X-ray Interactions, Radiation Units, and Radiation Biology

What is the primary x-ray beam?

A. The x-ray beam that exits the patient after passing through body tissues

B. Scatter radiation that changes direction after interacting with matter

C. Radiation emitted by the patient after absorbing x-ray energy

D. The x-ray beam leaving the x-ray tube and traveling toward the patient

D. The x-ray beam leaving the x-ray tube and traveling toward the patient.

What are the three possible paths of an X-ray photon?

A. Absorption, reflection, and refraction of the incident X-ray photon

B. Total absorption, transmission without energy loss, or scattering with energy loss

C. Ionization, excitation, and fluorescence of atoms within the absorbing material

D. Pair production, photodisintegration, and annihilation following photon interactions

B. Total absorption, transmission without energy loss, or scattering with energy loss.

What is transmission?

A. An X-ray photon passes through matter, without losing any energy

B. A photon is absorbed by an inner-shell electron, transferring its energy to the electron

C. A photon loses some of its energy, and changes direction while interacting with matter

D. A photon creates an electron-positron pair, converting its energy into two particles

A. An X-ray photon passes through matter, without losing any energy

What are the five major types of X-ray interactions with matter?

A. Coherent scattering, photoelectric absorption, Compton scattering, ionization, and excitation

B. Photoelectric absorption, Compton scattering, pair production, photodisintegration, and annihilation

C. Coherent scattering, photoelectric absorption, Compton scattering, pair production, and photodisintegration

D. Coherent scattering, Compton scattering, pair production, photodisintegration, and radiolysis

C. Coherent scattering, photoelectric absorption, Compton scattering, pair production, and photodisintegration

Which interactions occur in the diagnostic x-ray energy range?

A. Coherent scattering, photoelectric absorption, and Compton scattering

B. Pair production, photodisintegration, and nuclear interactions

C. Photoelectric absorption, pair production, and photodisintegration

D. Compton scattering, pair production, and electron-positron annihilation

A. Coherent scattering, photoelectric absorption, and Compton scattering.;

Which interactions occur mainly at therapeutic or extremely high energies?<br>A. Coherent scattering and Compton scattering<br>B. Photoelectric absorption and coherent scattering<br>C. Compton scattering and photoelectric absorption<br>D. Pair production and photodisintegration<br>

d. Pair production and photodisintegration.

What is classic coherent scattering?

A. A photon transfers energy to an outer-shell electron, causing it to be ejected from the atom

B. A photon transfers all its energy to an inner-shell electron, ejecting it from the atom

C. A low-energy x-ray interaction in which an atom emits an x-ray of the same energy

D. A high-energy photon disappears near a nucleus, producing an electron and a positron

C. A low-energy x-ray interaction in which an atom emits an x-ray of the same energy.

Which electrons interact during coherent scattering?<br>A. Outer-shell electrons<br>B. Inner-shell electrons<br>C. Nuclear electrons<br>D. Free electrons only<br>

a. Outer-shell electrons.

Does coherent scattering cause ionization?<br>A. Yes always<br>B. No<br>C. Only in bone<br>D. Only above 10 keV<br>

b. No.

Does coherent scattering transfer energy to the patient?
A. Yes all energy
B. Half the energy
C. Only to the nucleus
D. No significant energy

d. No significant energy

What happens to the incoming photon during photoelectric absorption?

A. It loses some energy and changes direction

B. It disappears because its energy is transferred to the electron

C. It splits into two lower energy photons

D. It passes through the atom without interaction

B. It disappears because its energy is transferred to the electron

What is a photoelectron in the photoelectric effect?

A. An electron emitted from the filament when heated during x-ray production

B. An electron released when an x-ray photon undergoes Compton scattering

C. An electron created when a photon converts into an electron-positron pair

D. An inner-shell electron ejected from an atom after absorbing an x-ray photon

d. An inner-shell electron ejected after absorbing an x-ray photon.

What does photoelectric absorption produce?

A. Two photons, each with an energy of 511 keV

B. Only heat without producing any charged particles

C. An ion pair consisting of a positive atom and a free electron

D. A nuclear fragment released from the atom's nucleus

C. An ion pair consisting of a positive atom and a free electron

What happens after a photoelectron is ejected?<br>A. An outer-shell electron fills the vacancy and may produce characteristic radiation<br>B. The nucleus emits a nuclear fragment<br>C. A positron annihilates<br>D. The photon scatters<br>

a. An outer-shell electron fills the vacancy and may produce characteristic radiation.

