52 Questions
What is the primary reason radiologic contrast agents are used in imaging?
To enhance the differential absorption of certain tissues and organs
What is the main difference between absorption and attenuation?
Absorption is the reduction of x-ray intensity, while attenuation includes scattering
What is the significance of atomic number and mass density of tissue on differential absorption?
They increase the differential absorption of x-rays
What is the purpose of the midterm and final exams in RADL 3010?
To evaluate student understanding of the first and second half of the course
What is the difference between monochromatic and polychromatic beams in terms of attenuation?
Monochromatic beams have a single energy, while polychromatic beams have a range of energies
What is the probability of PE effect and Compton scatter dependent on?
Photon energy, atomic number, and density
What is the term used to describe the reduction of photons or weakening of the primary beam following penetration through a given thickness?
Attenuation
What occurs when an X-ray or gamma ray beam interacts with atomic particles in matter?
Scattering
What is the energy transferred to the ejected electron in Compton Scattering?
Kinetic energy
What is the mathematical equation for Compton Scattering?
EP = ES + EB + EKE
What is the energy of the Compton scattered photon in the given example?
34.5 kV
What happens to the scattered photon as it travels through matter?
It loses energy
What is the probability of Compton scattering dependent on?
Energy of the incident x-ray
What is the result of Compton scattering in radiography?
Scattered x-rays provide no useful information
What is the term used to describe the energy transferred to the matter as the beam passes through?
Absorption
What type of scattering is described in the passage?
Compton scattering
What is the primary source of occupational radiation exposure received by radiographers?
Compton scattering
What happens to the energy of the x-ray photon in a photoelectric interaction?
It is absorbed by the inner shell electron
What is the energy of the photoelectron ejected from a calcium atom, if the electron binding energy is 4 kV and the incident x-ray energy is 30 kV?
26 kV
What is the relationship between the probability of a photoelectric interaction and the incident x-ray energy?
The probability decreases as the energy increases
What is the relationship between the probability of a photoelectric interaction and the atomic number of the absorbing material?
The probability is directly proportional to the third power of the atomic number
What is the effect of Compton scattering on image contrast?
It decreases image contrast
What happens to the photoelectron ejected from an atom in a photoelectric interaction?
It escapes with kinetic energy
What is the purpose of the binding energy in a photoelectric interaction?
To eject the electron from its orbit
What is the comparison of the probability of a photoelectric interaction between an 80 keV x-ray and fat (Z = 6.3) and barium (Z = 56) compared with soft tissue (Z = 7.4)?
Fat has a lower probability, barium has a higher probability
What is the effect of photoelectric absorption on the final image?
It is not related to the image
What is the result of an x-ray ejecting a K-shell electron from an atom?
An orbital vacancy is created, resulting in an unstable state.
What is the energy of the characteristic x-ray emitted when an outer shell electron drops into the vacancy created by the ejection of a K-shell electron?
The difference between the binding energies of the shells involved.
What happens to the x-rays that undergo photoelectric absorption in the body?
They are completely absorbed by the body.
What is the significance of characteristic x-rays in radiology?
They have no effect on the final radiographic image.
What is the difference between radiopaque and radiolucent structures?
Radiopaque structures absorb x-rays, while radiolucent structures transmit them.
How does the selection of kVp affect the differential absorption of x-rays?
Decreasing kVp increases differential absorption.
What is the relationship between the probability of photoelectric absorption and the atomic number of the tissue?
The probability is proportional to the third power of the atomic number.
How does the energy of the incident x-ray affect the probability of photoelectric absorption and Compton scattering?
Both probabilities decrease with increasing energy.
What is the effect of Compton scattering on image contrast?
Compton scattering decreases image contrast.
What is the result of a compromise between image contrast and patient dose in radiology?
Lower image contrast and higher patient dose.
What is the total mass attenuation coefficient a result of?
Various absorption and scattering processes
What is the symbol that represents the component of total linear attenuation coefficient due to the photoelectric effect?
τ
How does the probability of a photoelectric effect change with the atomic number of the absorbing material?
It is directly proportional to the third power of the atomic number
What is the general trend of the value of μ with increasing energy of the incident beam?
It decreases
Which of the following materials has a higher μ value at a given X-ray energy?
Bone
How does the value of σ/ρ change with increasing X-ray energy?
It decreases
What does the mass density of a tissue affect?
The number of electrons available for interaction
Why do Barium and Iodine compounds have a much higher atomic number and mass density than soft tissue?
Because they have a higher number of electrons and are densely packed
What is the result of dividing the total linear attenuation coefficient by its density?
The mass attenuation coefficient
What is the binding energy of the K shell electron for Barium?
37.4 keV
What happens to the probability of x-ray interaction when the mass density of a tissue is doubled?
It is doubled
Why do x-rays interact more with bone than with soft tissue?
Because bone has a higher mass density
What is the unit of the total linear attenuation coefficient?
m-1
What is the main difference between the total linear attenuation coefficient and the mass attenuation coefficient?
The total linear attenuation coefficient takes into account density, while the mass attenuation coefficient does not
What happens to Compton scattering as x-ray energy increases?
It decreases slowly
What is the purpose of using contrast agents in radiologic imaging?
To enhance differential absorption in homogeneous tissue
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
