacts and exploit the intra- and inter- band correlations, our deep network can effectively suppress CT-specific noise. In addition, our CNN is designed with a residual learning architecture for faster network training and better performance. Experimental results confirm that the proposed algorithm effectively removes complex noise patterns from CT images derived from a reduced X-ray dose. In addition, we show that the wavelet-domain CNN is efficient when used to remove noise from low-dose CT compared to existing approaches. Our results were rigorously evaluated by several radiologists at the Mayo Clinic and won second place at the 2016 "Low-Dose CT Grand Challenge." To the best of our knowledge, this work is the first deep-learning architecture for low-dose CT reconstruction which has been rigorously evaluated and proven to be effective. In addition, the proposed algorithm, in contrast to existing model-based iterative reconstruction (MBIR) methods, has considerable potential to benefit from

  18. Comparison study of positron emission tomography, X-ray CT and MRI in Parkinsonism with dementia

    International Nuclear Information System (INIS)

    Okada, Junichi; Peppard, R.; Calne, D.B.

    1989-01-01

    Brain atrophy and local cerebral metabolic rate of glucose (LCMR-glc) in Parkinson's disease with dementia and Parkinsonism-dementia complex (PDC) were studied using positron emission tomography (PET) with F-18-2-deoxy-2-fluoro-D-glucose, X-ray CT and magnetic resonance imaging (MRI). The group of Parkinson's disease with dementia (n=7) had a significantly decreased LCMR-glc in all regions when compared with the age-matched normal group. In the group of Parkinson's disease without dementia (n=6), LCMR-glc was also significantly lower than the control group, although it was higher than the group with associated dementia. Some of the normal aged persons had cortical atrophy. There was no correlation between LCMR-glc and cortical atrophy. Six Guamnian patients had PDC associated with amyotrophic lateral sclerosis (ALS), and four patients had it without ALS. LCMR-glc did not differ in the two groups. It was, however, significantly lower than that in 5 Guamanian and 10 Caucasian normal persons. The group of PDC had a noticeable cortical atrophy and ventricular dilatation, regardless of the presence or absence of ALS. There was correlation between decrease of LCMR-glc and cortical atrophy of the frontal, parietal and temporal lobes. Parkinson's disease and PDC were different from Alzheimer's disease in which a decreased LCMR-glc has been reported to be usually confined to the cerebral cortex. Cortical atrophy and ventricular dilatation were depicted on MRI and CT in the PDC group, but did not in the group of Parkinson's disease. PET was useful in the functional examination and both MRI and CT were useful in the anatomical examination of these diseases. (Namekawa, K)

  19. Comparison study of positron emission tomography, X-ray CT and MRI in Parkinsonism with dementia

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Junichi; Peppard, R; Calne, D B

    1989-05-01

    Brain atrophy and local cerebral metabolic rate of glucose (LCMR-glc) in Parkinson's disease with dementia and Parkinsonism-dementia complex (PDC) were studied using positron emission tomography (PET) with F-18-2-deoxy-2-fluoro-D-glucose, X-ray CT and magnetic resonance imaging (MRI). The group of Parkinson's disease with dementia (n=7) had a significantly decreased LCMR-glc in all regions when compared with the age-matched normal group. In the group of Parkinson's disease without dementia (n=6), LCMR-glc was also significantly lower than the control group, although it was higher than the group with associated dementia. Some of the normal aged persons had cortical atrophy. There was no correlation between LCMR-glc and cortical atrophy. Six Guamnian patients had PDC associated with amyotrophic lateral sclerosis (ALS), and four patients had it without ALS. LCMR-glc did not differ in the two groups. It was, however, significantly lower than that in 5 Guamanian and 10 Caucasian normal persons. The group of PDC had a noticeable cortical atrophy and ventricular dilatation, regardless of the presence or absence of ALS. There was correlation between decrease of LCMR-glc and cortical atrophy of the frontal, parietal and temporal lobes. Parkinson's disease and PDC were different from Alzheimer's disease in which a decreased LCMR-glc has been reported to be usually confined to the cerebral cortex. Cortical atrophy and ventricular dilatation were depicted on MRI and CT in the PDC group, but did not in the group of Parkinson's disease. PET was useful in the functional examination and both MRI and CT were useful in the anatomical examination of these diseases. (Namekawa, K).

  20. Comparison study of positron emission tomography, X-ray CT and MRI in Parkinsonism with dementia

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Junichi; Peppard, R.; Calne, D.B.

    1989-05-01

    Brain atrophy and local cerebral metabolic rate of glucose (LCMR-glc) in Parkinson's disease with dementia and Parkinsonism-dementia complex (PDC) were studied using positron emission tomography (PET) with F-18-2-deoxy-2-fluoro-D-glucose, X-ray CT and magnetic resonance imaging (MRI). The group of Parkinson's disease with dementia (n=7) had a significantly decreased LCMR-glc in all regions when compared with the age-matched normal group. In the group of Parkinson's disease without dementia (n=6), LCMR-glc was also significantly lower than the control group, although it was higher than the group with associated dementia. Some of the normal aged persons had cortical atrophy. There was no correlation between LCMR-glc and cortical atrophy. Six Guamnian patients had PDC associated with amyotrophic lateral sclerosis (ALS), and four patients had it without ALS. LCMR-glc did not differ in the two groups. It was, however, significantly lower than that in 5 Guamanian and 10 Caucasian normal persons. The group of PDC had a noticeable cortical atrophy and ventricular dilatation, regardless of the presence or absence of ALS. There was correlation between decrease of LCMR-glc and cortical atrophy of the frontal, parietal and temporal lobes. Parkinson's disease and PDC were different from Alzheimer's disease in which a decreased LCMR-glc has been reported to be usually confined to the cerebral cortex. Cortical atrophy and ventricular dilatation were depicted on MRI and CT in the PDC group, but did not in the group of Parkinson's disease. PET was useful in the functional examination and both MRI and CT were useful in the anatomical examination of these diseases. (Namekawa, K).

  1. X-ray CT for quantitative food microstructure engineering: The apple case

    International Nuclear Information System (INIS)

    Herremans, Els; Verboven, Pieter; Defraeye, Thijs; Rogge, Seppe; Ho, Quang Tri; Hertog, Maarten L.A.T.M.; Verlinden, Bert E.; Bongaers, Evi; Wevers, Martine; Nicolai, Bart M.

    2014-01-01

    Highlights: • Diffusivity of O 2 and CO 2 in Braeburn tissue were computed from X-ray micro-CT data. • Diffusivities were different for the distinct stages of ‘Braeburn’ browning disorder. • Microstructural gas transport constants were implemented in models of intact fruit. • We simulated internal O 2 concentrations for longterm storage treatments of Braeburn. • This engineering approach can optimize internal quality of apple during CA storage. - Abstract: Apple fruit is a major crop that can be supplied year-round due to low temperature storage in a controlled atmosphere with a reduced oxygen concentration and an increased carbon dioxide concentration. The low temperature and dedicated gas concentration levels are designed to provide optimal conditions that prevent ripening while maintaining the fundamental respiratory metabolism necessary for energy supply in the cells that ensures cell and tissue integrity during storage of the fruit. If the concentration of oxygen is too low or that of carbon dioxide too high, a fermentation metabolism is induced that causes the production of off-flavours, results in insufficient energy supply, leading to cell collapse and consequent tissue browning and cavity formation. The microstructural arrangement of cells and intercellular spaces in the apple create specific pathways for transport of the respiratory gasses oxygen and carbon dioxide. We used X-ray CT to characterise the changes in the microstructure of ‘Braeburn’ apple during the development of internal storage disorders. Multiscale modeling was applied to understand the changes in oxygen and carbon dioxide concentrations and respiration and fermentation rates in the apple during the disorder development in controlled atmosphere storage of ‘Braeburn’ apple fruit. The 3D microstructure geometries of healthy, brown tissue and tissue with cavities were created to solve the micro-scale gas-exchange model for O 2 and CO 2 using the finite volume method

  2. X-ray CT for quantitative food microstructure engineering: The apple case

    Energy Technology Data Exchange (ETDEWEB)

    Herremans, Els, E-mail: els.herremans@biw.kuleuven.be [BIOSYST-MeBioS, KU Leuven, Willem de Croylaan 42, 3001 Leuven (Belgium); Verboven, Pieter; Defraeye, Thijs; Rogge, Seppe; Ho, Quang Tri; Hertog, Maarten L.A.T.M. [BIOSYST-MeBioS, KU Leuven, Willem de Croylaan 42, 3001 Leuven (Belgium); Verlinden, Bert E. [VCBT, Flanders Centre of Postharvest Technology, Willem de Croylaan 42, 3001 Leuven (Belgium); Bongaers, Evi [Bruker microCT, Kartuizersweg 3B, 2550 Kontich (Belgium); Wevers, Martine [MTM, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven (Belgium); Nicolai, Bart M. [BIOSYST-MeBioS, KU Leuven, Willem de Croylaan 42, 3001 Leuven (Belgium); VCBT, Flanders Centre of Postharvest Technology, Willem de Croylaan 42, 3001 Leuven (Belgium)

    2014-04-01

    Highlights: • Diffusivity of O{sub 2} and CO{sub 2} in Braeburn tissue were computed from X-ray micro-CT data. • Diffusivities were different for the distinct stages of ‘Braeburn’ browning disorder. • Microstructural gas transport constants were implemented in models of intact fruit. • We simulated internal O{sub 2} concentrations for longterm storage treatments of Braeburn. • This engineering approach can optimize internal quality of apple during CA storage. - Abstract: Apple fruit is a major crop that can be supplied year-round due to low temperature storage in a controlled atmosphere with a reduced oxygen concentration and an increased carbon dioxide concentration. The low temperature and dedicated gas concentration levels are designed to provide optimal conditions that prevent ripening while maintaining the fundamental respiratory metabolism necessary for energy supply in the cells that ensures cell and tissue integrity during storage of the fruit. If the concentration of oxygen is too low or that of carbon dioxide too high, a fermentation metabolism is induced that causes the production of off-flavours, results in insufficient energy supply, leading to cell collapse and consequent tissue browning and cavity formation. The microstructural arrangement of cells and intercellular spaces in the apple create specific pathways for transport of the respiratory gasses oxygen and carbon dioxide. We used X-ray CT to characterise the changes in the microstructure of ‘Braeburn’ apple during the development of internal storage disorders. Multiscale modeling was applied to understand the changes in oxygen and carbon dioxide concentrations and respiration and fermentation rates in the apple during the disorder development in controlled atmosphere storage of ‘Braeburn’ apple fruit. The 3D microstructure geometries of healthy, brown tissue and tissue with cavities were created to solve the micro-scale gas-exchange model for O{sub 2} and CO{sub 2} using the

  3. Semi-automated scoring of pulmonary emphysema from X-ray CT: Trainee reproducibility and accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Owrangi, Amir M., E-mail: aowrangi@robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Entwistle, Brandon, E-mail: Brandon.Entwistle@londonhospitals.ca; Lu, Andrew, E-mail: Andrew.Lu@londonhospitals.ca; Chiu, Jack, E-mail: Jack.Chiu@londonhospitals.ca; Hussain, Nabil, E-mail: Nabil.Hussain@londonhospitals.ca; Etemad-Rezai, Roya, E-mail: Roya.EtemadRezai@lhsc.on.ca; Parraga, Grace, E-mail: gparraga@robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Graduate Program in Biomedical Engineering, Department of Medical Imaging, Department of Medical Biophysics, The University of Western Ontario, London (Canada)

    2013-11-01

    Objective: We developed a semi-automated tool to quantify emphysema from thoracic X-ray multi-detector (64-slice) computed tomography (CT) for training purposes and multi-reader studies. Materials and Methods: Thoracic X-ray CT was acquired in 93 ex-smokers, who were evaluated by six trainees with little or no expertise (trainees) and a single experienced thoracic radiologist (expert). A graphic user interface (GUI) was developed for emphysema quantification based on the percentile of lung where a score of 0 = no abnormalities, 1 = 1–25%, 2 = 26–50%, 3 = 51–75% and 4 = 76–100% for each lung side/slice. Trainees blinded to subject characteristics scored randomized images twice; accuracy was determined by comparison to expert scores, density histogram 15th percentile (HU{sub 15}), relative area at −950 HU (RA{sub 950}), low attenuation clusters at −950 HU (LAC{sub 950}), −856 HU (LAC{sub 856}) and the diffusing capacity for carbon monoxide (DL{sub CO%pred}). Intra- and inter-observer reproducibility was evaluated using coefficients-of-variation (COV), intra-class (ICC) and Pearson correlations. Results: Trainee–expert correlations were significant (r = 0.85–0.97, p < 0.0001) and a significant trainee bias (0.15 ± 0.22) was observed. Emphysema score was correlated with RA{sub 950} (r = 0.88, p < 0.0001), HU{sub 15} (r = −0.77, p < 0.0001), LAC{sub 950} (r = 0.76, p < 0.0001), LAC{sub 856} (r = 0.74, p = 0.0001) and DL{sub CO%pred} (r = −0.71, p < 0.0001). Intra-observer reproducibility (COV = 4–27%; ICC = 0.75–0.94) was moderate to high for trainees; intra- and inter-observer COV were negatively and non-linearly correlated with emphysema score. Conclusion: We developed a GUI for rapid and interactive emphysema scoring that allows for comparison of multiple readers with clinical and radiological standards.

  4. Development of a Radiation Dose Reporting Software for X-ray Computed Tomography (CT)

    Science.gov (United States)

    Ding, Aiping

    X-ray computed tomography (CT) has experienced tremendous technological advances in recent years and has established itself as one of the most popular diagnostic imaging tools. While CT imaging clearly plays an invaluable role in modern medicine, its rapid adoption has resulted in a dramatic increase in the average medical radiation exposure to the worldwide and United States populations. Existing software tools for CT dose estimation and reporting are mostly based on patient phantoms that contain overly simplified anatomies insufficient in meeting the current and future needs. This dissertation describes the development of an easy-to-use software platform, “VirtualDose”, as a service to estimate and report the organ dose and effective dose values for patients undergoing the CT examinations. “VirtualDose” incorporates advanced models for the adult male and female, pregnant women, and children. To cover a large portion of the ignored obese patients that frequents the radiology clinics, a new set of obese male and female phantoms are also developed and applied to study the effects of the fat tissues on the CT radiation dose. Multi-detector CT scanners (MDCT) and clinical protocols, as well as the most recent effective dose algorithms from the International Commission on Radiological Protection (ICRP) Publication 103 are adopted in “VirtualDose” to keep pace with the MDCT development and regulatory requirements. A new MDCT scanner model with both body and head bowtie filter is developed to cover both the head and body scanning modes. This model was validated through the clinical measurements. A comprehensive slice-by-slice database is established by deriving the data from a larger number of single axial scans simulated on the patient phantoms using different CT bowtie filters, beam thicknesses, and different tube voltages in the Monte Carlo N-Particle Extended (MCNPX) code. When compared to the existing CT dose software packages, organ dose data in this

  5. Breast tumor segmentation in high resolution x-ray phase contrast analyzer based computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brun, E., E-mail: emmanuel.brun@esrf.fr [European Synchrotron Radiation Facility (ESRF), Grenoble 380000, France and Department of Physics, Ludwig-Maximilians University, Garching 85748 (Germany); Grandl, S.; Sztrókay-Gaul, A.; Gasilov, S. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Barbone, G. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Mittone, A.; Coan, P. [Department of Physics, Ludwig-Maximilians University, Garching 85748, Germany and Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Bravin, A. [European Synchrotron Radiation Facility (ESRF), Grenoble 380000 (France)

    2014-11-01

    Purpose: Phase contrast computed tomography has emerged as an imaging method, which is able to outperform present day clinical mammography in breast tumor visualization while maintaining an equivalent average dose. To this day, no segmentation technique takes into account the specificity of the phase contrast signal. In this study, the authors propose a new mathematical framework for human-guided breast tumor segmentation. This method has been applied to high-resolution images of excised human organs, each of several gigabytes. Methods: The authors present a segmentation procedure based on the viscous watershed transform and demonstrate the efficacy of this method on analyzer based phase contrast images. The segmentation of tumors inside two full human breasts is then shown as an example of this procedure’s possible applications. Results: A correct and precise identification of the tumor boundaries was obtained and confirmed by manual contouring performed independently by four experienced radiologists. Conclusions: The authors demonstrate that applying the watershed viscous transform allows them to perform the segmentation of tumors in high-resolution x-ray analyzer based phase contrast breast computed tomography images. Combining the additional information provided by the segmentation procedure with the already high definition of morphological details and tissue boundaries offered by phase contrast imaging techniques, will represent a valuable multistep procedure to be used in future medical diagnostic applications.

  6. Breast tumor segmentation in high resolution x-ray phase contrast analyzer based computed tomography.

    Science.gov (United States)

    Brun, E; Grandl, S; Sztrókay-Gaul, A; Barbone, G; Mittone, A; Gasilov, S; Bravin, A; Coan, P

    2014-11-01

    Phase contrast computed tomography has emerged as an imaging method, which is able to outperform present day clinical mammography in breast tumor visualization while maintaining an equivalent average dose. To this day, no segmentation technique takes into account the specificity of the phase contrast signal. In this study, the authors propose a new mathematical framework for human-guided breast tumor segmentation. This method has been applied to high-resolution images of excised human organs, each of several gigabytes. The authors present a segmentation procedure based on the viscous watershed transform and demonstrate the efficacy of this method on analyzer based phase contrast images. The segmentation of tumors inside two full human breasts is then shown as an example of this procedure's possible applications. A correct and precise identification of the tumor boundaries was obtained and confirmed by manual contouring performed independently by four experienced radiologists. The authors demonstrate that applying the watershed viscous transform allows them to perform the segmentation of tumors in high-resolution x-ray analyzer based phase contrast breast computed tomography images. Combining the additional information provided by the segmentation procedure with the already high definition of morphological details and tissue boundaries offered by phase contrast imaging techniques, will represent a valuable multistep procedure to be used in future medical diagnostic applications.

  7. Measurement of position dependence of spectral distribution in primary X-ray beam of CT system using compton spectroscopy

    International Nuclear Information System (INIS)

    Matsumoto, Masao; Maeda, Koji; Maeda, Koji

    2005-01-01

    Our purpose is to acquire the diagnostic x-ray spectra of the CT system easily under clinical conditions by Compton scatter spectroscopy using a high resolution Schottky CdTe detector recently developed and to estimate the quality and quantity of these spectra compared the relative exposure measured using an ionization chamber with curves measured by the reconstructed spectra. Although the spectral broadening and the fluctuation were slightly shown, the errors of the relative exposure were under 10%. Though the experimental arrangement of this method is so easy and reconstructed algorithm is simple, these results suggested that this method is little influenced by the variation of dose rates or property of the incident x rays. We therefore propose that the Compton scatter spectroscopy with the newly developed Schottky CdTe detector is suitable for measuring the diagnostic x-ray spectra of the CT system under the clinical conditions and useful for quality assurance and quality control of the clinical x-ray CT system. (author)

  8. Analogue experiment of the crustal deformation by X-ray CT; X sen CT wo mochiita chikaku no henkei no analogue jikken

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Y.; Shi, B; Murakami, Y. [Geological Survey of Japan, Tsukuba (Japan)

    1997-05-27

    This paper reports a predictive result on a deformation experiment on sand beds using an X-ray computerized tomography (CT) equipment. The X-ray CT is a method to perform the following processes: X-rays are irradiated on a sample; decayed intensity data are measured along ray paths of the permeated X-rays; the data are inverted by using the Fourier transform; and spatial distribution of the coefficient of X-ray absorption inside the sample is acquired as a gray scale image. The deformation experiment was carried by putting sand into an acrylic container to a depth of 2 cm and manually pressing a plate in the horizontal direction. Sand blocks make a relative motion along a specific plane when they are deformed, but it was not possible to recognize faults clearly by naked eyes. Upon completion of the deformation, the experimental device was placed on the CT equipment to acquire images of the two-dimensional cross section. The higher the X-ray absorption coefficient, the brighter the picture elements. It can be seen that three inversed faults have been imaged clearly. Therefore, this equipment was verified usable as an effective observation equipment for an analogue deformation experiment. 4 refs., 2 figs.

  9. X-ray CT Scanning Reveals Long-Term Copper Pollution Effects on Functional Soil Structure

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Homstrup, Martin

    Soil structure plays the main role in the ability of the soil to fulfill essential soil functions such as the root growth, rate of water infiltration and retention, transport of gaseous and chemicals/pollutants through the soil. Soil structure is a dynamic soil property and affected by various...... factors such as soil type, land use, and soil contamination. In this study, we quantified the soil structure using X-ray CT scanning and revealed the effect of a long history of Copper (Cu) pollution on it. A fallow field at Hygum Denmark provides this opportunity as it had a long history of Copper...... sulphate contamination in a gradient with Cu content varies from 21 mg kg-1 to 3837 mg kg-1. Total 20 intact soil columns (diameter of 10 cm and height of 8 cm) were sampled at five locations along the Cu-gradient from a depth of 5 to 15 cm below surface level. The soil columns were scanned at a voxel...

  10. Optimisation of a propagation-based x-ray phase-contrast micro-CT system

    Science.gov (United States)

    Nesterets, Yakov I.; Gureyev, Timur E.; Dimmock, Matthew R.

    2018-03-01

    Micro-CT scanners find applications in many areas ranging from biomedical research to material sciences. In order to provide spatial resolution on a micron scale, these scanners are usually equipped with micro-focus, low-power x-ray sources and hence require long scanning times to produce high resolution 3D images of the object with acceptable contrast-to-noise. Propagation-based phase-contrast tomography (PB-PCT) has the potential to significantly improve the contrast-to-noise ratio (CNR) or, alternatively, reduce the image acquisition time while preserving the CNR and the spatial resolution. We propose a general approach for the optimisation of the PB-PCT imaging system. When applied to an imaging system with fixed parameters of the source and detector this approach requires optimisation of only two independent geometrical parameters of the imaging system, i.e. the source-to-object distance R 1 and geometrical magnification M, in order to produce the best spatial resolution and CNR. If, in addition to R 1 and M, the system parameter space also includes the source size and the anode potential this approach allows one to find a unique configuration of the imaging system that produces the required spatial resolution and the best CNR.

  11. Image research on acetabular teardrop shadow by X-ray plain-film and CT

    International Nuclear Information System (INIS)

    Wang Xiaoxuan; Zhai Yuejie; Yu Hongguang; Yang Yijun; Zhang Daiwei; Chen Aili; Song Quanjun

    2001-01-01

    Objective: To evaluate the anatomical structure of bone in the formation of acetabular teardrop shadow. Methods: The acetabular teardrop shadow of the X-ray plain-film in 100 children and 300 adults, and of CT in 43 cases were analysed, measured and compared. Results: In children, teardrop shadow appeared 'U' in 80.00%, 14.00% in teardrop, 6.00% in line. In adult teardrop shadow appeared 'U' in 41.33%, 53.33% in teardrop, 5.34% in line. There were significant differences between children and adult in the frequency of 'U' and teardrop (x 2 = 43.34, P 2 = 45.62, P < 0.01). In children, inpeduncle of teardrop shadow was formed of middle 1/3 substantia-line of acetabular concavity inside of pelvis; outpeduncle was formed of middle 1/3 substantia-line of bottom of acetabular. In adult, inpeduncle was formed of middle 1/3 or back 1/3 substantia line of acetabular concavity inside of pelvis; outpeduncle was formed of middle 1/3 or back 1/3 substantia-line of bottom of acetabular. Conclusion: In children, acetabular teardrop shadow was mainly formed of middle 1/3 bone of acetabular concavity. In adult, middle 1/3 or back 1/3 bone of acetabular concavity contribute to the shadow. The ahead 1/3 bone of acetabular concavity is not involved

  12. Comparison of methods for suppressing edge and aliasing artefacts in iterative x-ray CT reconstruction

    International Nuclear Information System (INIS)

    Zbijewski, Wojciech; Beekman, Freek J

    2006-01-01

    X-ray CT images obtained with iterative reconstruction (IR) can be hampered by the so-called edge and aliasing artefacts, which appear as interference patterns and severe overshoots in the areas of sharp intensity transitions. Previously, we have demonstrated that these artefacts are caused by discretization errors during the projection simulation step in IR. Although these errors are inherent to IR, they can be adequately suppressed by reconstruction on an image grid that is finer than that typically used for analytical methods such as filtered back-projection. Two other methods that may prevent edge artefacts are: (i) smoothing the projections prior to reconstruction or (ii) using an image representation different from voxels; spherically symmetric Kaiser-Bessel functions are a frequently employed example of such a representation. In this paper, we compare reconstruction on a fine grid with the two above-mentioned alternative strategies for edge artefact reduction. We show that the use of a fine grid results in a more adequate suppression of artefacts than the smoothing of projections or using the Kaiser-Bessel image representation

  13. An Efficient Augmented Lagrangian Method for Statistical X-Ray CT Image Reconstruction.

    Science.gov (United States)

    Li, Jiaojiao; Niu, Shanzhou; Huang, Jing; Bian, Zhaoying; Feng, Qianjin; Yu, Gaohang; Liang, Zhengrong; Chen, Wufan; Ma, Jianhua

    2015-01-01

    Statistical iterative reconstruction (SIR) for X-ray computed tomography (CT) under the penalized weighted least-squares criteria can yield significant gains over conventional analytical reconstruction from the noisy measurement. However, due to the nonlinear expression of the objective function, most exiting algorithms related to the SIR unavoidably suffer from heavy computation load and slow convergence rate, especially when an edge-preserving or sparsity-based penalty or regularization is incorporated. In this work, to address abovementioned issues of the general algorithms related to the SIR, we propose an adaptive nonmonotone alternating direction algorithm in the framework of augmented Lagrangian multiplier method, which is termed as "ALM-ANAD". The algorithm effectively combines an alternating direction technique with an adaptive nonmonotone line search to minimize the augmented Lagrangian function at each iteration. To evaluate the present ALM-ANAD algorithm, both qualitative and quantitative studies were conducted by using digital and physical phantoms. Experimental results show that the present ALM-ANAD algorithm can achieve noticeable gains over the classical nonlinear conjugate gradient algorithm and state-of-the-art split Bregman algorithm in terms of noise reduction, contrast-to-noise ratio, convergence rate, and universal quality index metrics.

  14. Multi-scale characteristics of coal structure by x-ray computed tomography (x-ray CT), scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP)

    Science.gov (United States)

    Cai, Ting-ting; Feng, Zeng-chao; Zhou, Dong

    2018-02-01

    It is of great benefit to study the material and structural heterogeneity of coal for better understanding the coalbed methane (CBM) storage and enrichment. In this paper, multi-scale X-ray computed tomography (CT), scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP) at multi scales were conducted to thoroughly study the material distribution, heterogeneity, pore development, porosity and permeability of coal. It is suitable and reasonable to divide the testing samples into three structural categories by average density and heterogeneity degree, and the meso structure in the three categories accords with the morphology on SEM images. The pore size distribution and pore development of each subsample cannot be correspondingly related to their respective structure category or morphology due to different observation scales, while the macro pore size development, accumulated macro pore volume and macro pores porosity accord with the meso structure category and morphology information by CT and SEM at the same scale very well. Given the effect of macro pores on permeability and the contribution of micro pores to CBM storage capacity, reservoirs with developed micro pores and macro pores may be the most suitable coal reservoir for CBM exploitation.

  15. Basic technological aspects and optimization problems in X-ray computed tomography (C.T.)

    International Nuclear Information System (INIS)

    Allemand, R.

    1987-01-01

    The current status and future prospects of physical performance are analysed and the optimization problems are approached for X-ray computed tomography. It is concluded that as long as clinical interest in computed tomography continues, technical advances can be expected in the near future to improve the density resolution, the spatial resolution and the X-ray exposure time. (Auth.)

  16. Evaluation of physical property of light-weight soil with air foam using X-ray CT method

    International Nuclear Information System (INIS)

    Otani, Jun; Mukunoki, Toshifumi; Kikuchi, Yoshiaki

    2000-01-01

    The objective of this paper is to investigate the physical property of light-weight soil made of dredged slurry mixed with air foam and cement using X-ray CT method. In this study, not only the specimen made in laboratory but also the one sampled at the in-situ construction site were used and the property in the soil was visualized and the distributions of the density an air porosity were evaluated quantitatively using the results of CT scanning. Here, the method of image processing analysis was also used for this evaluation study. Based on the results obtained in this study, it is concluded that the X-ray CT method is a powerful tool even for geotechnical engineering and this makes not only the visualization but also the quantitative ion discussion possible for the light-weight soil with air foam. (author)

  17. Application- and patient size-dependent optimization of x-ray spectra for CT

    International Nuclear Information System (INIS)

    Kalender, Willi A.; Deak, Paul; Kellermeier, Markus; Straten, Marcel van; Vollmar, Sabrina V.

    2009-01-01

    Although x-ray computed tomography (CT) has been in clinical use for over 3 decades, spectral optimization has not been a topic of great concern; high voltages around 120 kV have been in use since the beginning of CT. It is the purpose of this study to analyze, in a rigorous manner, the energies at which the patient dose necessary to provide a given contrast-to-noise ratio (CNR) for various diagnostic tasks can be minimized. The authors used cylindrical water phantoms and quasianthropomorphic phantoms of the thorax and the abdomen with inserts of 13 mm diameter mimicking soft tissue, bone, and iodine for simulations and measurements. To provide clearly defined contrasts, these inserts were made of solid water with a 1% difference in density (DD) to represent an energy-independent soft-tissue contrast of 10 Hounsfield units (HU), calcium hydroxyapatite (Ca) representing bone, and iodine (I) representing the typical contrast medium. To evaluate CT of the thorax, an adult thorax phantom (300x200 mm 2 ) plus extension rings up to a size of 460x300 mm 2 to mimic different patient cross sections were used. For CT of the abdomen, we used a phantom of 360x200 mm 2 and an extension ring of 460x300 mm 2 . The CT scanner that the authors used was a SOMATOM Definition (Siemens Healthcare, Forchheim, Germany) at 80, 100, 120, and 140 kV. Further voltage settings of 60, 75, 90, and 105 kV were available in an experimental mode. The authors determined contrast for the density difference, calcium, and iodine, and noise and 3D dose distributions for the available voltages by measurements. Additional voltage values and monoenergetic sources were evaluated by simulations. The dose-weighted contrast-to-noise ratio (CNRD) was used as the parameter for optimization. Simulations and measurements were in good agreement with respect to absolute values and trends regarding the dependence on energy for the parameters investigated. For soft-tissue imaging, the standard settings of 120-140 k

  18. A software-based x-ray scatter correction method for breast tomosynthesis

    International Nuclear Information System (INIS)

    Jia Feng, Steve Si; Sechopoulos, Ioannis

    2011-01-01

    Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%-29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%-62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter

  19. The evaluation of breast tissues removed during reductive mammaplasty with dual energy X-ray absorptiometry

    International Nuclear Information System (INIS)

    De Lorenzo, Antonino; Gravante, Gianpiero; Sorge, Roberto; Nicoli, Fabio; Caruso, Riccardo; Araco, Antonino; Servidio, Michele; Orlandi, Augusto; Cervelli, Valerio

    2009-01-01

    Purpose: We conducted a case-control study in which patients were evaluated with dual energy X-ray absorptiometry (DEXA) before and after breast reduction surgery, and results were correlated with the histological examination. Our goal was to confirm the DEXA as a precise technique for the measurement of breast composition, in order to propose it for the preoperative evaluation of plastic surgery patients. Materials and methods: We prospectively recruited all women that underwent reduction mammaplasty and excluded patients with contraindications to the operation or those that previously underwent bariatric surgery to reduce their weight. Patients were evaluated with DEXA 1 week before and after surgery. Results: From February to October 2006 we recruited 25 patients. The statistical analysis found a significant reduction of weight, BMI, regional fat free mass and fat mass after the operation. The comparison between DEXA and the histological analysis produced a correlation r = 0.989 (r 2 = 0.978), with a predictivity of 98% and a percentage of error 8.3% (95% confidence intervals -252.6, 273.7; 95% limits of agreements of Bland and Altman -436.0, 457.1). Similar results were obtained with the analysis of fat. Conclusions: Our study demonstrated that conventional segmental DEXA is a very precise technique to measure the amount of tissue removed in breast reductions and could open future application in the preoperative assessment of patients undergoing such operations.

  20. The evaluation of breast tissues removed during reductive mammaplasty with dual energy X-ray absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    De Lorenzo, Antonino [Division of Human Nutrition, University of Tor Vergata in Rome (Italy); Gravante, Gianpiero [Division of Human Nutrition, University of Tor Vergata in Rome (Italy); Department of Surgery, Whipps Cross University Hospital, London (United Kingdom)], E-mail: ggravante@hotmail.com; Sorge, Roberto [Laboratory of Biometry, University of Tor Vergata in Rome (Italy); Nicoli, Fabio; Caruso, Riccardo; Araco, Antonino [Department of Plastic Surgery, University of Tor Vergata in Rome (Italy); Servidio, Michele [Division of Human Nutrition, University of Tor Vergata in Rome (Italy); Orlandi, Augusto [Department of Biopathology, Anatomic Pathology Institute, University of Tor Vergata in Rome (Italy); Cervelli, Valerio [Department of Plastic Surgery, University of Tor Vergata in Rome (Italy)

    2009-06-15

    Purpose: We conducted a case-control study in which patients were evaluated with dual energy X-ray absorptiometry (DEXA) before and after breast reduction surgery, and results were correlated with the histological examination. Our goal was to confirm the DEXA as a precise technique for the measurement of breast composition, in order to propose it for the preoperative evaluation of plastic surgery patients. Materials and methods: We prospectively recruited all women that underwent reduction mammaplasty and excluded patients with contraindications to the operation or those that previously underwent bariatric surgery to reduce their weight. Patients were evaluated with DEXA 1 week before and after surgery. Results: From February to October 2006 we recruited 25 patients. The statistical analysis found a significant reduction of weight, BMI, regional fat free mass and fat mass after the operation. The comparison between DEXA and the histological analysis produced a correlation r = 0.989 (r{sup 2} = 0.978), with a predictivity of 98% and a percentage of error 8.3% (95% confidence intervals -252.6, 273.7; 95% limits of agreements of Bland and Altman -436.0, 457.1). Similar results were obtained with the analysis of fat. Conclusions: Our study demonstrated that conventional segmental DEXA is a very precise technique to measure the amount of tissue removed in breast reductions and could open future application in the preoperative assessment of patients undergoing such operations.

  1. Micro-CTvlab: A web based virtual gallery of biological specimens using X-ray microtomography (micro-CT).

    Science.gov (United States)

    Keklikoglou, Kleoniki; Faulwetter, Sarah; Chatzinikolaou, Eva; Michalakis, Nikitas; Filiopoulou, Irene; Minadakis, Nikos; Panteri, Emmanouela; Perantinos, George; Gougousis, Alexandros; Arvanitidis, Christos

    2016-01-01

    During recent years, X-ray microtomography (micro-CT) has seen an increasing use in biological research areas, such as functional morphology, taxonomy, evolutionary biology and developmental research. Micro-CT is a technology which uses X-rays to create sub-micron resolution images of external and internal features of specimens. These images can then be rendered in a three-dimensional space and used for qualitative and quantitative 3D analyses. However, the online exploration and dissemination of micro-CT datasets are rarely made available to the public due to their large size and a lack of dedicated online platforms for the interactive manipulation of 3D data. Here, the development of a virtual micro-CT laboratory (Micro-CT vlab ) is described, which can be used by everyone who is interested in digitisation methods and biological collections and aims at making the micro-CT data exploration of natural history specimens freely available over the internet. The Micro-CT vlab offers to the user virtual image galleries of various taxa which can be displayed and downloaded through a web application. With a few clicks, accurate, detailed and three-dimensional models of species can be studied and virtually dissected without destroying the actual specimen. The data and functions of the Micro-CT vlab can be accessed either on a normal computer or through a dedicated version for mobile devices.

  2. Characterising and linking X-ray CT derived macroporosity parameters to infiltration in soils with contrasting structures

    DEFF Research Database (Denmark)

    Müller, Karin; Katuwal, Sheela; Young, Iain

    2018-01-01

    with X-ray CT. Kunsat was significantly higher in the Andosol than in the Gleysol at all water potentials, and decreased significantly with depth in both soils. The in situ measurements guided the definition of new macroporosity parameters from the X-ray CT reconstructions. For the Andosol, Kunsat......Soils deliver the regulating ecosystem services of water infiltration and distribution, which can be controlled by macropores. Parameterizing macropore hydraulic properties is challenging due to the lack of direct measurement methods. With tension-disc infiltrometry hydraulic properties near...... saturation can be measured. Differentiating between hydrologically active and non-active pores, at a given water potential, indirectly assesses macropore continuity. Water flow through macropores is controlled by macropore size distribution, tortuosity, and connectivity, which can be directly derived by X...

  3. EVALUATION OF REINFORCING EFFECT ON FACEBOLTS FOR TUNNELING USING X-RAY CT AND CENTRIFUGE MODEL TEST

    Science.gov (United States)

    Takano, Daiki; Otani, Jun; Date, Kensuke; Yokot, Yasuhiro; Nagatani, Hideki

    The purpose of this paper is firstly to simulate the tunnel face failure in laboratory with four cases of model tests by pulling out tunnel model from a sandy ground that are without using auxiliary method nor facebolts and using facebolts with three different lengths of bolts, and secondary, to investigate the behavior of model ground using X-ray computed tomography (CT) scanner to visualize the failure zone in three dimensions. In addition to those results, a series of centrifuge model tests are conducted to confirm the results of X-ray CT test and also to discuss the ground behavior under full scale stress level. Finally, the effect of face bolting method is evaluated based on all the test results.

  4. A comparison of serial MRI with X-ray CT in a patient with Reye-like syndrome

    International Nuclear Information System (INIS)

    Fujii, Yasushi; Kuriyama, Masanori; Yoshimoto, Masahiro; Konishi, Yukuo; Fujisawa, Shinichi; Sudo, Masakatsu; Hayakawa, Katsumi

    1988-01-01

    Serial MRI and X-ray CT scans were performed on a one-year 7-month old girl with Reye-like syndrome. X-ray CT scan revealed marked hemispheric brain edema in the acute stage and moderate ventricular dilatation with diffuse low density area and cortical atrophy in the chronic stage. MRI performed in the chronic stage showed marked progressive changes. Linear high intensity areas were demonstrated on T 2 weighted MRI performed 21 days after the onset. These high intensity areas increased gradually and 60 days after the onset these high intensity areas spread to the grey matter. These high intensity changes seemed to be correspond to cortical necrosis, and those in the white matter to gliosis or degeneration of myelin. (author)

  5. Prediction of biopore- and matrix-dominated flow from X-ray CT-derived macropore network characteristics

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Schaap, Marcel G

    2016-01-01

    was to investigate the predictive performance of previously developed empirical models for both water and air flow and to explore the potential applicability of X-ray computed tomography (CT)-derived macropore network characteristics. For this purpose, 65 cylindrical soil columns (6 cm diameter and 3.5 cm height......Prediction and modeling of localized flow processes in macropores is of crucial importance for sustaining both soil and water quality. However, currently there are no reliable means to predict preferential flow due to its inherently large spatial variability. The aim of this study......) were extracted from the topsoil (5 cm to 8.5 cm depth) in a 15m15m grid from an agricultural field located in Silstrup, Denmark. All soil columns were scanned with an industrial X-ray CT scanner (129 μm resolution) and later employed for measurement of saturated hydraulic conductivity, air permeability...

  6. Planar strain analysis of liver undergoing microwave thermal ablation using x-ray CT.

    Science.gov (United States)

    Weiss, Noam; Goldberg, S Nahum; Nissenbaum, Yitzhak; Sosna, Jacob; Azhari, Haim

    2015-01-01

    To study the planar strain effects in liver during microwave (MW) thermal ablation as a means for tracking tissue expansion and contraction as a method for improving ablation monitoring. 1.4 mm circular metallic markers were inserted into 16 ex-vivo bovine fresh liver specimens, that were subsequently ablated (with the markers inside the specimen) by 40 W of microwave energy, for 1, 2, 3, 6, and 10 min. The markers were tracked during the ablation using an x-ray CT scanner. Images were acquired every 5-10 s enabling determination of the markers' coordinates over time. The 2D principal strains were calculated for triangles formed by subgroups of three markers, and their planar strain index, Ω, was plotted vs time. In addition, the radial distance of the markers from the antenna was measured at the end of each ablation. Subsequently, the tissue was sliced parallel to the imaged planes and the ablation zone was traced and digitized. The average ablation radius was then computed and compared to the radial distance. The planar strain, Ω(t), profile demonstrated an ascending pattern until reaching a maximum at about 180 s, with a mean peak value (Ω = 1.31 ± 0.04) indicating tissue expansion. Thereafter, Ω progressively declined over the remaining duration of the ablation treatment, indicating tissue contraction. Furthermore, when plotting the ablation size vs time and the markers' mean radial distance vs time, it was found that the two curves intercepted at a time corresponding to the time of peak planar strain. By detecting the point of maximal planar strain in tissues during MW application, it is possible to noninvasively identify the location of the ablation zone front. The fact that the liver tissue proximal to the ablated zone expands during the first part of the treatment and then contracts when the ablation front reaches it, may serve as an index for monitoring the thermal treatment.