What happens when an inner-shell vacancy occurs during the photoelectric effect?

A. The atom emits a scattered photon that changes direction and loses some of its original energy.

B. The atom absorbs another incoming photon to replace the missing inner-shell electron.

C. The atom releases an outer-shell electron without emitting energy or producing secondary radiation.

D. An outer-shell electron fills the vacancy, releasing characteristic x-rays or Auger electrons.

D. An outer-shell electron fills the vacancy, releasing characteristic x-rays or Auger electrons.

How does photoelectric absorption affect image contrast?

A. It contributes significantly to radiographic image contrast

B. It produces no noticeable change in radiographic image contrast

C. It decreases contrast by reducing differences between tissue densities

D. It affects scattered radiation without contributing to image contrast

A. It contributes significantly to radiographic image contrast

How does photoelectric absorption affect patient exposure?

A. It contributes no radiation dose to the patient during imaging

B. It primarily affects occupational exposure rather than patient exposure

C. It contributes significantly to patient radiation dose

D. It lowers the amount of radiation dose received by the patient

C. It contributes significantly to patient radiation dose.

What is Compton scattering?

A. A photon is absorbed completely by an inner-shell electron

B. A photon passes through matter without changing direction or energy

C. A nucleus emits a fragment after absorbing a high-energy photon

D. An x-ray photon ejects an outer-shell electron and scatters with reduced energy

D. An x-ray photon ejects an outer-shell electron and scatters with reduced energy.

Which electron participates in Compton scattering?<br>A. An inner-shell electron<br>B. An outer-shell electron<br>C. A nuclear electron<br>D. A positron<br>

b. An outer-shell electron.

What is a Compton electron?

A. An electron ejected from an inner atomic shell

B. A photon emitted during characteristic radiation

C. A positively charged particle produced during pair production

D. The recoil electron ejected during Compton scattering

D. The recoil electron ejected during Compton scattering.

What happens to the incoming photon during Compton scattering?

A. It loses some energy and travels in a different direction

B. It is completely absorbed by an atom during the interaction

C. It gains additional energy and travels in a different direction

D. It splits into two separate photons during the interaction

A. It loses some energy and travels in a different direction.

Why is Compton scattering important in radiography?

A. It improves image contrast by increasing differences between tissue and adipose densities

B. It has no significant effect on image quality or occupational radiation exposure

C. It produces scatter radiation that reduces image quality and contributes to occupational exposure

D. It causes pair production by converting a high-energy photon into two particles

C. It produces scatter radiation that reduces image quality and contributes to occupational exposure.

What happens to the vacancy created during Compton scattering?
A. It remains permanently vacant until another atom collides with it
B. It is filled by another electron nearly instantly
C. It causes photodisintegration and pair electrons
D. It emits a positron and a negatron

b. It is filled by another electron nearly instantly.

What is pair production?

A. A low-energy photon transfers its energy to an outer-shell electron, causing it to be ejected

B. A photon transfers its energy to an inner-shell electron, causing the electron to leave the atom

C. A high-energy photon disappears near a nucleus and produces an electron and a positron

D. A high-energy photon interacts with the nucleus, causing it to emit a nuclear fragment

C. A high-energy photon disappears near a nucleus and produces an electron and a positron

Where is pair production relevant?<br>A. Diagnostic radiography<br>B. High-energy radiation therapy<br>C. Dental x-rays<br>D. Mammography<br>

b. High-energy radiation therapy.

What is photodisintegration?

A. A low-energy interaction in which an X-ray photon scatters without losing energy

B. An interaction in which an X-ray photon transfers energy to an outer-shell electron

C. An interaction in which an X-ray photon ejects an inner-shell electron from an atom

D. A high-energy photon interacts with a nucleus and causes it to emit a nuclear fragment

D. A high-energy photon interacts with a nucleus and causes it to emit a nuclear fragment.

What does SI stand for?<br>A. International System of Units<br>B. Standard Ionization<br>C. Radiation Intensity<br>D. Sievert Index<br>

a. International System of Units.

What does the roentgen (R) measure?

A. The amount of radiation energy absorbed by body tissues

B. Exposure from x-rays or gamma rays in air

C. The rate of radioactive decay occurring in a radioactive material

D. The radiation dose equivalent received by exposed tissues

B. Exposure from x-rays or gamma rays in air.

What SI unit is replacing the roentgen for measuring radiation exposure?

