CABT Imaging Systems 2

Question 1

Which artifact in MRI is caused by the difference in resonant frequencies between water and fat protons?

Accepted Answer

Chemical shift artifact

Answer

Chemical shift artifact occurs because water and fat protons precess at slightly different frequencies, causing a spatial misregistration at tissue interfaces.

Question 2

In computed tomography, the Hounsfield unit (HU) value for air is approximately:

Accepted Answer

-1000

Answer

Air is assigned a Hounsfield unit value of -1000 on the CT attenuation scale, while water is defined as 0 HU.

Question 3

A biomedical technologist notices that an ultrasound image shows a bright echo directly behind a highly reflective structure. This is best described as:

Accepted Answer

Reverberation artifact

Answer

Reverberation artifact appears as multiple equally spaced bright lines behind a strongly reflective interface due to sound bouncing back and forth.

Question 4

What is the primary purpose of a grid in diagnostic radiography?

Accepted Answer

To reduce scattered radiation reaching the detector

Answer

A radiographic grid is placed between the patient and detector to absorb scattered radiation, improving image contrast.

Question 5

In fluoroscopy, the automatic brightness control (ABC) system primarily adjusts which parameters to maintain image quality?

Accepted Answer

kVp, mA, and pulse width

Answer

ABC systems dynamically adjust kVp, mA, and pulse width to maintain consistent image brightness as the beam passes through varying tissue thicknesses.

(CABT) Certified Associate in Biomedical Technology Practice Test

(CABT) Certified Associate in Biomedical Technology Practice Test

CABT Imaging Systems 2