  7. X-ray micro-CT and neutron CT as complementary imaging tools for non-destructive 3D imaging of rare silicified fossil plants

    Science.gov (United States)

    Karch, J.; Dudák, J.; Žemlička, J.; Vavřík, D.; Kumpová, I.; Kvaček, J.; Heřmanová, Z.; Šoltés, J.; Viererbl, L.; Morgano, M.; Kaestner, A.; Trtík, P.

    2017-12-01

    Computed tomography provides 3D information of inner structures of investigated objects. The obtained information is, however, strongly dependent on the used radiation type. It is known that as X-rays interact with electron cloud and neutrons with atomic nucleus, the obtained data often provide different contrast of sample structures. In this work we present a set of comparative radiographic and CT measurements of rare fossil plant samples using X-rays and thermal neutrons. The X-ray measurements were performed using large area photon counting detectors Timepix at IEAP CTU in Prague and Perkin Elmer flat-panel detector at Center of Excellence Telč. The neutron CT measurement was carried out at Paul Scherrer Institute using BOA beam-line. Furthermore, neutron radiography of fossil samples, provided by National Museum, were performed using a large-area Timepix detector with a neutron-sensitive converting 6LiF layer at Research Centre Rez, Czech Republic. The obtained results show different capabilities of both imaging approaches. While X-ray micro-CT provides very high resolution and enables visualization of fine cracks or small cavities in the samples neutron imaging provides high contrast of morphological structures of fossil plant samples, where X-ray imaging provides insufficient contrast.

  8. Influence of X-ray scatter radiation on image quality in Digital Breast Tomosynthesis (DBT)

    International Nuclear Information System (INIS)

    Rodrigues, M.J.; Di Maria, S.; Baptista, M.; Belchior, A.; Afonso, J.; Venâncio, J.; Vaz, P.

    2017-01-01

    Digital breast tomosynthesis (DBT) is a quasi-three-dimensional imaging technique that was developed to solve the principal limitation of mammography, namely the overlapping tissue effect. This issue in standard mammography (SM) leads to two main problems: low sensitivity (difficulty to detect lesions) and low specificity (non-negligible percentage of false positives). Although DBT is now being introduced in clinical practice the features of this technique have not yet been fully and accurately assessed. Consequently, optimization studies in terms of choosing the most suitable parameters which maximize image quality according to the known limits of breast dosimetry are currently performing. In DBT, scatter radiation can lead to a loss of contrast and to an increase of image noise by reducing the signal-to-difference-noise ratio (SDNR) of a lesion. Moreover the use of an anti-scatter grid is a concern due to the low exposure of the photon flux available per projection. For this reason the main aim of this study was to analyze the influence of the scatter radiation on image quality and the dose delivered to the breast. In particular a detailed analysis of the scatter radiation on the optimal energy that maximizes the SDNR was performed for different monochromatic energies and voltages. To reach this objective the PenEasy Monte Carlo (MC) simulation tool imbedded in the general-purpose main program PENELOPE, was used. After a successful validation of the MC model with measurements, 2D projection images of primary, coherent and incoherent photons were obtained. For that, a homogeneous breast phantom (2, 4, 6, 8 cm) with 25%, 50% and 75% glandular compositions was used, including a 5 mm thick tumor. The images were generated for each monochromatic X-ray energies in the range from 16 keV to 32 keV. For each angular projection considered (25 angular projections covering an arc of 50°) the scatter-to-primary ratio (SPR), the mean glandular dose (MGD) and the signal

  9. Breast tissue classification using x-ray scattering measurements and multivariate data analysis

    Science.gov (United States)

    Ryan, Elaine A.; Farquharson, Michael J.

    2007-11-01

    This study utilized two radiation scatter interactions in order to differentiate malignant from non-malignant breast tissue. These two interactions were Compton scatter, used to measure the electron density of the tissues, and coherent scatter to obtain a measure of structure. Measurements of these parameters were made using a laboratory experimental set-up comprising an x-ray tube and HPGe detector. The breast tissue samples investigated comprise five different tissue classifications: adipose, malignancy, fibroadenoma, normal fibrous tissue and tissue that had undergone fibrocystic change. The coherent scatter spectra were analysed using a peak fitting routine, and a technique involving multivariate analysis was used to combine the peak fitted scatter profile spectra and the electron density values into a tissue classification model. The number of variables used in the model was refined by finding the sensitivity and specificity of each model and concentrating on differentiating between two tissues at a time. The best model that was formulated had a sensitivity of 54% and a specificity of 100%.

  10. Breast tissue classification using x-ray scattering measurements and multivariate data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Elaine A; Farquharson, Michael J [School of Allied Health Sciences, City University, Charterhouse Square, London EC1M 6PA (United Kingdom)

    2007-11-21

    This study utilized two radiation scatter interactions in order to differentiate malignant from non-malignant breast tissue. These two interactions were Compton scatter, used to measure the electron density of the tissues, and coherent scatter to obtain a measure of structure. Measurements of these parameters were made using a laboratory experimental set-up comprising an x-ray tube and HPGe detector. The breast tissue samples investigated comprise five different tissue classifications: adipose, malignancy, fibroadenoma, normal fibrous tissue and tissue that had undergone fibrocystic change. The coherent scatter spectra were analysed using a peak fitting routine, and a technique involving multivariate analysis was used to combine the peak fitted scatter profile spectra and the electron density values into a tissue classification model. The number of variables used in the model was refined by finding the sensitivity and specificity of each model and concentrating on differentiating between two tissues at a time. The best model that was formulated had a sensitivity of 54% and a specificity of 100%.

  11. Cross-sectional imaging of large and dense materials by high energy X-ray CT using linear accelerator

    International Nuclear Information System (INIS)

    Kanamori, Takahiro; Kamata, Shouji; Ito, Shinichi.

    1989-01-01

    A prototype high energy X-ray CT (computed tomography) system has been developed which employs a linear accelerator as the X-ray source (max. photon energy: 12 MeV). One problem encountered in development of this CT system was to reduce the scattered photons from adjacent detectors, i.e. crosstalk, due to high energy X-rays. This crosstalk was reduced to 2% by means of detector shields using tungsten spacers. Spatial resolution was not affected by such small crosstalk as confirmed by numerical simulations. A second problem was to reduce the scattered photons from the test object. This was done using collimators. A third concern was to realize a wide dynamic range data processing which would allow applications to large and dense objects. This problem was solved by using a sample and hold data acquisition method to reduce the dark current of the photo detectors. The dynamic range of this system was experimentally confirmed over 60 dB. It was demonstrated that slits (width: 2 mm) in an iron object (diameter: 25 cm) could be imaged by this prototype CT system. (author)

  12. Cosolvent-free polymer gel dosimeters with improved dose sensitivity and resolution for x-ray CT dose response

    Energy Technology Data Exchange (ETDEWEB)

    Chain, J N M; McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston, K7L 3N6 (Canada); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, V8W 3P6 (Canada); Schreiner, L J, E-mail: kim.mcauley@chee.queensu.ca [Cancer Centre of Southeastern Ontario, Kingston, K7L 5P9 (Canada)

    2011-04-07

    This study reports new N-isopropylacrylamide (NIPAM) polymer gel recipes with increased dose sensitivity and improved dose resolution for x-ray CT readout. NIPAM can be used to increase the solubility of N, N'-methylenebisacrylamide (Bis) in aqueous solutions from approximately 3% to 5.5% by weight, enabling the manufacture of dosimeters containing up to 19.5%T, which is the total concentration of NIPAM and Bis by weight. Gelatin is shown to have a mild influence on dose sensitivity when gels are imaged using x-ray CT, and a stronger influence when gels are imaged optically. Phantoms that contain only 3% gelatin and 5 mM tetrakis hydroxymethyl phosphonium chloride are sufficiently stiff for dosimetry applications. The best cosolvent-free gel formulation has a dose sensitivity in the linear range ({approx}0.88 H Gy{sup -1}) that is a small improvement compared to the best NIPAM-based gels that incorporate isopropanol as a cosolvent ({approx}0.80 H Gy{sup -1}). This new gel formulation results in enhanced dose resolution ({approx}0.052 Gy) for x-ray CT readout, making clinical applications of this imaging modality more feasible.

  13. Cosolvent-free polymer gel dosimeters with improved dose sensitivity and resolution for x-ray CT dose response

    International Nuclear Information System (INIS)

    Chain, J N M; McAuley, K B; Jirasek, A; Schreiner, L J

    2011-01-01

    This study reports new N-isopropylacrylamide (NIPAM) polymer gel recipes with increased dose sensitivity and improved dose resolution for x-ray CT readout. NIPAM can be used to increase the solubility of N, N'-methylenebisacrylamide (Bis) in aqueous solutions from approximately 3% to 5.5% by weight, enabling the manufacture of dosimeters containing up to 19.5%T, which is the total concentration of NIPAM and Bis by weight. Gelatin is shown to have a mild influence on dose sensitivity when gels are imaged using x-ray CT, and a stronger influence when gels are imaged optically. Phantoms that contain only 3% gelatin and 5 mM tetrakis hydroxymethyl phosphonium chloride are sufficiently stiff for dosimetry applications. The best cosolvent-free gel formulation has a dose sensitivity in the linear range (∼0.88 H Gy -1 ) that is a small improvement compared to the best NIPAM-based gels that incorporate isopropanol as a cosolvent (∼0.80 H Gy -1 ). This new gel formulation results in enhanced dose resolution (∼0.052 Gy) for x-ray CT readout, making clinical applications of this imaging modality more feasible.

  14. Acquiring molecular interference functions of X-ray coherent scattering for breast tissues by combination of simulation and experimental methods

    International Nuclear Information System (INIS)

    Chaparian, A.; Oghabian, M. A.; Changizi, V.

    2009-01-01

    Recently, it has been indicated that X-ray coherent scatter from biological tissues can be used to access signature of tissue. Some scientists are interested in studying this effect to get early detection of breast cancer. Since experimental methods for optimization are time consuming and expensive, some scientists suggest using simulation. Monte Carlo codes are the best option for radiation simulation: however, one permanent defect with Monte Carlo codes has been the lack of a sufficient physical model for coherent (Rayleigh) scattering, including molecular interference effects. Materials and Methods: It was decided to obtain molecular interference functions of coherent X-ray scattering for normal breast tissues by combination of modeling and experimental methods. A Monte Carlo simulation program was written to simulate the angular distribution of scattered photons for the normal breast tissue samples. Moreover, experimental diffraction patterns of these tissues were measured by means of energy dispersive X-ray diffraction method. The simulation and experimental data were used to obtain a tabulation of molecular interference functions for breast tissues. Results: With this study a tabulation of molecular interference functions for normal breast tissues Was prepared to facilitate the simulation diffraction patterns of the tissues without any experimental. Conclusion: The method may lead to design new systems for early detection of breast cancer.

  15. Development of a high-energy x-ray CT and its application to iron and steel analysis

    International Nuclear Information System (INIS)

    Taguchi, Isamu

    1987-01-01

    X-ray computed tomographic scanners are extensively used in medicine but have rarely been applied to non-medical purposes. Steel specimens pose particularly difficult problems - very poor transmission of X-rays and the need for high resolving capability. There have thus been no effective tomographic methods for examining steel specimens. Due to the growing need for non-destructive, non-contact methods for observing and analyzing the internal conditions of steel and raw materials for steel, however, we have developed a new high-energy computed tomographic scanner for steel (CTS). Its major specifications and functions are as follows. Type : 2nd-generation CT, 8-channel, Scanning method : 6deg revolution, 30-time traversing, Slice width : 0.3 mm, Resolving capability : 0.1 x 0.1 mm X-ray source : 420 kV, 3 mA, X-ray detector : BGO scintillator, Standard sample size : 50 mm dia., 50 mm high, Data collection time : 9.5 or 5 min. The CTS was successfully applied to the observation and the analysis of porosities of stainless steel (SUS 304) bloom, pores of iron ore sinters and metallic phases of the meteirites found in Antarctic Continent. (author)

  16. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    KAUST Repository

    Wang, B; Pan, B; Tao, Ran; Lubineau, Gilles

    2017-01-01

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging

  17. Characterization of a Test for Invasive Breast Cancer Using X-ray Diffraction of Hair - Results of a Clinical Trial

    Directory of Open Access Journals (Sweden)

    Gary L. Corino

    2009-11-01

    Full Text Available Objective: To assess the performance of a test for breast cancer utilizing synchrotron x-ray diffraction analysis of scalp hair from women undergoing diagnostic radiology assessment. Design and Setting: A double-blinded clinical trial of women who attended diagnostic radiology clinics in Australia. Patients: 1796 women referred for diagnostic radiology, with no previous history of cancer. Main Outcome Measures: Sensitivity, specificity and accuracy of the hair test analysis compared to the gold standard of imaging followed by biopsy where indicated. Results: The hair-based assay had an overall accuracy of >77% and a negative predictive value of 99%. For all women, the sensitivity of both mammography and x-ray diffraction alone was 64%, but when used together the sensitivity rose to 86%. The sensitivity of the hair test for women under the age of 70 was 74%. Conclusion: In this large population trial the association between the presence of breast cancer and an altered hair fibre X-ray diffraction pattern previously reported has been confirmed. It appears that mammography and X-ray diffraction of hair detect different populations of breast cancers, and are synergistic when used together.

  18. The significance of X-ray mammography for breast cancer screening

    International Nuclear Information System (INIS)

    Schulz-Wendtland, R.; Kraemer, S.; Doeinghaus, K.; Saebel, M.; Lang, N.; Bautz, W.

    1997-01-01

    One high-priority health problem in our society are the high, age-specifically standardized mortality rates of breast cancer. Breast-conserving therapies are increasingly applied today whenever appropriate, as the patient outcome depends less on the local size of the tumor than on the existing micrometastases and general spreading of the tumor in terms of a systemic tumor lesion at the time of diagnosis and primary therapy. Among the available diagnostic methods, X-ray mammography is the modality of choice for detection of small, pre-clinical carcinoma or pre-invasive stages. Although one should not overestimate the true correct findings in detection of tumors less than 1 cm of size, the proportion of correct findings indicating T1-tumors or minimal cancer obtained in multiple screening projects is surprising. The fact that the number of detected cases involving the lymph nodes is 50% in patients with clinical symptoms and only 20% or even less in diognoses obtained by screening gives reason enough to speak of ''early detection'' in the latter case. Finally, the results of the HIP study, (reduction of mortality rates for women over 50 by 40%), and of the Oestergoetland study (for women between 40 and 70 years of age, 31%) are very convincing. Furthermore, a meta-analysis on the value of breast cancer screening reveals a mortality reduction of 22% in women between 40 and 49 years of age. Further improvement of the mammographic method and quality control in medical evaluation hopefully will contribute to more widespread screening activities also in Germany, and hence to a further reduction of mortality rates. (Orig./vhe) [de

  19. X-ray phase-contrast tomosynthesis for improved breast tissue discrimination

    International Nuclear Information System (INIS)

    Schleede, Simone; Bech, Martin; Grandl, Susanne; Sztrókay, Aniko; Herzen, Julia; Mayr, Doris; Stockmar, Marco; Potdevin, Guillaume

    2014-01-01

    Purpose: Attenuation-based tomosynthesis has proven to successfully resolve the glandular tissue overlap present in mammography. However, the ability of tomosynthesis to differentiate tumorous and glandular tissue remains limited, due to the small differences in X-ray attenuation in breast tissue. One possibility to overcome this limitation and to further increase the diagnostic value of tomosynthesis exams, is the application of recently developed grating-based phase-contrast methods, which provide complementary information on the phase shift and the local scattering power of the sample. In this study, we report on first phase-contrast breast tomosynthesis results of a mastectomy sample slice with an invasive ductal carcinoma. Material and methods: A slice of a mastectomy sample with histologically proven invasive ductal cancer was imaged at the synchrotron radiation source ESRF (Grenoble, France). We used a two-grating interferometer setup at the ninth fractional Talbot distance and with an X-ray energy of 23 keV. In grating interferometry absorption, differential phase, and scattering images are recorded simultaneously. The tomosynthesis scan comprises 61 projections. Multimodal tomosynthesis results were reconstructed using a standard filtered back-projection approach. Our findings are supported by a comparison of tomographic views to histopathology. Results: Phase-contrast tomosynthesis combines the advantage of improved soft-tissue discrimination in phase-contrast imaging with the ability of tomosynthesis to provide a third dimension so that improved feature visibility is not hampered by superposition artifacts. Our results indicate superior diagnostic value due to the depth resolution supplied in tomosynthesis imaging; a region of necrotic tissue that is obscured in a projection image can clearly be depicted in one single tomosynthesis slice. Compared to absorption tomosynthesis alone, soft tissue contrast is significantly enhanced in phase

  20. X-ray phase-contrast tomosynthesis for improved breast tissue discrimination.

    Science.gov (United States)

    Schleede, Simone; Bech, Martin; Grandl, Susanne; Sztrókay, Aniko; Herzen, Julia; Mayr, Doris; Stockmar, Marco; Potdevin, Guillaume; Zanette, Irene; Rack, Alexander; Weitkamp, Timm; Pfeiffer, Franz

    2014-03-01

    Attenuation-based tomosynthesis has proven to successfully resolve the glandular tissue overlap present in mammography. However, the ability of tomosynthesis to differentiate tumorous and glandular tissue remains limited, due to the small differences in X-ray attenuation in breast tissue. One possibility to overcome this limitation and to further increase the diagnostic value of tomosynthesis exams, is the application of recently developed grating-based phase-contrast methods, which provide complementary information on the phase shift and the local scattering power of the sample. In this study, we report on first phase-contrast breast tomosynthesis results of a mastectomy sample slice with an invasive ductal carcinoma. A slice of a mastectomy sample with histologically proven invasive ductal cancer was imaged at the synchrotron radiation source ESRF (Grenoble, France). We used a two-grating interferometer setup at the ninth fractional Talbot distance and with an X-ray energy of 23 keV. In grating interferometry absorption, differential phase, and scattering images are recorded simultaneously. The tomosynthesis scan comprises 61 projections. Multimodal tomosynthesis results were reconstructed using a standard filtered back-projection approach. Our findings are supported by a comparison of tomographic views to histopathology. Phase-contrast tomosynthesis combines the advantage of improved soft-tissue discrimination in phase-contrast imaging with the ability of tomosynthesis to provide a third dimension so that improved feature visibility is not hampered by superposition artifacts. Our results indicate superior diagnostic value due to the depth resolution supplied in tomosynthesis imaging; a region of necrotic tissue that is obscured in a projection image can clearly be depicted in one single tomosynthesis slice. Compared to absorption tomosynthesis alone, soft tissue contrast is significantly enhanced in phase-contrast tomosynthesis views, where fibrous structures

  1. Influence of X-ray scatter radiation on image quality in Digital Breast Tomosynthesis (DBT)

    Science.gov (United States)

    Rodrigues, M. J.; Di Maria, S.; Baptista, M.; Belchior, A.; Afonso, J.; Venâncio, J.; Vaz, P.

    2017-11-01

    Digital breast tomosynthesis (DBT) is a quasi-three-dimensional imaging technique that was developed to solve the principal limitation of mammography, namely the overlapping tissue effect. This issue in standard mammography (SM) leads to two main problems: low sensitivity (difficulty to detect lesions) and low specificity (non-negligible percentage of false positives). Although DBT is now being introduced in clinical practice the features of this technique have not yet been fully and accurately assessed. Consequently, optimization studies in terms of choosing the most suitable parameters which maximize image quality according to the known limits of breast dosimetry are currently performing. In DBT, scatter radiation can lead to a loss of contrast and to an increase of image noise by reducing the signal-to-difference-noise ratio (SDNR) of a lesion. Moreover the use of an anti-scatter grid is a concern due to the low exposure of the photon flux available per projection. For this reason the main aim of this study was to analyze the influence of the scatter radiation on image quality and the dose delivered to the breast. In particular a detailed analysis of the scatter radiation on the optimal energy that maximizes the SDNR was performed for different monochromatic energies and voltages. To reach this objective the PenEasy Monte Carlo (MC) simulation tool imbedded in the general-purpose main program PENELOPE, was used. After a successful validation of the MC model with measurements, 2D projection images of primary, coherent and incoherent photons were obtained. For that, a homogeneous breast phantom (2, 4, 6, 8 cm) with 25%, 50% and 75% glandular compositions was used, including a 5 mm thick tumor. The images were generated for each monochromatic X-ray energies in the range from 16 keV to 32 keV. For each angular projection considered (25 angular projections covering an arc of 50°) the scatter-to-primary ratio (SPR), the mean glandular dose (MGD) and the signal

  2. Engineering iodine-doped carbon dots as dual-modal probes for fluorescence and X-ray CT imaging.

    Science.gov (United States)

    Zhang, Miaomiao; Ju, Huixiang; Zhang, Li; Sun, Mingzhong; Zhou, Zhongwei; Dai, Zhenyu; Zhang, Lirong; Gong, Aihua; Wu, Chaoyao; Du, Fengyi

    2015-01-01

    X-ray computed tomography (CT) is the most commonly used imaging technique for noninvasive diagnosis of disease. In order to improve tissue specificity and prevent adverse effects, we report the design and synthesis of iodine-doped carbon dots (I-doped CDs) as efficient CT contrast agents and fluorescence probe by a facile bottom-up hydrothermal carbonization process. The as-prepared I-doped CDs are monodispersed spherical nanoparticles (a diameter of ~2.7 nm) with favorable dispersibility and colloidal stability in water. The aqueous solution of I-doped CDs showed wavelength-dependent excitation and stable photoluminescence similar to traditional carbon quantum dots. Importantly, I-doped CDs displayed superior X-ray attenuation properties in vitro and excellent biocompatibility. After intravenous injection, I-doped CDs were distributed throughout the body and excreted by renal clearance. These findings validated that I-doped CDs with high X-ray attenuation potency and favorable photoluminescence show great promise for biomedical research and disease diagnosis.

  3. Comparison of Tc-99m HM-PAO SPECT brain scan and x-ray CT in the detection of brain metastases

    International Nuclear Information System (INIS)

    Abdel-Dayem, H.M.; Sadek, S.; Sahwell, A.; Kubasek, H.; El-Sayed, M.; Ziada, G.; Mobarak, L.; Al-Huda, F.; Omar, Y.T.

    1986-01-01

    Tc-99m HM-PAO imaging was compared with x-ray CT in 14 patients with known or suspected brain metastases. Both studies were done within 3 days of each other. Static and single photon emission CT (SPECT) images were acquired after intravenous injection of 13 mCi of Tc-99m HM-PAO. All 14 patients underwent static and SPECT Tc-99m HM-PAO imaging and x-ray CT. Studies were positive in 7, 12, and 10 patients, respectively, by static, SPECT, and x-ray CT imaging, and negative in 7, 2, and 2. The number of lesions identified was 0 (static imaging), 32 (SPECT), and 26(x-ray CT). There were no ''suspicious'' studies by any modality. This study indicates that Tc-99m HM-PAO SPECT cerebral blood flow imaging is more sensitive than x-ray CT for detecting brain metastases, that biplane imaging is not sensitive and SPECT is essential, and that for Tc-99m HM-PAO SPECT brain imaging to regain its importance with respect to x-ray CT, acquisition time must be 10 minutes or less and determination of percentage brain uptake of the injected dose, and of regional distribution, is necessary

  4. Improvement of analysis precision upon the atomic number and electron density measurement by the dual x-ray CT

    Science.gov (United States)

    Imura, Yukino; Morii, Hisashi; Koike, Akifumi; Okunoyama, Takaharu; Neo, Yoichiro; Mimura, Hidenori; Aoki, Toru

    2010-08-01

    To identify the factor impairing the material identification parameters, which is provided by the dual-energy X-ray computed tomography method using a conventional X-ray tube and a CdTe detector, linear attenuation coefficient was measured by the radioactivity of radio isotopes and compared with theoretical figure. In our study, the atomic number and the electron density is calculated from the linear attenuation coefficient obtained in CT measurement by 64-channel CdTe line detector. To estimate accuracy of CdTe line sensor, it is needed to obtain the linear attenuation coefficient accurately. Using a single detector, the linear attenuation coefficient is verified for accuracy. The energy resolution of CdTe detectors and the method of reconstruction are discussed.

  5. Laboratory based study of dynamical processes by 4D X-ray CT with sub-second temporal resolution

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Jakůbek, Jan; Kumpová, Ivana; Pichotka, M.

    2017-01-01

    Roč. 12, February (2017), č. článku C02010. ISSN 1748-0221. [International Workshop on Radiation Imaging Detectors /18./. Barcelona, 03.07.2016-07.07.2016] R&D Projects: GA ČR(CZ) GA15-07210S; GA MŠk(CZ) LO1219 Keywords : computerized tomography (CT) * computed radiography (CR) * inspection with x-rays * pixelated detectors and associated VLSI electronics * X-ray radiography and digital radiography (DR) Subject RIV: JB - Sensors, Measurment, Regulation OBOR OECD: Electrical and electronic engineering Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/12/02/C02010

  6. Improved spatial resolution and lower-dose pediatric CT imaging: a feasibility study to evaluate narrowing the X-ray photon energy spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Benz, Mark G. [Safer Pediatric Imaging and Engineering Horizons International, Lincoln, VT (United States); Benz, Matthew W. [Southboro Medical Group, Southboro, MA (United States); Birnbaum, Steven B. [Dartmouth Hitchcock Clinic Manchester, Department of Radiology, Manchester, NH (United States); Chason, Eric; Sheldon, Brian W. [Brown University, Division of Engineering, Materials Science and Engineering Program, Providence, RI (United States); McGuire, Dale [R and D Manager, C and G Technologies Inc., Jeffersonville, IN (United States)

    2014-08-15

    This feasibility study has shown that improved spatial resolution and reduced radiation dose can be achieved in pediatric CT by narrowing the X-ray photon energy spectrum. This is done by placing a hafnium filter between the X-ray generator and a pediatric abdominal phantom. A CT system manufactured in 1999 that was in the process of being remanufactured was used as the platform for this study. This system had the advantage of easy access to the X-ray generator for modifications to change the X-ray photon energy spectrum; it also had the disadvantage of not employing the latest post-imaging noise reduction iterative reconstruction technology. Because we observed improvements after changing the X-ray photon energy spectrum, we recommend a future study combining this change with an optimized iterative reconstruction noise reduction technique. (orig.)

  7. Multispectral x-ray CT: multivariate statistical analysis for efficient reconstruction

    DEFF Research Database (Denmark)

    Kheirabadi, Mina; Mustafa, Wail; Lyksborg, Mark

    2017-01-01

    Recent developments in multispectral X-ray detectors allow for an efficient identification of materials based on their chemical composition. This has a range of applications including security inspection, which is our motivation. In this paper, we analyze data from a tomographic setup employing...

  8. Mobile 3D rotational X-ray: comparison with CT in sinus surgery

    International Nuclear Information System (INIS)

    Carelsen, B.; Bakker, N.H.; Boon, S.N.; Fokkens, W.J.; Freling, N.J.M.; Noordhoek, N.J.

    2004-01-01

    Clinical evaluation of a 3D rotational X-ray (3D-RX) system, comprising a modified Philips BV Pulsera C-arm system and a Philips 3D-RA workstation, demonstrates good diagnostic accuracy in functional endoscopic sinus surgery

  9. TH-AB-209-01: Making Benchtop X-Ray Fluorescence Computed Tomography (XFCT) Practical for in Vivo Imaging by Integration of a Dedicated High-Performance X-Ray Source in Conjunction with Micro-CT Functionality

    International Nuclear Information System (INIS)

    Manohar, N; Cho, S; Reynoso, F

    2016-01-01

    Purpose: To make benchtop x-ray fluorescence computed tomography (XFCT) practical for routine preclinical imaging tasks with gold nanoparticles (GNPs) by deploying, integrating, and characterizing a dedicated high-performance x-ray source and addition of simultaneous micro-CT functionality. Methods: Considerable research effort is currently under way to develop a polychromatic benchtop cone-beam XFCT system capable of imaging GNPs by stimulation and detection of gold K-shell x-ray fluorescence (XRF) photons. Recently, an ad hoc high-power x-ray source was incorporated and used to image the biodistribution of GNPs within a mouse, postmortem. In the current work, a dedicated x-ray source system featuring a liquid-cooled tungsten-target x-ray tube (max 160 kVp, ∼3 kW power) was deployed. The source was operated at 125 kVp, 24 mA. The tube’s compact dimensions allowed greater flexibility for optimizing both the irradiation and detection geometries. Incident x-rays were shaped by a conical collimator and filtered by 2 mm of tin. A compact “OEM” cadmium-telluride x-ray detector was implemented for detecting XRF/scatter spectra. Additionally, a flat panel detector was installed to allow simultaneous transmission CT imaging. The performance of the system was characterized by determining the detection limit (10-second acquisition time) for inserts filled with water/GNPs at various concentrations (0 and 0.010–1.0 wt%) and embedded in a small-animal-sized phantom. The phantom was loaded with 0.5, 0.3, and 0.1 wt% inserts and imaged using XFCT and simultaneous micro-CT. Results: An unprecedented detection limit of 0.030 wt% was experimentally demonstrated, with a 33% reduction in acquisition time. The reconstructed XFCT image accurately localized the imaging inserts. Micro-CT imaging did not provide enough contrast to distinguish imaging inserts from the phantom under the current conditions. Conclusion: The system is immediately capable of in vivo preclinical XFCT

  10. TH-AB-209-01: Making Benchtop X-Ray Fluorescence Computed Tomography (XFCT) Practical for in Vivo Imaging by Integration of a Dedicated High-Performance X-Ray Source in Conjunction with Micro-CT Functionality

    Energy Technology Data Exchange (ETDEWEB)

    Manohar, N; Cho, S [UT MD Anderson Cancer Center, Houston, TX (United States); Reynoso, F [UT MD Anderson Cancer Center, Houston, TX (United States); Washington University School of Medicine, St. Louis, MO (United States)

    2016-06-15

    Purpose: To make benchtop x-ray fluorescence computed tomography (XFCT) practical for routine preclinical imaging tasks with gold nanoparticles (GNPs) by deploying, integrating, and characterizing a dedicated high-performance x-ray source and addition of simultaneous micro-CT functionality. Methods: Considerable research effort is currently under way to develop a polychromatic benchtop cone-beam XFCT system capable of imaging GNPs by stimulation and detection of gold K-shell x-ray fluorescence (XRF) photons. Recently, an ad hoc high-power x-ray source was incorporated and used to image the biodistribution of GNPs within a mouse, postmortem. In the current work, a dedicated x-ray source system featuring a liquid-cooled tungsten-target x-ray tube (max 160 kVp, ∼3 kW power) was deployed. The source was operated at 125 kVp, 24 mA. The tube’s compact dimensions allowed greater flexibility for optimizing both the irradiation and detection geometries. Incident x-rays were shaped by a conical collimator and filtered by 2 mm of tin. A compact “OEM” cadmium-telluride x-ray detector was implemented for detecting XRF/scatter spectra. Additionally, a flat panel detector was installed to allow simultaneous transmission CT imaging. The performance of the system was characterized by determining the detection limit (10-second acquisition time) for inserts filled with water/GNPs at various concentrations (0 and 0.010–1.0 wt%) and embedded in a small-animal-sized phantom. The phantom was loaded with 0.5, 0.3, and 0.1 wt% inserts and imaged using XFCT and simultaneous micro-CT. Results: An unprecedented detection limit of 0.030 wt% was experimentally demonstrated, with a 33% reduction in acquisition time. The reconstructed XFCT image accurately localized the imaging inserts. Micro-CT imaging did not provide enough contrast to distinguish imaging inserts from the phantom under the current conditions. Conclusion: The system is immediately capable of in vivo preclinical XFCT

  11. Cardiac motion correction based on partial angle reconstructed images in x-ray CT

    International Nuclear Information System (INIS)

    Kim, Seungeon; Chang, Yongjin; Ra, Jong Beom

    2015-01-01

    Purpose: Cardiac x-ray CT imaging is still challenging due to heart motion, which cannot be ignored even with the current rotation speed of the equipment. In response, many algorithms have been developed to compensate remaining motion artifacts by estimating the motion using projection data or reconstructed images. In these algorithms, accurate motion estimation is critical to the compensated image quality. In addition, since the scan range is directly related to the radiation dose, it is preferable to minimize the scan range in motion estimation. In this paper, the authors propose a novel motion estimation and compensation algorithm using a sinogram with a rotation angle of less than 360°. The algorithm estimates the motion of the whole heart area using two opposite 3D partial angle reconstructed (PAR) images and compensates the motion in the reconstruction process. Methods: A CT system scans the thoracic area including the heart over an angular range of 180° + α + β, where α and β denote the detector fan angle and an additional partial angle, respectively. The obtained cone-beam projection data are converted into cone-parallel geometry via row-wise fan-to-parallel rebinning. Two conjugate 3D PAR images, whose center projection angles are separated by 180°, are then reconstructed with an angular range of β, which is considerably smaller than a short scan range of 180° + α. Although these images include limited view angle artifacts that disturb accurate motion estimation, they have considerably better temporal resolution than a short scan image. Hence, after preprocessing these artifacts, the authors estimate a motion model during a half rotation for a whole field of view via nonrigid registration between the images. Finally, motion-compensated image reconstruction is performed at a target phase by incorporating the estimated motion model. The target phase is selected as that corresponding to a view angle that is orthogonal to the center view angles of

  12. Cardiac motion correction based on partial angle reconstructed images in x-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungeon; Chang, Yongjin; Ra, Jong Beom, E-mail: jbra@kaist.ac.kr [Department of Electrical Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-05-15

    Purpose: Cardiac x-ray CT imaging is still challenging due to heart motion, which cannot be ignored even with the current rotation speed of the equipment. In response, many algorithms have been developed to compensate remaining motion artifacts by estimating the motion using projection data or reconstructed images. In these algorithms, accurate motion estimation is critical to the compensated image quality. In addition, since the scan range is directly related to the radiation dose, it is preferable to minimize the scan range in motion estimation. In this paper, the authors propose a novel motion estimation and compensation algorithm using a sinogram with a rotation angle of less than 360°. The algorithm estimates the motion of the whole heart area using two opposite 3D partial angle reconstructed (PAR) images and compensates the motion in the reconstruction process. Methods: A CT system scans the thoracic area including the heart over an angular range of 180° + α + β, where α and β denote the detector fan angle and an additional partial angle, respectively. The obtained cone-beam projection data are converted into cone-parallel geometry via row-wise fan-to-parallel rebinning. Two conjugate 3D PAR images, whose center projection angles are separated by 180°, are then reconstructed with an angular range of β, which is considerably smaller than a short scan range of 180° + α. Although these images include limited view angle artifacts that disturb accurate motion estimation, they have considerably better temporal resolution than a short scan image. Hence, after preprocessing these artifacts, the authors estimate a motion model during a half rotation for a whole field of view via nonrigid registration between the images. Finally, motion-compensated image reconstruction is performed at a target phase by incorporating the estimated motion model. The target phase is selected as that corresponding to a view angle that is orthogonal to the center view angles of

  13. Soil pore characteristics assessed from X-ray micro-CT derived images and correlations to soil friability

    DEFF Research Database (Denmark)

    Munkholm, Lars Juhl; Heck, R; Deen, B

    2012-01-01

    X-ray computed tomography (CT) scanning technology has, in recent decades, been shown to be a very powerful technique to visualize and quantify soil structure. The objective of this project was to quantify soilporecharacteristics, on undisturbed field moist soil, using a high resolution X-rayCT...... cores varied in porosity and porecharacteristics. A drop shatter test was used as a reference procedure to quantify soilfriability. The top 40 mm of the 80 mm high soil samples were scanned using a X-raymicro-CT scanner. The selected region of interest (36 × 36 × 36 mm) was reconstructed with a voxel...... of 49 m3 100 m− 3. The air-filled porosity, at sampling/testing, ranged between 5 and 32 m3 100 m− 3, with an average of 15 m3 100 m− 3. The porosity determined from CT imagery ranged between 1 and 31 m3 100 m− 3, with an average of 4.5 m3 100 m− 3. The number of branches, junctions and end points...

  14. An experimental study on the noise properties of x-ray CT sinogram data in Radon space

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jing; Liang Zhengrong; Eremina, Daria; Wang Su; Manzione, James [Department of Radiology, State University of New York, Stony Brook, NY 11794 (United States); Lu Hongbing [Department of Biomedical Engineering, Fourth Military Medical University, Xi' An, Shaanxi 710032 (China); Zhang Guangxiang; Chen, John [Department of Preventive Medicine, State University of New York, Stony Brook, NY 11794 (United States)], E-mail: jerome.liang@sunysb.edu

    2008-06-21

    Computed tomography (CT) has been well established as a diagnostic tool through hardware optimization and sophisticated data calibration. For screening purposes, the associated x-ray exposure risk must be minimized. An effective way to minimize the risk is to deliver fewer x-rays to the subject or lower the mAs parameter in data acquisition. This will increase the data noise. This work aims to study the noise property of the calibrated or preprocessed sinogram data in Radon space as the mAs level decreases. An anthropomorphic torso phantom was scanned repeatedly by a commercial CT imager at five different mAs levels from 100 down to 17 (the lowest value provided by the scanner). The preprocessed sinogram datasets were extracted from the CT scanner to a laboratory computer for noise analysis. The repeated measurements at each mAs level were used to test the normality of the repeatedly measured samples for each data channel using the Shapiro-Wilk statistical test merit. We further studied the probability distribution of the repeated measures. Most importantly, we validated a theoretical relationship between the sample mean and variance at each channel. It is our intention that the statistical test and particularly the relationship between the first and second statistical moments will improve low-dose CT image reconstruction for screening applications.

  15. Characterizing X-ray detectors for prototype digital breast tomosynthesis systems

    International Nuclear Information System (INIS)

    Kim, Y.-S.; Park, H.-S.; Park, S.-J.; Choi, S.; Lee, H.; Kim, H.-J.; Lee, D.; Choi, Y.-W.

    2016-01-01

    The digital breast tomosynthesis (DBT) system is a newly developed 3-D imaging technique that overcomes the tissue superposition problems of conventional mammography. Therefore, it produces fewer false positives. In DBT system, several parameters are involved in image acquisition, including geometric components. A series of projections should be acquired at low exposure. This makes the system strongly dependent on the detector's characteristic performance. This study compares two types of x-ray detectors developed by the Korea Electrotechnology Research Institute (KERI). The first prototype DBT system has a CsI (Tl) scintillator/CMOS based flat panel digital detector (2923 MAM, Dexela Ltd.), with a pixel size of 0.0748 mm. The second uses a-Se based direct conversion full field detector (AXS 2430, analogic) with a pixel size of 0.085 mm. The geometry of both systems is same, with a focal spot 665.8 mm from the detector, and a center of rotation 33 mm above the detector surface. The systems were compared with regard to modulation transfer function (MTF), normalized noise power spectrum (NNPS), detective quantum efficiency (DQE) and a new metric, the relative object detectability (ROD). The ROD quantifies the relative performance of each detector at detecting specified objects. The system response function demonstrated excellent linearity (R 2 >0.99). The CMOS-based detector had a high sensitivity, while the Anrad detector had a large dynamic range. The higher MTF and noise power spectrum (NPS) values were measured using an Anrad detector. The maximum DQE value of the Dexela detector was higher than that of the Anrad detector with a low exposure level, considering one projection exposure for tomosynthesis. Overall, the Dexela detector performed better than did the Anrad detector with regard to the simulated Al wires, spheres, test objects of ROD with low exposure level. In this study, we compared the newly developed prototype DBT system with two different types

  16. Evaluation of a breast software model for 2D and 3D X-ray imaging studies of the breast.

    Science.gov (United States)

    Baneva, Yanka; Bliznakova, Kristina; Cockmartin, Lesley; Marinov, Stoyko; Buliev, Ivan; Mettivier, Giovanni; Bosmans, Hilde; Russo, Paolo; Marshall, Nicholas; Bliznakov, Zhivko

    2017-09-01

    In X-ray imaging, test objects reproducing breast anatomy characteristics are realized to optimize issues such as image processing or reconstruction, lesion detection performance, image quality and radiation induced detriment. Recently, a physical phantom with a structured background has been introduced for both 2D mammography and breast tomosynthesis. A software version of this phantom and a few related versions are now available and a comparison between these 3D software phantoms and the physical phantom will be presented. The software breast phantom simulates a semi-cylindrical container filled with spherical beads of different diameters. Four computational breast phantoms were generated with a dedicated software application and for two of these, physical phantoms are also available and they are used for the side by side comparison. Planar projections in mammography and tomosynthesis were simulated under identical incident air kerma conditions. Tomosynthesis slices were reconstructed with an in-house developed reconstruction software. In addition to a visual comparison, parameters like fractal dimension, power law exponent β and second order statistics (skewness, kurtosis) of planar projections and tomosynthesis reconstructed images were compared. Visually, an excellent agreement between simulated and real planar and tomosynthesis images is observed. The comparison shows also an overall very good agreement between parameters evaluated from simulated and experimental images. The computational breast phantoms showed a close match with their physical versions. The detailed mathematical analysis of the images confirms the agreement between real and simulated 2D mammography and tomosynthesis images. The software phantom is ready for optimization purpose and extrapolation of the phantom to other breast imaging techniques. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. The possibility of using x-ray diffraction with hair to screen for pathologic conditions such as breast cancer

    International Nuclear Information System (INIS)

    James, Veronica; Cookson, David

    2000-01-01

    Mammalian hair exhibits a complex structure on length scales ranging from a few to hundreds of Angstroms. High-quality synchrotron x-ray images have yielded new insight about the structure and packing of the intermediate keratinous filaments that represent the bulk of a hair's volume. When comparing human hair diffraction patterns from healthy individuals and breast cancer patients significant differences have been seen, raising the possibility that fiber diffraction may be useful as a screening technique for certain pathologic conditions

  18. Determination of liquid's molecular interference function based on X-ray diffraction and dual-energy CT in security screening

    International Nuclear Information System (INIS)

    Zhang, Li; YangDai, Tianyi

    2016-01-01

    A method for deriving the molecular interference function (MIF) of an unknown liquid for security screening is presented. Based on the effective atomic number reconstructed from dual-energy computed tomography (CT), equivalent molecular formula of the liquid is estimated. After a series of optimizations, the MIF and a new effective atomic number are finally obtained from the X-ray diffraction (XRD) profile. The proposed method generates more accurate results with less sensitivity to the noise and data deficiency of the XRD profile. - Highlights: • EDXRD combined with dual-energy CT has been utilized for deriving the molecular interference function of an unknown liquid. • The liquid's equivalent molecular formula is estimated based on the effective atomic number reconstructed from dual-energy CT. • The proposed method provides two ways to estimate the molecular interference function: the simplified way and accurate way. • A new effective atomic number of the liquid could be obtained.

