Physics And Instrumention Flashcards
- Which of the following best describes the shape of the X-ray beam utilized in MDCT?
A. Pencil beam
B. Fan-shaped
C. Electron beam
D. Cone-shaped
D
- Collimation of the CT X-ray beam occurs:
- at the X-ray tube, regulating slice thickness
- Just beyond the patient, focusing off-axis transmitted radiation
- Before the detectors, limiting the amount is scatter radiation absorbed
1,3
- CT numbers are usually provided in the form of :
A. Hounsfield units
B. EMI numbers
C. Cormacks
D. u
A
- The mathematical technique allowing the reconstruction of motion-free images from helically acquired CT data is called:
A. Convolution
B. Radon transformation
C. Interpolation
D. Fourier reconstruction
C
- The full width at half maximum ( FWHM) of CT scanner is used to describe :
A. Spatial resolution
B. Contrast resolution
C. noise
D. Calibration accuracy
A
- A first generation CT scanner consists of an X-ray tube and two detectors that translate across the patients head while rotating in 1 degree increments for a total of:
A. 45 degrees
B. 90 degrees
C. 180 degrees
D. 360 degrees
C
- Which of the following abbreviation is used to identity a computerized network that stores, retrieves, communications, and displays digital medical images?
A. WORM
B. Pacs
C. DICOM
D. HIPAA
2
- The CT “window” controls the _____________ of the CT image as it appears to the viewer.
A. Density and detail
B. Spatial and contrast resolution
C. Contrast and brightness
D. Attenuation coefficient and Hounsfield value
C
- Voxels with equal dimensions along the X-, y-, and z-axes are referred to as:
A. Prospective
B. Isotropic
C. Retrospective
D. Anisotropic
B, it’s a DIstint advantage of MDCT
- Which of the following artifacts is not affected by the CT technologist?
A. Motion
B. Partial volume
C. Edge gradient
D. Ring
D
- When one is viewing a multiplanar reformation (MPR) image, each pixel represents ;
A. The maximum attenuation occurring within the voxel.
B. The average attenuation occurring within the voxel
C. The minimum attenuation occurring within the voxel
D. All attenuation occurring within the voxel above a set threshold value
B
- Statistical noise appears as _________ on a CT image.
A. Decreased contrast
B. Increased brightness
C. Concentric circles
D. Graininess
D
- An acquisition is made on a 64-slice MSCT system in which each detector element has a z-axis dimension of .625 mm. With a selected beam width of 40mm and the beam pitch set at 1.50, how much will the table move with each rotation of the gantry?
Dodd
