Exam 4: Physical Principles of Computed Tomography

The reduction of the intensity of a beam of x rays as it passes through the patient is:

The attenuation used by Hounsfield in his original experiments was: I. a heterogeneous beam II. a homogeneous beam III. a monoenergetic beam IV. a polychromatic beam

The total number of x-ray transmission measurements is equal to the:

Match the following concepts for each group. All answer selections will be used just once. -Cross-section or slice of tissue

In the attenuation of a heterogeneous beam of radiation: I. the beam quality changes, II. the beam quantity changes, III. the beam intensity changes

If the linear attenuation coefficients for fat and water are 0.185 and 0.205, respectively, and the scaling factor for the scanner is 1000, the CT number for fat is approximately:

Data processing includes all of the following except:

Which of the following is a limitation of radiography?

If the linear attenuation coefficients for bone and water are 0.380 and 0.190, respectively, and the scaling factor of the scanner is 1000, the computed tomography number for bone is:

If the field of view for an examination is 30 cm and the matrix size is 1024 *1024, what is the approximate pixel size?

The Compton effect occurs largely in soft tissues.

A limitation of conventional radiography is that it is qualitative rather than quantitative.

The center or mid point of the range of computed tomography numbers is called the:

Match the following concepts for each group. All answer selections will be used just once. -Image blur

Which of the following best describes the term "data acquisition geometry" in computed tomography?

In which of the following data acquisition methods is a volume of tissue (rather than a single slice) scanned during a single breath hold?

When a beam of x rays passes through the patient, the relative transmission or penetration measurement can be calculated by use of which of the following?

The radiation beam used by Hounsfield in his original experiments was:

A scaling factor of 1000 in the Hounsfield scale for K results in a:

Attenuation of a beam of radiation depends on: I. the atomic number II. the electrons per gram of tissue III. the energy if the radiation