Chapter 13 - X-Ray Interactions

When an x-ray photon passes through matter, it undergoes a process called

a. induction.

b. filtration.

c. attenuation.

d. resonance.

c. attenuation.

During the process of attenuation, x-ray photons in the beam

a. reduce in number.

b. lose energy.

c. produce ionizations.

d. all of the above.

d. all of the above.

During the process of attenuation, the x-ray photon may interact with

a. the nucleus.

b. the entire atom.

c. an orbital electron.

d. all of the above.

d. all of the above.

Which atomic shell possesses the highest binding energy?

a. K

b. L

c. M

d. All atomic shells possess the same binding energy.

a. K

In which element are the inner-shell electrons more tightly bound to the nucleus?

a. mercury (Z = 80)

b. tungsten (Z = 74)

c. lead (Z = 82)

d. chromium (Z = 24)

c. lead (Z = 82)

Which energy-level electrons possess the highest total energy?

a. K

b. L

c. M

d. N

d. N

As the electron shells move farther from the nucleus, total electron energies ____ and binding energies ____.

a. decrease; decrease

b. increase; increase

c. increase; decrease

d. decrease; increase

c. increase; decrease

When x-ray photons interact with matter and change direction, the process is called

a. absorption.

b. scatter.

c. resonance.

d. extrapolation.

b. scatter.

If a photon interacts with matter and scatters, the photon

a. no longer exists.

b. exists with greater energy.

c. exists with less energy.

d. is totally absorbed.

c. exists with less energy.

When an x-ray photon with a slightly greater energy than the binding energy of the inner-shell electron interacts with that inner-shell electron, the following interaction results:

a. Compton scattering

b. coherent scattering

c. photoelectric absorption

d. characteristic radiation

c. photoelectric absorption

During photoelectric absorption, a/an ____ shell electron is ejected.

a. inner-

b. middle-

c. outer-

d. all of the above

a. inner-

During photoelectric absorption, the ejected electron is called a/an

a. incident electron.

b. photoelectron.

c. characteristic electron.

d. recoil electron.

b. photoelectron.

A photoelectron

a. is matter and possesses energy.

b. typically travels 1-2 mm in soft tissue.

c. is capable of creating biological changes.

d. all of the above.

d. all of the above.

When an electron from an outer shell fills a vacancy in an inner shell,

a. the total energy of the electron increases.

b. the electron increases its mass.

c. a photon is released.

d. all of the above.

c. a photon is released.

During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shell, energy is released in the form of

a. a characteristic photon.

b. a primary radiation.

c. an incident electron.

d. a Bremsstrahlung photon.

a. a characteristic photon.

Secondary radiation energies are highest for which element?

a. hydrogen

b. carbon

c. barium

d. oxygen

c. barium

An interaction that occurs between very low energy x-ray photons and matter is called ____ scatter.

a. coherent

b. classical

c. unmodified

d. all of the above

d. all of the above

During coherent scattering, the scattered photon possesses ____ as the incident photon.

a. the same energy, the same frequency, and the same wavelength

b. the same energy, the same frequency, and a different wavelength

c. the same energy, a different frequency, and the same wavelength

d. a different energy, the same frequency, and the same wavelength

a. the same energy, the same frequency, and the same wavelength

Compton scattering occurs when an incident x-ray photon interacts with an ____ electron.

a. inner-shell electron with high binding energy and high kinetic energy

b. inner shell electron with low binding energy and low kinetic energy

c. outer shell electron with low binding energy and high kinetic energy

d. outer shell electron with high binding energy and low kinetic energy

c. outer shell electron with low binding energy and high kinetic energy

The electron dislodged during Compton scattering is called the

a. photoelectron.

b. recoil electron.

c. incident electron.

d. secondary electron.

b. recoil electron.

The photon that exits the atom after a Compton scattering interaction is called the Compton

a. scattered photon.

b. characteristic photon.

c. recoil photon.

d. secondary photon.

a. scattered photon.

During Compton scattering, the incident photon energy is divided between the

a. recoil electron and the scattered photon.

b. incident photon and the scattered photon.

c. incident photon and the recoil electron.

d. recoil electron and the photoelectron.

a. recoil electron and the scattered photon.

As the angle of deflection is increased from 0 to 180,

a. all energy is imparted to the incident photon.

b. less energy is imparted to the recoil electron.

c. greater energy is imparted to the scattered photon.

d. greater energy is imparted to the recoil electron.

d. greater energy is imparted to the recoil electron.

During fluoroscopic studies, the primary source of exposure to the radiographer is due to

a. the photoelectric effect.

b. Compton scattering.

c. recoil electrons.

d. pair-production interactions.

b. Compton scattering.

During which interaction with matter is the x-ray photon converted to matter in the form of two electrons?

a. pair production

b. Compton scattering

c. photoelectric absorption

d. coherent scattering

a. pair production

In which process is matter converted back to energy?

a. nuclear reaction

b. annihilation reaction

c. Compton scatter

d. photodisintegration

b. annihilation reaction

Which of the following interactions has a significant impact on the x-ray image?

a. photoelectric absorption

b. coherent scatter

c. pair production

d. photodisintegration

a. photoelectric absorption

Which of the following interactions has a significant impact on the x-ray image?

a. Compton scattering

b. coherent scatter

c. pair production

d. photodisintegration

a. Compton scattering

In the human body, ____ is the predominant interaction through most of the diagnostic x-ray range.

a. Compton scattering

b. coherent scatter

c. photoelectric interactions

d. photodisintegration

a. Compton scattering

Which of the following interactions with matter results in an impact upon image contrast, if excessive.

a. Compton scattering

b. coherent scatter

c. photoelectric interactions

d. photodisintegration

a. Compton scattering

Which of the following interactions is responsible for the contrast in UGI studies?

a. Compton scattering

b. coherent scatter

c. photoelectric interactions

d. photodisintegration

c. photoelectric interactions

In an effort to decrease the mAs of an exposure, the 15% rule of kVp change may be considered. Changing the original kVp of 84 using the 15% rule will have what impact?

a. a higher incidence of pair production interactions

b. greater Compton scatter interactions

c. greater photon absorption in the patient

d. an improvement in image contrast

b. greater Compton scatter interactions

The incidence of the photoelectric effect increases with

a. increasing kilovoltage.

b. increasing atomic number of the absorber.

c. decreasing x-ray wavelength.

d. photon energies above 1.02 mMeV.

b. increasing atomic number of the absorber.

In diagnostic radiology, radiographic image contrast is principally due to the predominance of

a. photodisintegration interactions.

b. Bremsstrahlung interactions.

c. photoelectric interactions.

d. Compton interactions.

c. photoelectric interactions.

An incident photon with 35 keV is most likely to interact with the K-shell electron of what atom?

a. iodine

b. lead

c. calcium

d. oxygen

a. iodine

Wearing lead aprons as a protective measure during fluoroscopic studies, relies on the photon interaction of

a. pair production.

b. Compton scattering.

c. Coherent scattering.

d. the photoelectric effect.

d. the photoelectric effect.

All of the following are true of coherent scattering EXCEPT:

a. There are two types of coherent interactions possible

b. The net result is a low-level ionization that is harmless

c. Coherent scattering generally occurs with photon energies of 10 keV or lower

d. Interactions may involve a single or multiple electrons in the atom

b. The net result is a low-level ionization that is harmless