Radiography: Radiobiology & Radiation Safety Ch 13
From book Radiography Essentials for Limited Practice 3rd Edition
Questions and Answers
- 1.
The conventional (British system) radiation unit for measuring patient dose is the:
- A.
Roentgen
- B.
Rem.
- C.
Rad.
- D.
Sievert
Correct Answer
C. Rad.Explanation
The correct answer is "rad." The rad (radiation absorbed dose) is the conventional unit used in the British system to measure patient dose from radiation. It represents the amount of radiation energy absorbed by a specific material, such as human tissue. The rad is commonly used in the field of radiology to quantify the dose received by patients during medical procedures involving radiation, such as X-rays or CT scans. Other units, such as the roentgen, rem, and sievert, are also used to measure radiation, but they are not specific to the British system.Rate this question:
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- 2.
What is the conventional (British system) radiation unit to express radiation intensity in air?
- A.
Coulomb/kilogram (C/kg)
- B.
Watt
- C.
Ohm
- D.
Roentgen
Correct Answer
D. RoentgenExplanation
The conventional (British system) radiation unit to express radiation intensity in air is the Roentgen. This unit measures the ionization produced by X-rays or gamma rays in a specified volume of air. It is commonly used in the field of radiation protection and is defined as the amount of radiation that produces one electrostatic unit of charge in one cubic centimeter of dry air at standard temperature and pressure.Rate this question:
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- 3.
The unit of the SI system used to measure the ionization of dry air nby an x-ray beam is:
- A.
R.
- B.
C/kg.
- C.
Rad.
- D.
Rem.
Correct Answer
B. C/kg.Explanation
The unit of the SI system used to measure the ionization of dry air by an x-ray beam is C/kg (Coulombs per kilogram). This unit is used to quantify the amount of electric charge generated per unit mass of air when exposed to an x-ray beam. The ionization of air occurs when the x-ray photons transfer energy to the air molecules, causing them to become ionized. The C/kg unit allows for a standardized measurement of the ionization process, providing a consistent and reliable way to quantify the effects of x-ray exposure on dry air.Rate this question:
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- 4.
The unit commonly used to report occupational dose to radiation workers in the United States is:
- A.
MR
- B.
Mrad
- C.
Mrem
- D.
MGy
Correct Answer
C. MremExplanation
The correct answer is mrem. In the United States, the unit commonly used to report occupational dose to radiation workers is millirem (mrem). This unit measures the effective dose of radiation received by the workers, taking into account the type of radiation and the sensitivity of different body tissues to radiation. It is important to monitor and report occupational doses to ensure the safety of radiation workers and to comply with regulatory standards.Rate this question:
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- 5.
What is the conventional (British System) radiation unit of absorbed dose?
- A.
Rad
- B.
Roentgen
- C.
Gray
- D.
Rem
Correct Answer
A. RadExplanation
The conventional (British System) radiation unit of absorbed dose is the Rad. The Rad is a unit used to measure the amount of energy absorbed by a material when exposed to radiation. It is commonly used in the field of radiation protection and is equal to 0.01 joules of energy absorbed per kilogram of material.Rate this question:
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- 6.
How many rad are equivalent to one (1) Gy?
- A.
10
- B.
100
- C.
1
- D.
0.1
Correct Answer
B. 100Explanation
One Gray (Gy) is equivalent to 100 rads.Rate this question:
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- 7.
What is the "weighting factor" that is assigned to the equivalent dose (EqD)?
- A.
The SI unit for expressing radiation exposure in human tissue
- B.
The unit to express the rate in which radiation gives up its energy to human tissue
- C.
A number assigned to each type of radiation based on the variation in biologic damage that is produced when an individual receives exposure from different types of radiation
- D.
A comparison of exposure factors and patient dose, expressed as a numeric value
Correct Answer
C. A number assigned to each type of radiation based on the variation in biologic damage that is produced when an individual receives exposure from different types of radiationExplanation
The "weighting factor" is a number assigned to each type of radiation based on the variation in biologic damage that is produced when an individual receives exposure from different types of radiation. This factor takes into account the different levels of harm caused by different types of radiation and helps in calculating the equivalent dose (EqD) which expresses the overall biological effect of radiation on human tissue.Rate this question:
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- 8.
In radiography, patient dose is usually calculated:
- A.
At the target organ
- B.
By using the personnel dosimeter worn on the collar
- C.
