Radiation Protection: X-Ray Interactions with Matter

T or F Some x-ray photons may pass through matter and not interact with that matter at all.

True - goes through the lungs

T or F As the atomic number of an element increases, the energy required to remove an inner shell electron decreases.

False - it increases because it has a higher bonding energy

T or F When a photon is absorbed, all of the energy is transferred to the matter.

True - all absorbed

T or F When a photon is absorbed, it no longer exists.

True

T or F During photoelectric interaction, the energy released during the filling of the inner shell is known as characteristic photons.

True

T or F During the photoelectric interaction, the incident x-ray photon must be greater than the binding energy of the inner-shell electron.

True - need at least greater than the BE

T or F A photoelectric interaction is more likely to occur when the x-ray photon energy is high.

False - low kVp = photoelectric

T or F A photoelectric interaction is more likely to occur with an electron that is loosely bound in its orbit than with an electron that is tightly bound.

True

T or F During coherent scattering, the photon has no loss of energy in the interaction.

True - just excites/vibrates it

T or F During coherent scattering, the scattered photon differs from the initial photon in direction.

True - less than 20*

T or F When a scattered photon is deflected back toward the source, it is traveling in the direction opposite to the incident photon and is called backscatter radiation.

True

T or F During pair production, the negatively charged electron is termed a negatron.

True - negative electron

T or F Photodisintegration is extremely relevant in diagnostic imaging ranges.

False - Nuc Med uses this at VERY high energies

T or F As kVp increases, the total number of photons transmitted through the patient without absorption increases.

True - high kVp fly's right through. Better for dose but bad for image quality

T or F As kVp increases, the percentage of Compton interactions decreases.

False - more scatter

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

a. radiation

b. filtration

c. attenuation

d. fluoroscopy

c. attenuation

During the process of attenuation, what will/might happen to the x-ray photons in the beam.

a. there is a reduction in the number

b. there is a loss of energy (attenuation absorbs)

c. they may interact

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 level possesses the most electrons?

a. K

b. L

c. M

d. N

d. N (higher atomic # = higher BE)

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)

As the electrons shells move further 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. radiation

d. binding energy

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. all of the above may occur

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, the ejected electron is called a/an .

a. incident electron

b. photoelectron

c. characteristic electron

d. nuclear electron

b. photoelectron

A photoelectron .

a. is matter

b. possesses energy

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. energy is released

b. energy is absorbed

c. a photon is released

d. more than one of the above

d. more than one of the above (not B)

Secondary radiation energies are highest for which element?

a. hydrogen

b. carbon

c. barium

d. oxygen

c. barium (scatter)

An interaction which 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

The electron dislodged during Compton scattering is called the .

a. photoelectron

b. recoil electron

c. incident electron

d. lost electron

b. recoil electron

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

a. scattered photon

b. scattered electron

c. recoil electron

d. photoelectron

a. scattered photon

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

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 (in pair production)