#1 Biological Aspects of Radiation
Radiation is said to be carcinogenic. What does carcinogenic mean? A. A cancer producing substance B. Causes genetic changes C. The ability to destroy cancer D. Causes cell death
A. A cancer producing substance: Radiation is a carcinogen (cancer-causing substance) because it can alter the genetic code on a DNA molecule.
An alteration in the sequence of bases in a DNA molecule will result in which of the following? A. A mutation B. A duplication C. A replication D. A chromatin
A. A mutation: A change in the sequence of bases that form genes in a DNA molecule will cause a variation in the offspring of its parents. This is known as a mutation.
Transfer RNA carries which of the following to the polysome in order to synthesize a protein? A. Amino acids B. Polypeptides C. Anticodons D. Chromosomes
A. Amino acids : A polysome is a group of ribosomes. Proteins are made up of amino acid groups. Ribosomal RNA assists in the synthesis of proteins.
Stochastic effects of radiation can be defined by which of the following? A. Cells that survive an initial irradiation but produce a late effect B. Cells that require a threshold dose before an effect will occur C. The greater the dose, the greater the biological effect D. The risk of malignancy is negligible
A. Cells that survive an initial irradiation but produce a late effect : The greater the dose, the greater the chance of a specific late effect. However, the severity of the effect does not increase with an increase in dose. Cancer and genetic defects are examples of stochastic effects.
The small segments of the DNA molecule that determine the characteristics of each cell are called what? A. Genes B. Centrioles C. Purines D. Spindle fibers
A. Genes: Genes are located on the DNA molecule which helps make up the chromosome. A dominant gene will carry a trait to an offspring. It takes both recessive genes to carry a recessive trait to an offspring.
Which of the following are considered extremely sensitive to radiation? A. Gonads B. Spinal cord C. Thyroid gland D. Lens of the eye
A. Gonads : Cells that divide very rapidly (spermatozoa and lymphocytes) are extremely sensitive to radiation because they are in the metaphase stage of mitosis more often.
Which of the following is the most sensitive to radiation? A. Lymphoid tissue B. Epithelial tissue C. Connective tissue D. Muscle tissue
A. Lymphoid tissue: Tissues are made up of cells. Tissues whose cells divide rapidly are most radiosensitive.
Where will most of a cell's genetic information be found? A. Nucleus B. Nucleolus C. Cytoplasm D. Daughter cell
A. Nucleus : A cell's genetic information is located in the DNA molecule which is found in the nucleus of a cell.
During the Compton effect, x rays most often interact with which of the fo A. Outer shell electrons B. Inner shell electrons C. The nucleus D. Protons
A. Outer shell electrons: Loosely bound, outer shell electrons absorb some of the x ray's energy and cause the remaining x ray energy to change direction.
What would be the probable result of any major radiation exposure during the first few days of pregnancy? A. Prenatal death B. Postnatal death C. A child with genetic deficiencies D. A normal birth and infant
A. Prenatal death : Major exposure during the first two weeks would probably cause a spontaneous abortion.
How will oxygen retention effect the radiosensitivity of a cell? A. Radiosensitivity will increase B. Radiosensitivity will decrease C. Radiosensitivity will be eliminated D. Radiosensitivity will not be effected
A. Radiosensitivity will increase: Well oxygenated cells will be 2 to 3 times more radiosensitive. This is important in the radiation treatment of tumors.
What characterizes the Compton effect? A. Recoil electron B. Total absorption of primary photon C. Photoelectron D. Primary photon does not lose energy
A. Recoil electron: The Compton effect produces a recoil electron (Compton electron), scatter photon, ionized atom and secondary characteristic radiation.
What do the letters "RBE" stand for? A. Relative biologic effectiveness B. Radiosensitive biologic effect C. Radioactive biological energy D. Radiation bypass effect
A. Relative biologic effectiveness: Relative biologic effectiveness (RBE) compares the biological effect of a 250 keV x ray with other radiations. For example, some radiation might produce twice the effect that a 250 keV x ray would.
The "Direct Hit" theory of cell irradiation can be described by which of the following statements? A. The DNA molecule is struck B. The cell nucleus is struck C. The cell cytoplasm is struck D. The cell is ionized
A. The DNA molecule is struck: A "direct hit" means the radiation struck the DNA molecule. Whereas, an "indirect hit" means the radiation struck a water molecule which released a free radical that struck the DNA.
