MULTISLICE CT PHYSICS PDF DOWNLOAD

MULTISLICE CT PHYSICS PDF DOWNLOAD
MULTISLICE CT PHYSICS PDF DOWNLOAD!

Basic physics of multidetector computed tomography (CT Scan) - how ct scan works, different generations of ct, how image is generated and. (1)Department of Radiation Therapy and Medical Physics, Hartford This article describes the principles and evolution of multislice CT (MSCT). Multislice CTPrinciples and Perspectives. Mindy M. Horrow, MD, FACR. Director of Body Imaging. Albert Einstein Medical Center. All photos retain the copyrights  Missing: physics ‎| ‎Must include: ‎physics.


MULTISLICE CT PHYSICS PDF DOWNLOAD

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MULTISLICE CT PHYSICS PDF DOWNLOAD


CT Physics: CT Reconstruction and Helical CT - XRayPhysics

The scanner gantry had a single detector which translated around the patient as the patient table moved in the cephalocaudal z-axis direction. As early as there are descriptions of reconstruction techniques using axial CT data to construct coronal and sagittal image planes [ 1 ].

Second multislice ct physics third generation CT scanners were improved by increasing the number of multislice ct physics and by converting the translation motion of the radiation source to rotation, respectively, resulting in exponential increases in imaging speed with improved image quality.

Utilizing these data image reconstruction has also been revolutionized.

MULTISLICE CT PHYSICS PDF DOWNLOAD

Standard two dimensional 2D images now are beyond axial, sagittal and coronal planes to multislice ct physics off axis and curved planar images. Three dimensional 3D surface rendered images are now commonly displayed in motion, adding a fourth dimension 4D [ 2 ]. Since multislice ct physics era, the addition of more imaging channels, rows or detectors has increased exponentially.

Subsequent improvements in the mechanics of the scanners have resulted in faster x-ray gantry rotation, faster z-axis movement of the CT table, thinner collimation and the development of electrocardiographic ECG gating. In helical CT, the scanner is multislice ct physics spinning and the patient table is constantly moving.

MULTISLICE CT PHYSICS PDF DOWNLOAD

Thus, no two CT multislice ct physics are acquired at the same slice z-position in the body. If the table is constantly moving, what then constitutes a slice that the scanner will reconstruct?

Modern helical CT averages or 'interpolates' data from two projections degrees apart. A photon will see the same attenuation whether it passes through tissue 'forward' or 'backward' - so that angles degrees apart are equivalent.

Multi-slice helical CT physics and technology

This interpolation is done to convert the helical path to transverse slices see what happens multislice ct physics the simulation if you only reconstruct degrees - you get spirals. This also explains the concept of slice broadening - each point reflects data from two z positions, separated by how far the table moves as the beam turns degrees.

As before, the thickness of tissue included multislice ct physics a single projection is the collimator width often 0. The relationship between speed of rotation and speed of table movement is referred to as pitch.

Generally pitch is kept between 1 and 2. At a pitch of 2, degrees of rotation brings the table a distance of one collimator width. Remember, each projection uses data from 2 projections spaced by degrees.

Your browser does not support the HTML canvas. Illustration of the helical CT scan. The helical path of the beam is drawn in blue. A single degree rotation of the tube is shaded in red.

Slices in helical CT are reconstructed by using multislice ct physics data from two projections degrees apart; this causes slice broadening, where the amount of tissue included is slightly greater than the collimator width.

An example tissue slice from two projections degrees apart is highlighted in multislice ct physics. The advantage of helical CT is that it is much faster than the step-and-shoot procedure since the entire scan is acquired in one fluid motion.



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