A. The gray (Gy)

B. The sievert (Sv)

C. The becquerel (Bq)

D. The coulomb per kilogram (C/kg)

D. The coulomb per kilogram (C/kg)

What is a limitation of the roentgen?

A. It measures radiation absorbed by body tissues rather than exposure in air

B. It measures exposure in air and not absorbed dose in tissue

C. It measures radioactive activity produced by unstable atomic nuclei

D. It measures neutron radiation rather than X-ray exposure in air

B. It measures exposure in air and not absorbed dose in tissue.

What is air kerma?

A. A measurement of radioactive activity released by unstable atoms per unit mass during thermionic emission

B. A measurement of equivalent radiation dose received by biological tissue when it is radioactive

C. A measurement of radiation exposure produced by X-rays in air using the roentgen

D. A measure of kinetic energy transferred from photons to charged particles per unit mass of air

D. A measure of kinetic energy transferred from photons to charged particles per unit mass of air

What is the SI unit of air kerma?

A. The gray often reported as mGy

B. The sievert often reported as mSv

C. The becquerel often reported as kBq

D. The roentgen often reported as mR

A. The gray often reported as mGy

What is the traditional unit of absorbed dose?<br>A. The rad<br>B. The gray<br>C. The rem<br>D. The sievert<br>

a. The rad.

What is the SI unit of absorbed dose in tissue?

A. The sievert often reported as mSv

B. The becquerel often reported as kBq

C. The roentgen often reported as mR

D. The gray often reported as mGy

D. The gray often reported as mGy

What is the rem?

A. A traditional unit used to measure the energy absorbed per unit mass of material and its effect

B. A traditional unit used to measure the amount of ionization produced in air and a molecule

C. A traditional unit of dose equivalent that accounts for radiation type and biological effectiveness

D. A traditional unit used to measure the rate of radioactive decay in a sample alive or dead

C. A traditional unit of dose equivalent that accounts for radiation type and biological effectiveness

What does dose equivalence measure?

A. The total energy absorbed by body tissues during radiation exposure

B. The amount of ionization produced by radiation in a specific volume of air

C. The expected biological damage from radiation, accounting for radiation type

D. The number of radioactive disintegrations occurring within a material per second

C. The expected biological damage from radiation, accounting for radiation type

What is the SI unit replacing the rem?
A. The gray
B. The becquerel
C. The sievert
D. The rad

c. The sievert

What is the curie?

A. A traditional unit measuring absorbed dose in tissue

B. A traditional unit measuring the activity of a radioactive material

C. A traditional unit measuring exposure in air

D. A traditional unit measuring equivalent dose in humans

B. A traditional unit measuring the activity of a radioactive material

What is the SI unit of radioactive activity?
A. The gray
B. The becquerel
C. The sievert
D. The roentgen

b. The becquerel

Why must whole-body and partial-body doses be distinguished?<br>A. The biological effects depend on which tissues are exposed and how much tissue receives radiation<br>B. Whole-body dose is always less harmful because radiation is distributed throughout the entire body<br>C. Partial-body dose is always more harmful because radiation affects a smaller area of the body<br>D. The biological effects depend only on the radiation type and not on which tissues are exposed<br>

a. The biological effects depend on which tissues are exposed and how much tissue receives radiation.

What is a partial-body exposure?<br>A. Radiation exposure distributed relatively evenly throughout the entire body<br>B. Radiation exposure caused by radioactive material entering and remaining inside the body<br>C. Radiation exposure received primarily from naturally occurring environmental sources<br>D. Radiation exposure limited primarily to a specific body region or tissue<br>

d. Radiation exposure limited primarily to a specific body region or tissue.

What is the goal when selecting an exposure technique?<br>A. To obtain the highest possible image contrast regardless of patient radiation dose<br>B. To obtain the lowest possible radiation dose while maintaining acceptable diagnostic image quality<br>C. To obtain a diagnostic-quality image with the lowest reasonable radiation dose<br>D. To obtain the shortest possible exposure time regardless of diagnostic image quality<br>

c. To obtain a diagnostic-quality image with the lowest reasonable radiation dose.

Is any ionizing radiation dose guaranteed to be completely risk-free?<br>A. No radiation protection aims to minimize risk<br>B. Yes doses below 1 mSv are completely risk-free<br>C. Yes doses below 10 mSv are completely risk-free<br>D. Depends natural background radiation is completely risk-free<br>

a. No radiation protection aims to minimize risk.

