CTPI 4012

Compton effects is/are

• Interaction between photon and free electron

• larger the angle through which the photon is scattered, the more the energy it loses

• the wavelength change produced depends upon the scattering material

• High energy radiation is scattered more than lower energy radiation

• amount of scattering that occurs depends on the electron density of the scattering material

Partial volume averaging on the CT image may be decreased by:

• Increasing matrix size

• Decreasing matrix size

• Decreasing slice thickness

• Increasing slice thickness

Quality control measurements to test the accuracy of the calibration of the CT scanner should be performed?

• Daily

• Weekly

• Monthly

• Annually

Scintillation crystals are used exclusively as detectors in __________________ CT scanners?

• Second Generation

• Third Generation

• Fourth Generation

• Fifth Generation

First generation CT scanners used a method of data acquisition based on a _______________ principle.

• Multiplana

• Rotation only

• Translate-rotate

• Rotate-rotate

A first generation CT Scanner consists of an x-ray tube and two detectors that translate across the patients's head while rotating in 1 degree increments for a total of:

• 45 degrees

• 90 degrees

• 180 degrees

• 360 degrees

Which of the following is the primary interaction between x-ray photons and tissue during CT examinations?

• Compton effect

• Coherent Scatter

• Bremsstrahlung effect

• Chraracteristic effect

Ring artifacts on the CT image are associated with which of the following tube-detector geometric relationships?

• Rotate-translate-rotate

• Rotate-rotate

• Rotate-stationary

• Translate-rotate

Which of the following would make noise in the image appear less noticeable?

1. increased mAs

2. increased slice thickness

3. increased window widths

• 1 only

• 2 only

• 3 only

• all above

Which of the following is TRUE regarding solid state detectors?

1. they are the detector type used on most CT scanners today

2. they can be used in both third-generation and fourth-generation CT systems

3. x-ray photons cause the detectors to generate a flash of light

• 1 only

• 2 only

• 3 only

• all above