How can radiation induce cancer in a person? A. It can alter a cells function B. A mutation can increase cell growth C. It can cause cell death D. Radiation destroys the immune system
B. A mutation can increase cell growth : Cancer is the rapid growth of a tissue. A change in the DNA molecule can be the reason for this rapid cell division.
Which of the following types of tissue will absorb the most radiation? A. Air sacs B. Bone C. Muscle D. Soft tissue
B. Bone: The more dense the tissue, the greater the probability that radiation will strike a subatomic particle. Bone is the most dense tissue in the above list.
A reddening of the skin due to radiation damage is called what? A. Emesis B. Erythema C. Euploidy D. Epidermal destruction
B. Erythema: Erythema is noticed in the treatment of cancer patients by radiation. Similar to a sunburn, it may show up 1 or 2 days after the exposure dose of 100 - 300 rad.
What is the name of the stage of cell division that is commonly referred to as the resting stage? A. Anaphase B. Interphase C. Metaphase D. Telophase
B. Interphase: Inter- means between. This is the stage between cell division when the DNA molecule is synthesized (combining parts to form a whole).
The radiation interaction with tissue that causes most of the cellular damage is which of the following? A. Excitation B. Ionization C. Classical scattering D. Thompson scattering
B. Ionization: The basic interaction is when radiation removes an electron from an atom leaving a positive ion (ionization). The atom will then react differently and may cause damage to that cell.
Which of these situations will cause the greatest effect from radiation exposure? A. Small dose over a long time period B. Large dose over a short time period C. Small dose over a short time period D. Large dose over a long time period
B. Large dose over a short time period: A large dose over a short period of time will not allow the cells to recover from their injury, but the same dose spread over a longer time would allow recovery. This is known as fractionation.
What is the process of cell division of somatic cells called? A. Meiosis B. Mitosis C. Synthesis D. Multiplication
B. Mitosis : Mitosis is the process by which somatic cells duplicate to replace cells and help the body grow. It is made up of four stages: prophase, metaphase, anaphase and telophase.
Which of the following interactions does NOT occur under 125 kVp? A. Compton effect B. Pair production C. Photoelectric absorption D. Coherent (classical) scatter
B. Pair production: Pair production requires an x ray to have 1.02 MeV of energy to produce a positron and electron.
Which of the following is the most common result of cell irradiation? A. Cell death B. Sterilization C. Mutation D. Uncontrolled growth
B. Sterilization: The most common result of cell irradiation would be complete recovery. Since it is not a choice, the next most common is when the cell is damaged enough that it cannot continue to reproduce.
Which of the following is considered the unit of heredity? A. The cell B. The gene C. The chromosome D. The DNA molecule
B. The gene: Genes are considered the basic unit of heredity. They are located within the chromosome and can be dominant or recessive.
Which of the following is NOT a stage of somatic cell division? A. Prophase B. Metaphase C. Nanophase D. Telophase
C. Nanophase: The order of somatic cell division (mitosis) is prophase, metaphase, anaphase and telophase.
Which statement is true concerning the effects of radiation exposure? A. No effects occur at low rem levels B. Damage is not passed on to offspring C. The body can repair most damage D. Mutations only occur at high exposure
C. The body can repair most damage: Just as the human body repairs itself from a wound, the body will also repair radiation damage.
Of the following blood cell producing organs, which are considered radiosensitive? 1. Spleen 2. Bone marrow 3. Lymphatic nodes A. 1 & 2 only B. 1 & 3 only C. 2 & 3 only D. 1, 2 & 3
D. 1, 2 & 3 : Organs that have a high degree of cell division also have a high sensitivity to radiation.
Which of the following are possible results from the exposure to radiation? 1. Changes in the DNA molecule 2. Sterilization of the cell 3. Death to the cell A. 1 only B. 2 only C. 1 & 3 only D. 1, 2 & 3
D. 1, 2 & 3 : The other possibility is that the cell will make a full recovery from any radiation damage. This is the most likely response.
A chromosome that has been damaged by radiation may cause which of the following? 1. A mutation 2. Cell death 3. Sterilization A. 1 only B. 2 only C. 2 & 3 only D. 1, 2 & 3
D. 1, 2 & 3: If a cell is permanently damaged, hopefully it is sterilized or killed. A mutation may cause the cell to change to a cancer cell and begin dividing very rapidly.