What is the fundamental principle of radiation protection?<br>A. Justify the examination and maintain image quality regardless of patient radiation dose<br>B. Optimize exposure and eliminate all radiation from diagnostic imaging procedures<br>C. Justify the examination and optimize exposure to minimize unnecessary radiation<br>D. Limit radiation exposure only for pregnant patients and children during diagnostic examinations<br>

c. Justify the examination and optimize exposure to minimize unnecessary radiation.

What are the two theories of cellular radiation damage?<br>A. Direct-hit theory and thermal-hit theory<br>B. Direct-hit theory and indirect-hit theory<br>C. Indirect-hit theory and chemical-hit theory<br>D. Direct-hit theory and mechanical-hit theory<br>

b. Direct-hit theory and indirect-hit theory.

What is the direct-hit theory?<br>A. Radiation interacts with water molecules producing free radicals<br>B. Radiation interacts with cellular proteins producing heat that damages tissues<br>C. Radiation interacts with cellular lipids producing hormones that alter normal cell functions<br>D. Radiation directly interacts with critical cellular molecules such as DNA<br>

d. Radiation directly interacts with critical cellular molecules such as DNA.

What is the indirect-hit theory?<br>A. Radiation interacts with water in the cell producing reactive substances that damage cellular structures<br>B. Radiation interacts directly with DNA causing damage without involving other molecules<br>C. Radiation interacts with the cell membrane producing damage without affecting other cellular structures<br>D. Radiation interacts with the nucleus causing damage without involving water molecules<br>

a. Radiation interacts with water in the cell producing reactive substances that damage cellular structures.

Which theory is more prevalent in radiation-induced biological damage?<br>A. Direct hit theory<br>B. Indirect hit theory<br>

b. Indirect hit theory.

What is radiolysis of water?<br>A. The freezing of water molecules caused by exposure to radiation<br>B. The evaporation of water molecules caused by exposure to ionizing radiation<br>C. The ionization of water molecules caused by exposure to visible light<br>D. The breakdown of water molecules by ionizing radiation<br>

d. The breakdown of water molecules by ionizing radiation.

What are free radicals?<br>A. Stable atoms or molecules with all electrons paired in their outer shells<br>B. Highly reactive atoms or molecules with unpaired electrons that can damage cells<br>C. Nonreactive molecules that protect cells from radiation-induced cellular damage<br>D. Charged particles that cannot interact with or damage living cells<br>

b. Highly reactive atoms or molecules with unpaired electrons that can damage cells.

What is radiosensitivity?<br>A. The relative susceptibility of cells or tissues to radiation-induced damage<br>B. The ability of cells to emit radiation during radioactive decay<br>C. The ability of cells to absorb radiation without experiencing biological damage<br>D. The resistance of all cells and tissues to radiation-induced damage<br>

a. The relative susceptibility of cells or tissues to radiation-induced damage.

What cellular characteristics influence radiosensitivity?<br>A. Cell color and shape and overall physical appearance<br>B. The rate and duration of cell division and the cell's level of differentiation<br>C. The cell's lipid content and water content and overall chemical composition<br>D. The cell's location in the body and its surrounding tissue environment<br>

b. The rate and duration of cell division and the cell's level of differentiation.

Why are rapidly dividing cells generally more radiosensitive?

A. They contain lower amounts of water and fewer cellular fluids than non-dividing cells

B. They have more stable DNA and stronger repair mechanisms than non-dividing cells

C. They are more vulnerable to radiation-induced disruption of cell division and DNA damage

D. They are protected by a thicker cell membrane that limits radiation penetration

C. They are more vulnerable to radiation-induced disruption of cell division and DNA damage

Which type of cell is most damaged by radiation?

A. Mature cells with specialized functions

B. Highly differentiated cells with limited division

C. Long-lived cells that rarely undergo mitosis

D. Undifferentiated cells that divide rapidly

D. Undifferentiated cells that divide rapidly

What are undifferentiated cells, and which are examples?