In DNA
- D.
At the skin
Correct Answer
D. At the skinExplanation
In radiography, patient dose is usually calculated at the skin. This is because the skin is the outermost layer of the body and is the first point of contact with the radiation beam. Measuring the dose at the skin provides an indication of the radiation exposure that the patient receives during the procedure. It is important to monitor the dose at the skin to ensure that it is within safe limits and to minimize the risk of radiation-related side effects or injuries.Rate this question:
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- 9.
Which of the following radiographic examinations typically delivers the greatest gonadal exposure?
- A.
Chest
- B.
Lumbar spine
- C.
Femur
- D.
KUB
Correct Answer
D. KUBExplanation
The KUB (Kidneys, Ureters, and Bladder) radiographic examination typically delivers the greatest gonadal exposure. This is because the KUB exam involves imaging the pelvic region, which is closer to the gonads compared to the other options (chest, lumbar spine, and femur). Therefore, the radiation dose received by the gonads is generally higher during a KUB examination.Rate this question:
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- 10.
According to the Laws of Bergonie and Tribondeau, which of the following types of cells is most radiosensitive?
- A.
Brain cells
- B.
Embryonic tissue
- C.
Cells of the gastric mucosa
- D.
Skin cells
Correct Answer
B. Embryonic tissueExplanation
Embryonic tissue is the most radiosensitive type of cell according to the Laws of Bergonie and Tribondeau. These laws state that cells that are rapidly dividing, undifferentiated, and have a long lifespan are more susceptible to radiation damage. Embryonic tissue fits all of these criteria as it undergoes rapid cell division and differentiation during development, and has a longer lifespan compared to other types of cells. Therefore, it is more prone to radiation damage compared to brain cells, cells of the gastric mucosa, and skin cells.Rate this question:
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- 11.
Which of the following results from an indirect hit?
- A.
Free radicals
- B.
Enzymes
- C.
DNA breakage
- D.
Genetic damage
Correct Answer
A. Free radicalsExplanation
An indirect hit refers to a situation where an external force or agent causes damage to a biological system without directly interacting with it. In this context, free radicals are the most likely result of an indirect hit. Free radicals are highly reactive molecules that can cause damage to cells and biomolecules, including DNA. They are formed when molecules in the body undergo oxidation processes due to exposure to environmental factors such as radiation or toxins. Therefore, in the case of an indirect hit, the formation of free radicals is a plausible consequence.Rate this question:
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- 12.
Temporary molecules and parts of molecules that form because of radiation interacting with water and are toxic to human tissue are called:
- A.
Deviant enzymes
- B.
Extreme ions
- C.
Antimatter
- D.
Free radicals
Correct Answer
D. Free radicalsExplanation
Free radicals are temporary molecules or parts of molecules that form when radiation interacts with water. These molecules are toxic to human tissue. They are highly reactive and can cause damage to cells and DNA. Free radicals are known to be involved in various diseases and aging processes.Rate this question:
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- 13.
Which of the following cells would not be as vulnerable to x-rays?
- A.
Thyroid cells
- B.
Skin cells
- C.
Nerve cells
- D.
Blood cells
Correct Answer
C. Nerve cellsExplanation
Nerve cells would not be as vulnerable to x-rays compared to the other options. This is because nerve cells are specialized cells that have a unique structure and function, including a protective covering called the myelin sheath. The myelin sheath acts as insulation for the nerve cells, providing them with additional protection against external factors such as x-rays. In contrast, thyroid cells, skin cells, and blood cells do not have the same level of protection and are therefore more vulnerable to the damaging effects of x-rays.Rate this question:
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- 14.
What is a direct hit?
- A.
Breakage of a DNA molecule as a result of an interaction with an x-ray photon
- B.
Chemical decomposition of water that reults from an interaction with an x-ray photon
- C.
Interruption of cell mitosis caused by an interaction with an x-ray photon
- D.
Accurate x-ray centering combined with appropriate exposure factors.
Correct Answer
A. Breakage of a DNA molecule as a result of an interaction with an x-ray photonExplanation
A direct hit refers to the breakage of a DNA molecule as a result of an interaction with an x-ray photon. When an x-ray photon directly interacts with a DNA molecule, it can cause damage to the molecular structure, leading to the breakage of the DNA molecule. This can have significant consequences for cell function and can potentially lead to genetic mutations or cell death.Rate this question:
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- 15.
