Lighting up the Lungs: using Synchrotron Dual K-edge Computed Tomography (#1084)
G. K. Aulakh1, B. Singh2, D. Chapman3
1 University of Saskatchewan, Small Animal Clinical Sciences/WCVM, Saskatoon, Saskatchewan, Canada
Structural and functional correlation of lung status during pre-clinical research can markedly improve the quality of experimental claims made by individual research teams. Therefore, we sought to image the lung airways and vasculature by employing high-resolution (8 µm) dual K-edge subtraction computed synchrotron x-ray tomography at the Canadian Light Source. Previously, we have shown that angiostatin, an endogenously cleaved anti-angiogenic molecule, protects against exuberant neutrophil migration, activation and vascular leak in murine endotoxin challenge model without diminishing the host immune response. We utilized barium and iodine based K-edge imaging by injecting a mix comprised of in-house prepared barium microparticles and standard iodine contrast solution via jugular vein. Lungs from respective treatments were excised and embedded in agarose under vacuum. Imaging was accomplished at four different energy levels, to cover the barium and iodine upper as well as lower K-edge. We observed well preserved architecture with very thin airway and vascular compartments in saline treated lungs. Conversely, endotoxin treatment produced markedly leaky vascular walls along with compromised alveolar septa. Angiostatin and endotoxin treatment offered complete protection against vascular leak as shown by well preserved vasculature as well as alveolar septa. This study presents evidence of the protective effect of angiostatin in endotoxin induced acute lung injury.
Keywords: computed tomography, dual K-edge imaging, acute lung injury, synchrotron x-ray imaging, angiostatin, barium and iodine contrast imaging, microangiography
Image fusion with a dental panoramic x-ray image and face image acquired with a KINECT (#1078)
K. Kawai1, K. Ogawa1, A. Katsumata2
1 Hosei University, Department of Applied Informatics, Faculty of Science and Engineering, Tokyo, Japan
The aim of this study was to make a fusion image combined with a patient’s face image and three dimensional teeth and jaw-bone image reconstructed with panoramic x-ray data. To make a face image, we used a KINECT sensor that was attached to the arm of the dental panoramic x-ray system. The x-ray tube and detector were located opposite to each other inside the arm, and the arm rotated around the patient’s head. We used depth data measured by the KINECT sensor to make a three dimensional face image of the patient. The three dimensional teeth and jaw-bone image at the standard dental arch was made with the tomosynthesis technique. The location of the standard dental arch was measured in advance with the dedicated phantom. The registration of two images was conducted with tungsten rubber markers. The experiments with a volunteershowed that the reconstructed fusion image was acceptable for clinical use.
Keywords: panoramic x-ray imaging, KINECT, fusion
Breast microcalcification classification using X-ray phase contrast imaging (#3554)
O. Caudevilla1, W. Zhou1, S. Glick2, J. G. Brankov1
1 Illinois Intitute of Technology, Electrical and Computer Engineering, Chicago, Illinois, United States of America
Ductal Carcinoma in situ (DCIS) is a pre-cancerous lesion that leads to breast cancer in up to 30% of the cases. Preventive screening is critical in detecting and treating DCIS before they develop into cancer. Malignant microcalcifications (MCs) are the main indicator of DCIS: 80% of DCIS diagnosis are done based on MC detection and classification. It has been observed that calcium hydroxyapatite (CaHA) MCs are more prompt to appear associated to DCIS than calcium oxalate (CaOX). Unfortunately digital mammograms show very little difference between them. Unlike the conventional X-ray mammography, which measures only X-ray absorption, analyzer based phase-contrast X-ray imaging (ABI) can also measure the mass density properties of the imaged object. In this paper we demonstrate how estimated density combined with absorption images can be used to differentiate CaHA and CaOX MCs.