A. Fully mature cells that perform specialized functions throughout the body, such as muscle, bone, and epithelial cells

B. Specialized cells that rarely divide or develop further, such as mature nerve and cranial cells

C. Fully developed cells that maintain normal tissue and organ functions, such as mature skin cells

D. Immature cells that have not specialized, such as stem cells and cells in developing gonads and young children

D. Immature cells that have not specialized, such as stem cells and cells in developing gonads and young children

What are four possible outcomes when radiation interacts with a cell?<br>A. No damage and damage followed by mutation and damage without repair or cell death<br>B. No damage and damage followed by repair and damage without repair or cell death<br>C. No damage and damage followed by repair and damage without repair or cell fusion<br>D. No damage and damage followed by mutation and damage without repair or cell fusion<br>

b. No damage and damage followed by repair and damage without repair or cell death.

What is one possible effect of radiation damage on mitosis?<br>A. Immediate completion of mitosis without errors<br>B. Permanent increase in chromosome number<br>C. Complete loss of all cell functions<br>D. Delayed cell division<br>

d. Delayed cell division.

What is another possible effect of radiation on the mitotic rate?<br>A. An altered rate of cell division<br>B. An unchanged rate of cell division<br>C. A complete stop of all cell metabolism<br>D. A change in cell color only<br>

a. An altered rate of cell division.

What factors affect cellular survival after radiation exposure?<br>A. Radiosensitivity and cell type and cell shape and total radiation dose<br>B. Radiation type and exposure rate and cell color and cell shape<br>C. Total radiation dose and exposure duration and the number of cells exposed<br>D. Radiosensitivity and damage type and radiation type and exposure rate and total dose<br>

d. Radiosensitivity and damage type and radiation type and exposure rate and total dose.

Can cells recover from radiation damage?<br>A. No all radiation damage is permanent<br>B. No only non-dividing cells can recover<br>C. Yes many cells can repair some radiation-induced damage<br>D. Yes all cells recover completely from lethal damage<br>

c. Yes many cells can repair some radiation-induced damage.

What is lethal cellular damage?<br>A. Damage severe enough to prevent a cell from functioning normally but still allow repair<br>B. Damage severe enough to cause cell death or loss of reproductive ability<br>C. Damage that affects the cell membrane and disrupts normal cellular function<br>D. Damage that delays cell division but allows the cell to survive and reproduce<br>

b. Damage severe enough to cause cell death or loss of reproductive ability.

What is genetic radiation damage?<br>A. Radiation damage to body cells that affects the exposed individual<br>B. Radiation damage to reproductive cells that may be passed to offspring<br>C. Radiation damage to blood cells that can weaken the immune system<br>D. Radiation damage to nerve cells that can affect normal sensation and function<br>

b. Radiation damage to reproductive cells that may be passed to offspring.

What are the three classic stages of acute radiation syndrome?<br>A. Initial stage and recovery stage and latent stage<br>B. Prodromal stage and recovery stage and manifest illness stage<br>C. Latent period and recovery period and genetic period<br>D. Prodromal stage and latent period and manifest illness stage<br>

d. Prodromal stage and latent period and manifest illness stage.

What is the prodromal stage?<br>A. The stage when specific radiation injuries become apparent<br>B. The initial stage in which early symptoms appear<br>C. The stage when symptoms temporarily subside<br>D. The stage when recovery is complete<br>

b. The initial stage in which early symptoms appear.

What does NVD stand for in acute radiation syndrome?<br>A. Nausea and vertigo and disorientation<br>B. Neurovascular damage<br>C. Nausea and vomiting and diarrhea<br>D. Nuclear violence dose<br>

c. Nausea and vomiting and diarrhea.

What is the latent period?<br>A. A period when symptoms may temporarily subside despite ongoing biological injury<br>B. A period when symptoms disappear completely and do not return after radiation exposure<br>C. A period when radiation exposure first occurs and begins affecting the body's tissues<br>D. A period when radiation injuries reach their greatest severity and produce noticeable symptoms<br>

a. A period when symptoms may temporarily subside despite ongoing biological injury.

What is the manifest illness stage?<br>A. The stage when the first noticeable signs of radiation sickness begin to appear<br>B. The stage when specific radiation injuries and symptoms become apparent<br>C. The stage when radiation sickness symptoms temporarily decrease or disappear<br>D. The stage when the body begins recovering and full healing is expected to occur<br>

b. The stage when specific radiation injuries and symptoms become apparent.

What can happen after the manifest illness stage?<br>A. Only complete recovery without complications<br>B. Only immediate death without recovery<br>C. Recovery or death depending on the dose and damage<br>D. Only genetic effects in offspring<br>

c. Recovery or death depending on the dose and damage.