Which of the following types of radiation effect is typical of the risk to a patient undergoing a diagnostic x-ray examination?
- A.
Short term effects
- B.
Genetic effects
- C.
Nonstochastic effects
- D.
Stochastic effects
Correct Answer
D. Stochastic effectsExplanation
Stochastic effects are typical of the risk to a patient undergoing a diagnostic x-ray examination. Stochastic effects are random and occur without a threshold dose, meaning that any amount of radiation exposure can increase the probability of these effects occurring. These effects are usually long-term and include the development of cancer and genetic mutations.Rate this question:
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- 16.
Which of the following is a stochastic radiation effect?
- A.
Breast cancer
- B.
Erythema
- C.
Decreased leukocyte count
- D.
"radiation sickness"
Correct Answer
A. Breast cancerExplanation
Breast cancer is a stochastic radiation effect because it is a type of cancer that can occur randomly and without a clear threshold dose. Stochastic effects are those that have a probability of occurring, and their severity does not depend on the dose of radiation received. In the case of breast cancer, exposure to radiation increases the likelihood of developing the disease, but the severity or likelihood of occurrence is not directly linked to the dose received.Rate this question:
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- 17.
Which of the following occur with high radiation doses?
- stochastic effects
- short-term somatic effects
- nonstochastic effects
- A.
1 and 2 only
- B.
1 and 3 only
- C.
2 and 3 only
- D.
1, 2, and 3
Correct Answer
C. 2 and 3 onlyExplanation
High radiation doses can cause both nonstochastic effects and short-term somatic effects. Nonstochastic effects occur when the severity of the effect increases with the dose, such as radiation burns or radiation sickness. Short-term somatic effects refer to the immediate health effects that occur shortly after exposure, such as nausea, vomiting, and hair loss. Stochastic effects, on the other hand, occur randomly and do not have a threshold dose, meaning they can occur even at low doses. Examples of stochastic effects include cancer and genetic mutations. Since the correct answer states that only options 2 and 3 occur with high radiation doses, it means that stochastic effects (option 1) do not occur at high doses.Rate this question:
- 18.
What is erythema?
- A.
Loss of hair caused by a high-radiation dose
- B.
Loss of hair caused by long-term, low-radiation dose
- C.
Reddening of the skin caused by high-radiation dose
- D.
Reddening of the skin caused by long-term, low-radiation dose
Correct Answer
C. Reddening of the skin caused by high-radiation doseExplanation
Erythema refers to the reddening of the skin caused by a high-radiation dose. This occurs when the skin is exposed to a significant amount of radiation, resulting in inflammation and dilation of blood vessels. The increased blood flow to the affected area causes the skin to appear red. It is important to note that erythema is specifically associated with a high dose of radiation, rather than a long-term, low dose.Rate this question:
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- 19.
What is the guiding philosophy of radiation protection?
- A.
ALRMA--as long as radiographs are made accessible
- B.
ALARA--as low as reasonably achievable
- C.
ALAIS--as long as ionizations are small
- D.
ALAP--as low as possible
Correct Answer
B. ALARA--as low as reasonably achievableExplanation
The guiding philosophy of radiation protection is to keep radiation exposure as low as reasonably achievable (ALARA). This means that the goal is to minimize radiation doses to individuals and the general public while still allowing for the benefits of radiation use. It recognizes that it may not be possible to completely eliminate radiation exposure, but efforts should be made to reduce it to the lowest level that is reasonably achievable. This principle is important in various industries and fields where radiation is used, such as healthcare, nuclear power, and industrial settings.Rate this question:
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- 20.
Which of the following statements reflects current scientific opinion regarding the effects of diagnostic levels of ionizing radiation?
- A.
It is carcinogenic after a certain number of examinations have been performed
- B.
Spontaneous abortion will occur if the patient is pregnant
- C.
Depression of the white blood cell count is followed by acute gastrointstinal distress
- D.
Ther is increased risk of cancer, leukemia, birth defects, and cataracts.
Correct Answer
D. Ther is increased risk of cancer, leukemia, birth defects, and cataracts.Explanation
The correct answer reflects the current scientific opinion that there is an increased risk of cancer, leukemia, birth defects, and cataracts due to diagnostic levels of ionizing radiation.Rate this question:
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- 21.
