Chapter three

Question 1

When a technical exposure factor of 100 kVp is selected, which of the following occurs?
A. The electrons will be accelerated from the anode to the cathode with an average energy of 33 keV.
B. The electrons will be accelerated from the cathode to the anode with an average energy of 33 keV.
C. The beam will contain all photons having energy of 100 keV.
D. The beam will contain photons having energies of 100 keV or less, with an average energy of about 33 keV.

Answer 1

D. The beam will contain photons having energies of 100 keV or less, with an average energy of about 22 keV.

Question 2

The passage of X-ray photons through a patient without interaction in body tissue is called:

Answer 2

Direct transmission

Question 3

In which of the following X-ray interactions with matter is the energy of the incident photon completely absorbed?\
Compton
Photoelectric
Incoherent
Rayleigh

Answer 3

Photoelectric

Question 4

What is the result of coherent scattering?

Answer 4

Usually just a small angle change in the direction of the incident photon.

Question 5

A technical exposure factor of 100 kVp means that the electrons bombarding the anode of the X-ray tube have a maximum energy of:

Answer 5

100 kVp or 100,000 eV

Question 6

A Compton scattered electron:

Answer 6

is absorbed within a few microns of the site of the original Compton interaction.

Question 7

Most scattered radiation produced during radiographic procedures is the direct result of which of the following?
Photoelectric absorption
Nuclear decay
Image-formation electrons
Compton interactions

Answer 7

Compton interactions

Question 8

A reduction in the number of primary photons in the X-ray beam through absorption and scatter as the beam passes through the patient in its path defines:

Answer 8

Attenuation

Question 9

Before interacting with matter, an incoming X-ray photon may be referred to as which of the following?
Attenuated photon
Primary photon
Ionized photon
Scattered photon

Answer 9

Primary photon

Question 10

Within the energy range of diagnostic radiology (23 to 150 kVp), which includes mammography, when kVp is decreased, the patient dose:

Answer 10

increases

Question 11

Which of the following statements best describes mass density?
It is the # of electrons per gram of tissue.
It is the same as radiographic density.
It relates the way the effective atomic number of biologic tissues influences absorption.
It is measured in grams per cubic centimeter.

Answer 11

It is measured in grams per cubic centimeter.

Question 12

Of the following interactions between x-radiation and matter, which does not occur in the range of diagnostic radiology?
Photoelectric absorption.
Pair production
Photodisintegration

Answer 12

Pair production and Photodisintegration

Question 13

The quality, or penetrating power, of an X-ray beam is controlled by:

Answer 13

kVp

Question 14

Small angle scatter:

Answer 14

Degrades the appearance of a completed radiographic image by blurring the sharp outlines of dense structures.

Question 15

For a diagnostic radiologic examination, the selection of technical exposure factors using an optimal kVp and mAs combination:

Answer 15

Produces an xray image of acceptable quality while minimizing patient dose.

Question 16

Within the energy range of diagnostic radiology, as absorption of electromagnetic energy in biologic tissue increases, the potential for biologic damage:

Answer 16

Increases

Question 17

Which of the following terms are synonymous?
Coherent scattering
Classical scattering
Unmodified scattering

Answer 17

Coherent, Classical and Unmodified

Question 18

Noninteracting and small-angle scattered photons comprise:

Answer 18

exit, or image formation, radiation

Question 19

Direct transmission means that X-ray photons:

Answer 19

Pass through biologic tissue without interaction.

Question 20

Which of the following has the same mass and magnitude of charge as a negatron?
Deuteron
Neutron
Positron
Proton

Answer 20

Positron

Question 21

Which of the following interactions between x-radiation and matter does not occur within the range of diagnostic radiology?
Coherent scattering
Compton scattering
Photoelectric absorption
Pair production

Answer 21

Pair production

Question 22

kVp controls:

Answer 22

quality, or penetrating power, of the X-ray photons in the beam.

Question 23

Primary radiation is synonymous with:

Answer 23

direct radiation

Question 24

Which of the following are radiographic image receptors?
Radiographic grid
Digital radiography receptor
Phosphor plate
Radiographic film

Answer 24

Digital radiography receptor, phosphor plate, radiographic film.

Question 25

The process most responsible for the contrast between bone and soft tissue in a diagnostic radiographic image is:

Answer 25

Photoelectric absorption.

Question 26

T/F? The radiographer also benefits when patient dose is minimal because less radiation is scattered from the pt.

Answer 26

TRUE

Question 27

T/F? The optimal xray image is formed when only indirect transmission photons reach the image receptor.

Answer 27

FALSE. When only direct transmission photons reach the image receptor.

Question 28

T/F? Coherent scattering does not contribute to radiographic fog in mammography because breast tissue is gently but firmly compressed during their imaging procedure.

Answer 28

TRUE

Question 29

T/F? During the process of Compton scattering, an X-ray photon interacts with an inner-shell electron of an atom of the irradiated object.

Answer 29

FALSE. An xray photon interacts with an outer shell electron.

Question 30

T/F? A photoelectron usually is absorbed within a few micrometers of the medium through which it travels, thereby increasing patient dose and contributing to biologic damage in tissue.

Answer 30

TRUE

Question 31

T/F? Absorption properties of different body structures must be identical to make diagnostically useful images possible.

Answer 31

Absorption properties of different body structures must be different.

Question 32

T/F? The intensity of radiation scatter in various directions is a major factor in the planning of protection for medical imaging personnel during a radiologic examination.

Answer 32

TRUE

Question 33

T/F? Pair production is also known as Rayleigh scattering.

Answer 33

FALSE. It is not.

Question 34

T/F? In the radiographic kilovoltage range, compact bone with a high calcium content by weight undergoes much more photoelectric absorption than does an equal mass of soft tissue and air.

Answer 34

TRUE