  19. X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    2016-01-01

    -derived parameters by using a best subsets regression analysis. The regression coefficients improved using CTmatrix, limiting macroporosity, and genus density, while the best model for t0.05 used CTmatrix only. The scanning resolution and the time for soil structure development after mechanical activities could......The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...

  20. Engineering iodine-doped carbon dots as dual-modal probes for fluorescence and X-ray CT imaging

    Directory of Open Access Journals (Sweden)

    Zhang M

    2015-11-01

    Full Text Available Miaomiao Zhang,1,* Huixiang Ju,2,* Li Zhang,1,* Mingzhong Sun,2 Zhongwei Zhou,2 Zhenyu Dai,3 Lirong Zhang,1 Aihua Gong,1 Chaoyao Wu,1 Fengyi Du1 1School of Medicine, Jiangsu University, Zhenjiang, People’s Republic of China; 2Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, Yancheng, Jiangsu, People’s Republic of China; 3Radiology Department, Affiliated Yancheng Hospital, School of Medicine, Southeast University, Yancheng, Jiangsu, People’s Republic of China *These authors contributed equally to this work Abstract: X-ray computed tomography (CT is the most commonly used imaging technique for noninvasive diagnosis of disease. In order to improve tissue specificity and prevent adverse effects, we report the design and synthesis of iodine-doped carbon dots (I-doped CDs as efficient CT contrast agents and fluorescence probe by a facile bottom-up hydrothermal carbonization process. The as-prepared I-doped CDs are monodispersed spherical nanoparticles (a diameter of ~2.7 nm with favorable dispersibility and colloidal stability in water. The aqueous solution of I-doped CDs showed wavelength-dependent excitation and stable photoluminescence similar to traditional carbon quantum dots. Importantly, I-doped CDs displayed superior X-ray attenuation properties in vitro and excellent biocompatibility. After intravenous injection, I-doped CDs were distributed throughout the body and excreted by renal clearance. These findings validated that I-doped CDs with high X-ray attenuation potency and favorable photoluminescence show great promise for biomedical research and disease diagnosis. Keywords: carbon dots, contrast agents, iodine-doped, CT imaging

  1. Quantitative X-ray CT analysis of calcification of the abdominal aorta and its relationship to obesity

    International Nuclear Information System (INIS)

    Shinagawa, Toshio; Hiraiwa, Yoshio; Mizuno, Seio; Kusunoki, Norio; Nitta, Yu; Matsubara, Takao; Iwainaka, Yoichi; Konishi, Hideo

    1992-01-01

    Quantitative analysis of abdominal aorta calcification by X-ray CT is useful method for non-invasive diagnosis of atherosclerosis. We recently examined the relationship between the X-ray CT measurement of abdominal aorta calcification and the degree of obesity. For this purpose, the body mass index (BMI) and the subcutaneous fat thickness (determined by X-ray CT at the umbilical level) were analyzed in relation to the abdominal aorta calcification index (ACI) in 845 patients (453 males and 392 females aged 40-79 years). Patients with BMI under 20 were classified as 'lean', those with BMI between 20-26 as 'normal' and those with BMI over 26 as 'obese'. 1. Among males, the ACI was highest in lean individuals and lowest in obese individuals. The difference in ACI between lean and obese males was significant in the middle aged group (40-65 years). Among females, no relationship was observed between the degree of obesity and ACI. 2. Among males, ACI was higher in individuals with low subcutaneous fat thickness and lower in individuals with greater subcutaneous fat thickness. The difference was significant in the middle aged group. Among females, no relationship was observed between the two parameters. 3. When the visceral fat to subcutaneous fat ratio (V/S) in 85 males and females aged 60-69 years was analyzed in relation to ACI, ACI tended to decrease as the V/S increased, in both males and females. 4. Relationships between BMI and subcutaneous fat thickness, between BMI and lipids and between lipids and ACI were also analyzed. (author)

  2. Ex-situ time-lapse x-ray CT study of 3D micro-structural fatigue damage evolution in uni-directional composites

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Wang, Ying; Zangenberg Hansen, Jens

    2016-01-01

    In this study, the progress of damage under tension-tension fatigue of a uni-directional (UD) glass fibre composite made from a non-crimp fabric is studied using transilluminated white light imaging (TWLI) and X-ray computed tomography (CT). TWLI images are automatically captured throughout...... to initiate already after the first cycle, whereas some grow gradually and others appear suddenly during cycling. The off-axis cracks are observed to saturate after a few thousand cycles. The UD fibre fracture damage in the region observed by X-ray CT is probably already saturated at the first interruption...... point, as no significant change is seen between the two X-ray images. However, the study indicates how TWLI can be used as an initial indicator to locate damage regions at an early stage for the future ex-situ X-ray CT experiments....

  3. Classification of fractures of the distal r[ius - Comparative evaluation of spiral CT images and X-rays

    International Nuclear Information System (INIS)

    Roehnert, W.; Nitzsche, H.; Franck, W.M.; Amlang, M.

    1998-01-01

    Within the framework of a prospective study 35 patients with fractures of the distal r[ius safely diagnosed to require surgery have been [ditionally scanned by spiral CT. For more exact diagnostic evaluation of the joint surfaces and the fractures, multiplane reconstructions have been m[e to enhance the information obtained from the primary, axial tomographic images. Two experts independently performed classification on the basis of the X-rays and the CT scans, applying the AO scheme and the method of Frykman. Classifications according to the AO scheme were found to agree for only 28.6 % of the patients, which means that 57.1 % of the fractures shown by the X-rays were more or less underassessed. Classification according to Frykman's method revealed fewer deviations and agreement in 51.4 % of the cases. Biplanar r[iography continues to be considered as the standard method for examination of distal r[ius fractures, but it is recommended to perform spiral CT scans for evaluation of more complex distal r[ius fractures because these may require different therapies according to fracture types. (orig./CB) [de

  4. Advanced high speed X-ray CT scanner for measurement and visualization of multi-phase flow

    International Nuclear Information System (INIS)

    Hori, Keiichi; Fujimoto, Tetsuro; Kawanishi, Kohei; Nishikawa, Hideo

    1998-01-01

    The development of an ultra-fast X-ray computed tomography (CT) scanner has been performed. The object of interest is in a transient or unsettled state, which makes the conventional CT scanner inappropriate. A concept of electrical switching of electron beam of X-ray generation unit is adopted to reduce the scanning time instead of a mechanical motion adopted by a conventional CT scanner. The mechanical motion is a major obstacle to improve the scanning speed. A prototype system with a scanning time of 3.6 milliseconds was developed at first. And, the feasibility was confirmed to measure the dynamic events of two-phase flow. However, faster scanning speed is generally required for the practical use in the thermalhydraulics research field. Therefore, the development of advanced type has been performed. This advanced type can operate under the scanning time of 0.5 milliseconds and is applicable for the measurement of the multi-phase flow with velocity up to 4-5 m/s. (author)

  5. Use of X-ray CT-defined regions of interest for the determination of SPECT recovery coefficients

    International Nuclear Information System (INIS)

    Tang, H.R.; Brown, J.K.; Hasegawa, B.H.

    1996-01-01

    For accurate activity per unit volume measurements in SPECT, recovery coefficients are usually applied based on the size and shape of objects being imaged to properly account for the resolution limitations of the gamma camera. Because of noise and limited spatial resolution, determination of object sizes and boundaries can be difficult using the SPECT images alone. We therefore have developed a technique which determines activity concentrations for SPECT using regions of interest (ROI's) obtained from coregistered X-ray CT images. In this study, experimental phantoms containing cylindrical and spherical objects were imaged on a combined X-ray CT/SPECT system and reconstructed data volumes were registered using the known geometry of the system. ROI's were defined on the registered CT images and used to help quantify activity concentration in localized regions and to measure object volumes. We have derived the recovery curves for these objects and scan technique. We have also tested a technique that demonstrates activity quantitation without the need for object and size dependent recovery coefficients in the case of low background

  6. Synchrotron radiation phase-contrast X-ray CT imaging of acupuncture points

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongming; Yan, Xiaohui; Zhang, Xinyi [Fudan University, Synchrotron Radiation Research Center, State Key Laboratory of Surface Physics and Department of Physics, Shanghai (China); Liu, Chenglin [Physics Department of Yancheng Teachers' College, Yancheng (China); Dang, Ruishan [The Second Military Medical University, Shanghai (China); Xiao, Tiqiao [Chinese Academy of Sciences, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Shanghai (China); Zhu, Peiping [Chinese Academy of Sciences, Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Beijing (China)

    2011-08-15

    Three-dimensional (3D) topographic structures of acupuncture points were investigated by using synchrotron radiation in-line X-ray phase contrast computerized tomography. Two acupuncture points, named Zhongji (RN3) and Zusanli (ST36), were studied. We found an accumulation of microvessels at each acupuncture point region. Images of the tissues surrounding the acupuncture points do not show such kinds of structure. This is the first time that 3D images have revealed the specific structures of acupuncture points. (orig.)

  7. Synchrotron radiation phase-contrast X-ray CT imaging of acupuncture points

    International Nuclear Information System (INIS)

    Zhang, Dongming; Yan, Xiaohui; Zhang, Xinyi; Liu, Chenglin; Dang, Ruishan; Xiao, Tiqiao; Zhu, Peiping

    2011-01-01

    Three-dimensional (3D) topographic structures of acupuncture points were investigated by using synchrotron radiation in-line X-ray phase contrast computerized tomography. Two acupuncture points, named Zhongji (RN3) and Zusanli (ST36), were studied. We found an accumulation of microvessels at each acupuncture point region. Images of the tissues surrounding the acupuncture points do not show such kinds of structure. This is the first time that 3D images have revealed the specific structures of acupuncture points. (orig.)

  8. X-ray absorption microtomography (microCT) and small beam diffraction mapping of sea urchin teeth.

    Science.gov (United States)

    Stock, S R; Barss, J; Dahl, T; Veis, A; Almer, J D

    2002-07-01

    Two noninvasive X-ray techniques, laboratory X-ray absorption microtomography (microCT) and X-ray diffraction mapping, were used to study teeth of the sea urchin Lytechinus variegatus. MicroCT revealed low attenuation regions at near the tooth's stone part and along the carinar process-central prism boundary; this latter observation appears to be novel. The expected variation of Mg fraction x in the mineral phase (calcite, Ca(1-x)Mg(x)CO(3)) cannot account for all of the linear attenuation coefficient decrease in the two zones: this suggested that soft tissue is localized there. Transmission diffraction mapping (synchrotron X-radiation, 80.8 keV, 0.1 x 0.1mm(2) beam area, 0.1mm translation grid, image plate area detector) simultaneously probed variations in 3-D and showed that the crystal elements of the "T"-shaped tooth were very highly aligned. Diffraction patterns from the keel (adaxial web) and from the abaxial flange (containing primary plates and the stone part) differed markedly. The flange contained two populations of identically oriented crystal elements with lattice parameters corresponding to x=0.13 and x=0.32. The keel produced one set of diffraction spots corresponding to the lower x. The compositions were more or less equivalent to those determined by others for camarodont teeth, and the high Mg phase is expected to be disks of secondary mineral epitaxially related to the underlying primary mineral element. Lattice parameter gradients were not noted in the keel or flange. Taken together, the microCT and diffraction results indicated that there was a band of relatively high protein content, of up to approximately 0.25 volume fraction, in the central part of the flange and paralleling its adaxial and abaxial faces. X-ray microCT and microdiffraction data used in conjunction with protein distribution data will be crucial for understanding the properties of various biocomposites and their mechanical functions.

  9. Three-dimensional modeling and simulation of asphalt concrete mixtures based on X-ray CT microstructure images

    Directory of Open Access Journals (Sweden)

    Hainian Wang

    2014-02-01

    Full Text Available X-ray CT (computed tomography was used to scan asphalt mixture specimen to obtain high resolution continuous cross-section images and the meso-structure. According to the theory of three-dimensional (3D reconstruction, the 3D reconstruction algorithm was investigated in this paper. The key to the reconstruction technique is the acquisition of the voxel positions and the relationship between the pixel element and node. Three-dimensional numerical model of asphalt mixture specimen was created by a self-developed program. A splitting test was conducted to predict the stress distributions of the asphalt mixture and verify the rationality of the 3D model.

  10. Quantitative Study of Porosity and Pore Features in Moldavites by Means of X-ray Micro-CT

    Directory of Open Access Journals (Sweden)

    Giovanni Pratesi

    2014-04-01

    Full Text Available X-ray micro-computer aided tomography (μ-CT, together with optical microscopy and imaging, have been applied to the study of six moldavite samples. These techniques enabled a complete characterization to be made of the textural features of both Muong Nong-type and common splashform moldavites. A detailed study of the size and distribution of pores or bubbles confirmed the marked variability in pore size among the samples, as well as within each sample, and indicated in the Muong Nong-type moldavites the presence of at least two deformation stages which occurred before and after pore formation.

  11. Low-Dose Contrast-Enhanced Breast CT Using Spectral Shaping Filters: An Experimental Study.

    Science.gov (United States)

    Makeev, Andrey; Glick, Stephen J

    2017-12-01

    Iodinated contrast-enhanced X-ray imaging of the breast has been studied with various modalities, including full-field digital mammography (FFDM), digital breast tomosynthesis (DBT), and dedicated breast CT. Contrast imaging with breast CT has a number of advantages over FFDM and DBT, including the lack of breast compression, and generation of fully isotropic 3-D reconstructions. Nonetheless, for breast CT to be considered as a viable tool for routine clinical use, it would be desirable to reduce radiation dose. One approach for dose reduction in breast CT is spectral shaping using X-ray filters. In this paper, two high atomic number filter materials are studied, namely, gadolinium (Gd) and erbium (Er), and compared with Al and Cu filters currently used in breast CT systems. Task-based performance is assessed by imaging a cylindrical poly(methyl methacrylate) phantom with iodine inserts on a benchtop breast CT system that emulates clinical breast CT. To evaluate detectability, a channelized hoteling observer (CHO) is used with sums of Laguerre-Gauss channels. It was observed that spectral shaping using Er and Gd filters substantially increased the dose efficiency (defined as signal-to-noise ratio of the CHO divided by mean glandular dose) as compared with kilovolt peak and filter settings used in commercial and prototype breast CT systems. These experimental phantom study results are encouraging for reducing dose of breast CT, however, further evaluation involving patients is needed.

  12. Application of micron X-ray CT based on micro-PIXE to investigate the distribution of Cs in silt particles for environmental remediation in Fukushima Prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Keizo, E-mail: keizo.ishii@qse.tohoku.ac.jp [Research Center for Remediation Engineering of Environments Contaminated with Radioisotopes, Graduate School of Engineering, Tohoku University, 6-6-01-2, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan); Hatakeyama, Taisuke; Itoh, Shin; Sata, Daichi [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan); Ohnuma, Tohru; Yamaguchi, Toshiro; Arai, Hiromu; Arai, Hirotsugu [Research Center for Remediation Engineering of Environments Contaminated with Radioisotopes, Graduate School of Engineering, Tohoku University, 6-6-01-2, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan); Matsuyama, Shigeo; Terakawa, Atsuki; Kim, Seong-Yun [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan)

    2016-03-15

    We used X-ray computed tomography (CT) using characteristic X-rays produced in micro-particle-induced X-ray emission (PIXE) to investigate the internal structure of silt particles and develop new methods to decontaminate soil containing radioactive cesium. We obtained 3D attenuation coefficient images of silt particles with a diameter of approximately 100 μm for V K and Cr K X-rays. Owing to the absorption edges of the Cs L-shell, the differences between the V K and Cr K X-ray images revealed the spatial distribution of Cs atoms in the silt particles. Cs atoms were distributed over the surfaces of the silt particles to a thickness of approximately 10 μm. This information is useful for the decontamination of silt contaminated by radiation from the Fukushima Daiichi nuclear disaster.

  13. Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

    Science.gov (United States)

    Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

    2018-04-01

    To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

  14. Comparison of X-ray, CT and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis

    International Nuclear Information System (INIS)

    Huang Zhenguo; Zhang Xuezhe; Hong Wen; Wang Guochun; Zhou Huiqiong; Lu Xin; Wang Wu

    2011-01-01

    Objective: To compare X-ray, CT, and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis (AS). Methods: Fifty-three patients with clinical suspected early stage of AS underwent X-ray and MRI scan. MR scan sequences for the sacroiliac joints consisted of T 1 -weighted, T 2 -weighted, short time inversion recovery (STIR) and three dimensional balance turbo field echo with water selective excitation (3D-BTFE-WATS) in all patients. In 24 of the patients, fat-saturated contrast-enhanced T 1 -weighted was used. Twenty-five of 53 patients underwent CT scan. The Chi-square test was used to analyse the uniformity of bone erosions detected by X-ray, CT, and MRI. Results: Of the 106 sacroiliac joints in 53 patients, 16 sacroiliac joints with bone erosions were detected by X-ray and 63 sacroiliac joints by MRI. Of the 50 sacroiliac joints in 25 patients, 26 sacroiliac joints with bone erosions were found by CT. With regard to the detection of bone erosions, there was no difference between Cf and MRI (χ 2 =0.16, P>0.05) and there was significant difference between CT and X-ray or MRI and X-ray (χ 2 =14.44 and 17.36, P<0.05). 3D-BTFE-WATS was better than other sequences in detection of bone erosions. Acute inflammatory changes were determined by MRI, which included subchondral bone marrow edema in 32 patients, synovitis in 35 patients, fat depositions in 16 patients, enthesitis in 15 patients, capsulitis in 9 patients, and cartilaginous disruption in 31 patients. Conclusions: MRI can detect acute inflammatory changes that can not display by X-ray and CT. Compared with radiography and CT, MRI is more useful in detection of abnormal sacroiliac joint changes in patients with early stage of AS. (authors)

  15. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part I. Morphology.

    Science.gov (United States)

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography has been applied to the study of titanium parts fabricated by additive manufacturing (AM). The AM method employed here was the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V), as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. Samples were chosen to examine the effect of build direction and complexity of design on the surface morphology and final dimensions of the piece.

  16. X-Ray Microtomography (μCT as a Useful Tool for Visualization and Interpretation of Shear Strength Test Results

    Directory of Open Access Journals (Sweden)

    Stefaniuk Damian

    2015-02-01

    Full Text Available The paper demonstrates the applicability of X-ray microtomography (ìCT to analysis of the results of shear strength examinations of clayey soils. The method of X-ray three-dimensional imaging offers new possibilities in soil testing. The work focuses on a non-destructive method of evaluation of specimen quality used in shear tests and mechanical behavior of soil. The paper presents the results of examination of 4 selected clayey soils. Specimens prepared for the triaxial test have been scanned using ìCT before and after the triaxial compression tests. The shear strength parameters of the soils have been estimated. Changes in soil structure caused by compression and shear failure have been presented as visualizations of the samples tested. This allowed for improved interpretation and evaluation of soil strength parameters and recognition of pre-existing fissures and the exact mode of failure. Basic geometrical parameters have been determined for selected cross-sections of specimens after failure. The test results indicate the utility of the method applied in soil testing.

  17. Dual-energy X-ray micro-CT imaging of hybrid Ni/Al open-cell foam

    International Nuclear Information System (INIS)

    Fíla, T.; Koudelka, P.; Zlámal, P.; Jiroušek, O.; Kumpová, I.; Vavřík, D.; Jung, A.

    2016-01-01

    In this paper, we employ dual-energy X-ray microfocus tomography (DECT) measurement to develop high-resolution finite element (FE) models that can be used for the numerical assessment of the deformation behaviour of hybrid Ni/Al foam subjected to both quasi-static and dynamic compressive loading. Cubic samples of hybrid Ni/Al open-cell foam with an edge length of [15]mm were investigated by the DECT measurement. The material was prepared using AlSi 7 Mg 0.3 aluminium foam with a mean pore size of [0.85]mm, coated with nanocrystalline nickel (crystallite size of approx. [50]nm) to form a surface layer with a theoretical thickness of [0.075]mm. CT imaging was carried out using state-of-the-art DSCT/DECT X-ray scanner developed at Centre of Excellence Telč. The device consists of a modular orthogonal assembly of two tube-detector imaging pairs, with an independent geometry setting and shared rotational stage mounted on a complex 16-axis CNC positioning system to enable unprecedented measurement variability for highly-detailed tomographical measurements. A sample of the metal foam was simultaneously irradiated using an XWT-240-SE reflection type X-ray tube and an XWT-160-TCHR transmission type X-ray tube. An enhanced dual-source sampling strategy was used for data acquisition. X-ray images were taken using XRD1622 large area GOS scintillator flat panel detectors with an active area of [410 × 410]mm and resolution [2048 × 2048]pixels. Tomographic scanning was performed in 1,200 projections with a 0.3 degree angular step to improve the accuracy of the generated models due to the very complex microstructure and high attenuation of the investigated material. Reconstructed data was processed using a dual-energy algorithm, and was used for the development of a 3D model and voxel model of the foam. The selected parameters of the models were compared with nominal parameters of the actual foam and showed good correlation

  18. Characterization of test specimens produced in reduced size for X-ray microtomography (µ-CT tests

    Directory of Open Access Journals (Sweden)

    E. E. BERNARDES

    Full Text Available Abstract The need to use reduced sample sizes, in order to attain improved spatial resolution in (µ-CT tests applied in Portland cement composites, makes researchers perform the fractionation of materials to obtain samples with dimensions compatible with the capacity of the scanning equipment, which might cause alterations in the microstructure under analysis. Therefore, a test specimen (TS with dimensions compatible with the scanning capacity of a microtomography system that operates with an X-ray tube and voltage ranging from 20 to 100 kV was proposed. Axial compression strength tests were made and their total porosity was assessed by an apparent density and solid fraction density ratio, which were obtained by means of mercury and helium pycnometry and µ-CT technique, respectively. The adoption of that TS has shown to be viable for providing a sample with a higher level of representation.

  19. Methane hydrate distribution from prolonged and repeated formation in natural and compacted sand samples: X-ray CT observations

    Energy Technology Data Exchange (ETDEWEB)

    Rees, E.V.L.; Kneafsey, T.J.; Seol, Y.

    2010-07-01

    To study physical properties of methane gas hydrate-bearing sediments, it is necessary to synthesize laboratory samples due to the limited availability of cores from natural deposits. X-ray computed tomography (CT) and other observations have shown gas hydrate to occur in a number of morphologies over a variety of sediment types. To aid in understanding formation and growth patterns of hydrate in sediments, methane hydrate was repeatedly formed in laboratory-packed sand samples and in a natural sediment core from the Mount Elbert Stratigraphic Test Well. CT scanning was performed during hydrate formation and decomposition steps, and periodically while the hydrate samples remained under stable conditions for up to 60 days. The investigation revealed the impact of water saturation on location and morphology of hydrate in both laboratory and natural sediments during repeated hydrate formations. Significant redistribution of hydrate and water in the samples was observed over both the short and long term.

  20. Cine-CT: A new technique in X-ray computed tomography

    International Nuclear Information System (INIS)

    Jaschke, W.; Georgi, M.; Lipton, M.J.; Gould, R.G.

    1988-01-01

    The 'Cine-CT' belongs to a new generation of CT devices permitting not only diagnostics on a morphological basis but also function studies. By means of Cine-CT's electron beam technique, image frequencies of up to 17 images per second and exposure times of 50 msec are possible. (orig.) [de

  1. Effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies

    International Nuclear Information System (INIS)

    Murase, Kenya; Nanjo, Takafumi; Ii, Satoshi; Miyazaki, Shohei; Hirata, Masaaki; Sugawara, Yoshifumi; Kudo, Masayuki; Sasaki, Kousuke; Mochizuki, Teruhito

    2005-01-01

    The purpose of this study was to investigate the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using multi-detector row CT (MDCT). Following the standard CT perfusion study protocol, continuous (cine) scans (1 s/rotation x 60 s) consisting of four 5 mm thick contiguous slices were performed using an MDCT scanner with a tube voltage of 80 kVp and a tube current of 200 mA. We generated the simulated images with tube currents of 50 mA, 100 mA and 150 mA by adding the corresponding noise to the raw scan data of the original image acquired above using a noise simulation tool. From the original and simulated images, we generated the functional images of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in seven patients with cerebrovascular disease, and compared the correlation coefficients (CCs) between the perfusion parameter values obtained from the original and simulated images. The coefficients of variation (CVs) in the white matter were also compared. The CC values deteriorated with decreasing tube current. There was a significant difference between 50 mA and 100 mA for all perfusion parameters. The CV values increased with decreasing tube current. There were significant differences between 50 mA and 100 mA and between 100 mA and 150 mA for CBF. For CBV and MTT, there was also a significant difference between 150 mA and 200 mA. This study will be useful for understanding the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using MDCT, and for selecting the tube current

  2. A field-to-desktop toolchain for X-ray CT densitometry enables tree ring analysis.

    Science.gov (United States)

    De Mil, Tom; Vannoppen, Astrid; Beeckman, Hans; Van Acker, Joris; Van den Bulcke, Jan

    2016-06-01

    Disentangling tree growth requires more than ring width data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree ring analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. Density-based pattern matching is developed and able to detect anomalies in ring series that can be corrected via interactive software. A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree ring analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Roentgen and X-ray computerized tomographic (CT) imaging of cysts in the maxilla

    International Nuclear Information System (INIS)

    Rahmatulla, M

    1999-01-01

    Two cysts in the maxilla were subjected to routine roentgen imaging followed by CT scanning. Roentgen investigation included periapical, occlusal, and panoramic views. CT imaging included axial and coronal scans. While roentgen views were adequate in establishing the diagnosis of the cystic lesions, CT scan was useful in understanding the precise antero-posterior expansion and depth of the lesion. Interpretation of CT scan of cystic jaw lesions without con-ventional radiographs can be misleading. Hence, the CT procedure may be used only as supplement to the routine radiographic investigations particularly in cystic lesions of the jaws. (author)

  4. The influence of mammographic X-ray spectra on absorbed energy distribution in breast: Monte Carlo simulation studies

    International Nuclear Information System (INIS)

    Delis, H.; Spyrou, G.; Tzanakos, G.; Panayiotakis, G.

    2005-01-01

    A mathematical model, based on Monte Carlo simulation, is proposed for deriving absorbed energy and dose distribution in mammography utilizing a mathematical water-like phantom. The model was validated for its accuracy against experimental and published data. The main factor discriminating absorbed energy distribution characteristics among different mammographic techniques was considered the X-ray spectrum. The absorbed energy distribution inside the phantom was investigated via percentage depth dose and isodose curves. The influence of the factors affecting X-ray spectrum (tube voltage, anode material, filter material and thickness) on absorbed energy distribution was examined. The hardness of the beam, due to increase of tube voltage or filtration, was found to be the major factor affecting absorbed energy distribution inside the phantom. In general, Mo and W anode systems demonstrated superior dosimetric characteristics against those of W-Mo or Rh. The model presented can be used for estimating absolute and relative breast dose values and their spatial distributions

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

    Science.gov (United States)

    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.

  6. Automatic quantification of mammary glands on non-contrast x-ray CT by using a novel segmentation approach

    Science.gov (United States)

    Zhou, Xiangrong; Kano, Takuya; Cai, Yunliang; Li, Shuo; Zhou, Xinxin; Hara, Takeshi; Yokoyama, Ryujiro; Fujita, Hiroshi

    2016-03-01

    This paper describes a brand new automatic segmentation method for quantifying volume and density of mammary gland regions on non-contrast CT images. The proposed method uses two processing steps: (1) breast region localization, and (2) breast region decomposition to accomplish a robust mammary gland segmentation task on CT images. The first step detects two minimum bounding boxes of left and right breast regions, respectively, based on a machine-learning approach that adapts to a large variance of the breast appearances on different age levels. The second step divides the whole breast region in each side into mammary gland, fat tissue, and other regions by using spectral clustering technique that focuses on intra-region similarities of each patient and aims to overcome the image variance caused by different scan-parameters. The whole approach is designed as a simple structure with very minimum number of parameters to gain a superior robustness and computational efficiency for real clinical setting. We applied this approach to a dataset of 300 CT scans, which are sampled with the equal number from 30 to 50 years-old-women. Comparing to human annotations, the proposed approach can measure volume and quantify distributions of the CT numbers of mammary gland regions successfully. The experimental results demonstrated that the proposed approach achieves results consistent with manual annotations. Through our proposed framework, an efficient and effective low cost clinical screening scheme may be easily implemented to predict breast cancer risk, especially on those already acquired scans.

  7. Synchrotron x-ray studies of the keel of the short-spined sea urchin lytechinus variegatus: absorption microtomography (microCT) and small beam diffraction mapping

    International Nuclear Information System (INIS)

    Stock, S.R.; Barss, J.; Dahl, T.; Veis, A.; Almer, J.D.; De Carlo, F.

    2003-01-01

    In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 microm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 microm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca(1-x)Mg(x)CO(3) of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.

  8. Multispectral x-ray CT: multivariate statistical analysis for efficient reconstruction

    Science.gov (United States)

    Kheirabadi, Mina; Mustafa, Wail; Lyksborg, Mark; Lund Olsen, Ulrik; Bjorholm Dahl, Anders

    2017-10-01

    Recent developments in multispectral X-ray detectors allow for an efficient identification of materials based on their chemical composition. This has a range of applications including security inspection, which is our motivation. In this paper, we analyze data from a tomographic setup employing the MultiX detector, that records projection data in 128 energy bins covering the range from 20 to 160 keV. Obtaining all information from this data requires reconstructing 128 tomograms, which is computationally expensive. Instead, we propose to reduce the dimensionality of projection data prior to reconstruction and reconstruct from the reduced data. We analyze three linear methods for dimensionality reduction using a dataset with 37 equally-spaced projection angles. Four bottles with different materials are recorded for which we are able to obtain similar discrimination of their content using a very reduced subset of tomograms compared to the 128 tomograms that would otherwise be needed without dimensionality reduction.

  9. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

    Science.gov (United States)

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts.

  10. Theoretical estimation of proton induced X-ray emission yield of the trace elements present in the lung and breast cancer

    International Nuclear Information System (INIS)

    Manjunatha, H.C.; Sowmya, N.

    2013-01-01

    X-rays may be produced following the excitation of target atoms induced by an energetic incident ion beam of protons. Proton induced X-ray emission (PIXE) analysis has been used for many years for the determination of elemental composition of materials using X-rays. Recent interest in the proton induced X-ray emission cross section has arisen due to their importance in the rapidly expanding field of PIXE analysis. One of the steps in the analysis is to fit the measured X-ray spectrum with theoretical spectrum. The theoretical cross section and yields are essential for the evaluation of spectrum. We have theoretically evaluated the PIXE cross sections for trace elements in the lung and breast cancer tissues such as Cl, K, Ca,Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, P, S, Sr, Hg and Pb. The estimated cross section is used in the evaluation of Proton induced X-ray emission spectrum for the given trace elements.We have also evaluated the Proton induced X-ray emission yields in the thin and thick target of the given trace elements. The evaluated Proton induced X-ray emission cross-section, spectrum and yields are graphically represented. Some of these values are also tabulated. Proton induced X-ray emission cross sections and a yield for the given trace elements varies with the energy. PIXE yield depends on a real density and does not on thickness of the target. (author)

  11. Hemorrhagic myocardial infarction after reperfusion detected by X-ray CT

    International Nuclear Information System (INIS)

    Tamura, Tsutomu; Toyoki, Takaaki; Ishikawa, Tomoko

    1992-01-01

    The purpose of this study was to determine whether computed tomography (CT) can detect hemorrhagic infarction occurring after intracoronary thrombolytic therapy (ICT) for acute myocardial infarction (AMI). In an experimental study, 12 dogs underwent 2-4 h of left anterior descending artery (LAD) occlusion, followed by reperfusion, and infusion of contrast material into the LAD. After CT examination, the heart was cut into transverse sections. A good correlation was obtained between the CT-enhanced area and the hemorrhagic area in the sliced heart section (r=0.895, p 0.1). The SPECT defect areas were consistently smaller than the CT enhancement areas. These results indicate that CT can detect hemorrhage into the myocardium after ICT, and that after ICT half the AMI patients showed hemorrhagic infarction. However, hemorrhage did not cause complete deterioration of the myocardium. (author)

  12. In vivo tomographic imaging of lung colonization of tumour in mouse with simultaneous fluorescence and X-ray CT.

    Science.gov (United States)

    Zhang, Bin; Gao, Fuping; Wang, Mengjiao; Cao, Xu; Liu, Fei; Wang, Xin; Luo, Jianwen; Wang, Guangzhi; Bai, Jing

    2014-01-01

    Non-invasive in vivo imaging of diffuse and wide-spread colonization within the lungs, rather than distinct solid primary tumors, is still a challenging work. In this work, a lung colonization mouse model bearing A549 human lung tumor was simultaneously scanned by a dual-modality fluorescence molecular tomography (FMT) and X-ray computed tomography (CT) system in vivo. A two steps method which incorporates CT structural information into the FMT reconstruction procedure is employed to provide concurrent anatomical and functional information. By using the target-specific fluorescence agent, the fluorescence tomographic results show elevated fluorescence intensity deep within the lungs which is colonized with diffuse and wide-spread tumors. The results were confirmed with ex vivo fluorescence reflectance imaging and histological examination of the lung tissues. With FMT reconstruction combined with the CT information, the dual-modality FMT/micro-CT system is expected to offer sensitive and noninvasive imaging of diffuse tumor colonization within the lungs in vivo. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Real-time fusion of coronary CT angiography with x-ray fluoroscopy during chronic total occlusion PCI.

    Science.gov (United States)

    Ghoshhajra, Brian B; Takx, Richard A P; Stone, Luke L; Girard, Erin E; Brilakis, Emmanouil S; Lombardi, William L; Yeh, Robert W; Jaffer, Farouc A

    2017-06-01

    The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with x-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. • Real-time semi-automated fusion of CTA/fluoroscopy is feasible during CTO PCI. • CTA fusion data can be toggled on/off as desired during CTO PCI • Real-time CT calcium and centreline overlay could benefit antegrade dissection/reentry-based CTO PCI.

  14. TH-AB-209-11: Breast Microcalcification Classification Using Spectral X-Ray Coherent Scatter Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ghammraoui, B; M Popescu, L; Badano, A [Food & Drug Administration, Silver Spring, MD (United States)

    2016-06-15

    Purpose: To investigate the ability of Coherent Scatter Computed Tomography (CSCT) to distinguish non-invasively between type I calcifications, consisting of calcium oxalate dihydrate (CO) compounds which are more often associated with benign lesions, and type II calcifications containing hydroxyapatite (HA) which are predominantly associated with malignant tumors. Methods: The coherent scatter cross sections of HA and CO were measured using an energy dispersive x-ray diffractometer. The measured cross sections were introduced into MC-GPU Monte Carlo simulation code for studying the applicability of CSCT to discriminate between the two types of microcalcifications within the whole breast. Simulations were performed on a virtual phantom with inserted HA and CO spots of different sizes and placed in regions of interest having different background compositions. We considered a polychromatic x-ray source and an energy resolving photon counting detector. We applied an algorithm that estimates scatter components in projection space in order to obtain material-specific images of the breast. As material components adipose, glandular, HA and CO were used. The relative contrast of HA and CO components were used for type I and type II microcalcification discrimination. Results: The reconstructed CSCT images showed material-specific component-contrast values, with the highest CO or HA component contrast corresponding generally to the actual CO or HA feature, respectively. The discrimination performance varies with the x-ray intensity, calcification size, and background composition. The results were summarized using receiver operating characteristic (ROC) analysis with the area under the curve (AUC) taken as an overall indicator of discrimination performance and showing high AUC values up to unity. Conclusion: The simulation results obtained for a uniform breast imaging phantom indicate that CSCT has potential to be used as a non-invasive method for discrimination between type

  15. Development of a Method to Assess the Precision Of the z-axis X-ray Beam Collimation in a CT Scanner

    Science.gov (United States)

    Kim, Yon-Min

    2018-05-01

    Generally X-ray equipment specifies the beam collimator for the accuracy measurement as a quality control item, but the computed tomography (CT) scanner with high dose has no collimator accuracy measurement item. If the radiation dose is to be reduced, an important step is to check if the beam precisely collimates at the body part for CT scan. However, few ways are available to assess how precisely the X-ray beam is collimated. In this regard, this paper provides a way to assess the precision of z-axis X-ray beam collimation in a CT scanner. After the image plate cassette had been exposed to the X-ray beam, the exposed width was automatically detected by using a computer program developed by the research team to calculate the difference between the exposed width and the imaged width (at isocenter). The result for the precision of z-axis X-ray beam collimation showed that the exposed width was 3.8 mm and the overexposure was high at 304% when a narrow beam of a 1.25 mm imaged width was used. In this study, the precision of the beam collimation of the CT scanner, which is frequently used for medical services, was measured in a convenient way by using the image plate (IP) cassette.

  16. First-order convex feasibility algorithms for x-ray CT

    DEFF Research Database (Denmark)

    Sidky, Emil Y.; Jørgensen, Jakob Heide; Pan, Xiaochuan

    2013-01-01

    Purpose: Iterative image reconstruction (IIR) algorithms in computed tomography (CT) are based on algorithms for solving a particular optimization problem. Design of the IIR algorithm, therefore, is aided by knowledge of the solution to the optimization problem on which it is based. Often times...... problems. Conclusions: Formulation of convex feasibility problems can provide a useful alternative to unconstrained optimization when designing IIR algorithms for CT. The approach is amenable to recent methods for accelerating first-order algorithms which may be particularly useful for CT with limited...

  17. Large area CMOS active pixel sensor x-ray imager for digital breast tomosynthesis: Analysis, modeling, and characterization.