The EDE limit for whole-body dose of occupational radiation exposure for nonpregnant workers older thatn age 18 who are involved in radiation use is:
- A.
1.25 rem per year
- B.
5.0 mrem per year
- C.
0.5 rem per year
- D.
5.0 rem per year
Correct Answer
D. 5.0 rem per yearExplanation
The EDE limit for whole-body dose of occupational radiation exposure for nonpregnant workers older than age 18 who are involved in radiation use is 5.0 rem per year. This means that these workers can be exposed to a maximum of 5.0 rem of radiation per year without exceeding the recommended limit. It is important for these workers to monitor and control their radiation exposure to ensure their safety and minimize any potential health risks associated with radiation exposure.Rate this question:
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- 22.
Which of the following are considered "low-dose techniques"?
- using optimum kVp
- using fast screens and fast film
- Using a minimum SID of 40 inches
- A.
1 and 2 only
- B.
1 and 3 only
- C.
2 and 3 only
- D.
1,2, and 3
Correct Answer
D. 1,2, and 3Explanation
The given answer, 1, 2, and 3, is correct because all three options listed are considered "low-dose techniques." Using optimum kVp means using the highest possible kilovoltage peak, which reduces the amount of radiation needed to produce an image. Using fast screens and fast film also reduces the exposure time and therefore the radiation dose. Finally, using a minimum source-image distance (SID) of 40 inches helps to reduce the radiation dose by increasing the distance between the patient and the x-ray source. Therefore, all three options contribute to reducing the radiation dose and are considered low-dose techniques.Rate this question:
- 23.
Which of the following changes decrease patient dose?
- using faster screens
- increasing the kVp using the 15% rule
- increasing the grid ratio to a 16:1 ratio
- A.
1 and 2 only
- B.
1 and 3 only
- C.
2 and 3 only
- D.
1, 2, and 3
Correct Answer
A. 1 and 2 onlyExplanation
Using faster screens and increasing the kVp using the 15% rule both decrease patient dose. Faster screens reduce the amount of radiation needed to produce an image, resulting in lower patient dose. Increasing the kVp using the 15% rule allows for a higher energy x-ray beam, which can penetrate the patient more easily and reduce the amount of radiation needed. Increasing the grid ratio to a 16:1 ratio, on the other hand, increases patient dose by requiring more radiation to penetrate the grid and reach the image receptor.Rate this question:
- 24.
When radiation exposure occurs during pregnancy, the greatest risk of birth defects occurs when the exposure:
- to the uterus exceeds r rad
- occures within the first trimester of pregnancy
- occurs within the third trimester of pregnancy
- A.
1 and 2 only
- B.
1 and 3 only
- C.
2 and 3 only
- D.
1, 2, and 3
Correct Answer
A. 1 and 2 onlyExplanation
Exposure to radiation during pregnancy can increase the risk of birth defects. The greatest risk of birth defects occurs when the exposure exceeds a certain amount (r rad). Additionally, the timing of the exposure is also important. The first trimester of pregnancy is considered to be the most critical period for fetal development, so exposure during this time poses the highest risk of birth defects. Therefore, the correct answer is 1 and 2 only, as it states that the risk is highest when the exposure to the uterus exceeds r rad and occurs within the first trimester of pregnancy.Rate this question:
- 25.
One of the earliste changes seen in the body as a result of exposure to radiation is blood changes. At what radiation dose is this seen?
- A.
25 rem (0.25 Sv)
- B.
150 rem (1.5 Sv)
- C.
200 rem (2.0 Sv)
- D.
600 rem (6.0 Sv)
Correct Answer
A. 25 rem (0.25 Sv)Explanation
Exposure to radiation can lead to various changes in the body, and one of the earliest changes is seen in the blood. At a radiation dose of 25 rem (0.25 Sv), these blood changes become apparent. It is important to note that different radiation doses can have different effects on the body, and higher doses can lead to more severe consequences. However, at a dose of 25 rem, blood changes can already be observed.Rate this question:
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- 26.
Death occurs if the body recieves a whole-body exposure of how much radiation?
- A.
150 rem (1.5 Sv)
- B.
200 rem (2.0 Sv)
- C.
300 rem (3.0 Sv)
- D.
