Loading...
  • scan
  • This complicates absolute calibration, as effective attenuation is a function of both the X-ray spectrum and the properties of the scan object. (carleton.edu)
  • In a conventional apparatus, the intensity of X-ray generated during a helical scan is maintained at a constant value. (google.com)
  • This X-ray intensity control is effective in a single-slice scan shown in FIG. 1B. (google.com)
  • As shown in FIG. 2B, however, X-ray intensity cannot be satisfactorily optimized for a multi-slice scan (also called a volume scan). (google.com)
  • It is an object of the present invention to further optimize X-ray intensity in a multi-slice scan. (google.com)
  • However, the operational flexibility of these devices is restricted by their inability to record sufficient x-ray transmission data to reconstruct more than a single 5-15mm thick cross section of tissue during one scan and the relatively long duration (2-60s) for each scan. (springer.com)
  • Other terms include computed axial tomography (CAT scan) and computer aided tomography. (wikipedia.org)
  • intensity
  • Recently, however, techniques of changing the intensity of X-rays in accordance with the X-ray transmission factor which changes in accordance with a region of the object have been proposed. (google.com)
  • In many of these proposals, the X-ray intensity is changed in accordance with a value at a given point on a scanogram. (google.com)
  • Therefore, an energy threshold cannot be applied, making this technique is susceptible to noise and other factors which can affect the linearity of the voltage to X-ray intensity relationship. (wikipedia.org)
  • diagnosis
  • In the acoustic stress wave tomography of trees (see also: tree diagnosis), concussion sensors are attached in one or several planes around a trunk or a branch and their positions are measured. (wikipedia.org)
  • Images
  • Present commercial x-ray computed tomography (CT) scanners are capable of producing single cross section images of the head, thorax, or abdomen which exhibit both high spatial and halftone resolution as described by Brooks and DiChiro (1976). (springer.com)
  • term
  • The term acoustic tomography refers to the perceptible sounds that are caused by the mechanical impulses used for measuring. (wikipedia.org)
  • include
  • These include computerized tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP). (wikipedia.org)
  • spectrum
  • Each registered photon is thus assigned to a specific bin depending on its energy, such that each pixel measures a histogram of the incident X-ray spectrum. (wikipedia.org)
  • high
  • This technique enables measurements at isolated high-energy ranges, in which the dominating undergoing interaction between the x-ray and the sample is the incoherent scattering. (spiedigitallibrary.org)
  • data
  • To acquire scanogram data, an X-ray tube 10 is fixed at a given rotational angle, as shown in FIGS. 1A and 2A. (google.com)
  • Magnetic Resonan
  • A digital autopsy is a non-invasive autopsy in which digital imaging technology, such as with Computerized Tomography (CT) or Magnetic Resonance Imaging (MRI) scans, is used to develop three-dimensional images for a virtual exploration of a human body. (wikipedia.org)
  • Proc
  • Takayuki Okamoto, Akinori Takahashi, and Ichirou Yamaguchi, "Simultaneous acquisition of spectral and spatial intensity distribution", Applied Spectroscopy 47: 1198-1202 (1993) F. V. Bulygin and G. N. Vishnyakov, "Spectrotomography -- a new method of obtaining spectrograms of two-dimensional objects", in Analytical Methods for Optical Tomography, Proc. (wikipedia.org)
  • microscopic
  • Other tests such as chest X-ray (X-ray scanning of the chest) and sputum cytology (microscopic examination of the mucus coughed up from the lungs) usually are not recommended as screening tests because they do not meet the criteria of reducing the risk of dying from lung cancer. (lungcancernewstoday.com)
  • calcium
  • They arise from the cells along the pituitary stalk, specifically from nests of odontogenic (tooth-forming) epithelium within the suprasellar/diencephalic region and, therefore, contain deposits of calcium that are evident on an x-ray. (wikipedia.org)
  • Medical
  • Conceptually, one can consider each of the dispersed images on the detector as a 2D projection of the 3D datacube, in a manner analogous to the way in which X-ray projections measured by medical computed tomography instruments are used to estimate the 3D volume distribution within a patient's body. (wikipedia.org)
  • Gd0.99, Pr0.01)2O2S sub-microphosphors synthesized by homogeneous precipitation method are very promising for a new green emitting material to be applied to the high resolution digital X-ray imaging field Gadolinium oxysulfide powder phosphors are intensively used for conversion of X-rays to visible light in medical X-ray imaging. (wikipedia.org)
  • Gd2O2S: Pr based solid state X-ray detectors have been successfully reintroduced to X-ray sampling in medical computed tomography (imaging by sections or sectioning, through the use of any kind of penetrating wave). (wikipedia.org)
  • visualize
  • Coronary catheterization uses pressure monitoring and blood sampling through a catheter inserted into the heart through blood vessels in the leg to determine the functioning of the heart, and, following injections of radiocontrast dye, uses X-ray fluoroscopy, typically at 30 frames per second, to visualize the position and volume of blood within the heart chambers and arteries. (wikipedia.org)
  • ADF-STEM tomography has recently been used to directly visualize the atomic structure of screw dislocations in nanoparticles. (wikipedia.org)
  • patients
  • CTA should be avoided in patients with kidney disease or severe diabetes, because x-ray contrast material can further harm kidney function. (wikipedia.org)
  • single
  • The standard abdominal X-ray protocol is usually a single anteroposterior projection in supine position. (wikipedia.org)
  • In 2010, a 3D resolution of 0.5±0.1×0.5±0.1×0.7±0.2 nm was achieved with a single-axis ADF-STEM tomography. (wikipedia.org)
  • Therefore
  • Abdominal x-ray is therefore not recommended for adults with acute abdominal pain presenting in the emergency department. (wikipedia.org)
  • patient
  • October 1 - Godfrey Hounsfield's invention, X-ray computed tomography, is first used on a patient with a cerebral cyst at Atkinson Morley Hospital in Wimbledon, London. (wikipedia.org)
  • A patient with a history of allergy to x-ray dye may be advised to take special medication for 24 hours before CTA to lessen the risk of allergic reaction or to undergo a different exam that does not call for contrast material injection. (wikipedia.org)
  • sample
  • The other disadvantage is the high X-ray damage to the sample. (wikipedia.org)
  • Another method of obtaining a tilt-series is the so-called conical tomography method, in which the sample is tilted, and then rotated a complete turn. (wikipedia.org)
  • transmission
  • Recently, however, techniques of changing the intensity of X-rays in accordance with the X-ray transmission factor which changes in accordance with a region of the object have been proposed. (google.com)