A person exhibiting radiation sickness would have which of the following symptoms? 1. Nausea 2. Diarrhea 3. Loss of appetite A. 1 only B. 3 only C. 1 & 2 only D. 1, 2 & 3
D. 1, 2 & 3: The destruction of the cells that line the gastrointestinal tract will result in these kinds of symptoms.
Which of the following determines what the final effect from radiation will be? 1. Type of radiation 2. Type of tissue 3. Energy of radiation A. 1 only B. 3 only C. 2 & 3 only D. 1, 2 & 3
D. 1, 2 & 3: Whether radiation will be harmful or not depends on the ionizing ability of the radiation (type and energy) and the radiosensitivity of the tissue irradiated.
High-level, whole body radiation exposure, delivered in a period of seconds to minutes, produces a clinical pattern known as what? A. Mortality irradiation B. Cumulative exposure C. Whole body dose D. Acute radiation syndrome
D. Acute radiation syndrome: Acute = sudden onset; syndrome = set of symptoms. With whole-body doses over 100 rem, persons may exhibit serious physical symptoms that lead to death.
Which of the following individuals should the radiographer be concerned about when using x rays? A. A child B. An adult C. A radiation worker D. All of the above need consideration
D. All of the above need consideration: Obviously, the radiographer should be concerned about a patient whether it is a child or adult. They also should make sure their fellow radiographer is protected from primary or scatter rays.
Which of the following are considered the building blocks in the synthesizing of proteins? A. Genes B. RNA molecules C. Chromosomes D. Amino acids
D. Amino acids: Proteins are large molecules formed by joining (synthesizing) smaller molecules (amino acids) together. Proteins are considered the basic building blocks of cells.
Irradiation of which of the following anatomical areas will affect the production of white blood cells? A. Lungs B. Liver C. Pancreas D. Bone marrow
D. Bone marrow: Bone marrow is found in long bones and the flat bones of the pelvis, skull and sternum.
The information that cells require for metabolism is coded in which of the following? A. Cytoplasm B. Spindle fibers C. RNA molecule D. DNA molecule
D. DNA molecule Metabolism is chemical changes in living cells by which energy is provided for the cell's vital activities. DNA carries the code of the cell that determines which vital activities the cell will perform.
What does genetically significant dose mean? A. Dose that will cause damage B. Dose that will cause genetic damage C. Dose that will cause a mutation D. Estimated dose received by the population
D. Estimated dose received by the population: GSD is an estimation of the exposure to the genetic cells of a population from all forms of radiation. It is an attempt to predict the impact of present exposure on future generations.
Which of the following would NOT occur from a significant exposure to radiation? A. Blood disorders B. Malignant growths develop C. Cataract formation D. Immunity to radiation damage
D. Immunity to radiation damage: A person could not become resistant (immune) to radiation by receiving radiation exposure.
Which of the following results in the total absorption of the primary x-ray photon? A. Compton effect B. Coherent (classical) scatter C. Pair production D. Photoelectric absorption
D. Photoelectric absorption: The term photoelectric means the photon is totally absorbed by the electron
The messenger RNA carries information to which of the following in order to synthesize proteins? A. DNA molecule B. Transfer RNA molecule C. Chromosome D. Ribosome
D. Ribosome: Messenger RNA carries information from the DNA molecule (in the nucleus) to the ribosome (in the cytoplasm). Here the message is passed to transfer RNA which arranges amino acids into proteins.
During a radiographic examination, which of the following would produce the greatest skin dose? A. High kilovoltage technique B. Low milliamperage technique C. Long SID D. Short SID
D. Short SID: A short, source-to-image receptor distance (SID) allows low energy x rays to reach the patient's skin. Regulations state the source-to-skin distance (SSD) can be no less than 12".
Which of the following does NOT affect the attenuation of an x-ray beam? A. Scatter B. Absorption C. Divergence D. Speed
D. Speed: All x rays travel at the same speed, the speed of light.
Somatic effects of radiation relate to which of the following? A. The fetus B. The newborn C. Future generations D. The exposed individual
D. The exposed individual: Somatic refers to the body. Cells of the body are called somatic cells, cells of the gonads are called genetic cells. Somatic effects relate to the individual.
How many matched pairs of chromosomes does a human somatic cell contain? A. 6 B. 13 C. 23 D. 46
C. 23: There are 46 chromosomes (23 pairs) in human somatic cells. This is known as the diploid number. This number is reduced to half in genetic cells and is called the haploid number.