600 rem (6.0 Sv)
Correct Answer
D. 600 rem (6.0 Sv)Explanation
Exposure to high levels of radiation can cause severe damage to the body's cells and tissues. The unit of measurement for radiation dose is rem (or Sv). In this question, the correct answer is 600 rem (6.0 Sv), which indicates that a whole-body exposure to this level of radiation can result in death. This level of radiation is extremely high and can cause extensive damage to the body's organs and systems, leading to fatal consequences.Rate this question:
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- 27.
Which radiographic examination gives the fetus the highest "fetal dose"?
- A.
Chest
- B.
Cervical spine
- C.
Lumbar spine
- D.
Pelvis
Correct Answer
D. PelvisExplanation
The pelvis radiographic examination gives the fetus the highest "fetal dose" because it involves exposing the pelvic area, which is closer to the uterus where the fetus is located. This means that the radiation has a shorter distance to travel and has a higher chance of affecting the fetus. In contrast, the chest, cervical spine, and lumbar spine radiographic examinations are farther away from the uterus and therefore result in a lower fetal dose.Rate this question:
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- 28.
Which of the following are nonstochastic radiation effects?
- sauzyres followed by coma
- erythema
- radiation sickness
- A.
1 and 2
- B.
1 and 3
- C.
2 and 3
- D.
1,2, and 3
Correct Answer
D. 1,2, and 3Explanation
Nonstochastic radiation effects are deterministic effects that occur when an individual is exposed to a high dose of radiation. These effects have a threshold dose below which they do not occur. In this case, all three options (sauzyres followed by coma, erythema, and radiation sickness) are examples of nonstochastic radiation effects.Rate this question:
- 29.
The reduction of a limited operator's exposure to ionizing radiation can be accomplished by:
- decreasing the time in the radiation field
- increasing the distance from the radiation field
- using low kVp exposure techniques
- A.
1 and 2
- B.
1 and 3
- C.
2 and 3
- D.
1,2, and 3
Correct Answer
A. 1 and 2Explanation
The reduction of a limited operator's exposure to ionizing radiation can be accomplished by decreasing the time in the radiation field and increasing the distance from the radiation field. By spending less time in the radiation field, the operator reduces their overall exposure. Similarly, by increasing the distance from the radiation field, the operator decreases their exposure as the intensity of radiation decreases with distance. Using low kVp exposure techniques, however, does not directly reduce the operator's exposure to ionizing radiation.Rate this question:
- 30.
Which of the following are considered low-dose techniques?
- increasing kVp, decreasing mAs
- Using slow intensifying screens
- Using a minumum source-image distance of 40 inches
- A.
1 and 2
- B.
1 and 3
- C.
2 and 3
- D.
1,2, and 3
Correct Answer
B. 1 and 3Explanation
Low-dose techniques in radiography aim to reduce the amount of radiation exposure to the patient. Increasing kVp (kilovoltage peak) allows for better penetration of the x-rays, reducing the need for higher mAs (milliamperage seconds) and therefore reducing the radiation dose. Using a minimum source-image distance of 40 inches helps to reduce the patient's exposure to scattered radiation. Using slow intensifying screens also helps to reduce the radiation dose by allowing for longer exposure times and therefore lower mAs settings. Therefore, options 1 and 3 are considered low-dose techniques.Rate this question:
- 31.
Which of the following changes will decrease patient dose?
- A.
Using a slower screen
- B.
Decreasing the filtration
- C.
Using high kVp techniques
- D.
Using a 36-inch SID
Correct Answer
C. Using high kVp techniquesExplanation
Using high kVp techniques will decrease patient dose because high kVp allows for better penetration of the X-rays through the patient's body, reducing the amount of radiation required to produce an image. This means that a lower dose of radiation is needed to achieve the desired image quality, resulting in a decrease in patient dose.Rate this question:
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- 32.
A _________ is a number assigned to each type of radiation based on its relative biologic effect compared with x-rays.
- A.
Quantity factor
- B.
Quality factor
- C.
Rem
- D.
Sievert
Correct Answer
B. Quality factorExplanation
A "quality factor" is a number assigned to each type of radiation to measure its potential biological harm in comparison to x-rays. This factor is used to assess the relative biological effectiveness (RBE) of different forms of ionizing radiation. The quality factor adjusts the absorbed dose (measured in grays for any type of radiation) to a more meaningful equivalent dose (measured in sieverts) by considering the type of radiation and its impact on living tissue. This makes it a crucial metric in radiation protection to gauge the true risk associated with different radiation types on biological systems.Rate this question:
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