    Science.gov (United States)

    Zhao, Chumin; Kanicki, Jerzy; Konstantinidis, Anastasios C; Patel, Tushita

    2015-11-01

    Large area x-ray imagers based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been proposed for various medical imaging applications including digital breast tomosynthesis (DBT). The low electronic noise (50-300 e-) of CMOS APS x-ray imagers provides a possible route to shrink the pixel pitch to smaller than 75 μm for microcalcification detection and possible reduction of the DBT mean glandular dose (MGD). In this study, imaging performance of a large area (29×23 cm2) CMOS APS x-ray imager [Dexela 2923 MAM (PerkinElmer, London)] with a pixel pitch of 75 μm was characterized and modeled. The authors developed a cascaded system model for CMOS APS x-ray imagers using both a broadband x-ray radiation and monochromatic synchrotron radiation. The experimental data including modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE) were theoretically described using the proposed cascaded system model with satisfactory consistency to experimental results. Both high full well and low full well (LFW) modes of the Dexela 2923 MAM CMOS APS x-ray imager were characterized and modeled. The cascaded system analysis results were further used to extract the contrast-to-noise ratio (CNR) for microcalcifications with sizes of 165-400 μm at various MGDs. The impact of electronic noise on CNR was also evaluated. The LFW mode shows better DQE at low air kerma (Ka<10 μGy) and should be used for DBT. At current DBT applications, air kerma (Ka∼10 μGy, broadband radiation of 28 kVp), DQE of more than 0.7 and ∼0.3 was achieved using the LFW mode at spatial frequency of 0.5 line pairs per millimeter (lp/mm) and Nyquist frequency ∼6.7 lp/mm, respectively. It is shown that microcalcifications of 165-400 μm in size can be resolved using a MGD range of 0.3-1 mGy, respectively. In comparison to a General Electric GEN2 prototype DBT system (at MGD of 2.5 mGy), an increased CNR (by ∼10) for

  18. Large area CMOS active pixel sensor x-ray imager for digital breast tomosynthesis: Analysis, modeling, and characterization

    International Nuclear Information System (INIS)

    Zhao, Chumin; Kanicki, Jerzy; Konstantinidis, Anastasios C.; Patel, Tushita

    2015-01-01

    Purpose: Large area x-ray imagers based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been proposed for various medical imaging applications including digital breast tomosynthesis (DBT). The low electronic noise (50–300 e − ) of CMOS APS x-ray imagers provides a possible route to shrink the pixel pitch to smaller than 75 μm for microcalcification detection and possible reduction of the DBT mean glandular dose (MGD). Methods: In this study, imaging performance of a large area (29 × 23 cm 2 ) CMOS APS x-ray imager [Dexela 2923 MAM (PerkinElmer, London)] with a pixel pitch of 75 μm was characterized and modeled. The authors developed a cascaded system model for CMOS APS x-ray imagers using both a broadband x-ray radiation and monochromatic synchrotron radiation. The experimental data including modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE) were theoretically described using the proposed cascaded system model with satisfactory consistency to experimental results. Both high full well and low full well (LFW) modes of the Dexela 2923 MAM CMOS APS x-ray imager were characterized and modeled. The cascaded system analysis results were further used to extract the contrast-to-noise ratio (CNR) for microcalcifications with sizes of 165–400 μm at various MGDs. The impact of electronic noise on CNR was also evaluated. Results: The LFW mode shows better DQE at low air kerma (K a < 10 μGy) and should be used for DBT. At current DBT applications, air kerma (K a ∼ 10 μGy, broadband radiation of 28 kVp), DQE of more than 0.7 and ∼0.3 was achieved using the LFW mode at spatial frequency of 0.5 line pairs per millimeter (lp/mm) and Nyquist frequency ∼6.7 lp/mm, respectively. It is shown that microcalcifications of 165–400 μm in size can be resolved using a MGD range of 0.3–1 mGy, respectively. In comparison to a General Electric GEN2 prototype DBT system (at MGD of 2.5 m

  19. Large area CMOS active pixel sensor x-ray imager for digital breast tomosynthesis: Analysis, modeling, and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chumin; Kanicki, Jerzy, E-mail: kanicki@eecs.umich.edu [Solid-State Electronics Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Konstantinidis, Anastasios C. [Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom and Diagnostic Radiology and Radiation Protection, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester M20 4BX (United Kingdom); Patel, Tushita [Department of Physics, University of Virginia, Charlottesville, Virginia 22908 (United States)

    2015-11-15

    Purpose: Large area x-ray imagers based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been proposed for various medical imaging applications including digital breast tomosynthesis (DBT). The low electronic noise (50–300 e{sup −}) of CMOS APS x-ray imagers provides a possible route to shrink the pixel pitch to smaller than 75 μm for microcalcification detection and possible reduction of the DBT mean glandular dose (MGD). Methods: In this study, imaging performance of a large area (29 × 23 cm{sup 2}) CMOS APS x-ray imager [Dexela 2923 MAM (PerkinElmer, London)] with a pixel pitch of 75 μm was characterized and modeled. The authors developed a cascaded system model for CMOS APS x-ray imagers using both a broadband x-ray radiation and monochromatic synchrotron radiation. The experimental data including modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE) were theoretically described using the proposed cascaded system model with satisfactory consistency to experimental results. Both high full well and low full well (LFW) modes of the Dexela 2923 MAM CMOS APS x-ray imager were characterized and modeled. The cascaded system analysis results were further used to extract the contrast-to-noise ratio (CNR) for microcalcifications with sizes of 165–400 μm at various MGDs. The impact of electronic noise on CNR was also evaluated. Results: The LFW mode shows better DQE at low air kerma (K{sub a} < 10 μGy) and should be used for DBT. At current DBT applications, air kerma (K{sub a} ∼ 10 μGy, broadband radiation of 28 kVp), DQE of more than 0.7 and ∼0.3 was achieved using the LFW mode at spatial frequency of 0.5 line pairs per millimeter (lp/mm) and Nyquist frequency ∼6.7 lp/mm, respectively. It is shown that microcalcifications of 165–400 μm in size can be resolved using a MGD range of 0.3–1 mGy, respectively. In comparison to a General Electric GEN2 prototype DBT system (at

  20. Cortical region of interest definition on SPECT brain images using X-ray CT registration

    Energy Technology Data Exchange (ETDEWEB)

    Tzourio, N.; Sutton, D. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot); Joliot, M. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot INSERM, Orsay (France)); Mazoyer, B.M. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot Antenne d' Information Medicale, C.H.U. Bichat, Paris (France)); Charlot, V. (Hopital Louis Mourier, Colombes (France). Service de Psychiatrie); Salamon, G. (CHU La Timone, Marseille (France). Service de Neuroradiologie)

    1992-11-01

    We present a method for brain single photon emission computed tomography (SPECT) analysis based on individual registration of anatomical (CT) and functional ([sup 133]Xe regional cerebral blood flow) images and on the definition of three-dimensional functional regions of interest. Registration of CT and SPECT is performed through adjustment of CT-defined cortex limits to the SPECT image. Regions are defined by sectioning a cortical ribbon on the CT images, copied over the SPECT images and pooled through slices to give 3D cortical regions of interest. The proposed method shows good intra- and interobserver reproducibility (regional intraclass correlation coefficient [approx equal]0.98), and good accuracy in terms of repositioning ([approx equal]3.5 mm) as compared to the SPECT image resolution (14 mm). The method should be particularly useful for analysing SPECT studies when variations in brain anatomy (normal or abnormal) must be accounted for. (orig.).

  1. Assessment of Brain absorbed X-ray dose during CT- Scan using ImPACT software in Tehran Univeristy hospitals

    Directory of Open Access Journals (Sweden)

    Khalilpour M

    2009-07-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 st1":*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: CT scan was first introduced into clinical practice in 1972, and since then has grown into one of the predominant diagnostic procedures. In 1998, the UK National Radiological Protection Board reported that 20% of the national collective dose from medical X-ray examinations derived from CT-scans, although it represented only 2% of all X- ray examinations the aim of this study was to determine the X-ray dosage received by patients in brain CT scan."n"n Methods: In this work, we have estimated patient dose arising from CT examination of brain in five hospitals in Tehran. Organ and effective doses were estimated for 150 patients who underwent CT examination of brain. "ImPACT" version 0.99v was used to estimate organ and effective dose. Brain examinations were performed with fixed Kvp, mAs and T (slice thickness for each scanner. "n"n Results: Patients, who were scanned by CT of emam Khomeini center (Toshiba Xvision /EX Scanner, received maximum organ dose (brain and minimum organ dose was delivered to patients who were scanned by CT of amir alam center (Toshiba Xvision /EX Scanner. Maximum effective dose was 1.7 mSv acquired in this study for emam Khomeini haspital, smaller than

  2. Quantitation of pulmonary nodule's border structure by means of Fourier transform by using chest X-ray CT images

    International Nuclear Information System (INIS)

    Shikata, Hidenori; Masuyama, Hiroshi; Kido, Shoji

    1998-01-01

    In order to evaluate quantitatively the border structure of pulmonary nodules by using chest X-ray CT images, we investigated whether the sum of high-frequency elements of the power spectrum in a Fourier-transformed nodule's contour line becomes a valuable measure of the border structure of pulmonary nodules. We expect that this measure clearly reflects the radiologic characteristics of a nodule, that is, the contour line is clear or unclear in benign or malignant nodules, respectively. We evaluated and analyzed images statistically for 31 patients (15 benign, 16 malignant), and we were able to recognize a measurable difference between the benign and malignant cases. We conclude that we can evaluate the border structure of a nodule by our proposed measure, and that this measure is valuable for quantitative differential diagnosis. (author)

  3. Standard practice for digital imaging and communication in nondestructive evaluation (DICONDE) for X-ray computed tomography (CT) test methods

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice facilitates the interoperability of X-ray computed tomography (CT) imaging equipment by specifying image data transfer and archival storage methods in commonly accepted terms. This document is intended to be used in conjunction with Practice E2339 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). Practice E2339 defines an industrial adaptation of the NEMA Standards Publication titled Digital Imaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, storage and archival storage. The goal of Practice E2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE test results on any system conforming to the DICONDE standard. Toward that end, Practice E2339 provides a data dictionary and a set of information modules that are applicable to all NDE modalities. This practice supplements Practice E2339 by providing information object definitio...

  4. Dual resolution cone beam breast CT: A feasibility study

    International Nuclear Information System (INIS)

    Chen Lingyun; Shen Youtao; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Ge Shuaiping; Liu Xinming; Wang Tianpeng; Yang, Wei T.; Whitman, Gary J.; Shaw, Chris C.

    2009-01-01

    Purpose: In this study, the authors investigated the feasibility of a dual resolution volume-of-interest (VOI) cone beam breast CT technique and compared two implementation approaches in terms of dose saving and scatter reduction. Methods: With this technique, a lead VOI mask with an opening is inserted between the x-ray source and the breast to deliver x-ray exposure to the VOI while blocking x rays outside the VOI. A CCD detector is used to collect the high resolution projection data of the VOI. Low resolution cone beam CT (CBCT) images of the entire breast, acquired with a flat panel (FP) detector, were used to calculate the projection data outside the VOI with the ray-tracing reprojection method. The Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the dual resolution 3D images. Breast phantoms with 180 μm and smaller microcalcifications (MCs) were imaged with both FP and FP-CCD dual resolution CBCT systems, respectively. Two approaches of implementing the dual resolution technique, breast-centered approach and VOI-centered approach, were investigated and evaluated for dose saving and scatter reduction with Monte Carlo simulation using a GEANT4 package. Results: The results showed that the breast-centered approach saved more breast absorbed dose than did VOI-centered approach with similar scatter reduction. The MCs in fatty breast phantom, which were invisible with FP CBCT scan, became visible with the FP-CCD dual resolution CBCT scan. Conclusions: These results indicate potential improvement of the image quality inside the VOI with reduced breast dose both inside and outside the VOI.

  5. Instruments for radiation measurement in life sciences (5). 'Development of imaging Technology in life sciences'. 5. X-ray CT for laboratory animals

    International Nuclear Information System (INIS)

    Tamegai, Toshiaki

    2007-01-01

    X-ray computed tomography, commercialized by EMI Co., UK, in 1973 and now used world-widely, is used not only for medical use but also for laboratory animals such as rats and mice to measure bone density and to obtain fine structures of bones. This paper introduces X-ray CT apparatus specifically designed for laboratory animals. Besides general explanations about the method, followed by emphasis on important performance of the measuring system, the paper explains technical aspects for obtaining the CT imaging scan procedure thus showing several photographs as example and introducing some clinical applications. (S. Ohno)

  6. Real-time fusion of coronary CT angiography with X-ray fluoroscopy during chronic total occlusion PCI

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshhajra, Brian B.; Takx, Richard A.P. [Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Department of Radiology and Division of Cardiology, Boston, MA (United States); Stone, Luke L.; Yeh, Robert W.; Jaffer, Farouc A. [Harvard Medical School, Cardiac Cathetrization Laboratory, Cardiology Division, Massachusetts General Hospital, Boston, MA (United States); Girard, Erin E. [Siemens Healthcare, Princeton, NJ (United States); Brilakis, Emmanouil S. [Cardiology Division, Dallas VA Medical Center and UT Southwestern Medical Center, Dallas, TX (United States); Lombardi, William L. [University of Washington, Cardiology Division, Seattle, WA (United States)

    2017-06-15

    The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with X-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. (orig.)

  7. Three-dimensional analysis of rodent paranasal sinus cavities from X-ray computed tomography (CT) scans

    Science.gov (United States)

    Phillips, Jonathan E.; Ji, Lunan; Rivelli, Maria A.; Chapman, Richard W.; Corboz, Michel R.

    2009-01-01

    Continuous isometric microfocal X-ray computed tomography (CT) scans were acquired from an AKR/J mouse, Brown-Norway rat, and Hartley guinea pig. The anatomy and volume of the paranasal sinus cavities were defined from 2-dimensional (2-D) and 3-dimensional (3-D) CT images. Realistic 3-D images were reconstructed and used to determine the anterior maxillary, posterior maxillary, and ethmoid sinus cavity airspace volumes (mouse: 0.6, 0.7, and 0.7 mm3, rat: 8.6, 7.7, and 7.0 mm3, guinea pig: 63.5, 46.6 mm3, and no ethmoid cavity, respectively). The mouse paranasal sinus cavities are similar to the corresponding rat cavities, with a reduction in size, while the corresponding maxillary sinus cavities in the guinea pig are different in size, location, and architecture. Also, the ethmoid sinus cavity is connected by a common drainage pathway to the posterior maxillary sinus in mouse and rat while a similar ethmoid sinus was not present in the guinea pig. We conclude that paranasal sinus cavity airspace opacity (2-D) or volume (3-D) determined by micro-CT scanning may be used to conduct longitudinal studies on the patency of the maxillary sinus cavities of rodents. This represents a potentially useful endpoint for developing and testing drugs in a small animal model of sinusitis. PMID:19794893

  8. A new method for x-ray scatter correction: first assessment on a cone-beam CT experimental setup

    International Nuclear Information System (INIS)

    Rinkel, J; Gerfault, L; Esteve, F; Dinten, J-M

    2007-01-01

    Cone-beam computed tomography (CBCT) enables three-dimensional imaging with isotropic resolution and a shorter acquisition time compared to a helical CT scanner. Because a larger object volume is exposed for each projection, scatter levels are much higher than in collimated fan-beam systems, resulting in cupping artifacts, streaks and quantification inaccuracies. In this paper, a general method to correct for scatter in CBCT, without supplementary on-line acquisition, is presented. This method is based on scatter calibration through off-line acquisition combined with on-line analytical transformation based on physical equations, to adapt calibration to the object observed. The method was tested on a PMMA phantom and on an anthropomorphic thorax phantom. The results were validated by comparison to simulation for the PMMA phantom and by comparison to scans obtained on a commercial multi-slice CT scanner for the thorax phantom. Finally, the improvements achieved with the new method were compared to those obtained using a standard beam-stop method. The new method provided results that closely agreed with the simulation and with the conventional CT scanner, eliminating cupping artifacts and significantly improving quantification. Compared to the beam-stop method, lower x-ray doses and shorter acquisition times were needed, both divided by a factor of 9 for the same scatter estimation accuracy

  9. An experimental study on the influence of scatter and beam hardening in x-ray CT for dimensional metrology

    International Nuclear Information System (INIS)

    Lifton, J J; McBride, J W; Malcolm, A A

    2016-01-01

    Scattered radiation and beam hardening introduce artefacts that degrade the quality of data in x-ray computed tomography (CT). It is unclear how these artefacts influence dimensional measurements evaluated from CT data. Understanding and quantifying the influence of these artefacts on dimensional measurements is required to evaluate the uncertainty of CT-based dimensional measurements. In this work the influence of scatter and beam hardening on dimensional measurements is investigated using the beam stop array scatter correction method and spectrum pre-filtration for the measurement of an object with internal and external cylindrical dimensional features. Scatter and beam hardening are found to influence dimensional measurements when evaluated using the ISO50 surface determination method. On the other hand, a gradient-based surface determination method is found to be robust to the influence of artefacts and leads to more accurate dimensional measurements than those evaluated using the ISO50 method. In addition to these observations the GUM method for evaluating standard measurement uncertainties is applied and the standard measurement uncertainty due to scatter and beam hardening is estimated. (paper)

  10. Chest tube placement in thorax trauma - comparison chest X-ray and computed tomography (CT)

    International Nuclear Information System (INIS)

    Heim, P.; Maas, R.; Buecheler, E.; Tesch, C.

    1998-01-01

    Estimation of chest tube placement in patients with thoracic trauma with regard to chest tube malposition in chest radiography in the supine position compared to additional computed tomography of the thorax. Material and methods: Apart from compulsory chest radiography after one or multiple chest tube insertions, 31 severely injured patients with thoracic trauma underwent a CT scan of the thorax. These 31 patients with 40 chest tubes constituted the basis for the present analysis. Results: In chest radiography in the supine position there were no chest tube malpositions (n=40); In the CT scans 25 correct positions, 7 pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions of the chest tubes were seen. Conclusion: In case of lasting clinical problems and questionable function of the chest tube, chest radiography should be supplemented by a CT scan of the thorax in order to estimate the position of the chest tube. (orig.) [de

  11. Imaging study of pancreatic ductal adenocarcinomas in Syrian hamsters using X-ray micro-computed tomography (CT)

    International Nuclear Information System (INIS)

    Kitahashi, Tsukasa; Mutoh, Michihiro; Tsurusaki, Masakatsu

    2010-01-01

    X-ray computed tomography (CT) has been used for diagnoses of human pancreatic cancer. Although micro-CT is a useful approach to evaluate macromorphology of organs/tissue also in animal models, reports on pancreatic tumors are limited. In this study, the utility of micro-CT was assessed in characterizing chemically induced pancreatic tumors in Syrian hamsters. Hamsters treated with or without N-nitrosobis(2-oxopropyl)amine (BOP) were injected with the antispasmodic agent, scopolamine butylbromide, and contrast agents, 5 or 10 mL/kg body weight of iopamidol or Fenestra VC at 18-38 weeks, then examined by micro-CT scanning with a respiratory gating system. Both peristaltic and respiratory movements were substantially suppressed by the combination of scopolamine butylbromide treatment and the respiratory gating system, resulting in improvements of image qualities. Iopamidol clearly visualized the pancreatic parenchyma and contrasted the margins among the pancreas and other abdominal organs/tissue. Meanwhile Fenestra VC predominantly contrasted abdominal vascular systems, but the margins among pancreas and other organs/tissue remained obscure. Six pancreatic tumors of 4-13 mm in diameter were detected in four of 15 animals, but not the five tumors of 1-4 mm in diameter. The inner tumor images were heterogeneously or uniformly visualized by iopamidol and Fenestra VC. Overall, iopamidol could clearly contrast between pancreatic parenchyma and the tumors as compared with Fenestra VC. All tumors confirmed were histopathologically diagnosed as pancreatic ductal adenocarcinomas. Thus, micro-CT could be useful to evaluate the carcinogenic processes and preventive methods of pancreatic cancer in hamsters and to assess the novel contrast agents for detection of small pancreatic cancer in humans. (author)

  12. Explaining Air and Water Transport in Undisturbed Soils By X-Ray CT Derived Macroporosity and CT- Number-Derived Matrix Density

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    The characterization of soil pore space geometry is important to predict the fluxes of air, water and solutes through soil and understand soil hydrogeochemical functions. X-ray computed tomography (CT) -derived parameters were evaluated as predictors of water, air and solute transport through soil....... Forty five soil columns (20-cm × 20-cm) were collected at an agricultural field in Estrup, Denmark. The soil columns were scanned in a medical CT-scanner. Subsequent to this, non-reactive tracer leaching experiments were performed in the laboratory together with measurements of air permeability (Ka...... is considered a robust indicator of preferential flow. Meanwhile, CT-derived limiting macro-porosity was the best predictor for Ka and log10Ksat. A best subsets regression analysis was performed combining macroporosity, limiting macroporosity and CTmatrix. The predictions of water and air flow improved using...

  13. Quantification of C2 cervical spine rotatory fixation by X-ray, MRI and CT

    Energy Technology Data Exchange (ETDEWEB)

    Gradl, Georg [Chirurgische Klinik und Poliklinik der Universitaet Rostock, Abteilung Unfall- und Wiederherstellungschirurgie, Rostock (Germany); Maier-Bosse, Tamara; Staebler, Axel [Institut fuer Radiologische Diagnostik der Universitaet Muenchen, Klinikum Grobetahadern, Munich (Germany); Penning, Randolph [Institut fuer Rechtsmedizin der Universitaet Muenchen, Munich (Germany)

    2005-02-01

    Atlanto-axial rotatory displacement is known to be a cause of childhood torticollis and may as well be responsible for chronic neck pain after rear-end automobile collisions. The objective was to determine whether quantification of C2 malrotation is possible by plain radiographs in comparison to CT as the golden standard. MR imaging was evaluated as to whether it was of equal value in the detection of bony landmarks. C2 vertebra of five human cadaveric cervical spine specimens, ligamentously intact, were rotated using a Steinmann pin in steps of 5 up to 15 right and 15 left. Plain radiographs, CT and MRI images were taken in each rotational step. Data were analyzed for quantification of C2 rotation by three independent examiners. A rotation of 5 led to a spinous process deviation (SPD) from the midline of 3 mm as measured on an a.p. plain radiograph. A coefficient of rotation was calculated (1.62 mm{sup -1}). Data analyzed by three examiners revealed a small coefficient of variation (0.03). MRI and CT measurements showed comparable results for the quantification of rotation; however, in both techniques the 15 rotation was underestimated. Quantification of upper cervical spine malrotation was possible on plain radiographs using the SPD and a rotation coefficient. MRI and CT were equally successful in the assessment of C2 malrotation. (orig.)

  14. Data Analysis of Medical Images: CT, MRI, Phase Contrast X-ray and PET

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark

    of micro-CT images followed by a statistical analysis of homogeneity, contrast, degradation, and other qualities. By combining knowledge from the different professions in the project, a new application for one of the developed gels - in-vivo dosimetry in radiotherapy - has been studied. Analysis...

  15. Quantification of C2 cervical spine rotatory fixation by X-ray, MRI and CT

    International Nuclear Information System (INIS)

    Gradl, Georg; Maier-Bosse, Tamara; Staebler, Axel; Penning, Randolph

    2005-01-01

    Atlanto-axial rotatory displacement is known to be a cause of childhood torticollis and may as well be responsible for chronic neck pain after rear-end automobile collisions. The objective was to determine whether quantification of C2 malrotation is possible by plain radiographs in comparison to CT as the golden standard. MR imaging was evaluated as to whether it was of equal value in the detection of bony landmarks. C2 vertebra of five human cadaveric cervical spine specimens, ligamentously intact, were rotated using a Steinmann pin in steps of 5 up to 15 right and 15 left. Plain radiographs, CT and MRI images were taken in each rotational step. Data were analyzed for quantification of C2 rotation by three independent examiners. A rotation of 5 led to a spinous process deviation (SPD) from the midline of 3 mm as measured on an a.p. plain radiograph. A coefficient of rotation was calculated (1.62 mm -1 ). Data analyzed by three examiners revealed a small coefficient of variation (0.03). MRI and CT measurements showed comparable results for the quantification of rotation; however, in both techniques the 15 rotation was underestimated. Quantification of upper cervical spine malrotation was possible on plain radiographs using the SPD and a rotation coefficient. MRI and CT were equally successful in the assessment of C2 malrotation. (orig.)

  16. Development of an MRI/x-ray/ultrasound compatible marker for pre-operative breast tumour localization

    International Nuclear Information System (INIS)

    Li Yangmei; Wang, Jianxiong; Holloway, Claire; Plewes, Donald B

    2005-01-01

    This paper describes an in vitro investigation into the composition, structure and development of an magnetic resonance imaging (MRI), ultrasound (US) and x-ray imaging compatible marker for breast tumour localization. The marker is composed of 0.4-0.6 mm glass and iron-containing aluminium microspheres suspended in a gelatin matrix. The final form of the marker is a cylindrical shape 7 mm long with 2.05 mm diameter to facilitate delivery through a 12 gauge biopsy needle. To get optimal reflectivity for the US contrast, the glass microsphere concentration was found to be 40% by weight. US contrast is independent of marker orientation and the cylindrical shape made its US signal appearance distinctive thus ensuring confident identification. To control the MRI contrast, iron content was varied to generate a clear and local susceptibility signal void to reflect the marker position. Optimal iron content was found to be 52 μg iron which produced a clear signal void in spoiled gradient recalled MR images. The appearance of the susceptibility artefact is determined by the marker's shape, orientation and echo time. The final marker produces a dark artefact in MRI while appears as a clear hyperintense structure with acoustic shadowing in US images. The x-ray image showed the marker as a radio-opaque structure. This in vitro study demonstrates that the marker forms an alternative to traditional wire localization currently used for breast surgical procedures and creates new opportunities for US guided surgical procedures

  17. Effects of x-ray and CT image enhancements on the robustness and accuracy of a rigid 3D/2D image registration

    International Nuclear Information System (INIS)

    Kim, Jinkoo; Yin Fangfang; Zhao Yang; Kim, Jae Ho

    2005-01-01

    A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration

  18. Body packers on your examination table: How helpful are plain x-ray images? A definitive low-dose CT protocol as a diagnosis tool for body packers.

    Science.gov (United States)

    Schulz, B; Grossbach, A; Gruber-Rouh, T; Zangos, S; Vogl, Th J; Eichler, K

    2014-12-01

    To analyze the clinical value and radiation dose of plain x-rays and CT in examining patients suspected of ingesting drug-filled packets. Thirty-eight patients with suspected internal concealment of drug-filled packets who were examined with plain x-rays or CT or both were included in the study. CT studies were performed using low-dose and standard-dose techniques. All radiographic images were analysed by two radiologists regarding identification of the packets and estimating the effective radiation dose from standard- and low-dose CT versus conventional x-ray examinations. Descriptive calculations were made regarding the number and density of packs and radiation dosage. The diagnostic performance of both radiologists with standard- and low-dose CT was calculated by analysing differences in the mean number of packs found. Thirty-one patients were positively identified as body packers with an average of 13 packs (min: n = 1, max: n = 58, total: n = 390); seven patients were not concealing drug packets. X-ray images were taken of 24 patients prior to CT, thus allowing a direct comparison between the two methods. The correct diagnosis was made in 42%, in 33% the radiologists were uncertain, and in 25% of drug packets were either not or wrongly identified. X-ray imaging had a positive predictive value of 20% with a negative predictive value of 81%. A total of 55 CT examinations were performed on all patients with a mean effective dose of 2 mSv (low dose) versus 9.3 mSv (standard dose). The visibility of packets on low-dose CT images compared to high-dose CT was not reduced: the radiologists identified 385 and 381 of the packets, respectively, with no difference regarding the examination technique (p = 0.24 and p = 0.253, respectively). The radiodensity of all drug-filled packets at CT ranged from 26-292 HU (mean 181.2 HU). X-ray imaging of supposed body packers leads to a significant risk of diagnostic errors and additional need for CT. Instead, a single abdominal low

  19. X-ray phase-contrast CT imaging of the acupoints based on synchrotron radiation

    International Nuclear Information System (INIS)

    Chenglin, Liu; Xiaohua, Wang; Hua, Xu; Fang, Liu; Ruishan, Dang; Dongming, Zhang; Xinyi, Zhang; Honglan, Xie; Tiqiao, Xiao

    2014-01-01

    In this paper, the morphology of the acupuncture point (abbreviated as acupoint hereafter) or tissue where there were no acupoints in the fractional rabbit hind limb was studied by in-line phase contrast CT imaging (PCI-CT) methods based on synchrotron radiation. The density of micro-vessels was calculated for tissues with acupoints or without acupoints. Differences between acupoints area and non-acupoint areas determined by the density of the micro-vessels propose a strong evidence of the existence of acupoints. Our results showed that there were two significantly higher densities of the micro-vessels, where two acupoints were located, respectively. In addition, there were large numbers of involutedly microvascular structure in the acupoint areas. Nevertheless, in non-acupoints area, the microvascular structure was relatively simple and flat

  20. X-ray phase-contrast CT imaging of the acupoints based on synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chenglin, Liu, E-mail: lclyctc@163.com [Physics Department of Yancheng Teachers’ College, Yancheng 224051 (China); Xiaohua, Wang; Hua, Xu [Physics Department of Yancheng Teachers’ College, Yancheng 224051 (China); Fang, Liu; Ruishan, Dang [Anatomy Department of Second Military Medical University, Shanghai 200433 (China); Dongming, Zhang; Xinyi, Zhang [Synchrotron Radiation Research Center of Fudan University, Shanghai 200433 (China); Honglan, Xie; Tiqiao, Xiao [Shanghai Synchrotron Radiation Facility of Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China)

    2014-10-15

    In this paper, the morphology of the acupuncture point (abbreviated as acupoint hereafter) or tissue where there were no acupoints in the fractional rabbit hind limb was studied by in-line phase contrast CT imaging (PCI-CT) methods based on synchrotron radiation. The density of micro-vessels was calculated for tissues with acupoints or without acupoints. Differences between acupoints area and non-acupoint areas determined by the density of the micro-vessels propose a strong evidence of the existence of acupoints. Our results showed that there were two significantly higher densities of the micro-vessels, where two acupoints were located, respectively. In addition, there were large numbers of involutedly microvascular structure in the acupoint areas. Nevertheless, in non-acupoints area, the microvascular structure was relatively simple and flat.

  1. Whole body X-ray CT scanner SCT-3000T series

    International Nuclear Information System (INIS)

    Saida, Teruhiko; Takemura, Kunihiko; Suzuki, Satoru; Sato, Yukio; Kawamoto, Yasushi; Goto, Mitsuhiro; Mishina, Yukio

    1989-01-01

    The whole body CT scanner, SCT-3000T series which improve the patient through-put and the diagnostic capability, has been developed. In the SCT-3000T series CT scanners, the great reduction of the reconstruction time and the scan cycle time has been achieved by developing the special purpose hardwares for image reconstruction such as the fast front end processor, the intelligent buffer memory. In case of the SCT-3000TX routine conditions of operation, including 3.0 sec scan, table increment, image reconstruction and image filing, the scan cycle time is about 9 seconds which is the shortest value among the competitive models. Furthermore, the higher diagnostic capability has been provided with the system, by adopting the 1024 x 1024 display matrices, and by developing the diagnostic softwares such as 3-D display program, arbitrary curved plane MPR program, r-CBF measurement program and etc. (author)

  2. Automated segmentation of murine lung tumors in x-ray micro-CT images

    Science.gov (United States)

    Swee, Joshua K. Y.; Sheridan, Clare; de Bruin, Elza; Downward, Julian; Lassailly, Francois; Pizarro, Luis

    2014-03-01

    Recent years have seen micro-CT emerge as a means of providing imaging analysis in pre-clinical study, with in-vivo micro-CT having been shown to be particularly applicable to the examination of murine lung tumors. Despite this, existing studies have involved substantial human intervention during the image analysis process, with the use of fully-automated aids found to be almost non-existent. We present a new approach to automate the segmentation of murine lung tumors designed specifically for in-vivo micro-CT-based pre-clinical lung cancer studies that addresses the specific requirements of such study, as well as the limitations human-centric segmentation approaches experience when applied to such micro-CT data. Our approach consists of three distinct stages, and begins by utilizing edge enhancing and vessel enhancing non-linear anisotropic diffusion filters to extract anatomy masks (lung/vessel structure) in a pre-processing stage. Initial candidate detection is then performed through ROI reduction utilizing obtained masks and a two-step automated segmentation approach that aims to extract all disconnected objects within the ROI, and consists of Otsu thresholding, mathematical morphology and marker-driven watershed. False positive reduction is finally performed on initial candidates through random-forest-driven classification using the shape, intensity, and spatial features of candidates. We provide validation of our approach using data from an associated lung cancer study, showing favorable results both in terms of detection (sensitivity=86%, specificity=89%) and structural recovery (Dice Similarity=0.88) when compared against manual specialist annotation.

  3. The development of an x-ray computerized tomography (CT) experimental system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, G N; Kijek, M M; Millar, J J [Royal Melbourne Inst. of Tech., VIC (Australia)

    1994-12-31

    This paper describes a prototype experimental CT system that has been recently developed at Applied Physics, RMIT/ Physics, La Trobe UCNV. The system incorporates the scanning mode of the first generation CAT-scanner and is designed to perform the scanning of small objects. A microcomputer is used to control the scanning motions and data collection. The performance of the system was examined by scanning a ball-point pen. 8 refs., 4 figs.

  4. The development of an x-ray computerized tomography (CT) experimental system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, G.N.; Kijek, M.M.; Millar, J.J. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    This paper describes a prototype experimental CT system that has been recently developed at Applied Physics, RMIT/ Physics, La Trobe UCNV. The system incorporates the scanning mode of the first generation CAT-scanner and is designed to perform the scanning of small objects. A microcomputer is used to control the scanning motions and data collection. The performance of the system was examined by scanning a ball-point pen. 8 refs., 4 figs.

  5. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    International Nuclear Information System (INIS)

    Wang, B; Pan, B; Tao, R; Lubineau, G

    2017-01-01

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging, the heat generated by the x-ray tube changes the imaging geometry of x-ray scanner, and further introduces noticeable errors in DVC measurements. In this work, to provide practical guidance high-accuracy DVC measurement, the errors in displacements and strains measured by DVC due to the self-heating for effect of a commercially available x-ray scanner were experimentally investigated. The errors were characterized by performing simple rescan tests with different scan durations. The results indicate that the maximum strain errors associated with the self-heating of the x-ray scanner exceed 400 µε . Possible approaches for minimizing or correcting these displacement and strain errors are discussed. Finally, a series of translation and uniaxial compression tests were performed, in which strain errors were detected and then removed using pre-established artificial dilatational strain-time curve. Experimental results demonstrate the efficacy and accuracy of the proposed strain error correction approach. (paper)

  6. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    KAUST Repository

    Wang, B

    2017-02-15

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging, the heat generated by the x-ray tube changes the imaging geometry of x-ray scanner, and further introduces noticeable errors in DVC measurements. In this work, to provide practical guidance high-accuracy DVC measurement, the errors in displacements and strains measured by DVC due to the self-heating for effect of a commercially available x-ray scanner were experimentally investigated. The errors were characterized by performing simple rescan tests with different scan durations. The results indicate that the maximum strain errors associated with the self-heating of the x-ray scanner exceed 400 µε. Possible approaches for minimizing or correcting these displacement and strain errors are discussed. Finally, a series of translation and uniaxial compression tests were performed, in which strain errors were detected and then removed using pre-established artificial dilatational strain-time curve. Experimental results demonstrate the efficacy and accuracy of the proposed strain error correction approach.

  7. Evaluation of Microstructure and Transport Properties of Deteriorated Cementitious Materials from Their X-ray Computed Tomography (CT) Images.

    Science.gov (United States)

    Promentilla, Michael Angelo B; Cortez, Shermaine M; Papel, Regina Anne Dc; Tablada, Bernadette M; Sugiyama, Takafumi

    2016-05-19

    Pore structure, tortuosity and permeability are considered key properties of porous materials such as cement pastes to understand their long-term durability performance. Three-dimensional image analysis techniques were used in this study to quantify pore size, effective porosity, tortuosity, and permeability from the X-ray computed tomography (CT) images of deteriorated pastes that were subjected to accelerated leaching test. X-ray microtomography is a noninvasive three-dimensional (3D) imaging technique which has been recently gaining attention for material characterization. Coupled with 3D image analysis, the digitized pore can be extracted and computational simulation can be applied to the pore network to measure relevant microstructure and transport properties. At a spatial resolution of 0.50 μm, the effective porosity (ψ e ) was found to be in the range of 0.04 to 0.33. The characteristic pore size ( d ) using a local thickness algorithm was found to be in the range of 3 to 7 μm. The geometric tortuosity (τ g ) based on a 3D random walk simulation in the percolating pore space was found to be in the range of 2.00 to 7.45. The water permeability values ( K ) using US NIST Permeability Stokes Solver range from an order of magnitudes of 10 -14 to 10 -17 m². Indications suggest that as effective porosity increases, the geometric tortuosity increases and the permeability decreases. Correlation among these microstructure and transport parameters is also presented in this study.

  8. Comparison of orthogonal kilovolt X-ray images and cone-beam CT matching results in setup error assessment and correction for EB-PBI during free breathing

    International Nuclear Information System (INIS)

    Wang Wei; Li Jianbin; Hu Hongguang; Ma Zhifang; Xu Min; Fan Tingyong; Shao Qian; Ding Yun

    2014-01-01

    Objective: To compare the differences in setup error (SE) assessment and correction between the orthogonal kilovolt X-ray images and CBCT in EB-PBI patients during free breathing. Methods: Nineteen patients after breast conserving surgery EB-PBI were recruited. Interfraction SE was acquired using orthogonal kilovolt X-ray setup images and CBCT, after on-line setup correction,calculate the residual error and compare the SE, residual error and setup margin (SM) quantified for orthogonal kilovolt X-ray images and CBCT. Wilcoxon sign-rank test was used to evaluate the differences. Results: The CBCT based SE (systematic error, ∑) was smaller than the orthogonal kilovolt X-ray images based ∑ in AP direction (-1.2 mm vs 2.00 mm; P=0.005), and there was no statistically significant differences for three dimensional directions in random error (σ) (P=0.948, 0.376, 0.314). After on-line setup correction,CBCT decreases setup residual error than the orthogonal kilovolt X-ray images in AP direction (Σ: -0.20 mm vs 0.50 mm, P=0.008; σ: 0.45 mm vs 1.34 mm, P=0.002). And also the CBCT based SM was smaller than orthogonal kilovolt X-ray images based SM in AP direction (Σ: -1.39 mm vs 5.57 mm, P=0.003; σ: 0.00 mm vs 3.2 mm, P=0.003). Conclusions: Compared with kilovolt X-ray images, CBCT underestimate the setup error in the AP direction, but decreases setup residual error significantly.An image-guided radiotherapy and setup error assessment using kilovolt X-ray images for EB-PBI plans was feasible. (authors)

  9. Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells.

    Science.gov (United States)

    Arifin, Dian R; Manek, Sameer; Call, Emma; Arepally, Aravind; Bulte, Jeff W M

    2012-06-01

    Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. The oblique view for spondylolysis in the growing period. X-ray projection angle to spondylolytic lumbar vertebra based on CT scanning

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Yoshimitsu; Minato, Izumi; Nagano, Junji; Inoue, Yoshiya; Takahashi, Yuji; Saito, Hidehiko [Seirei Hamamatsu General Hospital, Shizuoka (Japan)

    1996-02-01

    In this study, CT images of 239 vertebrae from 227 patients with spondylolysis in the growing period were obtained to analyze x-ray oblique separation images based on the relationship between x-ray incidence angle and CT. The age of the subjects ranged from 5 to 23 years (average 14.8 years), of which 224 patients were 18 years or lower. The CT images obtained were classified into four according to our classification, i.e., Type Ia, 112 vertebrae; Type Ib, 175; Type II, 66; Type III, 67. All patients underwent plain x-ray from 4 directions including 45deg. The angle of separation line and posterior margin of the vertebral body was obtained and the average angle of all slices was determined as separation angle. As a result, depiction level of separation line was better in 30deg oblique images than 45deg oblique images in Ia, Ib, and III groups. It is thus desirable to take the relationship between incidence angle of x-ray, separation angle, and CT classification into consideration. (S.Y.).

  11. The oblique view for spondylolysis in the growing period. X-ray projection angle to spondylolytic lumbar vertebra based on CT scanning

    International Nuclear Information System (INIS)

    Kobayashi, Yoshimitsu; Minato, Izumi; Nagano, Junji; Inoue, Yoshiya; Takahashi, Yuji; Saito, Hidehiko

    1996-01-01

    In this study, CT images of 239 vertebrae from 227 patients with spondylolysis in the growing period were obtained to analyze x-ray oblique separation images based on the relationship between x-ray incidence angle and CT. The age of the subjects ranged from 5 to 23 years (average 14.8 years), of which 224 patients were 18 years or lower. The CT images obtained were classified into four according to our classification, i.e., Type Ia, 112 vertebrae; Type Ib, 175; Type II, 66; Type III, 67. All patients underwent plain x-ray from 4 directions including 45deg. The angle of separation line and posterior margin of the vertebral body was obtained and the average angle of all slices was determined as separation angle. As a result, depiction level of separation line was better in 30deg oblique images than 45deg oblique images in Ia, Ib, and III groups. It is thus desirable to take the relationship between incidence angle of x-ray, separation angle, and CT classification into consideration. (S.Y.)

  12. A Novel Volume CT With X-Ray on a Trough-Like Surface and Point Detectors on Circle-Plus-Arc Curve

    National Research Council Canada - National Science Library

    Xu, H

    2001-01-01

    A novel imaging mode of cone-beam volume CT is proposed in this paper. It adopts a raster scanning x-ray source on a trough-like surface, and a group of point detectors distributing on a large circle plus an orthogonal arc...

