CT Registry Flashcards
Computed Tomography uses what
X-Rays to image individual slices through the body
X-Rays are directed
Into a localized section of the patient
How is an image seen (simple)
Detected signals are constructed into an image
CT system console controls what
Information about the pt
specific imaging parameters
post-processing techniques
filming and arching instructions
CT Console information goes…
To the Host computer, translated into systems machine language then to scan controller.
Scan Controller controls what
Responsible for timing and operation of pt table, gantry and high voltage generator
How is information from the scan controller sent
Electronic signals are converted into analog (continuous) waveform. DAS converter accomplishes this.
What does the Gantry contain
CT X-Ray tube
Detectors
The technique that allows the user to select the range of pixel values used in a 3D ct reformation is termed
Thresholding
A voxel’s dimension may be decreased by
Decreasing the section width
What may cause abnormal findings and will reduce the density of the liver?
Fatty Infiltrate
Patients whose posterior descending artery branches from the right coronary artery, and whose left posterior ventricle branches arise from the left circumflex artery, are said to be
Codominant
What does it mean to be Codominant
7% of the population is said to be codominant, meaning that the posterior descending artery (PDA) is supplied by the right coronary artery (RCA) and the left posterior ventricular branches arise from the left circumflex artery (LCA)
The articulation between the distal tibia and the fibula is called the
Syndesmoisis
For MDCT identified areas of calcium must demonstrate relative attenuation values greater than
+130 HU
1st generation scanner produced what type of x-ray beam:
Thin “pencil beam”
How many detectors did a 1st generation ct use
One detector
How did the tube/detectors assembly work/move in a 1st generation scanner
Across the patient then rotated by 1 degree
Total scan time for 1st generation ct
5 mins per image
Anatomy scanned on 1st generation
Head
2nd generation scanners produced what type of x-ray beam
Fan Beam
How many detectors did a 2nd generation use
Multiple @30, in a straight line called an array
How did the tube/detector assembly on a 2nd generation scanner work/move
Across the patient, then rotated by 5 degrees
Total scan time on a 2nd generation scanner
20 seconds per image