How much radiation exposure does it take to have a lethal dose where 50% of the humans would die within 60 days? A. 100 to 200 R B. 200 to 300 R C. 300 to 400 R D. 400 to 500 R
C. 300 to 400 R: For humans to receive an exposure large enough to kill 50% of them within 60 days there would have to be a nuclear accident (like Chernobyl) or nuclear war.
Radiosensitivity is affected by the amount of oxygen in the tissue. Which of the following terms describes well oxygenated tissue? A. Anoxic B. Hypoxic C. Aerobic D. Toxic
C. Aerobic : Aerobic (well oxygenated), anoxic (without oxygen), hypoxic (low oxygen), toxic (harmful). Additional oxygen creates additional free radicals which increases the damage to the tissue.
Which of the following will NOT reduce the intensity of an x-ray beam? A. Compton effect B. Photoelectric absorption C. Characteristic effect D. Pair production
C. Characteristic effect: The characteristic effect is a means of producing an x-ray beam. The intensity of the beam will be reduced by the Compton effect, photoelectric absorption and pair production.
If a human is exposed to radiation levels in the 100 to 200 R range, which of the following is expected? A. No clinical effects B. Slight reduction in lymphocytes C. Complete recovery in 90 days D. Death within 30 days
C. Complete recovery in 90 days : A human exposed to this level of radiation would experience nausea, vomiting, diarrhea and decreasing blood cell counts. However, they would be expected to completely recover.
Which of the following is responsible for most of the scatter radiation in the diagnostic range? A. Photoelectric absorption B. Bremsstrahlung radiation C. Compton effect D. Photon skipping
C. Compton effect : Photoelectric absorption totally absorbs the photon, nothing is left to scatter. Bremsstrahlung radiation makes up the primary beam before it scatters.
Where do the metabolic functions of a cell take place? A. Nucleus B. Chromosomes C. Cytoplasm D. DNA molecule
C. Cytoplasm: Metabolism is chemical changes in living cells by which energy is provided for the cell's vital activities.
Which of the following would describe the shape of a DNA molecule? A. Elliptical B. Hypocycloidal C. Double helix D. Circular
C. Double helix : A helix is anything that has a spiral shape. DNA is composed of two long chains that spiral around each other.
The somatic effects of radiation refer to which of the following? A. Exposure to the trunk B. Exposure to the reproductive organs C. Exposure to the body tissues D. Exposure to the nervous system
C. Exposure to the body tissues: Somatic refers to all the cells of the body except the genetic (ova and spermatozoa) cells. Radiating the body tissues may cause changes to the somatic cells.
What is the molecule called that has one or more unpaired electrons and is unusually chemically reactive? A. Ion B. Mutation C. Free radical D. Excited molecule
C. Free radical: During the radiolysis of water, free radicals are produced. They are highly energized and travel at high speeds causing more damage than the radiation.
Which of the following organs is considered radiosensitive? A. Liver B. Spleen C. Gonads D. Thyroid
C. Gonads: The function of the gonads is to produce germ cells (sperm and ova). An exposure of as little as 10 rads can reduce sperm counts and delay menstruation.
Which of the following refers to the single set of chromosomes in a genetic cell? A. Diploid number B. Triploid number C. Haploid number D. Semiloid number
C. Haploid number : The first division produces two cells with the normal diploid number (23 pairs of chromosomes), these divide again to produce two more cells with a haploid number (23 single chromosomes).
When radiation exposure causes hematopoietic death, what is the main reason why the person died? A. Hemorrhage B. Respiratory distress C. Immune system is destroyed D. Heart failure
C. Immune system is destroyed: Since the lymphocytes are the cells that are easiest to destroy, the person will die from infection.
Which of the following is NOT a function of a DNA molecule? A. It carries the genetic code B. It duplicates exact copies of itself C. It synthesizes proteins D. It divides during mitosis
C. It synthesizes proteins: The synthesizing (combining parts into a whole) of proteins is the function of RNA.
Which of the following cells would be affected by a relatively small amount of radiation exposure? A. Muscle B. Nerve C. Leukocyte D. Liver
C. Leukocyte : White blood cells divide very rapidly and therefore are very radiosensitive
Which of the following is a byproduct of photoelectric absorption? 1. Bremsstrahlung radiation 2. Photoelectron 3. Recoil electron A. 1 only B. 2 only C. 2 & 3 only D. 1, 2 & 3
Other byproducts of photoelectric absorption would be an ionized atom and secondary characteristic radiation.