  13. Metal artifact reduction in x-ray computed tomography (CT) by constrained optimization

    International Nuclear Information System (INIS)

    Zhang Xiaomeng; Wang Jing; Xing Lei

    2011-01-01

    Purpose: The streak artifacts caused by metal implants have long been recognized as a problem that limits various applications of CT imaging. In this work, the authors propose an iterative metal artifact reduction algorithm based on constrained optimization. Methods: After the shape and location of metal objects in the image domain is determined automatically by the binary metal identification algorithm and the segmentation of ''metal shadows'' in projection domain is done, constrained optimization is used for image reconstruction. It minimizes a predefined function that reflects a priori knowledge of the image, subject to the constraint that the estimated projection data are within a specified tolerance of the available metal-shadow-excluded projection data, with image non-negativity enforced. The minimization problem is solved through the alternation of projection-onto-convex-sets and the steepest gradient descent of the objective function. The constrained optimization algorithm is evaluated with a penalized smoothness objective. Results: The study shows that the proposed method is capable of significantly reducing metal artifacts, suppressing noise, and improving soft-tissue visibility. It outperforms the FBP-type methods and ART and EM methods and yields artifacts-free images. Conclusions: Constrained optimization is an effective way to deal with CT reconstruction with embedded metal objects. Although the method is presented in the context of metal artifacts, it is applicable to general ''missing data'' image reconstruction problems.

  14. Clinical implementation of a low energy x-ray therapy device in the treatment of breast cancer

    International Nuclear Information System (INIS)

    Haworth, A.; University of Western Australia, WA; Joseph, D.; Lanzon, P.; Caswell, N.; Ebert, M.; University of Western Asutralia, WA

    2001-01-01

    Full text: A low energy device producing x-rays of maximum operating potential of 50kV is used to treat primary breast tumours intraoperatively. In pathologically favourable cases, the treatment replaces conventional external beam irradiation. For patients at greater risk of local recurrence, the treatment replaces conventional 'boost' therapy. The dosimetry of the device will be described in a companion paper. QA tests prior to irradiation include: output calibration/verification; isotropy verification and external radiation monitor (the secondary beam termination device) functionality. The internal radiation monitor count (similar to setting monitor units on a linac) for a prescribed dose is calculated from tables of measured depth dose and applicator factors. The spherical applicator which best suits the size of the excised tumour is lightly sutured into position maintaining as much distance between the skin surface as possible to minimise skin erythema. Radiation protection is achieved with the use of portable lead shields and tungsten impregnated silicon drapes. Patients entered into a TROG randomised clinical trial comparing intraoperative with conventional postoperative radiotherapy after conservative breast surgery for women with early stage breast cancer will be studied in collaboration with the CRC/University College London, Cancer Trials Centre (UK) to record the effects of local tumour control, cosmesis, patient satisfaction and health economics. QA tests take approximately 15 minutes to perform and a treatment prescription of 5Gy at 1cm depth with a 5cm applicator would take approximately 30 minutes. A low energy x-ray device may be used intraoperatively in selected cases to replace conventional radiotherapy minimising the inconvenience for patients and reducing waiting lists on treatment machines. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

  15. Intraoperative Radiation Using Low-Kilovoltage X-Rays for Early Breast Cancer: A Single Site Trial.

    Science.gov (United States)

    Silverstein, Melvin J; Epstein, Melinda S; Lin, Kevin; Chen, Peter; Khan, Sadia; Snyder, Lincoln; Guerra, Lisa E; De Leon, Cristina; Mackintosh, Ralph; Coleman, Colleen; Lopez, January; Kim, Brian

    2017-10-01

    Two prospective, randomized trials, TARGIT-A and ELIOT, have shown intraoperative radiation therapy (IORT) to be a safe alternative to whole breast radiation therapy following breast-conserving surgery for selected low-risk patients. However, minimal data are available about the clinical effectiveness of this modality of treatment using the Xoft ® Axxent ® Electronic Brachytherapy (eBx ® ) System ® . A total of 201 patients with 204 early-stage breast cancers were enrolled in a prospective X-ray IORT trial from June 2010 to September 2013. All tumors were treated with breast-conserving surgery and IORT. Data were collected at 1 week, 1 month, 6 months, 1 year, and yearly thereafter. With a median follow-up of 50 months, there have been seven ipsilateral breast tumor events (IBTE), no regional or distant recurrences, and no breast cancer-related deaths. One IBTE was within the IORT field, four outside of the IORT field but within the same quadrant as the index cancer, and two were new biologically different cancers in different quadrants. Three events were in patients who deviated from the protocol criteria. Kaplan-Meier analysis projects that 2.9% of patients will recur locally at 4 years. Recurrence rates observed in this trial were comparable to those of the TARGIT-A and ELIOT trials as well as the retrospective TARGIT-R trial. The low complication rates previously reported by our group as well as the low recurrence rates reported in this study support the cautious use and continued study of IORT in selected women with low-risk breast cancer.

  16. Analysis about X-ray and CT images of pleural mesothelioma case of death. Examination about 2003 mesothelioma case of death 878 examples

    International Nuclear Information System (INIS)

    Kato, Katsuya; Kanazawa, Susumu; Kishimoto, Takumi; Genba, Kenichi; Aoe, Keisuke; Takeshima, Yukio; Inai, Kouki

    2008-01-01

    We investigated a clinical record and images for 212 examples in 878 examples diagnosed as mesothelioma in the death votes of 2003. CT images demonstrated pleural plaque to be obtained 42.0%, but in chest X-ray films only 9.8% demonstrated pleural plaque. For examination of CT findings of 117 examples, cases to present extensive irregular findings of pleura were 81.2%. Cases we made the ''no irregularity'' and ''slightness irregularity'' were 18.8%. (author)

  17. Effective data-domain noise and streak reduction for X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhi; Zamyatin, Alexander A. [Toshiba Medical Research Institute USA, Inc., Vernon Hills, IL (United States); Akino, Naruomi [Toshiba Medical System Corporation, Tokyo (Japan)

    2011-07-01

    Streaks and noise caused by photon starvation can seriously impair the diagnostic value of the CT imaging. Existing processing methods often have several parameters to tune. The parameters can be ad hoc to the data sets. Iterative methods can achieve better results, however, at the cost of more hardware resources or longer processing time. This paper reports a new scheme of adaptive Gaussian filtering, which is based on the diffusion-derived scale-space concept. In scale-space view, filtering by Gaussians of different sizes is similar to decompose the data into a sequence of scales. The scale measure, which is the variance of the filter, should be linearly related to the noise standard deviation instead of the variance of the noise. This is a fundamental deviation in the way of using filters. The new filter has only one parameter that remains stable once tuned. Singlepass processing can usually reach the desired results. (orig.)

  18. Effects of infrared laser on the bone repair assessed by x-ray microtomography (μct) and histomorphometry

    Science.gov (United States)

    Paolillo, Alessandra Rossi; Paolillo, Fernanda Rossi; da Silva, Alessandro M. Hakme; Reiff, Rodrigo Bezerra de Menezes; Bagnato, Vanderlei Salvador; Alves, José Marcos

    2015-06-01

    The bone fracture is important public health problems. The lasertherapy is used to accelerate tissue healing. Regarding diagnosis, few methods are validated to follow the evolution of bone microarchitecture. The aim of this study was to evaluate the effects of lasertherapy on bone repair with x-ray microtomography (μCT) and histomorphometry. A transverse rat tibia osteotomy with a Kirchner wire and a 2mm width polymeric spacer beads were used to produce a delayed bone union. Twelve rats were divided into two groups: (i) Control Group: untreated fracture and; (ii) Laser Group: fracture treated with laser. Twelve sessions of treatment (808nm laser, 100mW, 125J/cm2, 50seconds) were performed. The μCT scanner parameters were: 100kV, 100μA, Al+Cu filter and 9.92μm resolution. A volume of interest (VOI) was chosen with 300 sections above and below the central region of the fracture, totaling 601sections with a 5.96mm. The softwares CT-Analyzer, NRecon and Mimics were used for 2D and 3D analysis. A histomorphometry analysis was also performed. The connectivity (Conn) showed significant increase for Laser Group than Control Group (32371+/-20689 vs 17216+/-9467, pcartilaginous (0.19+/-0.05% vs 0.11+/-0.09%) and fibrotic (0.21+/-0.12% vs 0.09+/-0.11%) tissues]. The negative effect was presence of the cartilaginous and fibrotic tissues which may be related to the Kirchner wire and the non-absorption of the polymeric that may have influenced negatively the light distribution through the bone. However, the positive effect was greater bone connectivity, indicating improvement in bone microarchitecture.

  19. Micro X-ray CT imaging of pore-scale changes in unconsolidated sediment under confining pressure

    Science.gov (United States)

    Schindler, M.; Prasad, M.

    2017-12-01

    Micro X-ray computed tomography was used to image confining-pressure induced changes in a dry, unconsolidated quartz sand pack while simultaneously recording ultrasonic P-wave velocities. The experiments were performed under in-situ pressure of up to 4000 psi. The majority of digital rock physics studies rely on micro CT images obtained under ambient pressure and temperature conditions although effective rock properties strongly depend on in situ conditions. Goal of this work is to be able to obtain micro CT images of rock samples while pore and confining pressure is applied. Simultaneously we recorded ultrasonic P-wave velocities. The combination of imaging and velocity measurements provides insight in pore-scale changes in the rock and their influence on elastic properties. We visually observed a reduction in porosity by more than a third of the initial value as well as extensive grain damage, changes in pore and grain size distribution and an increase in contact number and contact radius with increasing confining pressure. An increase in measured ultrasonic P-wave velocities with increasing pressure was observed. We used porosity, contact number and contact radius obtained from micro CT images to model P-wave velocity with the contact-radius model by Bachrach et al. (1998). Our observations showed that the frame of unconsolidated sediments is significantly altered starting at pressures of only 1000 psi. This finding indicates that common assumptions in rock physics models (the solid frame remains unchanged) are violated for unconsolidated sediments. The effects on the solid frame should be taken into account when modeling the pressure dependence of elastic rock properties.

  20. Two and three-dimensional morphometric analysis of trabecular bone using X-ray microtomography (μCT)

    International Nuclear Information System (INIS)

    Silva, Alessandro Marcio Hakme da; Silva, Orivaldo Lopes da; Silva Junior, Nelson Ferreira da; Alves, Jose Marcos

    2014-01-01

    Introduction: trabecular bones have a porous microstructure and can be modeled as linear elastic solids, heterogeneous and anisotropic. In the literature, few investigations have compared the two- dimensional (2D) and three-dimensional (3D) morphometric analyses of cancellous bone. Methods: In this investigation eighteen cylindrical samples of cancellous bone (10 mm of diameter and 20 mm of height) were obtained from six bovine head femurs, with similar values for the weight and age, of the same race and gender. The samples were harvested and freeze at - 20 °C before carrying out the micro CT analysis. The CT-Analyzer software was used to measure in three directions (superior-inferior, lateral-medial and anterior-posterior) parameters such as trabecular thickness, trabecular separation, trabecular number and the eigenvalues of the fabric tensor (M). Results: the Comparison of 2D and 3D analyses for the parameters: 2D (plate model) trabecular thickness, trabecular separation and trabecular number were statistically different (p = 0) showing that measurements are not similar to the 3D ones. However, 2D (rod model) trabecular thickness and 3D trabecular thickness measurements presented no significant difference (p = 0.26). The eigenvalues show that the bovine trabecular microstructure has a tendency to transversally isotropic symmetry. Discussion: The method proved to be quite interesting for the characterization of the bone structure through 3D measurements of trabecular bone morphometric parameters in the three possible directions of loading. The results show that x-ray microtomography (μCT) is a technique of great potential for characterization and generating bone quality parameters for the diagnosis of bone metabolism diseases. (author)

  1. Two and three-dimensional morphometric analysis of trabecular bone using X-ray microtomography (μCT)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alessandro Marcio Hakme da; Silva, Orivaldo Lopes da; Silva Junior, Nelson Ferreira da, E-mail: alhakme@sc.usp.br [Universidade de Sao Paulo (EESC/FMRP/IQSC/USP), Sao Carlos, SP (Brazil); Alves, Jose Marcos [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Departamento de Engenharia Eletrica e Computacao

    2014-07-01

    Introduction: trabecular bones have a porous microstructure and can be modeled as linear elastic solids, heterogeneous and anisotropic. In the literature, few investigations have compared the two- dimensional (2D) and three-dimensional (3D) morphometric analyses of cancellous bone. Methods: In this investigation eighteen cylindrical samples of cancellous bone (10 mm of diameter and 20 mm of height) were obtained from six bovine head femurs, with similar values for the weight and age, of the same race and gender. The samples were harvested and freeze at - 20 °C before carrying out the micro CT analysis. The CT-Analyzer software was used to measure in three directions (superior-inferior, lateral-medial and anterior-posterior) parameters such as trabecular thickness, trabecular separation, trabecular number and the eigenvalues of the fabric tensor (M). Results: the Comparison of 2D and 3D analyses for the parameters: 2D (plate model) trabecular thickness, trabecular separation and trabecular number were statistically different (p = 0) showing that measurements are not similar to the 3D ones. However, 2D (rod model) trabecular thickness and 3D trabecular thickness measurements presented no significant difference (p = 0.26). The eigenvalues show that the bovine trabecular microstructure has a tendency to transversally isotropic symmetry. Discussion: The method proved to be quite interesting for the characterization of the bone structure through 3D measurements of trabecular bone morphometric parameters in the three possible directions of loading. The results show that x-ray microtomography (μCT) is a technique of great potential for characterization and generating bone quality parameters for the diagnosis of bone metabolism diseases. (author)

  2. Feasibility of using single photon counting X-ray for lung tumor position estimation based on 4D-CT

    Energy Technology Data Exchange (ETDEWEB)

    Aschenbrenner, Katharina P.; Hesser, Juergen W. [Heidelberg Univ., Mannheim (Germany). Dept. of Experimental Radiation Oncology; Heidelberg Univ. (Germany). IWR; Guthier, Christian V. [Heidelberg Univ., Mannheim (Germany). Dept. of Experimental Radiation Oncology; Lyatskaya, Yulia [Brigham and Women' s Center, Boston, MA (United States); Harvard Medical School, Boston, MA (United States); Boda-Heggemann, Judit; Wenz, Frederik [Heidelberg Univ., Mannheim (Germany). Dept. of Radiation Oncology

    2017-10-01

    In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i.e. a few millimeters. 18 patient cases with four dimensional CT (4D-CT), which serves as a-priori information, are included in the study. ULD cone beam projections are simulated from the 4D-CTs including Poisson noise. The projections from the breathing phases which correspond to different tumor positions are compared to the ULD projection by means of Poisson log-likelihood (PML) and correlation coefficient (CC), and template matching under these metrics. The results indicate that in full thorax imaging five photons per pixel suffice for a standard deviation in tumor positions of less than half a breathing phase. Around 50 photons per pixel are needed to achieve this accuracy with the field of view restricted to the tumor region. Compared to CC, PML tends to perform better for low photon counts and shifts in patient setup. Template matching only improves the position estimation in high photon counts. The quality of the reconstruction is independent of the projection angle. The accuracy of the proposed ULD single photon counting system is in the range of a few millimeters and therefore comparable to state-of-the-art tumor tracking methods. At the same time, a reduction in photons per pixel by three to four orders of magnitude relative to commercial systems with flatpanel detectors can be achieved. This enables continuous kV image-based position estimation during all fractions since the additional dose to the

  3. Feasibility of using single photon counting X-ray for lung tumor position estimation based on 4D-CT.

    Science.gov (United States)

    Aschenbrenner, Katharina P; Guthier, Christian V; Lyatskaya, Yulia; Boda-Heggemann, Judit; Wenz, Frederik; Hesser, Jürgen W

    2017-09-01

    In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i.e. a few millimeters. 18 patient cases with four dimensional CT (4D-CT), which serves as a-priori information, are included in the study. ULD cone beam projections are simulated from the 4D-CTs including Poisson noise. The projections from the breathing phases which correspond to different tumor positions are compared to the ULD projection by means of Poisson log-likelihood (PML) and correlation coefficient (CC), and template matching under these metrics. The results indicate that in full thorax imaging five photons per pixel suffice for a standard deviation in tumor positions of less than half a breathing phase. Around 50 photons per pixel are needed to achieve this accuracy with the field of view restricted to the tumor region. Compared to CC, PML tends to perform better for low photon counts and shifts in patient setup. Template matching only improves the position estimation in high photon counts. The quality of the reconstruction is independent of the projection angle. The accuracy of the proposed ULD single photon counting system is in the range of a few millimeters and therefore comparable to state-of-the-art tumor tracking methods. At the same time, a reduction in photons per pixel by three to four orders of magnitude relative to commercial systems with flatpanel detectors can be achieved. This enables continuous kV image-based position estimation during all fractions since the additional dose to the

  4. Feasibility of using single photon counting X-ray for lung tumor position estimation based on 4D-CT

    International Nuclear Information System (INIS)

    Aschenbrenner, Katharina P.; Hesser, Juergen W.; Boda-Heggemann, Judit; Wenz, Frederik

    2017-01-01

    In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i.e. a few millimeters. 18 patient cases with four dimensional CT (4D-CT), which serves as a-priori information, are included in the study. ULD cone beam projections are simulated from the 4D-CTs including Poisson noise. The projections from the breathing phases which correspond to different tumor positions are compared to the ULD projection by means of Poisson log-likelihood (PML) and correlation coefficient (CC), and template matching under these metrics. The results indicate that in full thorax imaging five photons per pixel suffice for a standard deviation in tumor positions of less than half a breathing phase. Around 50 photons per pixel are needed to achieve this accuracy with the field of view restricted to the tumor region. Compared to CC, PML tends to perform better for low photon counts and shifts in patient setup. Template matching only improves the position estimation in high photon counts. The quality of the reconstruction is independent of the projection angle. The accuracy of the proposed ULD single photon counting system is in the range of a few millimeters and therefore comparable to state-of-the-art tumor tracking methods. At the same time, a reduction in photons per pixel by three to four orders of magnitude relative to commercial systems with flatpanel detectors can be achieved. This enables continuous kV image-based position estimation during all fractions since the additional dose to the

  5. A new parameter enhancing breast cancer detection in computer-aided diagnosis of X-ray mammograms

    International Nuclear Information System (INIS)

    Tanki, Nobuyoshi; Murase, Kenya; Nagao, Michinobu

    2006-01-01

    The purpose of this study was to introduce a new parameter which enhances breast cancer detection using X-ray mammography. We used the database of X-ray mammograms generated by the Japan Society of Radiological Technology. The new parameter called 'quasi-fractal dimension (Q-FD)' was calculated from the relationship between the cutoff values for the maximum image intensity in the lesion set at 21 levels from 20% to 100% at equal intervals and the number of pixels with an intensity exceeding the cutoff value. In addition to Q-FD, the image features such as curvature (C) and eccentricity (E) were extracted. The conventional fractal dimension (C-FD) was also calculated using the box-counting method. We used artificial neural networks (ANNs) as a classification method. When using C, E, C-FD and age as inputs in ANNs and taking the number of neurons in the hidden layer as 50, we found the area under the receiver operating characteristic curve (A Z ) was 0.87±0.07 in the task differentiating between benign and malignant masses. When Q-FD was added to inputs in addition to the above parameters, the A Z value was significantly improved to become 0.93±0.09. These results suggested that Q-FD is effective for discriminating between benign and malignant masses. (author)

  6. Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

    International Nuclear Information System (INIS)

    Koukou, V; Martini, N; Sotiropoulou, P; Nikiforidis, G; Fountos, G; Michail, C; Kalyvas, N; Valais, I; Kandarakis, I; Bakas, A; Kounadi, E

    2015-01-01

    Dual energy mammography has the ability to improve the detection of microcalcifications leading to early diagnosis of breast cancer. In this simulation study, a prototype dual energy mammography system, using a CMOS based imaging detector with different X-ray spectra, was modeled. The device consists of a 33.91 mg/cm 2 Gd 2 O 2 S:Tb scintillator screen, placed in direct contact with the sensor, with a pixel size of 22.5 μm. Various filter materials and tube voltages of a Tungsten (W) anode for both the low and high energy were examined. The selection of the filters applied to W spectra was based on their K- edges (K-edge filtering). Hydroxyapatite (HAp) was used to simulate microcalcifications. Calcification signal-to-noise ratio (SNR tc ) was calculated for entrance surface dose within the acceptable levels of conventional mammography. Optimization was based on the maximization of SNR tc while minimizing the entrance dose. The best compromise between SNR tc value and dose was provided by a 35kVp X-ray spectrum with added beam filtration of 100μm Pd and a 70kVp Yb filtered spectrum of 800 μm for the low and high energy, respectively. Computer simulation results show that a SNR tc value of 3.6 can be achieved for a calcification size of 200 μm. Compared with previous studies, this method can improve detectability of microcalcifications

  7. Prospective study of the reproducibility of X-rays and CT scans for assessing trochanteric fracture comminution in the elderly: a series of 110 cases.

    Science.gov (United States)

    Isida, Ronald; Bariatinsky, Varenka; Kern, Gregory; Dereudre, Gregoire; Demondion, Xavier; Chantelot, Christophe

    2015-10-01

    Trochanteric fractures are common but difficult to analyse in the elderly on plain X-rays. Fixation failures are related to the severity of the comminution, but comminution and the degree of instability are not easy to determine on standard X-rays. Use of computed tomography (CT) improves assessment of complex fractures, but this finding has not been confirmed versus intraoperative data. The primary objective of this prospective study was to determine the error rate when evaluating comminution on X-rays and CT scans. The secondary objectives were to determine whether CT data on comminution and stability were consistent with intraoperative findings and to define the fracture characteristics. Standard X-ray assessment underestimates the complexity of trochanteric fractures and is not very reproducible. Between January and December 2013, all proximal femur fractures in the trochanter area of patients aged 75 years or older (mean age 85) were analysed prospectively with standard X-rays and computed tomography (CT). One hundred and ten patients (88 women and 22 men) with trochanteric fractures were included in the study. Fracture stability was evaluated using the Müller AO classification; the other fracture characteristics were evaluated independently. A senior surgeon evaluated the anonymised X-rays. A radiologist specialised in musculoskeletal imaging interpreted the CT scan images. All patients underwent total hip arthroplasty (110 patients) and 104 fixations of the greater trochanter. The X-ray and CT findings were compared to the intraoperative findings (gold standard) to evaluate their reproducibility. The reproducibility of the X-ray evaluation was poor for comminution, with a kappa of 0.4, sensitivity of 44 % and a negative predictive value of 29 % but a positive predictive value and specificity of 100 %. The CT evaluation had a kappa of 0.94, sensitivity of 95 % and negative predictive value of 79 %. According to the AO classification, unstable fractures were

  8. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits Bone x-rays are the fastest and easiest ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams ...

  9. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology Report ...

  10. Application of X-ray CT investigation of CO{sub 2}-brine flow in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Lanlan; Liu, Yu; Song, Yongchen; Yang, Mingjun; Zhao, Yuechao; Zhao, Jiafei; Zhang, Yi; Shen, Zijian [Dalian University of Technology, Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian (China); Xue, Ziqiu [Research Institute of Innovative Technology for the Earth, Kizugawa City, Kyoto (Japan); Suekane, Tetsuya [Tokyo Institute Technology, Department of Energy Sciences, Nagatsuta, Yokohama (Japan)

    2015-05-15

    A clear understanding of two-phase flows in porous media is important for investigating CO{sub 2} geological storage. In this study, we conducted an experiment of CO{sub 2}/brine flow process in porous media under sequestration conditions using X-ray CT technique. The flow properties of relative permeability, porosity heterogeneity, and CO{sub 2} saturation were observed in this experiment. The porous media was packed with glass beads having a diameter of 0.2 mm. The porosity distribution along the flow direction is heterogeneous owing to the diameter and shape of glass beads along the flow direction. There is a relationship between CO{sub 2} saturation and porosity distribution, which changes with different flow rates and fractional flows. The heterogeneity of the porous media influences the distribution of CO{sub 2}; moreover, gravity, fractional flows, and flow rates influence CO{sub 2} distribution and saturation. The relative permeability curve was constructed using the steady-state method. The results agreed well with the relative permeability curve simulated using pore-network model. (orig.)

  11. Characterization of low density carbon foams by x-ray computed tomography (CT) and ion microtomography (IMF)

    International Nuclear Information System (INIS)

    Moddeman, W.E.; Kramer, D.P.; Firsich, D.W.; Trainer, P.D.; Yancy, R.N.; Weirup, D.L.; Logan, C.M.; Pontau, A.E.; Antolak, A.J.; Morse, D.H.

    1990-01-01

    Two NDT techniques were used to characterize low-density, microcellular, carbon foams fabricated from a salt replica process. In this paper the two techniques are x-ray computed tomography (CT) and ion microtomography (IMT); data are presented on carbon foams that contain high-density regions. The data show that densities which differ by 3 ) materials. The data reveal that the carbon foams produced by this replica process have small density variations; the density being ∼30% greater at the outer edges than when compared to the interior of the foam. In addition, the density gradient is found to be rather sharp, that is the density drops-off rapidly from the outer edges to a uniform one in the interior of the foam. This edge build-up in carbon density was explained in terms of polymer concentrating on the foam exterior during drying which immediately followed a polymer infusion processing step. Supporting analytical data from other techniques show the foam material to be >88.8% carbon

  12. Dynamic re-weighted total variation technique and statistic Iterative reconstruction method for x-ray CT metal artifact reduction

    Science.gov (United States)

    Peng, Chengtao; Qiu, Bensheng; Zhang, Cheng; Ma, Changyu; Yuan, Gang; Li, Ming

    2017-07-01

    Over the years, the X-ray computed tomography (CT) has been successfully used in clinical diagnosis. However, when the body of the patient to be examined contains metal objects, the image reconstructed would be polluted by severe metal artifacts, which affect the doctor's diagnosis of disease. In this work, we proposed a dynamic re-weighted total variation (DRWTV) technique combined with the statistic iterative reconstruction (SIR) method to reduce the artifacts. The DRWTV method is based on the total variation (TV) and re-weighted total variation (RWTV) techniques, but it provides a sparser representation than TV and protects the tissue details better than RWTV. Besides, the DRWTV can suppress the artifacts and noise, and the SIR convergence speed is also accelerated. The performance of the algorithm is tested on both simulated phantom dataset and clinical dataset, which are the teeth phantom with two metal implants and the skull with three metal implants, respectively. The proposed algorithm (SIR-DRWTV) is compared with two traditional iterative algorithms, which are SIR and SIR constrained by RWTV regulation (SIR-RWTV). The results show that the proposed algorithm has the best performance in reducing metal artifacts and protecting tissue details.

  13. Parallel statistical image reconstruction for cone-beam x-ray CT on a shared memory computation platform

    International Nuclear Information System (INIS)

    Kole, J S; Beekman, F J

    2005-01-01

    Statistical reconstruction methods offer possibilities of improving image quality as compared to analytical methods, but current reconstruction times prohibit routine clinical applications. To reduce reconstruction times we have parallelized a statistical reconstruction algorithm for cone-beam x-ray CT, the ordered subset convex algorithm (OSC), and evaluated it on a shared memory computer. Two different parallelization strategies were developed: one that employs parallelism by computing the work for all projections within a subset in parallel, and one that divides the total volume into parts and processes the work for each sub-volume in parallel. Both methods are used to reconstruct a three-dimensional mathematical phantom on two different grid densities. The reconstructed images are binary identical to the result of the serial (non-parallelized) algorithm. The speed-up factor equals approximately 30 when using 32 to 40 processors, and scales almost linearly with the number of cpus for both methods. The huge reduction in computation time allows us to apply statistical reconstruction to clinically relevant studies for the first time

  14. Performance evaluation of 3-D enhancement filters for detection of lung cancer from 3-D chest X-ray CT images

    International Nuclear Information System (INIS)

    Shimizu, Akinobu; Hagai, Makoto; Toriwaki, Jun-ichiro; Hasegawa, Jun-ichi.

    1995-01-01

    This paper evaluates the performance of several three dimensional enhancement filters used in procedures for detecting lung cancer shadows from three dimensional (3D) chest X-ray CT images. Two dimensional enhancement filters such as Min-DD filter, Contrast filter and N-Quoit filter have been proposed for enhancing cancer shadows in conventional 2D X-ray images. In this paper, we extend each of these 2D filters to a 3D filter and evaluate its performance experimentally by using CT images with artificial and true lung cancer shadows. As a result, we find that these 3D filters are effective for determining the position of a lung cancer shadow in a 3D chest CT image, as compared with the simple procedure such as smoothing filter, and that the performance of these filters become lower in the hilar area due to the influence of the vessel shadows. (author)

  15. Analyses of the internal structure of the oscillating vibro-packed fuels by the micro focus X-rays CT method

    International Nuclear Information System (INIS)

    Mizuta, Yasutoshi

    2003-02-01

    The purpose of this study is to support the development of vibro-packed fuel technology at Japan Nuclear Cycle Development Institute. 3-dimensional (3-D) data was built from the multi-cross sectional images obtained by the micro focus X-rays CT method in the vibro-packed fuel models. The structural analyses were carried out about the obtained 3-D CT images. The packing-rate distribution and the density distribution were measured as well as the number distribution of particles, etc. Consequently, it is obtained that vibrate conditions and a vibrating state have strong correlation, and it is also shown that the 3-D analyses of the internal structure by the micro focus X-rays CT method are effective in performance evaluation of vibro-packed fuels. (author)

  16. A statistical survey of x-ray CT cases at the Clinic of Oral and Maxillofacial Radiology, Chiba Hospital, Tokyo Dental College

    International Nuclear Information System (INIS)

    Kitagawa, Hiromi; Wakoh, Mamoru; Shibuya, Hitoshi; Yamada, Masayuki; Harada, Takuya; Yamamoto, Kazuhiro; Makihara, Masahiro; Kuroyanagi, Kinya

    1997-01-01

    Statistical study was performed of x-ray CT cases at the Clinic of Oral and Maxillofacial Radiology, Chiba Hospital, Tokyo Dental College since a Toshiba CT Scanner TCT-700S was settled in 1988, until December 1994. Total number of cases photographed was 2645 cases, Male; 1447 (54.7%), Female; 1198 cases (45.3%). Total number of cases yearly photographed have increased every year. 95.43% of the cases were the diseases of oral surgery regions. X-ray CT has been used to malignant tumors (730 cases; 29.7%), cyst (435 cases; 17.7%), inflammation (362 cases; 14.7%), benign tumors (261 cases; 10.6%), injury (171 cases; 7.0%), salivary gland diseases (126 cases; 5.1%) and others. The number of tumors and cyst have been increasing every year. Average number of slices in every diseases were counted. Malignant tumor, injury, temporomandibular joint diseases, and congenital anomalies and malformations were counted many slices. Percentages of number of enhanced CT cases have been increased every year. Recently, number of enhanced CT cases have more number than non-enhanced CT cases. This attitude is correlated with the number of malignant tumors which have been increasing every year. Total number of cases of three dimensional imaging CT (3D-CT) was 316 cases. 3D-CT has been used to injury (146 cases; 46.2%), temporomandibular joint diseases (52 cases; 16.4%), congenital anomalies and malformations (49 cases; 15.5%), tumors (21 cases; 6.7%), cyst (13 cases; 4.1%) and others. The need of x-ray CT in our field and the tendency of dental treatment at Chiba Hospital might be changed in the future. In order to this situation, this type of statistical study will be performed again. (author)

  17. Experimental investigation for determination of optimal X-ray beam tube voltages in a newly developed digital breast tomosynthesis system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye-Suk, E-mail: radiosugar@yonsei.ac.kr [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju, Gangwon 220-710 (Korea, Republic of); Kim, Ye-Seul, E-mail: radiohesugar@gmail.com [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju, Gangwon 220-710 (Korea, Republic of); Choi, Young-Wook, E-mail: ywchoi@keri.re.kr [Korea Electrotechnology Research Institute (KERI), Ansan, Geongki 426-170 (Korea, Republic of); Choi, JaeGu, E-mail: jgchoi88@paran.com [Korea Electrotechnology Research Institute (KERI), Ansan, Geongki 426-170 (Korea, Republic of); Rhee, Yong-Chun, E-mail: ycrhee@yonsei.ac.kr [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju, Gangwon 220-710 (Korea, Republic of); Kim, Hee-Joung, E-mail: hjk1@yonsei.ac.kr [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju, Gangwon 220-710 (Korea, Republic of)

    2014-11-01

    Our purpose was to investigate optimal tube voltages (kVp) for a newly developed digital breast tomosynthesis (DBT) process and to determine tube current–exposure time products (mA s) for the average glandular dose (AGD), which is similar to that of the two views in conventional mammography (CM). In addition, the optimal acquisition parameters for this system were compared with those of CM. The analysis was based on the contrast-to-noise ratio (CNR) from the simulated micro-calcifications on homogeneous phantoms, and the figure of merit (FOM) was retrieved from the CNR and AGD at X-ray tube voltages ranging from 24 to 40 kVp at intervals of 2 kV. The optimal kVp increased more than 2 kV with increasing glandularity for thicker (≥50 mm) breast phantoms. The optimal kVp for DBT was found to be 4–7 kV higher than that calculated for CM with breast phantoms thicker than 50 mm. This is likely due to the greater effect of noise and dose reduction by kVp increment when using the lower dose per projection in DBT. It is important to determine optimum acquisition conditions for a maximally effective DBT system. The results of our study provide useful information to further improve DBT for high quality imaging.

  18. Estimates of Average Glandular Dose with Auto-modes of X-ray Exposures in Digital Breast Tomosynthesis

    Directory of Open Access Journals (Sweden)

    Izdihar Kamal

    2015-05-01

    Full Text Available Objectives: The aim of this research was to examine the average glandular dose (AGD of radiation among different breast compositions of glandular and adipose tissue with auto-modes of exposure factor selection in digital breast tomosynthesis. Methods: This experimental study was carried out in the National Cancer Society, Kuala Lumpur, Malaysia, between February 2012 and February 2013 using a tomosynthesis digital mammography X-ray machine. The entrance surface air kerma and the half-value layer were determined using a 100H thermoluminescent dosimeter on 50% glandular and 50% adipose tissue (50/50 and 20% glandular and 80% adipose tissue (20/80 commercially available breast phantoms (Computerized Imaging Reference Systems, Inc., Norfolk, Virginia, USA with auto-time, auto-filter and auto-kilovolt modes. Results: The lowest AGD for the 20/80 phantom with auto-time was 2.28 milliGray (mGy for two dimension (2D and 2.48 mGy for three dimensional (3D images. The lowest AGD for the 50/50 phantom with auto-time was 0.97 mGy for 2D and 1.0 mGy for 3D. Conclusion: The AGD values for both phantoms were lower against a high kilovolt peak and the use of auto-filter mode was more practical for quick acquisition while limiting the probability of operator error.

  19. A software-based x-ray scatter correction method for breast tomosynthesis

    OpenAIRE

    Jia Feng, Steve Si; Sechopoulos, Ioannis

    2011-01-01

    Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients.

  20. In Situ Local Contact Angle Measurement in a CO2-Brine-Sand System Using Microfocused X-ray CT.

    Science.gov (United States)

    Lv, Pengfei; Liu, Yu; Wang, Zhe; Liu, Shuyang; Jiang, Lanlan; Chen, Junlin; Song, Yongchen

    2017-04-11

    The wettability of porous media is of major interest in a broad range of natural and engineering applications. The wettability of a fluid on a solid surface is usually evaluated by the contact angle between them. While in situ local contact angle measurements are complicated by the topology of porous media, which can make it difficult to use traditional methods, recent advances in microfocused X-ray computed tomography (micro-CT) and image processing techniques have made it possible to measure contact angles on the scale of the pore sizes in such media. However, the effects of ionic strength, CO 2 phase, and flow pattern (drainage or imbibition) on pore-scale contact angle distribution are still not clear and have not been reported in detail in previous studies. In this study, we employed a micro-CT scanner for in situ investigation of local contact angles in a CO 2 -brine-sand system under various conditions. The effects of ionic strength, CO 2 phase, and flow pattern on the local contact-angle distribution were examined in detail. The results showed that the local contact angles vary over a wide range as a result of the interaction of surface contaminants, roughness, pore topology, and capillarity. The wettability of a porous surface could thus slowly weaken with increasing ionic strength, and the average contact angle could significantly increase when gaseous CO 2 (gCO 2 ) turns into supercritical CO 2 (scCO 2 ). Contact angle hysteresis also occurred between drainage and imbibition procedures, and the hysteresis was more significant under gCO 2 condition.

  1. Morphology of bone defects in patient with unilateral cleft lip and palate. Cone beam x-ray CT evaluation

    International Nuclear Information System (INIS)

    Kyo, Iyu; Kubota, Masato; Sato, Yuki; Nakano, Haruhisa; Maki, Koutaro

    2006-01-01

    Orthodontic treatment planning of the cleft lip and palate vary according to the morphology of the alveolar bone and palatal bone. The purpose of this study is to evaluate the three-dimensional anatomy of the alveolar and palatal bone in children with complete unilateral cleft lip and palate. Thirty-three nonsyndromic consecutive patients with complete unilateral cleft lip and palate were treated by the cleft palate team at Showa University. Each patient had lip and palate surgeries at Showa University. Cone beam CT radiographs (CB MercuRay, Hitachi) were taken prior to secondary bone grafting, and were classified according to the method of Kita et al. 1997. Cone beam CT radiographs showed multiple types of alveolar and palatal bone morphology, and focused on special types described in the method of Kita et al. It was most frequently found that bone defects in the alveolar crest showed similar patterns in both buccal and palatal aspect, and the buccal bone defect in the nasal floor was larger than the palatal bone defect in the nasal floor. In 80% of the patients, the palatal bone defect showed similar patterns in both anterior and posterior aspects, and the anterior palatal bone defect was smaller than the posterior palatal bone defect. In addition, inadequate bone bridges were frequently found at the cleft site. It is suggested that patients with unilateral cleft lip and palate have various types of alveolar and palatal bone morphology, and are required to take three-dimensional radiographic X-rays prior to any orthodontic treatment. (author)

  2. Lung cancer screening with thoracic X-ray and CT. Current situation; Lungenkarzinomscreening mit Roentgenthorax oder CT. Aktuelle Datenlage

    Energy Technology Data Exchange (ETDEWEB)

    Stackelberg, O. von; Kauczor, H.U. [Universitaetsklinikum Heidelberg, Diagnostische und Interventionelle Radiologe, Heidelberg (Germany); Translationales Lungen Forschungszentrum Heidelberg (TLRC), Mitglied des Deutschen Zentrums fuer Lungenforschung (DZL), Heidelberg (Germany)

    2016-09-15

    Attempts at the early detection of lung cancer using imaging methods began as far back as the 1950s. Several studies attempted to demonstrate a reduction of lung cancer mortality by chest radiography screening but all were unsuccessful. Even the first small screening studies using computed tomography (CT) could not demonstrate a reduction in lung cancer-specific mortality until in 2011 the results of the largest randomized controlled low-dose CT screening study in the USA (NLST) were published. The NLST results could show a significant 20 % reduction of lung cancer mortality in elderly and heavy smokers using CT. Confirmation of the NLST results are urgently needed so that the data of the largest European study (NELSON) are eagerly awaited. Pooled with the data from several smaller European studies these results will provide important information and evidence for the establishment of future CT screening programs in Europe. Randomized controlled trials are the basis of evidence-based medicine; therefore, the positive results of the methodologically very good NLST study cannot be ignored, even if it is the only such study completed so far with highly convincing conclusions. The NLST results clearly demonstrate that positive effects for the health of the population can only be expected if the processes are clearly defined and the quality is assured. (orig.) [German] Bestrebungen zur Frueherkennung von Lungenkrebs mit bildgebenden Methoden gibt es schon lange. Alle Studien, die eine Reduktion der Lungenkrebsmortalitaet mittels Roentgenthoraxscreening nachzuweisen versuchten, scheiterten. Auch die ersten kleineren Screeningstudien mit der CT konnten keine Reduktion der Lungenkrebssterblichkeit nachweisen, bis 2011 die Ergebnisse der bisher groessten randomisierten kontrollierten Niedrigdosis-CT-Screeningstudie (NLST) aus den USA veroeffentlicht wurden. Diese konnten eine signifikante 20 %ige Reduktion der Lungenkrebssterblichkeit bei Personen, die aelter und starke

  3. Body packers on your examination table: How helpful are plain x-ray images? A definitive low-dose CT protocol as a diagnosis tool for body packers

    International Nuclear Information System (INIS)

    Schulz, B.; Grossbach, A.; Gruber-Rouh, T.; Zangos, S.; Vogl, Th. J.; Eichler, K.

