Radiology LEA #6 Safety

Which of the following statements is true of the average dose of background radiation received by an individual in the United States? A. The average dose of background radiation a person living in the United States receives each year is 6.2 mSv B. Geographic areas that contain more radioactive materials are associated with increased amounts of cosmic radiation. C. Geographic areas at higher elevations are associated with increased amounts of cosmic radiation. D. A wood home has a higher natural radiation level than a brick home.

C.

Which types of cells are more sensitive to radiation: (1) rapidly dividing, (2) slowly dividing, (3) young, and/or (4) old? A. 2 and 3 B. 1 and 4 C. 1 and 3 D. 2 and 4

C.

Your patient is receiving radiation treatments for breast cancer. She reports having a burning sore throat and great difficulty swallowing. Which stage of the radiation injury sequence is your patient in? A. Recovery B. Cumulative effects C. Injury D. Latent

C.

A nonthreshold dose-response curve suggests that A. radiation exposure below the threshold will not damage tissues. B. radiation exposure below the threshold is safe for living tissue. C. radiation exposure above the threshold amount causes some damage to tissues. D. radiation exposure, no matter how small, causes damage to living tissue.

D.

Explain to your patient the steps, in order, in the formation of hydrogen peroxide, a toxin that will cause damage to living tissues. 1. Free radicals combine 2. Free radical formation 3. Cellular dysfunction and biologic damage 4. X-ray photons are absorbed by water A. 2, 4, 1, 3 B. 2, 1, 4, 3 C. 1, 2, 3, 4 D. 4, 2, 1, 3

D.

Precautions should be taken during dental imaging procedures to which of the following critical organs in the head and neck region? (1) skin, (2) thyroid gland, (3) lens of the eye, and (4) bone marrow A. 2, 4 B. 1, 2, 3 C. 1, 2, 4 D. 1, 2, 3, 4

D.

Stochastic biologic effects from radiation A. cause significant damage to cell or cell death. B. are directly related to exposure and effect. C. have a dose threshold. D. occur as a result of exposure, but severity is not determined by dose.

D.

The bombing at Nagasaki and Hiroshima took place in 1945; an increase in the incidence of cancer was noted in 1956. Which effects apply to the cancer incidence? A. Short-term, somatic B. Long-term, genetic C. Short-term, genetic D. Long-term, somatic

D.

What specific mechanism of radiation injury may result in the formation of hydrogen peroxide when x-ray energy is absorbed by patients? A. An ejected high-speed electron may interact with other atoms within absorbing tissues. B. Unequal charge distribution may result in negative electrical potential. C. Creation of a magnetic field may cause polarization. D. Free radical formation created by the ionization of water may occur.

D.

Which of the following is the least sensitive to x-rays? A. Lymphoid tissue B. Intestines C. Bone marrow D. Salivary glands

D.

You could be exposed to each of these radiation sources in your daily activities. Which of these sources is human-made? A. Radioactive potassium B. Atomic fallout C. Terrestrial radiation D. Radon gas

B.

(1) All ionizing radiations cause damage to living tissues. (2) Although very little radiation is used in dentistry, damage to the cells does occur. A. Both statements are false. B. The first statement is true; the second statement is false. C. Both statements are true. D. The first statement is false; the second statement is true.

C.

(1) More radiation damage takes place with high dose rates (2) because a rapid delivery of radiation does not allow time for cellular damage to be repaired. A. The first statement is false; the second statement is true. B. Both statements are true. C. Both statements are false. D. The first statement is true; the second statement is false.

C.

Which of the following is an example of stochastic effects? A. Hair loss B. Radiation sickness C. Cancer D. Erythema

C.

According to the dose-response curve, when dose and damage are plotted on a graph, a _____________________ relationship is seen. A. linear, nonthreshold B. nonlinear, threshold C. nonlinear, nonthreshold D. linear, threshold

A.

The indirect theory proposes that A. toxins are created from the formation of free radicals. B. changes occur to the deoxyribonucleic acid (DNA) of a cell. C. direct injuries occur more frequently than indirect injuries. D. ionizing radiation strikes critical areas within cells.

A.

Uranium is an example of __________ radiation. A. terrestrial B. artificial C. internal D. cosmic

A.

Which of the following is associated with long-term radiation effects? A. Small amounts of radiation absorbed over a long period B. Symptoms include diarrhea, hair loss, and hemorrhage. C. The injury period in the sequence of radiation injury is seen within minutes, days, or weeks of radiation exposure. D. Acute radiation syndrome

A.

Which of the following statements is true of somatic effects of irradiation? A. Changes are not transmitted to future generations. B. Mutations occur that affect the health of offspring. C. Changes are in the genetic cells of the individual. D. Damage cannot be repaired.

A.

Your patient was out in the hot, bright sun yesterday. While in the sun she began experiencing pain and noticed her skin had turned bright red. Shortly after arriving home, she began to experience chills, nausea, severe pain, and blistering. Why would your patient experience the symptoms so quickly? A. The latent period was decreased by the increased dose and dose rate. B. The latent period was increased by the increased dose and dose rate. C. The latent period was decreased by the increased area of tissue irradiated and the number of sensitive cells. D. The latent period was not affected

A.

________________ is/are the single largest contributor to artificial radiation exposure (0.00053 Sv/year). A. Medical radiation B. Fallout from atomic weapons C. Consumer products D. The nuclear fuel cycle

A.

Cellular injuries following the latent period may include (1) cell death, (2) cessation of mitotic activity, and/or (3) abnormal mitotic activity. A. 1, 3 B. 1, 2, 3 C. 1 only D. 1, 2

B.

Which of the following cells would be the most sensitive to x-rays? A. Muscle B. Blood C. Bone D. Nerve

B.

Which of the following is a sign or symptom of acute radiation syndrome (ARS)? A. Cancer B. Hair loss C. Genetic defects D. Birth abnormalities

B.

Which of the following statements is true regarding the direct theory of radiation injury? A. It involves absorption of an x-ray photon by water within a cell. B. It involves damage to the critical areas of a cell through direct contact with the x-ray photon. C. It involves the formation of toxins that damage the cell. D. It involves the formation of free radicals.

B.