Exam 4 Flashcards
A biologic reaction is produced by 4 Gyt of a test radiation. It takes 16 Gyt of 250-kVp x-rays to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?
RBE = Dose of standard radiation(16 Gy) / Dose of test radiation (4 Gy)
4
Which of the following is/are considered low-LET radiation(s)?
- X-rays
- Alpha particles
- Gamma rays
1 and 3 only
Because the genetic information to be passed on to future generations is contained in the strict sequence of nitrogenous bases, the loss or change of a base in the DNA chain represents a (an)
- covalent cross-link
- aneuploidy
- bleb
- mutation
mutation
Because the master molecule is unique in any given cell, no similar molecules in the cell are available to replace it; if a critical location on the master molecule is a target receiving multiple hits from ionizing radiation, the master molecule may be inactivated. If this occurs, what is the consequence for the affected cell?
- Loss of all intracellular fluid
- Increased pressure on the cell membrane leading to immediate rupture
- Disruption of cell chemistry only
- Normal cell function will cease, and the cell will die
Normal cell function will cease, and the cell will die
Which of the following curves illustrates the radiation sensitivity of a particular type of cell?
- Dose–response curve
- Cell extrapolation curve
- Cell survival curve
- Cell specialization curve
Cell survival curve
Which of the following groups of cells is the least radiosensitive?
- Nerve cells in an embryo-fetus
- Lymphocytes
- Adult nerve cells
- Immature spermatogonia
Adult nerve cells
A periodic blood count is not recommended as a method for monitoring occupational radiation exposure because
- biologic damage from ionizing radiation cannot be determined from a blood test.
- biologic damage has already been sustained when an irregularity is seen in the blood count.
- a traditional blood count is a relatively insensitive test that is unable to indicate exposures of less than 10 cGy.
2 and 3 only
Based on current data, which of the following would be considered a safe radiation dose for the gonads of both males and females?
- 0 Gy tissue
- 3 Gy tissue
- 1 Gy tissue
- 5 Gy tissue
0 Gy tissue
When LET increases, the chance of producing a significant biologic response in the radiosensitive DNA macromolecule
- grows
- remains constant, not increasing or decreasing
- decreases considerably
- decreases slightly
grows
Direct action may occur after exposure to any type of radiation, but it is much more likely to happen after exposure to
- high-LET radiation such as alpha particles
- low-LET radiation such as x-rays
- non-ionizing radiation such as microwaves
- low-LET radiation such as gamma rays
high-LET radiation such as alpha particles
If a person receives radiation exposure sufficient to cause the gastrointestinal syndrome, fatality occurs primarily because of
- catastrophic damage to the epithelial cells that line the gastrointestinal track, resulting in the death of the exposed person within 3 to 5 days from a combination of infection, fluid loss, and electrolytic imbalance
- edema in the cranial vault
- meningitis
- convulsive seizures
catastrophic damage to the epithelial cells that line the gastrointestinal track, resulting in the death of the exposed person within 3 to 5 days from a combination of infection, fluid loss, and electrolytic imbalance
Which of the following is not a form of acute radiation syndrome?
- gastrointestinal syndrome
- carcinogenic syndrome
- cerebrovascular syndrome
- hematopoietic syndrome
carcinogenic syndrome
The term LD 50/30 signifies the whole-body dose of radiation that can be lethal to
- 50% of the exposed population in 50 days
- 50% of the exposed population in 30 days
- 30% of the exposed population in 30 days
- 30% of the exposed population in 50 days
50% of the exposed population in 30 days
Which of the following are classified as early tissue reactions of ionizing radiation?
- Male and female sterility, embryologic defects, and cancer
- Blood disorders, fever, and genetic effects
- Erythema, cataract formation, and cancer
- Nausea, epilation, and intestinal disorders
Nausea, epilation, and intestinal disorders
Research has shown that repeated radiation injuries have a
- sigmoidal effect
- cumulative effect
- no discernible effect
- threshold effect
cumulative effect