    2014-01-01

    Aim: To analyze the clinical value and radiation dose of plain x-rays and CT in examining patients suspected of ingesting drug-filled packets. Materials and methods: Thirty-eight patients with suspected internal concealment of drug-filled packets who were examined with plain x-rays or CT or both were included in the study. CT studies were performed using low-dose and standard-dose techniques. All radiographic images were analysed by two radiologists regarding identification of the packets and estimating the effective radiation dose from standard- and low-dose CT versus conventional x-ray examinations. Descriptive calculations were made regarding the number and density of packs and radiation dosage. The diagnostic performance of both radiologists with standard- and low-dose CT was calculated by analysing differences in the mean number of packs found. Results: Thirty-one patients were positively identified as body packers with an average of 13 packs (min: n = 1, max: n = 58, total: n = 390); seven patients were not concealing drug packets. X-ray images were taken of 24 patients prior to CT, thus allowing a direct comparison between the two methods. The correct diagnosis was made in 42%, in 33% the radiologists were uncertain, and in 25% of drug packets were either not or wrongly identified. X-ray imaging had a positive predictive value of 20% with a negative predictive value of 81%. A total of 55 CT examinations were performed on all patients with a mean effective dose of 2 mSv (low dose) versus 9.3 mSv (standard dose). The visibility of packets on low-dose CT images compared to high-dose CT was not reduced: the radiologists identified 385 and 381 of the packets, respectively, with no difference regarding the examination technique (p = 0.24 and p = 0.253, respectively). The radiodensity of all drug-filled packets at CT ranged from 26–292 HU (mean 181.2 HU). Conclusion: X-ray imaging of supposed body packers leads to a significant risk of diagnostic

  4. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  5. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... fracture. guide orthopedic surgery, such as spine repair/fusion, joint replacement and fracture reductions. look for injury, ... CT Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology ...

  6. Computer-assisted diagnosis: applications in chest and breast X-ray

    International Nuclear Information System (INIS)

    Garcia, P.; Souto, M.; Correa, J.; Carrascal, F.; Mendez, A.; Martin Carreira, J.; Lado, J.M.; Vidal, J.J.

    1996-01-01

    Progress in the area of computers during the last years has focussed attention on its potential benefits as applied to computer aided diagnosis (CAD) in radiology. these CAD systems are being dedicated mainly to chest and breast radiology. Different schemes have been under investigation at our laboratory. Both automatic discrimination between normal and abnormal interstitial patterns by fractal dimension analysis and measurement of total lung capacity (TLC) have shown encouraging results (r=0.967, p<0.001). Automatic classification of mammograms in patterns with different risk to develop breast carcinoma and computer detection of breast masses with a sensitivity of 65% for a total number of 2.6 false positives per image suggest that CAD is a realistic goal in selected areas. (Author) 42 refs

  7. Contrast-Enhanced Proton Radiography for Patient Set-up by Using X-Ray CT Prior Knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Spadea, Maria Francesca, E-mail: mfspadea@unicz.it [Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro (Italy); Fassi, Aurora [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Zaffino, Paolo [Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro (Italy); Riboldi, Marco; Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit—CNAO Foundation, Pavia (Italy); Depauw, Nicolas [Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong (Australia); Seco, Joao [Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-11-01

    Purpose: To obtain a contrasted image of the tumor region during the setup for proton therapy in lung patients, by using proton radiography and x-ray computed tomography (CT) prior knowledge. Methods and Materials: Six lung cancer patients' CT scans were preprocessed by masking out the gross tumor volume (GTV), and digitally reconstructed radiographs along the planned beam's eye view (BEV) were generated, for a total of 27 projections. Proton radiographies (PR) were also computed for the same BEV through Monte Carlo simulations. The digitally reconstructed radiograph was subtracted from the corresponding proton image, resulting in a contrast-enhanced proton radiography (CEPR). Michelson contrast analysis was performed both on PR and CEPR. The tumor region was then automatically segmented on CEPR and compared to the ground truth (GT) provided by physicians in terms of Dice coefficient, accuracy, precision, sensitivity, and specificity. Results: Contrast on CEPR was, on average, 4 times better than on PR. For 10 lateral projections (±45° off of 90° or 270°), although it was not possible to distinguish the tumor region in the PR, CEPR offers excellent GTV visibility. The median ± quartile values of Dice, precision, and accuracy indexes were 0.86 ± 0.03, 0.86 ± 0.06, and 0.88 ± 0.02, respectively, thus confirming the reliability of the method in highlighting tumor boundaries. Sensitivity and specificity analysis demonstrated that there is no systematic over- or underestimation of the tumor region. Identification of the tumor boundaries using CEPR resulted in a more accurate and precise definition of GTV compared to that obtained from pretreatment CT. Conclusions: In most proton centers, the current clinical protocol is to align the patient using kV imaging with bony anatomy as a reference. We demonstrated that CEPR can significantly improve tumor visualization, allowing better patient set-up and permitting image guided proton therapy (IGPT)

  8. Quantification of Soil Physical Properties by Using X-Ray Computerized Tomography (CT) and Standard Laboratory (STD) Methods

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Maria Ambert [Iowa State Univ., Ames, IA (United States)

    2003-12-12

    The implementation of x-ray computerized tomography (CT) on agricultural soils has been used in this research to quantify soil physical properties to be compared with standard laboratory (STD) methods. The overall research objective was to more accurately quantify soil physical properties for long-term management systems. Two field studies were conducted at Iowa State University's Northeast Research and Demonstration Farm near Nashua, IA using two different soil management strategies. The first field study was conducted in 1999 using continuous corn crop rotation for soil under chisel plow with no-till treatments. The second study was conducted in 2001 and on soybean crop rotation for the same soil but under chisel plow and no-till practices with wheel track and no-wheel track compaction treatments induced by a tractor-manure wagon. In addition, saturated hydraulic (K{sub s}) conductivity and the convection-dispersion (CDE) model were also applied using long-term soil management systems only during 2001. The results obtained for the 1999 field study revealed no significant differences between treatments and laboratory methods, but significant differences were found at deeper depths of the soil column for tillage treatments. The results for standard laboratory procedure versus CT method showed significant differences at deeper depths for the chisel plow treatment and at the second lower depth for no-till treatment for both laboratory methods. The macroporosity distribution experiment showed significant differences at the two lower depths between tillage practices. Bulk density and percent porosity had significant differences at the two lower depths of the soil column. The results obtained for the 2001 field study showed no significant differences between tillage practices and compaction practices for both laboratory methods, but significant differences between tillage practices with wheel track and no-wheel compaction treatments were found along the soil

  9. The Yield from Routine Chest X-Rays in Stage 3 Breast Cancer ...

    African Journals Online (AJOL)

    Context: Cancer of the breast is a common malignancy in Nigerian women and various imaging examinations, including the chest radiograph are routinely requested in all patients with this disease. Objective: The objective of this study was to determine the positive yield from routine chest radiographs in Nigerian patients ...

  10. TH-AB-209-10: Breast Cancer Identification Through X-Ray Coherent Scatter Spectral Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kapadia, A; Morris, R; Albanese, K; Spencer, J; McCall, S; Greenberg, J [Duke University, Durham, NC (United States)

    2016-06-15

    Purpose: We have previously described the development and testing of a coherent-scatter spectral imaging system for identification of cancer. Our prior evaluations were performed using either tissue surrogate phantoms or formalin-fixed tissue obtained from pathology. Here we present the first results from a scatter imaging study using fresh breast tumor tissues obtained through surgical excision. Methods: A coherent-scatter imaging system was built using a clinical X-ray tube, photon counting detectors, and custom-designed coded-apertures. System performance was characterized using calibration phantoms of biological materials. Fresh breast tumors were obtained from patients undergoing mastectomy and lumpectomy surgeries for breast cancer. Each specimen was vacuum-sealed, scanned using the scatter imaging system, and then sent to pathology for histological workup. Scatter images were generated separately for each tissue specimen and analyzed to identify voxels containing malignant tissue. The images were compared against histological analysis (H&E + pathologist identification of tumors) to assess the match between scatter-based and histological diagnosis. Results: In all specimens scanned, the scatter images showed the location of cancerous regions within the specimen. The detection and classification was performed through automated spectral matching without the need for manual intervention. The scatter spectra corresponding to cancer tissue were found to be in agreement with those reported in literature. Inter-patient variability was found to be within limits reported in literature. The scatter images showed agreement with pathologist-identified regions of cancer. Spatial resolution for this configuration of the scanner was determined to be 2–3 mm, and the total scan time for each specimen was under 15 minutes. Conclusion: This work demonstrates the utility of coherent scatter imaging in identifying cancer based on the scatter properties of the tissue. It

  11. Emphysema quantification and lung volumetry in chest X-ray equivalent ultralow dose CT - Intra-individual comparison with standard dose CT.

    Science.gov (United States)

    Messerli, Michael; Ottilinger, Thorsten; Warschkow, René; Leschka, Sebastian; Alkadhi, Hatem; Wildermuth, Simon; Bauer, Ralf W

    2017-06-01

    To determine whether ultralow dose chest CT with tin filtration can be used for emphysema quantification and lung volumetry and to assess differences in emphysema measurements and lung volume between standard dose and ultralow dose CT scans using advanced modeled iterative reconstruction (ADMIRE). 84 consecutive patients from a prospective, IRB-approved single-center study were included and underwent clinically indicated standard dose chest CT (1.7±0.6mSv) and additional single-energy ultralow dose CT (0.14±0.01mSv) at 100kV and fixed tube current at 70mAs with tin filtration in the same session. Forty of the 84 patients (48%) had no emphysema, 44 (52%) had emphysema. One radiologist performed fully automated software-based pulmonary emphysema quantification and lung volumetry of standard and ultralow dose CT with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparison of emphysema and lung volume. Lung volumes were compared using the concordance correlation coefficient. The median low-attenuation areas (LAA) using filtered back projection (FBP) in standard dose was 4.4% and decreased to 2.6%, 2.1% and 1.8% using ADMIRE 3, 4, and 5, respectively. The median values of LAA in ultralow dose CT were 5.7%, 4.1% and 2.4% for ADMIRE 3, 4, and 5, respectively. There was no statistically significant difference between LAA in standard dose CT using FBP and ultralow dose using ADMIRE 4 (p=0.358) as well as in standard dose CT using ADMIRE 3 and ultralow dose using ADMIRE 5 (p=0.966). In comparison with standard dose FBP the concordance correlation coefficients of lung volumetry were 1.000, 0.999, and 0.999 for ADMIRE 3, 4, and 5 in standard dose, and 0.972 for ADMIRE 3, 4 and 5 in ultralow dose CT. Ultralow dose CT at chest X-ray equivalent dose levels allows for lung volumetry as well as detection and quantification of emphysema. However, longitudinal emphysema analyses should be performed with the same scan protocol and

  12. Accuracy of technetium-99m sestamibi scintimammography and X-ray mammography in premenopausal women with suspected breast cancer

    International Nuclear Information System (INIS)

    Lumachi, F.; Ferretti, G.; Povolato, M.; Geatti, O.; Marzola, M.C.; Zucchetta, P.; Bui, F.; Brandes, A.A.

    2001-01-01

    The aim of this study was to evaluate the usefulness of technetium-99m sestamibi scintimammography (SSM) and combined use of SSM and X-ray mammography (MG) in premenopausal patients with small (≤2 cm) suspicious breast lesions. Eighty-seven premenopausal women (median age 47 years, range 32-52) with breast lesions ranging from 4 to 20 mm in greatest diameter (median 12 mm) and detected by MG, underwent SSM prior to open breast biopsy. A planar camera and single-photon emission tomography (SPET) technique were used in 23 (26.4%) and 64 (73.6%) patients, respectively. At histological examination, 72 (82.8%) breast cancers (pT1a=3, pT1b=27, pT1c=42) and 15 (17.2%) benign masses were found. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MG and SSM were 80.6% vs 80.6%, 60.0% vs 93.3% (P<0.05), 90.6% vs 98.3%, 39.1% vs 50.0% and 77.0% vs 82.8%, respectively. MG + SSM together had a sensitivity of 94.4% (P<0.05 vs SSM alone) and an accuracy of 82.8% for the detection of breast cancer. Tumours undetected by both MG and SSM were significantly (P<0.05) smaller than those correctly diagnosed. Patients with false-negative MG were younger (P<0.05) than those with tumours correctly detected, while SSM sensitivity was independent (P=NS) of age. In conclusion, in premenopausal patients with small breast lesions, the sensitivity of SSM and MG is similar (P=NS), whereas the specificity of SSM is significantly higher (P<0.05) than that of MG. Furthermore, the combination of MG and SSM offers significantly improved sensitivity and accuracy in comparison with the individual techniques, suggesting a complementary role of SSM in the detection of breast cancer in younger patients. (orig.)

  13. Measurement of erosion of stainless steel by molten lead-free solder using micro-focus x-ray CT system

    International Nuclear Information System (INIS)

    Nishikawa, Hiroshi; Takemoto, Tadashi; Kang, Songai

    2009-01-01

    The severe erosion damage, which is caused by a molten lead-free solder, of wave solder equipment made into stainless steel has been encountered in operation. Then, the higher maintenance frequency and reduced life time of wave solder machine component is a serious issue in a manufacturing process. In this study, the evaluation method of erosion of stainless steel by molten lead-free solders was investigated using micro-focus X-ray systems for fluoroscopic and computed tomography (CT). As a result, it was found that the fluoroscopic image could truly reconstruct the cross-shape of the stainless steel sample after immersion test without destruction. In the case of X-ray systems for fluoroscopic and CT used in this study, three-dimensional data can be obtained. Therefore, it was possible to easily check the whole picture of the test sample after immersion test and to decide the maximum erosion depth of test sample. (author)

  14. Skull x-ray

    Science.gov (United States)

    X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

  15. Neck x-ray

    Science.gov (United States)

    X-ray - neck; Cervical spine x-ray; Lateral neck x-ray ... There is low radiation exposure. X-rays are monitored so that the lowest amount of radiation is used to produce the image. Pregnant women and ...

  16. Computer aided monitoring of breast abnormalities in X-ray mammograms

    OpenAIRE

    Selvan, Arul; Saatchi, Reza; Ferris, Christine

    2011-01-01

    X­ray mammography is regarded as the most effective tool for the detection and diagnosis of breast cancer, but the interpretation of mammograms is a difficult and \\ud error­prone task. Computer­aided detection (CADe) systems address the problem that radiologists often miss signs of cancers that are retrospectively visible in mammograms. Furthermore, computer­aided diagnosis (CADx) systems assist the radiologist in the classification of mammographic lesions as benign or malignant[1].\\ud This p...

  17. Preliminary investigation of the NMR, optical and x-ray CT dose-response of polymer gel dosimeters with cosolvents and increased crosslinker levels

    International Nuclear Information System (INIS)

    Koeva, V I; McAuley, K B; Jirasek, A; Schreiner, L J

    2009-01-01

    Three co-solvents (glycerol, N-propanol and isopropanol) have been investigated for increasing the solubility of N,N'-methylene-bisacrylamide (Bis) crosslinker in polymer gel dosimeter recipes. Using isopropanol, the crosslinker solubility increased from approximately from 3 to 10% by weight, enabling the manufacture of polymer gel dosimeters with higher levels of crosslinking than was previously possible. The new dosimeter recipes can be imaged effectively using Nuclear Magnetic Resonance (NMR), optical and x-ray Computed Tomography (CT) techniques.

  18. Preliminary investigation of the NMR, optical and x-ray CT dose-response of polymer gel dosimeters with cosolvents and increased crosslinker levels

    Energy Technology Data Exchange (ETDEWEB)

    Koeva, V I; McAuley, K B [Chemical Engineering Department, Queen' s University, Kingston, K7L 3N6 (Canada); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, V8W 6V5 (Canada); Schreiner, L J [Cancer Centre of Southeastern Ontario, Kingston, K7L 5P9 (Canada)], E-mail: Kim.McAuley@chee.queensu.ca

    2009-05-01

    Three co-solvents (glycerol, N-propanol and isopropanol) have been investigated for increasing the solubility of N,N'-methylene-bisacrylamide (Bis) crosslinker in polymer gel dosimeter recipes. Using isopropanol, the crosslinker solubility increased from approximately from 3 to 10% by weight, enabling the manufacture of polymer gel dosimeters with higher levels of crosslinking than was previously possible. The new dosimeter recipes can be imaged effectively using Nuclear Magnetic Resonance (NMR), optical and x-ray Computed Tomography (CT) techniques.

  19. Trabecular bone analysis in CT and X-ray images of the proximal femur for the assessment of local bone quality.

    Science.gov (United States)

    Fritscher, Karl; Grunerbl, Agnes; Hanni, Markus; Suhm, Norbert; Hengg, Clemens; Schubert, Rainer

    2009-10-01

    Currently, conventional X-ray and CT images as well as invasive methods performed during the surgical intervention are used to judge the local quality of a fractured proximal femur. However, these approaches are either dependent on the surgeon's experience or cannot assist diagnostic and planning tasks preoperatively. Therefore, in this work a method for the individual analysis of local bone quality in the proximal femur based on model-based analysis of CT- and X-ray images of femur specimen will be proposed. A combined representation of shape and spatial intensity distribution of an object and different statistical approaches for dimensionality reduction are used to create a statistical appearance model in order to assess the local bone quality in CT and X-ray images. The developed algorithms are tested and evaluated on 28 femur specimen. It will be shown that the tools and algorithms presented herein are highly adequate to automatically and objectively predict bone mineral density values as well as a biomechanical parameter of the bone that can be measured intraoperatively.

  20. WE-AB-BRA-11: Improved Imaging of Permanent Prostate Brachytherapy Seed Implants by Combining an Endorectal X-Ray Sensor with a CT Scanner

    International Nuclear Information System (INIS)

    Steiner, J; Matthews, K; Jia, G

    2016-01-01

    Purpose: To test feasibility of the use of a digital endorectal x-ray sensor for improved image resolution of permanent brachytherapy seed implants compared to conventional CT. Methods: Two phantoms simulating the male pelvic region were used to test the capabilities of a digital endorectal x-ray sensor for imaging permanent brachytherapy seed implants. Phantom 1 was constructed from acrylic plastic with cavities milled in the locations of the prostate and the rectum. The prostate cavity was filled a Styrofoam plug implanted with 10 training seeds. Phantom 2 was constructed from tissue-equivalent gelatins and contained a prostate phantom implanted with 18 strands of training seeds. For both phantoms, an intraoral digital dental x-ray sensor was placed in the rectum within 2 cm of the seed implants. Scout scans were taken of the phantoms over a limited arc angle using a CT scanner (80 kV, 120–200 mA). The dental sensor was removed from the phantoms and normal helical CT and scout (0 degree) scans using typical parameters for pelvic CT (120 kV, auto-mA) were collected. A shift-and add tomosynthesis algorithm was developed to localize seed plane location normal to detector face. Results: The endorectal sensor produced images with improved resolution compared to CT scans. Seed clusters and individual seed geometry were more discernable using the endorectal sensor. Seed 3D locations, including seeds that were not located in every projection image, were discernable using the shift and add algorithm. Conclusion: This work shows that digital endorectal x-ray sensors are a feasible method for improving imaging of permanent brachytherapy seed implants. Future work will consist of optimizing the tomosynthesis technique to produce higher resolution, lower dose images of 1) permanent brachytherapy seed implants for post-implant dosimetry and 2) fine anatomic details for imaging and managing prostatic disease compared to CT images. Funding: LSU Faculty Start-up Funding

  1. WE-AB-BRA-11: Improved Imaging of Permanent Prostate Brachytherapy Seed Implants by Combining an Endorectal X-Ray Sensor with a CT Scanner

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, J; Matthews, K; Jia, G [Louisiana State University, Baton Rouge, LA (United States)

    2016-06-15

    Purpose: To test feasibility of the use of a digital endorectal x-ray sensor for improved image resolution of permanent brachytherapy seed implants compared to conventional CT. Methods: Two phantoms simulating the male pelvic region were used to test the capabilities of a digital endorectal x-ray sensor for imaging permanent brachytherapy seed implants. Phantom 1 was constructed from acrylic plastic with cavities milled in the locations of the prostate and the rectum. The prostate cavity was filled a Styrofoam plug implanted with 10 training seeds. Phantom 2 was constructed from tissue-equivalent gelatins and contained a prostate phantom implanted with 18 strands of training seeds. For both phantoms, an intraoral digital dental x-ray sensor was placed in the rectum within 2 cm of the seed implants. Scout scans were taken of the phantoms over a limited arc angle using a CT scanner (80 kV, 120–200 mA). The dental sensor was removed from the phantoms and normal helical CT and scout (0 degree) scans using typical parameters for pelvic CT (120 kV, auto-mA) were collected. A shift-and add tomosynthesis algorithm was developed to localize seed plane location normal to detector face. Results: The endorectal sensor produced images with improved resolution compared to CT scans. Seed clusters and individual seed geometry were more discernable using the endorectal sensor. Seed 3D locations, including seeds that were not located in every projection image, were discernable using the shift and add algorithm. Conclusion: This work shows that digital endorectal x-ray sensors are a feasible method for improving imaging of permanent brachytherapy seed implants. Future work will consist of optimizing the tomosynthesis technique to produce higher resolution, lower dose images of 1) permanent brachytherapy seed implants for post-implant dosimetry and 2) fine anatomic details for imaging and managing prostatic disease compared to CT images. Funding: LSU Faculty Start-up Funding

  2. X-ray CT imaging and image-based modelling study of gas exchange in the rice rhizosphere

    Science.gov (United States)

    Affholder, Marie-Cecile; Keyes, Samuel David; Roose, Tiina; Heppell, James; Kirk, Guy

    2016-04-01

    We used X-ray computer tomography and image-based modelling to investigate CO2 uptake by rice roots growing in submerged soil, and its consequences for the chemistry and biology of the rhizosphere. From previous work, three processes are known to greatly modify the rhizophere of rice and other wetland plants: (1) oxygenation of the submerged, anoxic soil by O2 transported through the root gas channels (aerenchyma); (2) oxidation of ferrous iron and resulting accumulation of ferric oxide; and (3) pH changes due to protons formed in iron oxidation and released from the roots to balance excess intake of cations over anions. A further process, so far not much investigated, is the possibility of CO2 uptake by the roots. Large amounts of CO2 accumulate in submerged soils because CO2 formed in soil respiration escapes only slowly by diffusion through the water-saturated soil pores. There is therefore a large CO2 gradient between the soil and the aerenchyma inside the root, and CO2 may be taken up by the roots and vented to the atmosphere. The extent of this and its consequences for rhizosphere chemistry and biology are poorly understood. We grew rice plants in a submerged, strongly-reduced, Philippine rice soil contained in 10-cm diameter, 20-cm deep Perspex pots. Four-week old rice seedlings, grown in nutrient culture, were transplanted into the pots at either 1 or 4 plants per pot, planted closely together. After 3 and 4 weeks, the pots were analysed with an X-ray CT scanner (Custom Nikon/Xtek Hutch; 80 mm by 56 mm field of view and 40 μm voxel size). Gas bubbles were extracted from the data by 3D median filtering and roots using a region-growth method. The images showed prominent and abundant gas bubbles in the soil bulk, but no or very few bubbles in the soil close to roots. There was a clear relation between the absence of gas bubbles and the presence of roots, as well as an increasing concentration of bubbles with depth through the soil. Analysis of the bubbles

  3. Diagnosis of sports injuries of the spinal column. If the X-ray doesn't show enough, CT and MRI will fill the gaps

    International Nuclear Information System (INIS)

    Halbsguth, A.

    1996-01-01

    Exact anamnestic exploration is a key to the successful clarification of sports lesions of the spinal column. Today, X-ray diagnostics still is of the greatest importance. Should it be impossible to diagnose the clinical situation extensively by this method recourse should be taken to computed tomography (CT) and nuclear magnetic resonance tomography (NMRT). As a rule, CT is used to clarify bone pathology and NMRT to examine soft tissue lesions. Especially complex vertebral parts - the articlular process and adjacent parts of the transverse process and lamina often are difficult to assess by a sceleton scintigraphy, thus allowing a detailed search using other methods. (orig.) [de

  4. MiR-34a is up-regulated in response to low dose, low energy X-ray induced DNA damage in breast cells

    International Nuclear Information System (INIS)

    Stankevicins, Luiza; Almeida, Carlos Eduardo de; Moura Gallo, Claudia Vitoria de; Almeida da Silva, Ana Paula; Ventura dos Passos, Flavia; Santos Ferreira, Evelin dos; Menks Ribeiro, Maria Cecilia; G David, Mariano; J Pires, Evandro; Ferreira-Machado, Samara Cristina; Vassetzky, Yegor

    2013-01-01

    MicroRNAs are non-coding RNAs involved in the regulation of gene expression including DNA damage responses. Low doses of low energy X-ray radiation, similar to those used in mammographic exams, has been described to be genotoxic. In the present work we investigated the expression of miR-34a; a well described p53-regulated miRNA implicated in cell responses to X-ray irradiation at low doses. Non-cancerous breast cell line MCF-10A and cancerous T-47D and MCF-7 cell lines were submitted to a low-energy X-ray irradiation (ranging from 28–30 Kv) using a dose of 5 Gy. The expression level of miR-34a, let-7a and miR-21 was assessed by qRT-PCR at 4 and 24 hours post-irradiation. DNA damage was then measured by comet assay and micronuclei estimation in MCF-10A and MCF-7 cell lines, where an increase of miR-34a levels could be observed after irradiation. The rate of apoptotic cells was estimated by nuclear staining and fluorescence microscopy. These experiments were also performed at low doses (3; 12 and 48 mGy) in MCF-10A and MCF-7 cell lines. We have observed an increase in miR-34a expression 4 hours post-irradiation at 5 Gy in MCF-10A and MCF-7 cell lines while its level did not change in T-47D, a breast cancer cell line bearing non-functional p53. At low doses, miR-34a was up-regulated in non-tumoral MCF-10A to a higher extent as compared to MCF-7. MiR-34a levels decreased 24 hours post-irradiation. We have also observed DNA damage and apoptosis at low-energy X-ray irradiation at low doses and the high dose in MCF-10A and MCF-7 4 and 24 hours post-irradiation relative to the mock control. Low energy X-ray is able to promote DNA strand breaks and miR-34a might be involved in cell responses to low energy X-ray DNA damage. MiR-34a expression correlates with X-ray dose, time after irradiation and cell type. The present study reinforces the need of investigating consequences of low dose X-ray irradiation of breast cells

  5. Marrow, ovary, and breast doses delivered by CHR diagnostic x-ray examinations: an update

    International Nuclear Information System (INIS)

    Schlenker, R.A.; Oltman, B.G.

    1977-01-01

    The mean absorbed dose averaged over the marrow volume in a RANDO phantom is 232 +- 14 mrad and 175 +- 26 mrad when the ANL examination is made using 1 mm Al and 3 mm Al added filtration, respectively; it is 606 +- 69 mrad when the MIT examination is made. The absorbed dose averaged over the ovaries is 243 +- 25 mrad and 162 +- 38 mrad for 1 mm Al and 3 mm Al at ANL and 606 +- 40 mrad for the MIT examination. Breast doses are 388 +- 35 mrad, 226 +- 9 mrad, and 333 +- 103 mrad. Dose reduction could be achieved by using a faster film-screen combination for the MIT examination, by routinely using 3 mm Al added filtration at ANL and by improving the collimation at ANL

  6. Phase-contrast X-ray CT imaging of the kidney. Differences between ethanol fixation and formalin fixation

    International Nuclear Information System (INIS)

    Shirai, Ryota; Kunii, Takuya; Maruyama, Hiroko; Takeda, Tohoru; Yoneyama, Akio; Lwin, Thet Thet

    2012-01-01

    A phase-contrast X-ray imaging technique using an X-ray interferometer that provides approximately 1000 times higher sensitivity than the conventional X-ray imaging method for low-atomic number elements based on the difference in the mass attenuation coefficient has recently been developed. In the present study, we compared rat kidneys fixed in 100% ethanol and in 10% formalin to evaluate the effects of ethanol in enhancing image contrast in phase-contrast imaging because ethanol causes significant dehydration of tissues and enhances density differences between tissue components. The experiments were conducted at the Photon Factory in Tsukuba, and the X-ray energy was set at 35 keV. Fine anatomical structures in the kidney such as the glomeruli, tubules, and vessels were observed. Particularly clear renal images were obtained with ethanol fixation. The pixel value ratio between the cortex and medulla was about 43% in ethanol-fixed kidneys and 21% in formalin-fixed kidneys. In other words, the contrast in ethanol-fixed kidneys was about two times higher than that in formalin-fixed kidneys. Histological examination showed significantly condensed features in the cortex. The results of this study suggest that the ethanol fixation technique may be useful for enhancing the image contrast of renal structures in the phase-contrast X-ray imaging technique. (author)

  7. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    Science.gov (United States)

    Zhao, C; Konstantinidis, A C; Zheng, Y; Anaxagoras, T; Speller, R D; Kanicki, J

    2015-12-07

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm(-1) and a DQE of around 0.5 at spatial frequencies  CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered.

  8. CT diagnosis in diseases of the breast

    International Nuclear Information System (INIS)

    Han Hongbin; Xie Jingxia

    1998-01-01

    Purpose: To study the CT signs of breast diseases, and discuss the value of CT in the diagnosis of breast cancer and the axillary lymph node (LN) metastases. Materials and methods: Fifty three cases were reported, including breast cancer 30 cases and benign diseases 23 cases. CT were performed in all patients, 44 also had mammography examination. Results: (1) The CT appearance of breast cancer: round or irregular mass, spiculate border, duct retraction, involved Cooper's ligament, deformed adipose space etc. Benign hyperplasia: Irregular mass and symmetrical thickening of breast glands. Cystic hyperplasia: typically multiple, round, liquid-density mass. (2) CT was comparable to mammography in terms of differential diagnosis, however with breast mass located near the axilla or for evaluation of the thoracic wall. CT was superior to mammography. CT was also helpful in detecting LN metastases. Conclusion: CT is valuable in detecting and differentiating breast diseases as well as in the diagnosis of LN metastases

  9. X-ray diagnostics - benefits and risks

    International Nuclear Information System (INIS)

    Bartholomaeus, Melanie

    2016-01-01

    The brochure on benefits and risks of X-ray diagnostics discusses the following issues: X radiation - a pioneering discovery and medical sensation, fundamentals of X radiation, frequency of X-ray examinations in Germany in relation to CT imaging, radiation doses resulting from X-ray diagnostics, benefits of X-ray diagnostics - indication and examples, risks - measures for radiation exposure reductions, avoidance of unnecessary examinations.

  10. Diagnosis of fibroadenoma and breast cancer: ultrasonography vs. X-ray mammography

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jong Gi; Im, Jung gi; Choi, Byung Ihn; Kim, Choo Wan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1993-12-15

    To evaluate the clinical value of ultrasonography in the diagnosis of fibroadenoma and carcinoma as compared with mammography, we performed a blind retrospective analysis of 85 sonograms and 40 mammograms of 85 breasts that were proved pathologically to have diseases. The lesions included 30 ductal carcinomas, 29 fibroadenomas, 14mammary dysplasias, 2 medullary carcinomas, 1 intraductal papillary carcinoma, and 9 cases of other pathology. The sonograms were reviewed in regards to the border, shape and internal echo pattern of the lesion and the shadows from the margin of the lesion. The mammograms were reviewed in regards to the parenchymal pattern, shape, margin,and calcification of the lesion. The accuracy, sensitivity, and specificity of mammography and ultrasonography in the diagnosis of fibroadenoma were 77%/92%, 40%/93%, and 100%/92%, respectively. The accuracy, sensitivity, and specificity of mammography and ultrasonography in the diagnosis of carcinoma were 85%/85%, 76%/82%, and 91%/86%,respectively. Ultrasonography is more accurate and more sensitive than mammography in the diagnosis offibroadenoma, but not in the diagnosis of carcinoma

  11. Diagnosis of fibroadenoma and breast cancer: ultrasonography vs. X-ray mammography

    International Nuclear Information System (INIS)

    Song, Jong Gi; Im, Jung gi; Choi, Byung Ihn; Kim, Choo Wan

    1993-01-01

    To evaluate the clinical value of ultrasonography in the diagnosis of fibroadenoma and carcinoma as compared with mammography, we performed a blind retrospective analysis of 85 sonograms and 40 mammograms of 85 breasts that were proved pathologically to have diseases. The lesions included 30 ductal carcinomas, 29 fibroadenomas, 14mammary dysplasias, 2 medullary carcinomas, 1 intraductal papillary carcinoma, and 9 cases of other pathology. The sonograms were reviewed in regards to the border, shape and internal echo pattern of the lesion and the shadows from the margin of the lesion. The mammograms were reviewed in regards to the parenchymal pattern, shape, margin,and calcification of the lesion. The accuracy, sensitivity, and specificity of mammography and ultrasonography in the diagnosis of fibroadenoma were 77%/92%, 40%/93%, and 100%/92%, respectively. The accuracy, sensitivity, and specificity of mammography and ultrasonography in the diagnosis of carcinoma were 85%/85%, 76%/82%, and 91%/86%,respectively. Ultrasonography is more accurate and more sensitive than mammography in the diagnosis offibroadenoma, but not in the diagnosis of carcinoma

  12. Development of the three dimensional image display program for limited cone beam X-ray CT for dental use (Ortho-CT)

    International Nuclear Information System (INIS)

    Arai, Yoshinori; Hashimoto, Koji; Shinoda, Koji

    2000-01-01

    We have already developed and reported a limited cone beam X-ray CT system for dental use (Ortho-CT). This system has been used clinically since 1997. In this study, we report a 3D surface display program for Ortho-CT which has been newly-developed by the authors. The 3D surface display software has been developed using visual C ++ (Microsoft Co. WA. USA) and a personal computer (Pentium 450MHz Intel Co. CA USA, Windows NT 4.0 Microsoft WA. USA). In this software, the 3D surface images are recorded as AVI files and can be displayed on the personal computer. The 3D images can be rotated and a stepwise change of the threshold voxel value for binary image formation can be automatically used. We have applied these 3D surface images to clinical studies from January 1999 to May 1999 at the Radiology section in our Dental hospital. The images can be displayed very easily in personal computers using AVI files. Thirty-five cases have been reconstructed using 3D surface images in this way. The 3D surface image is useful in the diagnosis of fractures of the mandibular head and impacted teeth. Only teeth are observed when a relative threshold voxel value is set at a high level such as about 0.37. When the threshold is changed to a lower value (about 0.3), we can observe both teeth and the surface of the bone. We have developed a 3D surface display program for personal computers. The images are useful for the diagnosis of the pathosis in the maxillofacial region. (author)

  13. Effects on image quality of a 2D antiscatter grid in x-ray digital breast tomosynthesis: Initial experience using the dual modality (x-ray and molecular) breast tomosynthesis scanner

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Tushita, E-mail: tp3rn@virginia.edu [Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Peppard, Heather [Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia 22908 (United States); Williams, Mark B. [Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia 22908 (United States); Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908 (United States)

    2016-04-15

    Purpose: Radiation scattered from the breast in digital breast tomosynthesis (DBT) causes image degradation, including loss of contrast between cancerous and background tissue. Unlike in 2-dimensional (2D) mammography, an antiscatter grid cannot readily be used in DBT because changing alignment between the tube and detector during the scan would result in unacceptable loss of primary radiation. However, in the dual modality breast tomosynthesis (DMT) scanner, which combines DBT and molecular breast tomosynthesis, the tube and detector rotate around a common axis, thereby maintaining a fixed tube-detector alignment. This C-arm geometry raises the possibility of using a 2D (cellular) focused antiscatter grid. The purpose of this study is to assess change in image quality when using an antiscatter grid in the DBT portion of a DMT scan under conditions of fixed radiation dose. Methods: Two 2D focused prototype grids with 80 cm focal length were tested, one stack-laminated from copper (Cu) and one cast from a tungsten-polymer (W-poly). They were reciprocated using a motion scheme designed to maximize transmission of primary x-ray photons. Grid-in and grid-out scatter-to-primary ratios (SPRs) were measured for rectangular blocks of material simulating 30%, 50%, and 70% glandular tissue compositions. For assessment of changes in image quality through the addition of a grid, the Computerized Imaging Reference Systems, Inc., phantom Model 011A containing a set of 1 cm thick blocks simulating a range of glandular/adipose ratios from 0/100 to 100/0 was used. To simulate 6.5 and 8.5 cm thick compressed breasts, 1 cm thick slices of PMMA were added to the Model 011A phantom. DBT images were obtained with and without the grid, with exposure parameters fixed for a given compressed thickness. Signal-difference-to-noise ratios (SDNRs), contrast, and voxel value-based attenuation coefficients (μ) were measured for all blocks from reconstructed phantom images. Results: For 4, 6, and

  14. Iodine imaging in thyroid by fluorescent X-ray CT with 0.05 mm spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, T. E-mail: ttakeda@md.tsukuba.ac.jp; Yu, Q.; Yashiro, T.; Zeniya, T.; Wu, J.; Hasegawa, Y.; Thet Thet Lwin; Hyodo, K.; Yuasa, T.; Dilmanian, F.A.; Akatsuka, T.; Itai, Y

    2001-07-21

    Fluorescent X-ray computed tomography (FXCT) at a 0.05 mm in-plane spatial resolution and 0.05 mm slice thickness depicted the cross sectional distribution of endogenous iodine within thyroid. The distribution obtained from the FXCT image correlated closely to that obtained from the pathological pictures.

  15. An image acquisition and registration strategy for the fusion of hyperpolarized helium-3 MRI and x-ray CT images of the lung

    Science.gov (United States)

    Ireland, Rob H.; Woodhouse, Neil; Hoggard, Nigel; Swinscoe, James A.; Foran, Bernadette H.; Hatton, Matthew Q.; Wild, Jim M.

    2008-11-01

    The purpose of this ethics committee approved prospective study was to evaluate an image acquisition and registration protocol for hyperpolarized helium-3 magnetic resonance imaging (3He-MRI) and x-ray computed tomography. Nine patients with non-small cell lung cancer (NSCLC) gave written informed consent to undergo a free-breathing CT, an inspiration breath-hold CT and a 3D ventilation 3He-MRI in CT position using an elliptical birdcage radiofrequency (RF) body coil. 3He-MRI to CT image fusion was performed using a rigid registration algorithm which was assessed by two observers using anatomical landmarks and a percentage volume overlap coefficient. Registration of 3He-MRI to breath-hold CT was more accurate than to free-breathing CT; overlap 82.9 ± 4.2% versus 59.8 ± 9.0% (p < 0.001) and mean landmark error 0.75 ± 0.24 cm versus 1.25 ± 0.60 cm (p = 0.002). Image registration is significantly improved by using an imaging protocol that enables both 3He-MRI and CT to be acquired with similar breath holds and body position through the use of a birdcage 3He-MRI body RF coil and an inspiration breath-hold CT. Fusion of 3He-MRI to CT may be useful for the assessment of patients with lung diseases.

  16. An image acquisition and registration strategy for the fusion of hyperpolarized helium-3 MRI and x-ray CT images of the lung

    International Nuclear Information System (INIS)

    Ireland, Rob H; Woodhouse, Neil; Hoggard, Nigel; Swinscoe, James A; Foran, Bernadette H; Hatton, Matthew Q; Wild, Jim M

    2008-01-01

    The purpose of this ethics committee approved prospective study was to evaluate an image acquisition and registration protocol for hyperpolarized helium-3 magnetic resonance imaging ( 3 He-MRI) and x-ray computed tomography. Nine patients with non-small cell lung cancer (NSCLC) gave written informed consent to undergo a free-breathing CT, an inspiration breath-hold CT and a 3D ventilation 3 He-MRI in CT position using an elliptical birdcage radiofrequency (RF) body coil. 3 He-MRI to CT image fusion was performed using a rigid registration algorithm which was assessed by two observers using anatomical landmarks and a percentage volume overlap coefficient. Registration of 3 He-MRI to breath-hold CT was more accurate than to free-breathing CT; overlap 82.9 ± 4.2% versus 59.8 ± 9.0% (p 3 He-MRI and CT to be acquired with similar breath holds and body position through the use of a birdcage 3 He-MRI body RF coil and an inspiration breath-hold CT. Fusion of 3 He-MRI to CT may be useful for the assessment of patients with lung diseases.

  17. Evaluation of patient dose in imaging using a cone-beam CT dosimetry by X-ray films for radiotherapeutic dose

    International Nuclear Information System (INIS)

    Yoshida, Yuri; Morita, Yasuhiko; Honda, Eiichi; Tomotake, Yoritoki; Ichikawa, Tetsuo

    2008-01-01

    A limited cone-beam X-ray CT (3DX multi-image micro CT; 3DX-FPD) is widely used in dentistry because it provides a lower cost, smaller size, and higher spatial resolution than a CT for medicine. Our recent research suggested that the patient dose of 3DX-FPD was less than 7/10 of that of CT, and it was several to 10 times more than that of dental or panoramic radiography. The purpose of this study was to evaluate the spatial dose distribution from 3DX-FPD and to estimate the influence of dose by positioning of the region of interest. Dosimetry of the organs and the tissues was performed using an anthropomorphic Alderson Rando phantom and X-ray films for measurement of radiotherapeutic dose. Measurements of dose distribution were performed using a cylinder-type tank of water made of acrylic resin imitating the head and X-ray films. The results are summarized as follows: The dose was higher as the ratio of the air region included in the region of interest increased. The dose distribution was not homogeneous and the dose was highest in the skin region. The dose was higher for several seconds after the beginning of exposure. It was concluded that patient positioning, as well as exposure conditions including the size of the exposure field and tube current, could greatly influence the patient dose in 3DX-FPD. In addition, it is necessary to consider the influence of image quality for the treatment of dental implants. (author)

  18. Comparative Investigation of Ce3+ Doped Scintillators in a Wide Range of Photon Energies Covering X-ray CT, Nuclear Medicine and Megavoltage Radiation Therapy Portal Imaging Applications

    Science.gov (United States)

    Valais, Ioannis G.; Michail, Christos M.; David, Stratos L.; Liaparinos, Panagiotis F.; Fountos, George P.; Paschalis, Theodoros V.; Kandarakis, Ioannis S.; Panayiotakis, George S.

