PTLC RADIATION PRODUCTION AND CHARACTERISTICS

During an x-ray examinations, which sequence best describes the energy transformations that occur in the imaging system?

Electrical energy → Electromagnetic energy & Thermal energy

A radiographer states that an astronaut has less mass on the Moon because the Moon has weaker gravity. Which statement correctly explains this concept?

The astronaut's mass remains constant, but the weight decreases because of reduced gravity

Which situation best demonstrates potential energy rather than kinetic energy?

A stretched spring before it is released

During electron capture, which process occurs within the unstable nucleus?

An inner-shell electron is captured, converting a proton into a neutron

Which statement correctly distinguishes matter from energy?

Matter has mass and occupies space, whereas energy is the ability to perform work

A patient undergoing a radiographic examination is said to be irradiated because:

The patient’s tissues intercept and absorb part or all of the x-ray beam.

Approximately what percentage of the kinetic energy of the projectile elections striking the anode is converted into heat.

99%

Under which condition are characteristic x-rays produced within the x-ray tube?

Electron excite only outer-shell electrons.

Bremsstrahlung radiation is produced when a projectile electron undergoes which interaction within the target atom?

Slows near the target nucleus.

What is the meaning of the German term “Bremsstrahlung”?

Slowed-down radiation

Which type of X-rays constitutes the majority of the X-ray beam used in diagnostic imaging?

Bremsstrahlung x-rays

A minimum tube potential of approximately 69 kVp is required to produce useful tungsten K-characteristic x-rays. Which tube potential satisfies this requirement?

69 kVp

Which characteristic best describes the energy of characteristic x-rays?

Discrete energies

What type of emission spectrum is produced by Bremsstrahlung x-rays?

Continuous spectrum

If the milliampere (mA) is increased while all other exposure factors remain constant, what is the primary effect on the x-ray beam?

Increases x-ray quantity

In diagnostic radiography, a 15% increase in kVp is approximately equivalent to which change in exposure?

Doubling the mAs

What is the primary effect of increasing the amount of added filtration in the x-ray beam?

Decrease beam quantity and increase beam quality.

What does the term beam hardening refer to?

Increasing tube current output.

How does increasing the atomic number of the target material generally affect x-ray production?

Increases both x-ray quantity and quality.

Which type of x-ray generator produces the lowest voltage ripple?

High-frequency generator

The maximum energy of an x-ray photon produced by an x-ray tube is numerically equal to which exposure factor?

kVp

Which interaction contributes slightly to image noise but has minimal significance in diagnostic radiology?

Coherent scattering.

Coherent scattering most commonly occurs when x-ray photon energies are:

Below 10 keV

What happens to the energy of an x-ray photon during coherent scattering?

It retains the same photon energy

During Compton scattering, the incident x-ray photon primarily interacts with:

Outer-shell electrons

What is the name of the electron ejected during a Compton interaction?

Compton electron

What is the primary effect of Compton scattering on a radiographic image?

Reduces image contrast

Which statement correctly describes the photoelectric effect?

The incident photon is completely absorbed

What is the electron ejected during the photoelectric effect called?

Photoelectron

The probability of the photoelectric effect is directly proportional to which power of the atomic number (Z)?

Z^3

Which statement correctly describes the probability of Compton scattering?

It is independent of the atomic number of the absorber

What is the minimum photon energy required for pair production to occur?

1.02 MeV

In which imaging modality is pair production most clinically important?

Positron Emission Tomography

Photodisintegration occurs only when the energy of the incident photon exceeds approximately:

10 MeV

Which two x-ray interactions are considered the most important in diagnostic radiology?

Compton scattering and the photoelectric effect

Which statement about the photoelectric effect is TRUE?

The incident x-ray photon is completely absorbed

The atomic number of an element is equal to the number of:

Protons

Most of the mass of an atom is found in the:

Nucleus

Isotopes are atoms that have the same:

Atomic number only

Which property is characteristic of x-rays?

Travel at light speed

X-rays are classified as:

Electromagnetic waves

Which property allows x-rays to produce radiographic images?

Differential penetration

Which statement about x-rays is TRUE?

They travel at light speed.

Which is an example of ionizing radiation?

X-rays

The primary biological effect of ionizing radiation is:

Atomic ionization

Radioactivity is the spontaneous emission of radiation from an:

Unstable nucleus

Which type of radioactive decay emits a helium nucleus?

Alpha decay

Which type of radiation has the greatest penetrating power?

Gamma rays

Half-life is defined as the time required for half of the radioactive nuclei in a sample to undergo radioactive decay.

Half of the radioactive nuclei to undergo radioactive decay

Half of the orbital electrons to escape from their atoms

EMR