Keywords: Microcalcifications, Phase-contrast, breast, DCIS
A Novel Phase Contrast System (#3587)
J. Dey1, J. Xu1, K. Ham2, N. Bhusal1, V. Singh2, 3
1 LSU, Physics and Astronomy, Baton Rouge, Louisiana, United States of America
A novel single-phase-grating Phase contrast system was simulated using Sommerfield-Rayleigh diffraction integrals. We accomplish in one X-ray optic the functionality that requires 2-3 optics in Miao et al Nature Physics 2015. We retain all their benefits of not requiring the absorption grating (analyzer) in Talbot-Lau interferometers. This will reduce the dose-requirement (approximately by a factor of two). We observed interference pattern (pitch 0.2mm) with grating to detector distance of 50mm for parallel beam source. The interference pattern can be tuned to different applications depending on detector resolution. Our eventual goal is to achieve compact interferometry of the design lengths required for a clinical mammogram system.
Keywords: Phase Contrast X-ray, Far Field System, Near Field System, Talbot-Lau interferometers
Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov-light threshold (#1967)
S. Yamamoto1, S. Koyama1, M. Komori1
1 Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
It is commonly thought that UV or visible light luminescence imaging of water or other subjects such as acrylic resin and biological subjects during X-ray irradiation at the energy below 120 keV is impossible because the secondary electrons produced in this energy range do not emit Cerenkov light. Contrary to this consensus, we found luminescence imaging of water or other subjects were possible with X-ray irradiations of this energy range. We placed one of subjects in a black box, visible light luminescence images were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray irradiation at energy below 120 keV. The water, acrylic block and biological subjects emitted luminescence and the imaging was possible with the irradiation of the X-ray below 120 keV. The luminescence intensity increased with irradiated dose. The luminescence images were observed in only the X-ray irradiated areas. Luminescence imaging of water or biological subjects was possible during X-ray irradiations lower energy than the Cerenkov-light threshold and this method has the potential to be a new approach for dose estimation and distribution measurements in low-energy X-ray imaging systems.
Keywords: luminescence, imaging, X-ray photons, Cerenkov-light
Beam hardening correction for bi-material objects using Grangeat-based consistency measure (#2474)
S. Abdurahman1, R. Frysch1, R. Bismark1, M. Friebe1, O. Beuing2, G. Rose1
1 Otto von Guericke University, Institute for Medical Engineering, Magdeburg, Saxony-Anhalt, Germany
Due to the polychromatic nature of X-ray spectrum and the energy-dependent attenuation coefficient of the imaged object, beam hardening artifacts can be present in computed tomography reconstructed volumes. These artifacts appear as cupping and streak artifacts and degrade the image quality. Clinical CT scanners employ water correction to reduce the cupping artifacts in soft tissues. Here, the polychromatic attenuation values in the projections are transformed to monochromatic attenuation values using a polynomial model with an assumption that human body primarily consists of soft tissues. However, the water correction is not sufficient to correct both the cupping artifacts present in bone and the bone induced streak artifacts. Water correction method can be extended to include bone correction using 2D linearization with two different polynomials. We present an algorithm to estimate both the polynomials concurrently using consistency conditions derived from Grangeat’s fundamental relation. First, the initial volume is reconstructed, and the bone structures are segmented. The error due to the beam hardening in bone is approximated by the forward projection of segmented bone volumes. Both the water and the bone correction polynomials are iteratively estimated with the minimization of beam hardening error by enforcing consistency conditions on a projection pair. Finally, the water and bone corrected projections are obtained using optimized polynomials, original and bone projections. Our results from simulated and clinical datasets show that the method reduces cupping and streak artifacts without increasing computational complexity. The algorithm requires neither calibration nor prior knowledge like X-ray and material attenuation spectrums. Thus, the proposed method can be applied in clinical, preclinical and industrial computed tomography systems where bi-material volumes are used.
Keywords: Cone beam computed tomography, Beam hardening artifacts, Consistency conditions, Grangeat’s fundamental relation