    2010-02-01

    The aim of the present work is to study the performance of scintillators currently used in PET and animal PET systems, under conditions met in radiation therapy and PET/CT imaging. The results of this study will be useful in applications where both CT and PET photons as well as megavoltage cone beam CT (MV CBCT) photons could be detected using a common detector unit. To this aim crystal samples of GSO, LSO, LYSO, LuYAP and YAP scintillators, doped with cerium (Ce+3) were examined under a wide energy range of photon energies. Evaluation was performed by determining the absolute luminescence efficiency (emitted light flux over incident X-ray exposure) in the energy range employed in X-ray CT, in Nuclear Medicine (70 keV up to 662 keV) and in radiotherapy 6 MV (approx. 2.0 MeV mean energy)-18 MV (approx. 4.5 MeV mean energy). Measurements were performed using an experimental set-up based on a photomultiplier coupled to a light integration sphere. The emission spectrum under X-ray excitation was measured, using an optical grating monochromator, to determine the spectral compatibility to optical photon detectors incorporated in medical imaging systems. Maximum absolute luminescence efficiency values were observed at 70 keV for YAP:Ce and LuYAP:Ce and at 140 keV for LSO:Ce, LYSO:Ce and GSO:Ce. Highest absolute efficiency between the scintillators examined was observed for LSO:Ce, followed by LYSO:Ce. The detector optical gain (DOG) exhibited a significant variation with the increase of energy between 70 keV to 2.0 MeV. All scintillators exhibited low compatibility when combined with GaAsP (G5645) photodetector.

  19. TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Sommerville, M; Tambasco, M [San Diego State University, San Diego, CA (United States); Poirier, Y [CancerCare Manitoba, Winnipeg, MB (Canada)

    2015-06-15

    Purpose: To experimentally validate a rotational kV x-ray source characterization technique by computing CT dose in an anthropomorphic thorax phantom using an in-house dose computation algorithm (kVDoseCalc). Methods: The lateral variation in incident energy spectra of a GE Optima big bore CT scanner was found by measuring the HVL along the internal, full bow-tie filter axis. The HVL and kVp were used to generate the x-ray spectra using Spektr software, while beam fluence was derived by dividing the integral product of the spectra and in-air mass-energy absorption coefficients by in-air dose measurements along the bow-tie filter axis. Beams produced by the GE Optima scanner were modeled at 80 and 140 kVp tube settings. kVDoseCalc calculates dose by solving the linear Boltzmann transport equation using a combination of deterministic and stochastic methods. Relative doses in an anthropomorphic thorax phantom (E2E SBRT Phantom) irradiated by the GE Optima scanner were measured using a (0.015 cc) PTW Freiburg ionization chamber, and compared to computations from kVDoseCalc. Results: The agreement in relative dose between dose computation and measurement for points of interest (POIs) within the primary path of the beam was within experimental uncertainty for both energies, however points outside the primary beam were not. The average absolute percent difference for POIs within the primary path of the beam was 1.37% and 5.16% for 80 and 140 kVp, respectively. The minimum and maximum absolute percent difference for both energies and all POIs within the primary path of the beam was 0.151% and 6.41%, respectively. Conclusion: The CT x-ray source characterization technique based on HVL measurements and kVp can be used to accurately compute CT dose in an anthropomorphic thorax phantom.

  20. Identification of human breast pathologies by X-ray elastic scattering; Identificacao de patologias mamarias atraves do espalhamento elastico de raios X

    Energy Technology Data Exchange (ETDEWEB)

    Conceicao, Andre L.C.; Antoniassi, Marcelo; Poletti, Martin E., E-mail: andre_conceicao@yahoo.com.b [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2011-07-01

    In this paper we determine the scattering profiles of normal, benign and malignant human breast samples in a momentum transfer range of 0.07nm{sup -1} {<=}q{<=}70.55nm{sup -1}, resulted from combining WAXS (wide angle x-ray scattering) and SAXS (small angle x-ray scattering) data. The results showed considerable differences between the scattering profiles of each tissue type. Based on this fact, some parameters, representing structural features, were extracted from these scattering profiles and submitted to a discriminant analysis. From statistical analysis, the ratio between the peak intensities at q=19.8nm{sup -1} and q=13.9nm{sup -1} and the intensity of third order axial collagen peak arose as two potentials breast tissue classifiers and, from combining them it was possible differentiate among normal, benign and malignant lesions. (author)

  1. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    International Nuclear Information System (INIS)

    Zhao, C; Kanicki, J; Konstantinidis, A C; Zheng, Y; Speller, R D; Anaxagoras, T

    2015-01-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm −1 and a DQE of around 0.5 at spatial frequencies  <1 mm −1 . In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNR i ) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (∼1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered. (paper)

  2. Correlation analysis between expression of PCNA, Ki-67 and COX-2 and X-ray features in mammography in breast cancer.

    Science.gov (United States)

    Qiu, Xiaoming; Mei, Jixin; Yin, Jianjun; Wang, Hong; Wang, Jinqi; Xie, Ming

    2017-09-01

    This study investigated expression of proliferating cell nuclear antigen (PCNA), proliferation-associated nuclear antigen (Ki-67) and cyclooxygenase-2 (COX-2) in tissues of breast invasive ductal carcinoma, and analyzed the correlations between these indexes and X-ray features in mammography. A total of 90 patients who were admitted to Huangshi Central Hospital and diagnosed as breast invasive ductal carcinoma from January 2014 to January 2016 were selected. The expression of PCNA, Ki-67 and COX-2 in cancer tissues and cancer-adjacent normal tissues of patients were detected by immunohistochemical staining, and X-ray features in mammography of patients were observed. By using Spearman correlation analysis, the correlations between expression of PCNA, Ki-67 and COX-2 and X-ray features in mammography in breast cancer were investigated. As a result, the positive expression rates of PCNA, Ki-67 and COX-2 in cancer tissues of the patient groups were respectively 42.2, 45.6 and 51.1%, which were significantly higher than those in cancer-adjacent normal tissues of the control group (pcorrelation with age and tumor size (p>0.05). PCNA, Ki-67 and COX-2 expression in cancer tissues of the patient group had no correlation with the existence of lumps and localized density-increased shadows (p>0.05), but were associated with manifestations of architectural distortion, calcification as well as skin and nipple depression (pcorrelation analysis revealed that there was a significantly positive correlation between the expression of PCNA and COX-2 in cancer tissues of the patient group (r=0.676, pcorrelation between the expression of Ki-67 and COX-2 (r=0.724, pcorrelation with the expression of Ki-67 (p>0.05). In conclusion, PCNA, Ki-67 and COX-2 expression is of great significance in the occurrence, invasion and metastasis of breast invasive ductal carcinoma. There is a strong correlation between PCNA, Ki-67 and COX-2 expression levels and X-ray features in mammography in breast

  3. WE-H-206-03: Promises and Challenges of Benchtop X-Ray Fluorescence CT (XFCT) for Quantitative in Vivo Imaging

    International Nuclear Information System (INIS)

    Cho, S.

    2016-01-01

    Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) is limited to penetration within the optical diffusion limit (∼1 mm in the skin). Ultrasonic imaging, on the contrary, provides fine spatial resolution but suffers from both poor contrast in early-stage tumors and strong speckle artifacts. In PAT, pulsed laser light penetrates tissue and generates a small but rapid temperature rise, which induces emission of ultrasonic waves due to thermoelastic expansion. The ultrasonic waves, orders of magnitude less scattering than optical waves, are then detected to form high-resolution images of optical absorption at depths up to 7 cm, conquering the optical diffusion limit. PAT is the only modality capable of imaging across the length scales of organelles, cells, tissues, and organs (up to whole-body small animals) with consistent contrast. This rapidly growing technology promises to enable multiscale biological research and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT may also hold the key to label-free early detection of cancer by in vivo quantification of hypermetabolism, the quintessential hallmark of malignancy. Learning Objectives: To understand the contrast mechanism of PAT To understand the multiscale applications of PAT Benjamin M. W. Tsui: Multi-modality molecular imaging instrumentation and techniques have been major developments in small animal imaging that has contributed significantly

  4. WE-H-206-03: Promises and Challenges of Benchtop X-Ray Fluorescence CT (XFCT) for Quantitative in Vivo Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S. [UT MD Anderson Cancer Center (United States)

    2016-06-15

    Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) is limited to penetration within the optical diffusion limit (∼1 mm in the skin). Ultrasonic imaging, on the contrary, provides fine spatial resolution but suffers from both poor contrast in early-stage tumors and strong speckle artifacts. In PAT, pulsed laser light penetrates tissue and generates a small but rapid temperature rise, which induces emission of ultrasonic waves due to thermoelastic expansion. The ultrasonic waves, orders of magnitude less scattering than optical waves, are then detected to form high-resolution images of optical absorption at depths up to 7 cm, conquering the optical diffusion limit. PAT is the only modality capable of imaging across the length scales of organelles, cells, tissues, and organs (up to whole-body small animals) with consistent contrast. This rapidly growing technology promises to enable multiscale biological research and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT may also hold the key to label-free early detection of cancer by in vivo quantification of hypermetabolism, the quintessential hallmark of malignancy. Learning Objectives: To understand the contrast mechanism of PAT To understand the multiscale applications of PAT Benjamin M. W. Tsui: Multi-modality molecular imaging instrumentation and techniques have been major developments in small animal imaging that has contributed significantly

  5. X-Ray

    Science.gov (United States)

    ... enema. What you can expect During the X-ray X-rays are performed at doctors' offices, dentists' offices, ... as those using a contrast medium. Your child's X-ray Restraints or other techniques may be used to ...

  6. Abdominal x-ray

    Science.gov (United States)

    Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

  7. Chest X-Ray

    Medline Plus

    Full Text Available ... talk with you about chest radiography also known as chest x-rays. Chest x-rays are the ... treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray ...

  8. In vivo quantification of plant starch reserves at micrometer resolution using X-ray microCT imaging and machine learning.

    Science.gov (United States)

    Earles, J Mason; Knipfer, Thorsten; Tixier, Aude; Orozco, Jessica; Reyes, Clarissa; Zwieniecki, Maciej A; Brodersen, Craig R; McElrone, Andrew J

    2018-03-08

    Starch is the primary energy storage molecule used by most terrestrial plants to fuel respiration and growth during periods of limited to no photosynthesis, and its depletion can drive plant mortality. Destructive techniques at coarse spatial scales exist to quantify starch, but these techniques face methodological challenges that can lead to uncertainty about the lability of tissue-specific starch pools and their role in plant survival. Here, we demonstrate how X-ray microcomputed tomography (microCT) and a machine learning algorithm can be coupled to quantify plant starch content in vivo, repeatedly and nondestructively over time in grapevine stems (Vitis spp.). Starch content estimated for xylem axial and ray parenchyma cells from microCT images was correlated strongly with enzymatically measured bulk-tissue starch concentration on the same stems. After validating our machine learning algorithm, we then characterized the spatial distribution of starch concentration in living stems at micrometer resolution, and identified starch depletion in live plants under experimental conditions designed to halt photosynthesis and starch production, initiating the drawdown of stored starch pools. Using X-ray microCT technology for in vivo starch monitoring should enable novel research directed at resolving the spatial and temporal patterns of starch accumulation and depletion in woody plant species. No claim to original US Government works New Phytologist © 2018 New Phytologist Trust.

  9. Synthesis of PEG-Iodine-Capped Gold Nanoparticles and Their Contrast Enhancement in In Vitro and In Vivo for X-Ray/CT

    International Nuclear Information System (INIS)

    Sun-Hee, K.; Eun-Mi, K.; Chang-Moon, L.; Dong, W.K.; Seok, T.L.; Myung-Hee, S.; Hwan-Jeong, J.

    2012-01-01

    We designed gold nanoparticles (AuNPs) capped with iodine and polyethylene glycol (PEG) to provide effective enhancement for X-ray CT imaging. The methoxy PEG-iodine-capped AuNPs were prepared through the chemisorption of iodine and substitution of methoxy PEG-SH onto the surface of gold nanoparticles, and severe aggregation in TEM was not observed. The binding energies of Au 4f 7/2 and I 3d 5/2 of the methoxy PEG-iodine-capped AuNPs were obtained as 84.1 eV and 619.3 eV, respectively. The binding energy shift of methoxy PEG-iodine-capped AuNPs would be resulted from the chemisorption between gold nanoparticles and iodine atoms. The methoxy PEG-iodine-capped AuNPs have higher enhancement compared to PEG-capped gold nanoparticles in the same amount of gold in vitro. After postinjection of methoxy PEG-iodine-capped AuNPs into the mice, dramatic contrast enhancement at the heart, aorta, liver, and kidney was observed, this was maintained up to 5 days, and there was no evidence of apparent toxicity. In conclusion, methoxy PEG-iodine-capped AuNPs might be a good candidate as a CT contrast agent for blood pool imaging, and this will also contribute to the prolongation of a blood circulation time for X-ray CT imaging.

  10. Combined bilateral idiopathic necrosis of the humerus and femur heads: Bone scan, X-ray, CT, and MRI findings

    International Nuclear Information System (INIS)

    Piepenburg, R.; Hahn, K.; Doll, G.; Grimm, J.

    1992-01-01

    Untreated aseptic bone necroses close to a joint commonly leads to severe secondary arthrosis and destruction of the joint within a short time. Therefore, only a diagnosis in an early stage of the disease offers the chance of a successful joint- preserving therapy. In cases of clinically suspected aseptic bone necrosis but still negative or doubtful X-ray findings, bone scans or MRI are reliable methods of verifying the diagnosis. (orig./MG) [de

  11. Rapid fusion of 2D X-ray fluoroscopy with 3D multislice CT for image-guided electrophysiology procedures

    Science.gov (United States)

    Zagorchev, Lyubomir; Manzke, Robert; Cury, Ricardo; Reddy, Vivek Y.; Chan, Raymond C.

    2007-03-01

    Interventional cardiac electrophysiology (EP) procedures are typically performed under X-ray fluoroscopy for visualizing catheters and EP devices relative to other highly-attenuating structures such as the thoracic spine and ribs. These projections do not however contain information about soft-tissue anatomy and there is a recognized need for fusion of conventional fluoroscopy with pre-operatively acquired cardiac multislice computed tomography (MSCT) volumes. Rapid 2D-3D integration in this application would allow for real-time visualization of all catheters present within the thorax in relation to the cardiovascular anatomy visible in MSCT. We present a method for rapid fusion of 2D X-ray fluoroscopy with 3DMSCT that can facilitate EP mapping and interventional procedures by reducing the need for intra-operative contrast injections to visualize heart chambers and specialized systems to track catheters within the cardiovascular anatomy. We use hardware-accelerated ray-casting to compute digitally reconstructed radiographs (DRRs) from the MSCT volume and iteratively optimize the rigid-body pose of the volumetric data to maximize the similarity between the MSCT-derived DRR and the intra-operative X-ray projection data.

  12. Non-destructive failure analysis and measurement for molded devices and complex assemblies with X-ray CT and 3D image processing techniques

    International Nuclear Information System (INIS)

    Yin, Xiaoming; Liew, Seaw Jia; Jiang, Ting Ying; Xu, Jian; Kakarala, Ramakrishna

    2013-01-01

    In both automotive and healthcare sectors, reliable failure analysis and accurate measurement of molded devices and complex assemblies are important. Current methods of failure analysis and measurement require these molded parts to be cross-sectioned so that internal features or dimensions can be accessible. As a result, the parts are deemed unusable and additional failure introduced by sectioning may cause misinterpretation of the results. X-ray CT and 3D image processing techniques provide a new nondestructive solution for failure analysis and measurement of molded devices and complex assemblies. These techniques simplify failure analysis and measurement of molded devices and assemblies, and improve the productivity of molding manufacturing significantly.

  13. Energy Calibration of a Silicon-Strip Detector for Photon-Counting Spectral CT by Direct Usage of the X-ray Tube Spectrum

    Science.gov (United States)

    Liu, Xuejin; Chen, Han; Bornefalk, Hans; Danielsson, Mats; Karlsson, Staffan; Persson, Mats; Xu, Cheng; Huber, Ben

    2015-02-01

    The variation among energy thresholds in a multibin detector for photon-counting spectral CT can lead to ring artefacts in the reconstructed images. Calibration of the energy thresholds can be used to achieve homogeneous threshold settings or to develop compensation methods to reduce the artefacts. We have developed an energy-calibration method for the different comparator thresholds employed in a photon-counting silicon-strip detector. In our case, this corresponds to specifying the linear relation between the threshold positions in units of mV and the actual deposited photon energies in units of keV. This relation is determined by gain and offset values that differ for different detector channels due to variations in the manufacturing process. Typically, the calibration is accomplished by correlating the peak positions of obtained pulse-height spectra to known photon energies, e.g. with the aid of mono-energetic x rays from synchrotron radiation, radioactive isotopes or fluorescence materials. Instead of mono-energetic x rays, the calibration method presented in this paper makes use of a broad x-ray spectrum provided by commercial x-ray tubes. Gain and offset as the calibration parameters are obtained by a regression analysis that adjusts a simulated spectrum of deposited energies to a measured pulse-height spectrum. Besides the basic photon interactions such as Rayleigh scattering, Compton scattering and photo-electric absorption, the simulation takes into account the effect of pulse pileup, charge sharing and the electronic noise of the detector channels. We verify the method for different detector channels with the aid of a table-top setup, where we find the uncertainty of the keV-value of a calibrated threshold to be between 0.1 and 0.2 keV.

  14. X-ray astronomy

    International Nuclear Information System (INIS)

    Giacconi, R.; Gursky, H.

    1974-01-01

    This text contains ten chapters and three appendices. Following an introduction, chapters two through five deal with observational techniques, mechanisms for the production of x rays in a cosmic setting, the x-ray sky and solar x-ray emission. Chapters six through ten include compact x-ray sources, supernova remnants, the interstellar medium, extragalactic x-ray sources and the cosmic x-ray background. Interactions of x rays with matter, units and conversion factors and a catalog of x-ray sources comprise the three appendices. (U.S.)

  15. TH-AB-209-07: High Resolution X-Ray-Induced Acoustic Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, L; Tang, S [University of Oklahoma, Norman, OK (United States); Ahmad, M [Stanford University, Palo Alto, CA (United States); Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

    2016-06-15

    Purpose: X-ray radiographic absorption imaging is an invaluable tool in medical diagnostics, biology and materials science. However, the use of conventional CT is limited by two factors: the detection sensitivity to weak absorption material and the radiation dose from CT scanning. The purpose of this study is to explore X-ray induced acoustic computed tomography (XACT), a new imaging modality, which combines X-ray absorption contrast and high ultrasonic resolution to address these challenges. Methods: First, theoretical models was built to analyze the XACT sensitivity to X-ray absorption and calculate the minimal radiation dose in XACT imaging. Then, an XACT system comprised of an ultrashort X-ray pulse, a low noise ultrasound detector and a signal acquisition system was built to evaluate the X-ray induced acoustic signal generation. A piece of chicken bone and a phantom with two golden fiducial markers were exposed to 270 kVp X-ray source with 60 ns exposure time, and the X-ray induced acoustic signal was received by a 2.25MHz ultrasound transducer in 200 positions. XACT images were reconstructed by a filtered back-projection algorithm. Results: The theoretical analysis shows that X-ray induced acoustic signals have 100% relative sensitivity to X-ray absorption, but not to X-ray scattering. Applying this innovative technology to breast imaging, we can reduce radiation dose by a factor of 50 compared with newly FDA approved breast CT. The reconstructed images of chicken bone and golden fiducial marker phantom reveal that the spatial resolution of the built XACT system is 350µm. Conclusion: In XACT, the imaging sensitivity to X-ray absorption is improved and the imaging dose is dramatically reduced by using ultrashort pulsed X-ray. Taking advantage of the high ultrasonic resolution, we can also perform 3D imaging with a single X-ray pulse. This new modality has the potential to revolutionize x-ray imaging applications in medicine and biology.

  16. X-ray micro-CT and neutron CT as complementary imaging tools for non-destructive 3D imaging of rare silicified fossil plants

    Czech Academy of Sciences Publication Activity Database

    Karch, J.; Dudák, J.; Žemlička, J.; Vavřík, Daniel; Kumpová, Ivana; Kvaček, J.; Heřmanová, Z.; Šoltés, J.; Viererbl, L.; Morgano, M.; Kaestner, A.; Trtík, P.

    2017-01-01

    Roč. 12, December (2017), č. článku C12004. ISSN 1748-0221 R&D Projects: GA MŠk(CZ) LO1219 Keywords : inspection with neutrons * X-ray detectors * X ray radiography Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/12/12/C12004/pdf

  17. Ultralow dose CT for pulmonary nodule detection with chest X-ray equivalent dose - a prospective intra-individual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Messerli, Michael [University Zurich, Department of Nuclear Medicine, University Hospital Zurich, Zurich (Switzerland); Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard; Desbiolles, Lotus; Bauer, Ralf W.; Wildermuth, Simon [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University of Montreal, Department of Radiology, CHU Sainte-Justine, Montreal, Quebec (Canada); Rengier, Fabian [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Warschkow, Rene [Cantonal Hospital St. Gallen, Department of Surgery, St. Gallen (Switzerland); Alkadhi, Hatem [University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland); Leschka, Sebastian [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland)

    2017-08-15

    To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection. 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001). Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray. (orig.)

  18. X-ray radiotherapy

    International Nuclear Information System (INIS)

    Tronc, D.

    1995-01-01

    major medical equipment companies manufacture X-ray therapy systems - General Electric, Mitsubishi, Philips, Siemens and Varian. In this crowded marketplace where the useful lifespan of machines exceeds 10 years, purchase prices are less than $1 million per unit. X-ray therapy remains the most common and cheapest form of accelerator therapy. Ongoing technical developments aim to achieve better matching of dose delivery to tumour volume; multileaf collimators shape the X-ray field to the biomedical target, and portal imaging from behind the patient can control positioning and dose delivery. Combined compact X-ray sources are being developed with both treatment and realtime dosimetry control, incorporating CT scanning into one single device. Integrated diagnosis and therapy is the direction for R&D investment, and this should lead to smaller hospital space requirements, lower operating costs, and elimination of external data handling, resulting in simpler and more cost effective clinical procedures

  19. GPU acceleration of 3D forward and backward projection using separable footprints for X-ray CT image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng; Fessler, Jeffrey A. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Electrical Engineering and Computer Science

    2011-07-01

    Iterative 3D image reconstruction methods can improve image quality over conventional filtered back projection (FBP) in X-ray computed tomography. However, high computational costs deter the routine use of iterative reconstruction clinically. The separable footprint method for forward and back-projection simplifies the integrals over a detector cell in a way that is quite accurate and also has a relatively efficient CPU implementation. In this project, we implemented the separable footprints method for both forward and backward projection on a graphics processing unit (GPU) with NVDIA's parallel computing architecture (CUDA). This paper describes our GPU kernels for the separable footprint method and simulation results. (orig.)

  20. In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography (CT) and Light Microscopy (LM) Correlated with Scanning Electron Microscopy (SEM).

    Science.gov (United States)

    Meyer, Jörg; Thomas, Christian; Tappe, Frank; Ogbazghi, Tekie

    2016-06-16

    In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of micro-characterization, plays an important role. Commonly, different techniques like X-ray computed tomography (CT), light microscopy (LM) and scanning electron microscopy (SEM) are used separately. Similarly, the results have to be treated for each technique independently. Here a comprehensive study is shown which demonstrates the potentials leveraged by linking CT, LM and SEM. In depth characterization is performed on a white emitting LED, which can be operated throughout all characterization steps. Major advantages are: planned preparation of defined cross sections, correlation of optical properties to structural and compositional information, as well as reliable identification of different functional regions. This results from the breadth of information available from identical regions of interest (ROIs): polarization contrast, bright and dark-field LM images, as well as optical images of the LED cross section in operation. This is supplemented by SEM imaging techniques and micro-analysis using energy dispersive X-ray spectroscopy.

  1. Reconstruction of Intima and Adventitia Models into a State Undeformed by a Catheter by Using CT, IVUS, and Biplane X-Ray Angiogram Images

    Directory of Open Access Journals (Sweden)

    Jinwon Son

    2017-01-01

    Full Text Available The number of studies on blood flow analysis using fluid-structure interaction (FSI analysis is increasing. Though a 3D blood vessel model that includes intima and adventitia is required for FSI analysis, there are difficulties in generating it using only one type of medical imaging. In this paper, we propose a 3D modeling method for accurate FSI analysis. An intravascular ultrasound (IVUS image is used with biplane X-ray angiogram images to calculate the position and orientation of the blood vessel. However, these images show that the blood vessel is deformed by the catheter inserted into the blood vessel for IVUS imaging. To eliminate such deformation, a CT image was added and the two models were registered. First, a 3D model of the undeformed intima was generated using a CT image. In the second stage, a model of intima and adventitia deformed by the catheter was generated by combining the IVUS image and the X-ray angiogram images. A 3D model of intima and adventitia with the deformation caused by insertion of the catheter eliminated was generated by matching these 3D blood vessel models in different states. In addition, a 3D blood vessel model including bifurcation was generated using the proposed method.

  2. Chest X-Ray

    Medline Plus

    Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

  3. X-ray sky

    International Nuclear Information System (INIS)

    Gruen, M.; Koubsky, P.

    1977-01-01

    The history is described of the discoveries of X-ray sources in the sky. The individual X-ray detectors are described in more detail, i.e., gas counters, scintillation detectors, semiconductor detectors, and the principles of X-ray spectrometry and of radiation collimation aimed at increased resolution are discussed. Currently, over 200 celestial X-ray sources are known. Some were identified as nebulae, in some pulsations were found or the source was identified as a binary star. X-ray bursts of novae were also observed. The X-ray radiation is briefly mentioned of spherical star clusters and of extragalactic X-ray sources. (Oy)

  4. What is the clinical significance of chest CT when the chest x-ray result is normal in patients with blunt trauma?

    Science.gov (United States)

    Kea, Bory; Gamarallage, Ruwan; Vairamuthu, Hemamalini; Fortman, Jonathan; Lunney, Kevin; Hendey, Gregory W; Rodriguez, Robert M

    2013-08-01

    Computed tomography (CT) has been shown to detect more injuries than plain radiography in patients with blunt trauma, but it is unclear whether these injuries are clinically significant. This study aimed to determine the proportion of patients with normal chest x-ray (CXR) result and injury seen on CT and abnormal initial CXR result and no injury on CT and to characterize the clinical significance of injuries seen on CT as determined by a trauma expert panel. Patients with blunt trauma older than 14 years who received emergency department chest imaging as part of their evaluation at 2 urban level I trauma centers were enrolled. An expert trauma panel a priori classified thoracic injuries and subsequent interventions as major, minor, or no clinical significance. Of 3639 participants, 2848 (78.3%) had CXR alone and 791 (21.7%) had CXR and chest CT. Of 589 patients who had chest CT after a normal CXR result, 483 (82.0% [95% confidence interval [CI], 78.7-84.9%]) had normal CT results, and 106 (18.0% [95% CI, 15.1%-21.3%]) had CTs diagnosing injuries-primarily rib fractures, pulmonary contusion, and incidental pneumothorax. Twelve patients had injuries classified as clinically major (2.0% [95% CI, 1.2%-3.5%]), 78 were clinically minor (13.2% [95% CI, 10.7%-16.2%]), and 16 were clinically insignificant (2.7% (95% CI, 1.7%-4.4%]). Of 202 patients with CXRs suggesting injury, 177 (87.6% [95% CI, 82.4%-91.5%]) had chest CTs confirming injury and 25 (12.4% [95% CI, 8.5%-17.6%]) had no injury on CT. Chest CT after a normal CXR result in patients with blunt trauma detects injuries, but most do not lead to changes in patient management. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. The "Air in the CT X-ray Tube Oil" Artifact-Examples of the Quality Control Images and the Evaluation of Four Potential Clinical Patients' Head Computed Tomography Cases.

    Science.gov (United States)

    Törmänen, Juhani; Rautiainen, Jari; Tahvonen, Pirita; Leinonen, Kimmo; Nieminen, Miika T; Tervonen, Osmo

    We present a newly reposted scanner-based artifact-with 4 potential patients' head computed tomography (CT) cases-the "Air in the CT X-ray Tube Oil" artifact with a 64-slice multidetector CT. This artifact mimics diseases, which cause hypodense findings in CT images. It can be difficult to notice in the clinical patient imaging but can be also very difficult to verify in quality control tests.

  6. Surface and bulk 3D analysis of natural and processed ruby using electron probe micro analyzer and X-ray micro CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Rakesh K., E-mail: rakesh.materialscience@gmail.com; Singh, Saroj K.; Mishra, B.K.

    2016-08-15

    Highlights: • Firm linking between two advance techniques: Micro-CT and EPMA for mineral analysis. • Attempt to identify and differentiate the treated gem stone from natural counterpart. • 3D structural and surface elemental analysis of the natural gem stone. - Abstract: The change in surface compositional and bulk structural characteristics of the natural ruby stone, before and after heat treatment with lead oxide has been analyzed using two advance characterization techniques like: X-ray micro CT scan (μ-CT) and electron probe micro analyzer (EPMA). The analytical correlation between these two techniques in identification as well as in depth study of the ores and minerals before and after processing has been presented. Also, we describe the aesthetic enhancement of a low quality defective ruby stone by lead oxide filling and the sequential analysis of this ruby stone before and after treatment using these two advanced techniques to identify and to confirm the change in its aesthetic value. The cracks healing and pores filling by the metal oxide on the surface of the ruby have been analyzed using μ-CT and EPMA. Moreover, in this work we describe the advance characterization of the repaired gem stones especially ruby stones. This work will light up the path for in-depth understanding of diffusion mechanism and abstract information of impurity particles inside the minerals. Based on these observations, EPMA and micro CT are shown to be powerful tools for the identification as well as research in gem stones.

  7. TU-FG-BRB-04: A New Optimization Method for Pre-Treatment Patient-Specific Stopping-Power by Combining Proton Radiography and X-Ray CT

    International Nuclear Information System (INIS)

    Collins-Fekete, C; Schulte, R; Beaulieu, L; Seco, J

    2016-01-01

    Purpose: The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work is to develop a robust and systematic method that yields accurate patient specific RSPs by combining pre-treatment X-ray CT and daily proton radiography. Methods: The method is formulated as a penalized least squares optimization (PLSO) problem min(|Ax-B|). The matrix A represents the cumulative path-length crossed in each material computed by calculating proton trajectories through the X-ray CT. The material RSPs are denoted by x and B is the pRad, expressed as water equivalent thickness. The equation is solved using a convex-conic optimizer. Geant4 simulations were made to assess the feasibility of the method. RSP extracted from the Geant4 materials were used as a reference and the clinical HU-RSP curve as a comparison. The PLSO was first tested on a Gammex RMI-467 phantom. Then, anthropomorphic phantoms of the head, pelvis and lung were studied and resulting RSPs were evaluated. A pencil beam was generated in each phantom to evaluate the proton range accuracy achievable by using the optimized RSPs. Finally, experimental data of a pediatric head phantom (CIRS) were acquired using a recently completed experimental pCT scanner. Results: Numerical simulations showed precise RSP (<0.75%) for Gammex materials except low-density lung (LN-300) (1.2%). Accurate RSP have been obtained for the head (µ=−0.10%, 1.5σ=1.12%), lung (µ=−0.33, 1.5σ=1.02%) and pelvis anthropomorphic phantoms (µ=0.12, 1.5σ=0,99%). The range precision has been improved with an average R80 difference to the reference (µ±1.5σ) of −0.20±0.35%, −0.47±0.92% and −0.06±0.17% in the head, lung and pelvis phantoms respectively, compared to the 3.5% clinical margin. Experimental HU-RSP curve have been produced on the CIRS pediatric head. Conclusion: The proposed PLSO with prior knowledge X-ray CT shows promising potential (R80 σ<1.0% over

  8. SU-E-T-143: Effect of X-Ray and Cone Beam CT Reconstruction Parameters On Estimation of Bone Volume of Mice Used in Aging Research

    Energy Technology Data Exchange (ETDEWEB)

    Russ, M; Pang, M; Troen, B; Rudin, S; Ionita, C [University at Buffalo, Buffalo, NY (United States)

    2014-06-01

    Purpose: To investigate the variations in bone volume calculations in mice involved in aging research when changing cone beam micro-CT x-ray and reconstruction parameters. Methods: Mouse spines were placed on an indexed turn table that rotated 0.5° per projection and imaged by a self-built micro CT machine containing a CCD-based high-resolution x-ray detector. After the full 360° rotation data set of object images was obtained, a standard filtered back-projection cone beam reconstruction was performed. Four different kVp's between 40–70 kVp in 10kVp increments were selected. For each kVp two mAs settings were used. Each acquisition was reconstructed using two voxel sizes (12 and 25μm) and two step angles, 0.5° and 1°, respectively. A LabView program was written to determine the total bone volume contained in the mouse's total spine volume (bone plus gaps) as a measure of spine health. First, the user selected the desired 512×512 reconstruction to view the whole spine volume which was then used to select a gray-level threshold that allowed for viewing of the bone structure, then another threshold to include gaps. The program returned bone volume, bone × gap volume, and their ratio, BVF. Results: The calculated bone volume fractions were compared as a function of tube potential. Cases with 25μm slice thickness showed trials with lower kVp's had greater image contrast, which resulted in higher calculated bone volume fractions. Cases with 12μm reconstructed slice thickness were significantly noisier, and showed no clear maximum BVF. Conclusion: Using the projection images and reconstructions acquired from the micro CT, it can be shown that the micro-CT x-ray and reconstruction parameters significantly affect the total bone volume calculations. When comparing mice cohorts treated with different therapies researchers need to be aware of such details and use volumes which were acquired and processed in identical conditions.

  9. Material-specific imaging system using energy-dispersive X-ray diffraction and spatially resolved CdZnTe detectors with potential application in breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barbes, Damien, E-mail: damien.barbes@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Tabary, Joachim, E-mail: joachim.tabary@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Paulus, Caroline, E-mail: caroline.paulus@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Hazemann, Jean-Louis, E-mail: jean-louis.hazemann@neel.cnrs.fr [Univ.Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Verger, Loïck, E-mail: loick.verger@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France)

    2017-03-11

    This paper presents a coherent X-ray-scattering imaging technique using a multipixel energy-dispersive system. Without any translation, the technique produces specific 1D image from data recorded by a single CdZnTe detector pixel using subpixelation techniques. The method is described in detail, illustrated by a simulation and then experimentally validated. As the main considered application of our study is breast imaging, this validation involves 2D imaging of a phantom made of plastics mimicking breast tissues. The results obtained show that our system can specifically image the phantom using a single detector pixel. For the moment, in vivo breast imaging applications remain difficult, as the dose delivered by the system is too high, but some adjustments are considered for further work.

  10. Phantom studies on the artifacts of barium on 18F-FDG DHC/CT images induced by X-ray attenuation correction

    International Nuclear Information System (INIS)

    Wang Wei; Zhu Jiarui; Wang Xinqiang; Zhao Wenrui; Chuan Ling; Xu Genxiang; Gao Chunhua; Fang Tingzheng

    2007-01-01

    Objective: Attenuation correction (AC) based on X-ray transmission map may result in false positive readings or artifacts on PET images, some of them due to the internal residue of high density contrast media used in diagnostic X-ray imaging. The aim of this study was to experimentally estimate the impacts of different concentrations and volumes of barium contrast on X-CT AC (CTAC) for dual-head coincidence (DHC/CT) images. Methods: A cylindrical phantom containing 18 F solution (3.7 kBq/ml), in which plastic fingertips enclosed with different concentrations (0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0 kg/L)and volumes(0.5, 1.0, 1.5, 2.0, 2.5 ml) of BaSO 4 contrast media were inserted, was used to modulate routine 18 F-fluorodeoxyglucose (FDG) imaging study on a DHC/CT scanner (GE Discovery VH). Sequential 18 F emission and X-CT transmission acquisitions followed by data processing and reconstruction were carried out in clinical settings. For comparison, both visual and quantitative analyses were performed on CTAC and non-AC (NAC) images of the phantom. Results: In NAC images, the radioactivity distribution within the whole phantom was non-uniform with lower counts in the center; the plastic fingertips were all seen as 'cold spots' with much lower counts in the contrast region than in their surrounding areas. On the contrary, in CTAC images, the radioactivity distribution within the whole phantom was almost uniform; while most plastic fingertips with media concentration ≥0.1 kg/L and volume >0.5 ml were all depicted as 'hot spots' with higher counts than in surrounding areas. Conclusions: Barium contrast with relative high concentration or large volume can induce artifacts on CTAC DHC/CT images. In clinical setting, proper interpretation of CTAC DHC/CT images should refer to NAC DHC/CT images to exclude any artifacts related to the contrast media residues. (authors)

  11. 3D mapping of water in oolithic limestone at atmospheric and vacuum saturation using X-ray micro-CT differential imaging

    Energy Technology Data Exchange (ETDEWEB)

    Boone, M.A., E-mail: marijn.boone@ugent.be [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium); Unit Sustainable Materials Management, VITO, Boerentang 200, 2400 Mol (Belgium); De Kock, T.; Bultreys, T. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium); De Schutter, G. [Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Technologiepark-Zwijnaarde 904, 9052 Ghent (Belgium); Vontobel, P. [Spallation Neutron Source Division, Paul Scherrer Institute (PSI), 5232 Villigen (Switzerland); Van Hoorebeke, L. [Department of Physics and Astronomy—UGCT, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); Cnudde, V. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium)

    2014-11-15

    Determining the distribution of fluids in porous sedimentary rocks is of great importance in many geological fields. However, this is not straightforward, especially in the case of complex sedimentary rocks like limestone, where a multidisciplinary approach is often needed to capture its broad, multimodal pore size distribution and complex pore geometries. This paper focuses on the porosity and fluid distribution in two varieties of Massangis limestone, a widely used natural building stone from the southeast part of the Paris basin (France). The Massangis limestone shows locally varying post-depositional alterations, resulting in different types of pore networks and very different water distributions within the limestone. Traditional techniques for characterizing the porosity and pore size distribution are compared with state-of-the-art neutron radiography and X-ray computed microtomography to visualize the distribution of water inside the limestone at different imbibition conditions. X-ray computed microtomography images have the great advantage to non-destructively visualize and analyze the pore space inside of a rock, but are often limited to the larger macropores in the rock due to resolution limitations. In this paper, differential imaging is successfully applied to the X-ray computed microtomography images to obtain sub-resolution information about fluid occupancy and to map the fluid distribution in three dimensions inside the scanned limestone samples. The detailed study of the pore space with differential imaging allows understanding the difference in the water uptake behavior of the limestone, a primary factor that affects the weathering of the rock. - Highlights: • The water distribution in a limestone was visualized in 3D with micro-CT. • Differential imaging allowed to map both macro and microporous zones in the rock. • The 3D study of the pore space clarified the difference in water uptake behavior. • Trapped air is visualized in the moldic

  12. Direct observation of characteristic dissociation behaviors of hydrate-bearing cores by rapid-scanning X-ray CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ebinuma, T.; Oyama, H.; Utiumi, T.; Nagao, J.; Narita, H. [National Inst. of Advanced Industrial Science and Technology, Toyohiraku, Sapporo (Japan)

    2008-07-01

    Methane hydrate has significant potential as a new source of energy. Major considerations in developing production methods of methane from hydrates are the fundamental properties of hydrate-bearing sediments, and the dissociation behavior of methane hydrate and the gas and water flow generated by its dissociation in sediments. Marine methane hydrates occur several hundred meters below the sea floor, in a variety of forms. The pore-space filling-type is considered to be the most suited to exploitation, as it is contained within the pore spaces of sandy sediments, and has relatively larger gas permeability compared to other forms. However, shallow sandy sediments are not usually consolidated, and methane hydrate is unstable at normal pressure and temperature. Therefore, common methods are not suitable, and new experimental methods have been developed to study the properties of hydrate-bearing sediment and its dissociation process. This paper presented the results of an experimental study involving the dissociation of artificial methane-hydrate-bearing sediments. The experiment was performed using X-ray computed tomography in order to directly observe dissociation behavior in the sediments and the gas and water flows generated by dissociation. The paper described the depressurization process and presented a schematic diagram of rapid scanning X-ray computed tomography scanner and core holder with tri-axial structure. The experimental apparatus for dissociation of methane hydrate was also illustrated. The thermal stimulation process and hot water injection process were explained. It was concluded that dissociation by depressurization demonstrated that the temperature reduction induced by depressurization depended on the phase equilibrium state of methane hydrate, and that dissociation preferentially occurred at the periphery of the core. This behavior was due to the heat flux from the outside of the core, where the heat flux controlled the dissociation rate. 10 refs

  13. X-ray, CT and DXA study of bone loss on medieval remains from North-West Italy.

    Science.gov (United States)

    Borrè, Alda; Boano, Rosa; Di Stefano, Marco; Castiglione, Anna; Ciccone, Giovannino; Isaia, Giovanni Carlo; Panattoni, Gian Luigi; Faletti, Carlo

    2015-07-01

    The aim of this study was to investigate whether the population differences in osteoporosis observed nowadays is a reflection of the times and modern lifestyle factors, or whether they were also present in the past. The study was performed on the skeletal remains of medieval and post-medieval populations from a burial ground in the North-West of Italy. Some individuals had been buried inside the church (privileged subjects), others outside in the parvis (members of rural population), and others still to the north of the church. X-ray, computed tomography and dual-energy X-ray absorptiometry studies were carried out on the lumbar spines and/or femurs of 27 male and 28 female individuals to determine any associations between cortical index, bone mineral density (BMD), gender, age and social status. No statistically significant differences were observed in cortical index values according to gender, age or place of burial. Conversely, statistically significant differences in average BMD values were observed according to place of burial; in particular, among those buried inside the church, a lower BMD was observed compared to the parvis group (1.09 vs. 1.42, p < 0.001) and the north group (1.09 vs. 1.49, p < 0.001). The differences observed in the BMD values may be related to the different lifestyle of the rural population, i.e. more dietary calcium intake, more sun exposure and vigorous physical activity, compared to that of the privileged individuals.

  14. MO-FG-CAMPUS-IeP2-05: Feasibility Demonstration of High-Voltage Clinical CT and Impact On X-Ray Penetration Through Metal Objects

    International Nuclear Information System (INIS)

    Jin, Y; De Man, B; Robinson, V; Gjesteby, L; Wang, G; Verburg, J; Giantsoudi, D; Paganetti, H

    2016-01-01

    Purpose: To demonstrate the possibility and quantify the impact of operating a clinical CT scanner at exceptionally high x-ray tube voltage for better penetration through metal objects and facilitating metal artifact reduction. Methods: We categorize metal objects according to the data corruption severeness (level of distortion and complete photon starvation fraction). To demonstrate feasibility and investigate the impact of high voltage scanning we modified a commercial GE LightSpeed VCT scanner (generator and software) to enable CT scans with x-ray tube voltages as high as 175 kVp. A 20 cm diameter water phantom with two metal rods (10 mm stainless and 25 mm titanium) and a water phantom with realistic metal object (spine cage) were used to evaluate the data corruption and image artifacts in the absence of any algorithm correction. We also performed simulations to confirm our understanding of the transmitted photon levels through metal objects with different size and composition. Results: The reconstructed images at 175 kVp still have significant dark shading artifacts, as expected since no special scatter correction or beam hardening was performed but show substantially lower noise and photon starvation than at lower kVp due to better beam penetration. Analysis of the raw data shows that the photon starved data is reduced from over 4% at 140 kVp to below 0.2% at 175 kVp. The simulations indicate that for clinically relevant titanium and stainless objects a 175 kVp tube voltage effectively avoids photon starvation. Conclusion: The use of exceptionally high tube voltage on a clinical CT system is a practical and effective solution to avoid photon starvation caused by certain metal implants. Sparse and hybrid high-voltage protocols are being considered to maintain low patient dose. This opens the door to algorithmic physics-based corrections rather than treating the data as missing and relying on missing data algorithms. Some of the authors are employees of General

  15. MO-FG-CAMPUS-IeP2-05: Feasibility Demonstration of High-Voltage Clinical CT and Impact On X-Ray Penetration Through Metal Objects

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y; De Man, B [GE Global Research, Niskayuna, NY (United States); Robinson, V [GE, Global Research, Niskayuna, NY (United States); Gjesteby, L [Rensselaer Polytechnic Institute, Troy, NY (United States); Wang, G [Rensselaer Polytechnic Institute Troy, NY (United States); Verburg, J [Massachusetts, General Hospital, Boston, MA (United States); Giantsoudi, D; Paganetti, H [Massachusetts General Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: To demonstrate the possibility and quantify the impact of operating a clinical CT scanner at exceptionally high x-ray tube voltage for better penetration through metal objects and facilitating metal artifact reduction. Methods: We categorize metal objects according to the data corruption severeness (level of distortion and complete photon starvation fraction). To demonstrate feasibility and investigate the impact of high voltage scanning we modified a commercial GE LightSpeed VCT scanner (generator and software) to enable CT scans with x-ray tube voltages as high as 175 kVp. A 20 cm diameter water phantom with two metal rods (10 mm stainless and 25 mm titanium) and a water phantom with realistic metal object (spine cage) were used to evaluate the data corruption and image artifacts in the absence of any algorithm correction. We also performed simulations to confirm our understanding of the transmitted photon levels through metal objects with different size and composition. Results: The reconstructed images at 175 kVp still have significant dark shading artifacts, as expected since no special scatter correction or beam hardening was performed but show substantially lower noise and photon starvation than at lower kVp due to better beam penetration. Analysis of the raw data shows that the photon starved data is reduced from over 4% at 140 kVp to below 0.2% at 175 kVp. The simulations indicate that for clinically relevant titanium and stainless objects a 175 kVp tube voltage effectively avoids photon starvation. Conclusion: The use of exceptionally high tube voltage on a clinical CT system is a practical and effective solution to avoid photon starvation caused by certain metal implants. Sparse and hybrid high-voltage protocols are being considered to maintain low patient dose. This opens the door to algorithmic physics-based corrections rather than treating the data as missing and relying on missing data algorithms. Some of the authors are employees of General

  16. X-ray induced formation of γ-H2AX foci after full-field digital mammography and digital breast-tomosynthesis.

    Directory of Open Access Journals (Sweden)

    Siegfried A Schwab

    Full Text Available PURPOSE: To determine in-vivo formation of x-ray induced γ-H2AX foci in systemic blood lymphocytes of patients undergoing full-field digital mammography (FFDM and to estimate foci after FFDM and digital breast-tomosynthesis (DBT using a biological phantom model. MATERIALS AND METHODS: The study complies with the Declaration of Helsinki and was performed following approval by the ethic committee of the University of Erlangen-Nuremberg. Written informed consent was obtained from every patient. For in-vivo tests, systemic blood lymphocytes were obtained from 20 patients before and after FFDM. In order to compare in-vivo post-exposure with pre-exposure foci levels, the Wilcoxon matched pairs test was used. For in-vitro experiments, isolated blood lymphocytes from healthy volunteers were irradiated at skin and glandular level of a porcine breast using FFDM and DBT. Cells were stained against the phosphorylated histone variant γ-H2AX, and foci representing distinct DNA damages were quantified. RESULTS: Median in-vivo foci level/cell was 0.086 (range 0.067-0.116 before and 0.094 (0.076-0.126 after FFDM (p = 0.0004. In the in-vitro model, the median x-ray induced foci level/cell after FFDM was 0.120 (range 0.086-0.140 at skin level and 0.035 (range 0.030-0.050 at glandular level. After DBT, the median x-ray induced foci level/cell was 0.061 (range 0.040-0.081 at skin level and 0.015 (range 0.006-0.020 at glandular level. CONCLUSION: In patients, mammography induces a slight but significant increase of γ-H2AX foci in systemic blood lymphocytes. The introduced biological phantom model is suitable for the estimation of x-ray induced DNA damages in breast tissue in different breast imaging techniques.

  17. Minimum miscibility pressure estimation for a CO{sub 2}/n-decane system in porous media by X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu; Jiang, Lanlan; Tang, Lingyue; Song, Yongchen; Zhao, Jiafei; Zhang, Yi; Wang, Dayong; Yang, Mingjun [Dalian University of Technology, Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian (China)

    2015-07-15

    Accurate determination of gas-fluid miscibility conditions is important to optimize the displacement efficiency during CO{sub 2}-enhanced oil recovery. This paper presents a new technique to investigate the phase behavior and to estimate the minimum miscibility pressure (MMP) of a CO{sub 2}/n-decane system using an X-ray computerized tomography (CT) scanner. CT scans of the CO{sub 2}/n-decane system are taken at various pressures during the experiments. The image intensity values taken from the CT images have a linear relationship with the densities of the measured objects; therefore, we can estimate the miscible point of CO{sub 2} and n-decane because the difference between the intensity values for each phase decays to zero as the pressure increases toward the MMP. This paper provides experimental evidence for the validity of the new CT method by comparing the results with previous studies and presents an application of the method to investigate the MMP of the CO{sub 2}/n-decane system in porous media. Additionally, the influence of porous media on the equilibrium state when the CO{sub 2}/n-decane system is close to miscibility is discussed. (orig.)

  18. Amorphous In-Ga-Zn-O thin-film transistor active pixel sensor x-ray imager for digital breast tomosynthesis.

    Science.gov (United States)

    Zhao, Chumin; Kanicki, Jerzy

    2014-09-01

    The breast cancer detection rate for digital breast tomosynthesis (DBT) is limited by the x-ray image quality. The limiting Nyquist frequency for current DBT systems is around 5 lp/mm, while the fine image details contained in the high spatial frequency region (>5 lp/mm) are lost. Also today the tomosynthesis patient dose is high (0.67-3.52 mGy). To address current issues, in this paper, for the first time, a high-resolution low-dose organic photodetector/amorphous In-Ga-Zn-O thin-film transistor (a-IGZO TFT) active pixel sensor (APS) x-ray imager is proposed for next generation DBT systems. The indirect x-ray detector is based on a combination of a novel low-cost organic photodiode (OPD) and a cesium iodide-based (CsI:Tl) scintillator. The proposed APS x-ray imager overcomes the difficulty of weak signal detection, when small pixel size and low exposure conditions are used, by an on-pixel signal amplification with a significant charge gain. The electrical performance of a-IGZO TFT APS pixel circuit is investigated by SPICE simulation using modified Rensselaer Polytechnic Institute amorphous silicon (a-Si:H) TFT model. Finally, the noise, detective quantum efficiency (DQE), and resolvability of the complete system are modeled using the cascaded system formalism. The result demonstrates that a large charge gain of 31-122 is achieved for the proposed high-mobility (5-20 cm2/V s) amorphous metal-oxide TFT APS. The charge gain is sufficient to eliminate the TFT thermal noise, flicker noise as well as the external readout circuit noise. Moreover, the low TFT (sensor imager under 1 mR, indicating good image quality under low dose. A threefold reduction of current tomosynthesis dose is expected if proposed technology is combined with an advanced DBT image reconstruction method. The proposed a-IGZO APS x-ray imager with a pixel pitch6.67 lp/mm) and a low dose (<0.4 mGy) in next generation DBT systems.

  19. Normalized glandular dose (DgN) coefficients for flat-panel CT breast imaging

    International Nuclear Information System (INIS)

    Thacker, Samta C; Glick, Stephen J

    2004-01-01

    The development of new digital mammography techniques such as dual-energy imaging, tomosynthesis and CT breast imaging will require investigation of optimal camera design parameters and optimal imaging acquisition parameters. In optimizing these acquisition protocols and imaging systems it is important to have knowledge of the radiation dose to the breast. This study presents a methodology for estimating the normalized glandular dose to the uncompressed breast using the geometry proposed for flat-panel CT breast imaging. The simulation uses the GEANT 3 Monte Carlo code to model x-ray transport and absorption within the breast phantom. The Monte Carlo software was validated for breast dosimetry by comparing results of the normalized glandular dose (DgN) values of the compressed breast to those reported in the literature. The normalized glandular dose was then estimated for a range of breast diameters from 10 cm to 18 cm using an uncompressed breast model with a homogeneous composition of adipose and glandular tissue, and for monoenergetic x-rays from 10 keV to 120 keV. These data were fit providing expressions for the normalized glandular dose. Using these expressions for the DgN coefficients and input variables such as the diameter, height and composition of the breast phantom, the mean glandular dose for any spectra can be estimated. A computer program to provide normalized glandular dose values has been made available online. In addition, figures displaying energy deposition maps are presented to better understand the spatial distribution of dose in CT breast imaging

  20. Pocket book on setting techniques for medical imaging. X-ray diagnostics, angiography, CT, MRT. 4. rev. and enl. ed.; Taschenatlas Einstelltechnik. Roentgendiagnostik, Angiografie, CT, MRT

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Torsten B.; Reif, Emil [Caritas-Krankenhaus, Dillingen/Saar (Germany)

    2009-07-01

    The pocketbook on setting techniques for medical imaging is concerned with the problem to prepare appropriate images for diagnostic purposes using modern high-technology instruments like x-ray diagnostics, angiography, computerized tomography and magnetic resonance tomography. The following issues are covered: Head, spinal column, upper extremities, lower extremities, thorax, gastrointestinal tract, intravenous organ examination, angiography, computerized tomography, NMR imaging.

  1. Case of neuro-Behcet syndrome with brainstem lesions confirmed by MRI. Relationship between X-ray CT and MRI findings and neurological symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Shunya; Haida, Munetaka; Ohsuga, Hitoshi; Takagi, Shigeharu; Shinohara, Yukito

    1988-03-01

    A 49-year-old man presented with a 30-year history of oral and genital aphthous ulcers and joint pain. One day before his admission he developed double vision and weakness in the right extremities. Neurological examination revealed right 5th nerve palsy, left 6th to 18th nerve palsy, left Horner's sign, and motor and sensory impairment in the right upper and lower extremities. X-ray CT showed diffuse, weak, low-density areas in the brainstem. T1 weighted images showed low signals in the left side of the mid-pons, the left tegmentum and the right basis of the upper pons, and the left tegmentum of the midbrain. T2 weighted images showed high signals in the whole pons and the left side of the midbrain. MRI allowed the differentiation of reversible lesions, such as brain edema, and irreversible lesions, such as necrosis and demyelination of the tissue. (Namekawa, K.).

  2. Scaling-law for the energy dependence of anatomic power spectrum in dedicated breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Shi, Linxi; Glick, Stephen J.; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2013-01-15

    Purpose: To determine the x-ray photon energy dependence of the anatomic power spectrum of the breast when imaged with dedicated breast computed tomography (CT). Methods: A theoretical framework for scaling the empirically determined anatomic power spectrum at one x-ray photon energy to that at any given x-ray photon energy when imaged with dedicated breast CT was developed. Theory predicted that when the anatomic power spectrum is fitted with a power curve of the form k f{sup -{beta}}, where k and {beta} are fit coefficients and f is spatial frequency, the exponent {beta} would be independent of x-ray photon energy (E), and the amplitude k scales with the square of the difference in energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues. Twenty mastectomy specimens based numerical phantoms that were previously imaged with a benchtop flat-panel cone-beam CT system were converted to 3D distribution of glandular weight fraction (f{sub g}) and were used to verify the theoretical findings. The 3D power spectrum was computed in terms of f{sub g} and after converting to linear attenuation coefficients at monoenergetic x-ray photon energies of 20-80 keV in 5 keV intervals. The 1D power spectra along the axes were extracted and fitted with a power curve of the form k f{sup -{beta}}. The energy dependence of k and {beta} were analyzed. Results: For the 20 mastectomy specimen based numerical phantoms used in the study, the exponent {beta} was found to be in the range of 2.34-2.42, depending on the axis of measurement. Numerical simulations agreed with the theoretical predictions that for a power-law anatomic spectrum of the form k f{sup -{beta}}, {beta} was independent of E and k(E) =k{sub 1}[{mu}{sub g}(E) -{mu}{sub a}(E)]{sup 2}, where k{sub 1} is a constant, and {mu}{sub g}(E) and {mu}{sub a}(E) represent the energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues, respectively. Conclusions: Numerical

  3. Chest X-Ray

    Medline Plus

    Full Text Available ... some concerns about chest x-rays. However, it’s important to consider the likelihood of benefit to your health. While a chest x-ray use a ... posted: How to Obtain and Share ...

  4. Chest X-Ray

    Medline Plus

    Full Text Available ... X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey Rubin, a radiologist ... about chest x-rays, visit Radiology Info dot org. Thank you for your time! Spotlight Recently posted: ...

  5. X-ray apparatus

    International Nuclear Information System (INIS)

    Sell, L.J.

    1981-01-01

    A diagnostic x-ray device, readily convertible between conventional radiographic and tomographic operating modes, is described. An improved drive system interconnects and drives the x-ray source and the imaging device through coordinated movements for tomography

  6. X-ray - skeleton

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this ... Degenerative bone conditions Osteomyelitis Risks There is low radiation exposure. X-rays machines are set to provide the smallest ...

  7. Wobbled splatting-a fast perspective volume rendering method for simulation of x-ray images from CT

    International Nuclear Information System (INIS)

    Birkfellner, Wolfgang; Seemann, Rudolf; Figl, Michael; Hummel, Johann; Ede, Christopher; Homolka, Peter; Yang Xinhui; Niederer, Peter; Bergmann, Helmar

    2005-01-01

    3D/2D registration, the automatic assignment of a global rigid-body transformation matching the coordinate systems of patient and preoperative volume scan using projection images, is an important topic in image-guided therapy and radiation oncology. A crucial part of most 3D/2D registration algorithms is the fast computation of digitally rendered radiographs (DRRs) to be compared iteratively to radiographs or portal images. Since registration is an iterative process, fast generation of DRRs-which are perspective summed voxel renderings-is desired. In this note, we present a simple and rapid method for generation of DRRs based on splat rendering. As opposed to conventional splatting, antialiasing of the resulting images is not achieved by means of computing a discrete point spread function (a so-called footprint), but by stochastic distortion of either the voxel positions in the volume scan or by the simulation of a focal spot of the x-ray tube with non-zero diameter. Our method generates slightly blurred DRRs suitable for registration purposes at framerates of approximately 10 Hz when rendering volume images with a size of 30 MB. (note)

  8. Preliminary investigation of the NMR, optical and x-ray CT dose-response of polymer gel dosimeters incorporating cosolvents to improve dose sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Koeva, V I; McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Olding, T [Department of Physics, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada); Schreiner, L J [Cancer Centre of Southeastern Ontario, Kingston, ON, K7L5P9 (Canada)], E-mail: kim.mcauley@chee.queensu.ca

    2009-05-07

    This study reports on efforts to increase the dose sensitivity of polymer gel dosimeters used in 3D radiation dosimetry. The potential of several different cosolvents is investigated, with the aim of increasing the solubility of N,N'-methylene-bisacrylamide crosslinker in polymer gel dosimeters. Glycerol and isopropanol increase the limit for the crosslinker solubility from approximately 3% to 5% and 10% by weight, respectively. This enables the manufacture of polymer gel dosimeters with much higher levels of crosslinking than was previously possible. New dosimeter recipes containing up to 5 wt% N,N'-methylene-bisacrylamide were subjected to spatially uniform radiation and were studied using nuclear magnetic resonance (NMR), as well as x-ray and optical CT techniques. The resulting dosimeters exhibit dose sensitivities that are up to 2.7 times higher than measured for a typical dosimeters with 3% N,N'-methylene-bisacrylamide without the addition of cosolvent. Two additional cosolvents (n-propanol and sec-butanol) were deemed unsuitable for practical dosimeters due to incompatibility with gelatin, cloudiness prior to irradiation, and immiscibility with water when large quantities of cosolvent were used. The dosimeters with high N,N'-methylene-bisacrylamide content that used isopropanol or glycerol as cosolvents had high optical clarity prior to irradiation, but did not produce suitable optical CT results for non-uniformly irradiated gels due to polymer development outside of the high dose regions of the pencil beams and significant light scatter. Further experiments are required to determine whether cosolvents can be used to manufacture gels with sufficiently high dose sensitivity for readout using x-ray computed tomography.

  9. Preliminary investigation of the NMR, optical and x-ray CT dose-response of polymer gel dosimeters incorporating cosolvents to improve dose sensitivity

    International Nuclear Information System (INIS)

    Koeva, V I; McAuley, K B; Olding, T; Jirasek, A; Schreiner, L J

    2009-01-01

    This study reports on efforts to increase the dose sensitivity of polymer gel dosimeters used in 3D radiation dosimetry. The potential of several different cosolvents is investigated, with the aim of increasing the solubility of N,N'-methylene-bisacrylamide crosslinker in polymer gel dosimeters. Glycerol and isopropanol increase the limit for the crosslinker solubility from approximately 3% to 5% and 10% by weight, respectively. This enables the manufacture of polymer gel dosimeters with much higher levels of crosslinking than was previously possible. New dosimeter recipes containing up to 5 wt% N,N'-methylene-bisacrylamide were subjected to spatially uniform radiation and were studied using nuclear magnetic resonance (NMR), as well as x-ray and optical CT techniques. The resulting dosimeters exhibit dose sensitivities that are up to 2.7 times higher than measured for a typical dosimeters with 3% N,N'-methylene-bisacrylamide without the addition of cosolvent. Two additional cosolvents (n-propanol and sec-butanol) were deemed unsuitable for practical dosimeters due to incompatibility with gelatin, cloudiness prior to irradiation, and immiscibility with water when large quantities of cosolvent were used. The dosimeters with high N,N'-methylene-bisacrylamide content that used isopropanol or glycerol as cosolvents had high optical clarity prior to irradiation, but did not produce suitable optical CT results for non-uniformly irradiated gels due to polymer development outside of the high dose regions of the pencil beams and significant light scatter. Further experiments are required to determine whether cosolvents can be used to manufacture gels with sufficiently high dose sensitivity for readout using x-ray computed tomography.

  10. Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review.

    Science.gov (United States)

    Giacomelli, Irai Luis; Schuhmacher Neto, Roberto; Marchiori, Edson; Pereira, Marisa; Hochhegger, Bruno

    2018-04-01

    The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

  11. Research on the radiation doses to adults receiving from main types of medical X-ray CT examinations

    International Nuclear Information System (INIS)

    Gao Linfeng; Wang Bin; Yao Jie; Qian Aijun; Zheng Junzheng; Zhuo Weihai; Qu Liangyong

    2013-01-01

    To study and master the doses to examinees receiving from the wide spread X-CT examinations, is a key issue for strengthening the medical radiation protection. In the studies of the medical exposure levels during the Eleventh Five-Year Plan period in Shanghai, based on the brands of X-CT scanners and their distributions in different levels of hospitals, a total of 45 sets (about 30% of all) of scanners were selected for the field study. Among the 8 commonly performed examinations, the scan parameters and their relevant dosimetry information for 500 adults were collected, and their typical effective doses were estimated with the dose conversion factors. The results showed that the averages of weighted CT dose index (CTDI w ) were 55.4, 12.5 and 18.4 mGy, and the dose length products (DLP) were averaged to be 603, 294 and 415 mGy·cm, for the skull, chest and abdomen X-CT scans, respectively. The typical effective doses were estimated to be 1.4, 5.3, and 7.5 mSv for adults in the head, chest and abdomen X-CT scans, respectively. The values of CTDI w for skull scans were generally higher than those for the ear canal, eye, or sinus examinations. It is clear that the optimization between the image quality and the radiation dose should be further strengthened. Particular attentions should be paid in selecting the scanning parameters for various types of X-CT scans, and the diagnostic reference levels for X-CT examinations should be continuously improved. (authors)

  12. X-ray microfluorescence as a tool to analyze elemental changes in femur head induced by chemotherapy drugs for the treatment of breast cancer

    Science.gov (United States)

    Pickler, A.; Mota, C. L.; Mantuano, A.; Salata, C.; Nogueira, L. P.; Almeida, A. P.; Alessio, R.; Sena, G.; Braz, D.; de Almeida, C. E. V.; Barroso, R. C.

    2015-11-01

    Recently some developments in a large number of investigative techniques have been made with the objective to obtain a micrometer spatial resolution imaging of elemental concentrations. The X-ray microfluorescence analysis (μXRF) is one of those techniques which is based on the localized excitation of a small area on the surface of sample, providing information of all elements contained in the material under study. Breast cancer is the most common malignancy in Brazilian women. The main treatment strategies for the breast cancer are surgery and chemotherapy. As bone loss is one of the possible chemotherapy side effects, in this work was used μXRF technique on femoral head samples of female Wistar rats to evaluate Ca, Fe and Zn concentrations in order to investigate possible elemental changes in bone caused by the chemotherapy. Fifteen female rats were divided randomly in groups (five rats each). G1 group received doses of doxorubicin/cyclophosphamide drugs and G2 group was treated with docetaxel/cyclophosphamide drugs. μXRF measurements were carried out at the X-ray XRF beamline in the Brazilian Synchrotron Light Laboratory. The results showed significant decrease especially in Ca concentrations when comparing the treated groups with the control group.

  13. Chest X-Ray

    Medline Plus

    Full Text Available ... I’d like to talk with you about chest radiography also known as chest x-rays. Chest x-rays are the most ... far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! ...

  14. Chest X-Ray

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  15. Adaptation Measurement of CAD/CAM Dental Crowns with X-Ray Micro-CT: Metrological Chain Standardization and 3D Gap Size Distribution

    Directory of Open Access Journals (Sweden)

    L. Tapie

    2016-01-01

    Full Text Available Computer-Aided Design and Manufacturing systems are increasingly used to produce dental prostheses, but the parts produced suffer from a lack of evaluation, especially concerning the internal gap of the final assembly, that is, the space between the prepared tooth and the prosthesis. X-ray micro-Computed Tomography (micro-CT is a noninvasive imaging technique enabling the internal inspection of the assembly. It has proved to be an efficient tool for measuring the gap. In this study, a critical review of the protocols using micro-CT to quantify the gap is proposed as an introduction to a new protocol aimed at minimizing errors and enabling comparison between CAD/CAM systems. To compare different systems, a standardized protocol is proposed including two reference geometries. Micro-CT is used to acquire the reference geometries. A new 3D method is then proposed and a new indicator is defined (Gap Size Distribution (GSD. In addition, the usual 2D measurements are described and discussed. The 3D gap measurement method proposed can be used in clinical case geometries and has the considerable advantage of minimizing the data processing steps before performing the measurements.

  16. A sparsity-based iterative algorithm for reconstruction of micro-CT images from highly undersampled projection datasets obtained with a synchrotron X-ray source

    Science.gov (United States)

    Melli, S. Ali; Wahid, Khan A.; Babyn, Paul; Cooper, David M. L.; Gopi, Varun P.

    2016-12-01

    Synchrotron X-ray Micro Computed Tomography (Micro-CT) is an imaging technique which is increasingly used for non-invasive in vivo preclinical imaging. However, it often requires a large number of projections from many different angles to reconstruct high-quality images leading to significantly high radiation doses and long scan times. To utilize this imaging technique further for in vivo imaging, we need to design reconstruction algorithms that reduce the radiation dose and scan time without reduction of reconstructed image quality. This research is focused on using a combination of gradient-based Douglas-Rachford splitting and discrete wavelet packet shrinkage image denoising methods to design an algorithm for reconstruction of large-scale reduced-view synchrotron Micro-CT images with acceptable quality metrics. These quality metrics are computed by comparing the reconstructed images with a high-dose reference image reconstructed from 1800 equally spaced projections spanning 180°. Visual and quantitative-based performance assessment of a synthetic head phantom and a femoral cortical bone sample imaged in the biomedical imaging and therapy bending magnet beamline at the Canadian Light Source demonstrates that the proposed algorithm is superior to the existing reconstruction algorithms. Using the proposed reconstruction algorithm to reduce the number of projections in synchrotron Micro-CT is an effective way to reduce the overall radiation dose and scan time which improves in vivo imaging protocols.

  17. Correction method of nonlinearity due to logarithm operation for X-ray CT projection data with noise in photon-starved state

    International Nuclear Information System (INIS)

    Iwamoto, Shin-ichiro; Shiozaki, Akira

    2007-01-01

    In the acquisition of projection data of X-ray CT, logarithm operation is indispensable. But noise distribution is nonlinearly projected by the logarithm operation, and this deteriorates the precision of CT number. This influence becomes particularly remarkable when only a few photons are caught with a detector. It generates a strong streak artifact (SA) in a reconstructed image. Previously we have clarified the influence of the nonlinearity by statistical analysis and proposed a correction method for such nonlinearity. However, there is a problem that the compensation for clamp processing cannot be performed and that the suppression of SA is not enough in photon shortage state. In this paper, we propose a new technique for correcting the nonlinearity due to logarithm operation for noisy data by combining the previously presented method and an adaptive filtering method. The technique performs an adaptive filtering only when the number of captured photons is very few. Moreover we quantitatively evaluate the influence of noise on the reconstructed image in the proposed method by the experiment using numerical phantoms. The experimental results show that there is less influence on spatial resolution despite suppressing SA effectively and that CT number are hardly dependent on the number of the incident photons. (author)

  18. Rod displacement measurements by x-ray CT and its impact on thermal-hydraulics in tight-lattice rod bundle (Joint research)

    International Nuclear Information System (INIS)

    Mitsutake, Toru; Misawa, Takeharu; Kureta, Masatoshi; Akimoto, Hajime

    2005-06-01

    In tight-lattice simulated rod bundles with about 1 mm gap between rods, a rod displacement might affect thermal-hydraulic characteristics since the displacement has a strong impact on the flow area change along the heated section. It should be important to estimate how large the rod position displacement could quantitatively affect critical power for the tight-lattice rod bundle from the point of improvement of prediction capability of subchannel analysis. In the present study, the inside-structure observation of the simulated seven-rod bundle of Reduced Moderation Water Reactor (RMWR) was made through the whole length of the test assembly. Based on the measured rod position data, the relation between the rod position displacement and the heat transfer characteristics was investigated experimentally and through the two kinds of subchannel analysis, the nominal rod position case and the measured rod position case, the effect on the predicted critical power was estimated. The high-energy X-ray computer tomograph (CT) of Fuels Monitoring Facilities (FMF) at the O-arai Engineering Center in Japan Nuclear Cycle Institute (JNC) was applied for the inside-structure observation of the test assembly. The CT view of the cross sections within the test assembly assured the hexagonal rod position arrangement was almost the same as expected by design. The measured data with the X-ray CT facility showed that all rod displacements were small, 0.5 millimeters at maximum and 0.2 millimeters in average. In the heat transfer experiments for the seven-rod bundle, the boiling transition (BT) position and the rod surface temperature behavior was measured. All thermocouples on the center rod downstream from the BT-onset axial height showed almost simultaneous temperature increase due to BT. And the thermocouples located on the same axial heights showed quite similar time-variation behaviors in the vapor cooling heat transfer regime. These results demonstrated the effect of the

  19. Wavelet-based feature extraction applied to small-angle x-ray scattering patterns from breast tissue: a tool for differentiating between tissue types

    International Nuclear Information System (INIS)

    Falzon, G; Pearson, S; Murison, R; Hall, C; Siu, K; Evans, A; Rogers, K; Lewis, R

    2006-01-01

    This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks

  20. TU-EF-207-05: Dedicated Cone-beam Breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, S. [Univ. of Massachusetts Medical School (United States)

    2015-06-15

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation.

  1. TU-EF-207-05: Dedicated Cone-beam Breast CT

    International Nuclear Information System (INIS)

    Vedantham, S.

    2015-01-01

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation

  2. Comparative study on findings of the brain computed tomography (X-ray-CT) and dynamic topography of VEP (VDT)

    International Nuclear Information System (INIS)

    Matsuura, Masashi

    1985-01-01

    Comparative study between morphological Xray-CT and functional VDT was conducted on 20 cases of cerebral diseases with visual dysfunction. Subjects were patients with cerebral infarction, intracranial hemorrhage, hemispherectomy, traumatic brain atrophy, brain tumor, Creutzfeldt-Jakob disease, anoxic encephalopathy, porencephaly, microcephaly and optic tract lesion. VEP topography was performed by flash stimulation and brain electrical activity mappings were displayed by EEG topography computer. In 9 cases out of 20, abolished function in VDT was correlated to the defective findings of Xray-CT. Cases with homonymous hemianopsia showed 2 types of BEAM. In cases with a lesion in the inner surface of the occipital lobe, asymmetric electric activity was distributed along the sagittal axis of the scalp. While, in cases with outer surface lesion of the occipital lobe, asymmetric electric activity appeared along the coronary axis. In cases with multi focal brain lesions in Xray-CT, there was no regular tendency in abnormality of VDT. Various aberration of VEP and VDT, such as component defect, stagnation, reduction, condensation and abnormal flow were demonstrated. In a case of optic tract lesion, Xray-CT showed no pathological findings but VDT showed a remarkable asymmetry of brain activity. (author)

  3. Clinical aspects of intraoperative radiotherapy in early breast cancer: short-term complications after IORT in women treated with low energy x-rays

    International Nuclear Information System (INIS)

    Tuschy, Benjamin; Berlit, Sebastian; Romero, Simone; Sperk, Elena; Wenz, Frederik; Kehl, Sven; Sütterlin, Marc

    2013-01-01

    To assess postoperative complications, clinical outcome and histological findings in patients undergoing intraoperative radiotherapy with low energy x-rays for early breast cancer. We retrospectively analysed data of 208 women who underwent intraoperative irradiation during breast conserving surgery (BCS) between 2002 and 2007. Demographic, clinical and surgical parameters as well as short-term complications within the first postoperative week and histological findings were evaluated. Toxicities were assessed using the CTC/EORTC Score. Postoperative complications were rare and the immediate toxicity low, without any grade 3/4 acute toxicity. The most frequent postoperative side effects were suggillation (24%) and palpable seroma (17.3%). In 78.6% of the axillary seroma and in 25% of the breast seroma a needle aspiration was inevitable. Erythema grade I-II of the breast was found in 27 women (13%); whereas in 7 patients (3.4%), mastitis was confirmed. In 57.7% of the cases, the pathological assessment revealed ductal invasive breast cancer and tumour size ranged between 0.1 and 4.5 cm (mean = 1.6 cm). IORT using Intrabeam ® during BCS is safe, although it is associated with postoperative adverse events such as seroma. These should be mentioned and explained to women in detail during the preoperative discussion. This explicitly clinical description is useful for daily clinical practice; especially for giving a detailed analysis of the postoperative side effects during preoperative counselling

  4. Dedicated breast CT: radiation dose for circle-plus-line trajectory

    International Nuclear Information System (INIS)

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; Noo, Frederic

    2012-01-01

    Purpose: Dedicated breast CT prototypes used in clinical investigations utilize single circular source trajectory and cone-beam geometry with flat-panel detectors that do not satisfy data-sufficiency conditions and could lead to cone beam artifacts. Hence, this work investigated the glandular dose characteristics of a circle-plus-line trajectory that fulfills data-sufficiency conditions for image reconstruction in dedicated breast CT. Methods: Monte Carlo-based computer simulations were performed using the GEANT4 toolkit and was validated with previously reported normalized glandular dose coefficients for one prototype breast CT system. Upon validation, Monte Carlo simulations were performed to determine the normalized glandular dose coefficients as a function of x-ray source position along the line scan. The source-to-axis of rotation distance and the source-to-detector distance were maintained constant at 65 and 100 cm, respectively, in all simulations. The ratio of the normalized glandular dose coefficient at each source position along the line scan to that for the circular scan, defined as relative normalized glandular dose coefficient (RD g N), was studied by varying the diameter of the breast at the chest wall, chest-wall to nipple distance, skin thickness, x-ray beam energy, and glandular fraction of the breast. Results: The RD g N metric when stated as a function of source position along the line scan, relative to the maximum length of line scan needed for data sufficiency, was found to be minimally dependent on breast diameter, chest-wall to nipple distance, skin thickness, glandular fraction, and x-ray photon energy. This observation facilitates easy estimation of the average glandular dose of the line scan. Polynomial fit equations for computing the RD g N and hence the average glandular dose are provided. Conclusions: For a breast CT system that acquires 300-500 projections over 2π for the circular scan, the addition of a line trajectory with equal

  5. Flash X-ray

    International Nuclear Information System (INIS)

    Sato, Eiichi

    2003-01-01

    Generation of quasi-monochromatic X-ray by production of weakly ionized line plasma (flash X-ray), high-speed imaging by the X-ray and high-contrast imaging by the characteristic X-ray absorption are described. The equipment for the X-ray is consisted from the high-voltage power supply and condenser, turbo molecular pump, and plasma X-ray tube. The tube has a long linear anticathode to produce the line plasma and flash X-ray at 20 kA current at maximum. X-ray spectrum is measured by the imaging plate equipped in the computed radiography system after diffracted by a LiF single crystal bender. Cu anticathode generates sharp peaks of K X-ray series. The tissue images are presented for vertebra, rabbit ear and heart, and dog heart by X-ray fluoroscopy with Ce anticathode. Generation of K-orbit characteristic X-ray with extremely low bremsstrahung is to be attempted for medical use. (N.I.)

  6. X-ray computed tomography (CT) study of small, deep and recent infarcts (SDRIs) of the cerebral hemispheres in adults

    International Nuclear Information System (INIS)

    Launay, M.; N'Diaye, M.; Bories, J.

    1985-01-01

    The evolution of CT signs of small deep infarcts of the cerebral hemispheres in thirty adults, in the first five weeks, has been retrospectively studied. The relevant literature has been reviewed and an attempt has been made to present a synthesis, accompanied by a commentary. It is impossible now to give the frequency of each type of evolution, but the main data are as follows: 1. The shortest delay in apparance of an hypodense area is about 17 to 21 h, but at 27 h the densities may be still normal. 2. The evolution of the hypodense area is also variable: after a minimum attenuation is reached - at approximately 72 h - there is a risk of ''fogging effect'', which reduces the visibility of ischemic lesions; it could be seen from the end of the 1st week to the beginning of the 4th, but its frequency and its duration have yet to be better determined. 3. In our series, contrast enhancement has been found in the gray matter of the basal ganglia between the 8th and the 22nd days - but according to some observations recorded in the literature, it may be found from the second to the twenty sixth day - and there was no obvious contrast enhancement in the white matter. The significance of the evolving CT signs is discussed in connection with the clinical applications, principally in the management of these patients and with the attempts to correlate the clinical and CT findings. (orig.)

  7. SU-F-J-42: Comparison of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Cranial Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, J; Shi, W; Andrews, D; Werner-Wasik, M; Lu, B; Yu, Y; Dicker, A; Liu, H [Thomas Jefferson University Hospital, Philadelphia, PA (United States)

    2016-06-15

    Purpose: To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac x-ray imaging systems for cranial radiotherapy. Method: Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (Version 2.5), which is integrated with a BrainLab ExacTrac imaging system (Version 6.1.1). The phantom study was based on a Rando head phantom, which was designed to evaluate isocenter-location dependence of the image registrations. Ten isocenters were selected at various locations in the phantom, which represented clinical treatment sites. CBCT and ExacTrac x-ray images were taken when the phantom was located at each isocenter. The patient study included thirteen patients. CBCT and ExacTrac x-ray images were taken at each patient’s treatment position. Six-dimensional image registrations were performed on CBCT and ExacTrac, and residual errors calculated from CBCT and ExacTrac were compared. Results: In the phantom study, the average residual-error differences between CBCT and ExacTrac image registrations were: 0.16±0.10 mm, 0.35±0.20 mm, and 0.21±0.15 mm, in the vertical, longitudinal, and lateral directions, respectively. The average residual-error differences in the rotation, roll, and pitch were: 0.36±0.11 degree, 0.14±0.10 degree, and 0.12±0.10 degree, respectively. In the patient study, the average residual-error differences in the vertical, longitudinal, and lateral directions were: 0.13±0.13 mm, 0.37±0.21 mm, 0.22±0.17 mm, respectively. The average residual-error differences in the rotation, roll, and pitch were: 0.30±0.10 degree, 0.18±0.11 degree, and 0.22±0.13 degree, respectively. Larger residual-error differences (up to 0.79 mm) were observed in the longitudinal direction in the phantom and patient studies where isocenters were located in or close to frontal lobes, i.e., located superficially. Conclusion: Overall, the average residual-error differences were within 0.4 mm in the translational

  8. Amorphous In–Ga–Zn–O thin-film transistor active pixel sensor x-ray imager for digital breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chumin; Kanicki, Jerzy, E-mail: kanicki@eecs.umich.edu [Solid-State Electronic Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-09-15

    Purpose: The breast cancer detection rate for digital breast tomosynthesis (DBT) is limited by the x-ray image quality. The limiting Nyquist frequency for current DBT systems is around 5 lp/mm, while the fine image details contained in the high spatial frequency region (>5 lp/mm) are lost. Also today the tomosynthesis patient dose is high (0.67–3.52 mGy). To address current issues, in this paper, for the firs