RadBio Chapter 7

A biologic reaction is produced by 4 Gyt of a test radiation. It takes 16Gyt of 250-kvp x rays to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?

4

Which of the following is/are considered low-LET radiation

X-rays and gamma rays

The radiation dose required to produce mitotic death is

less than the dose needed to produce apoptosis in slowly dividing cells or nondividing cells

Because the genetic information to be passed on to future generations is contained in the strict sequence of nitrogenous bases, the loss of change of a base in the DNA chain represents

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 multiple hits from ionizing radiation, the master molecule may be inactivated. If this occurs, what is the consequence for the affected cell?

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?

Cell survival curve

Which of the following groups of cells is least radio sensitive?

Adult nerve cells

OH + OH=

H2O2

Which of the following humans is most radiosensitive?

An embryo fetus during the first trimester of pregnancy

Normal white blood cell count for an adult ranges from

5000- 10,000/mm3 of blood

One micron (um) =

10-6m

A periodic blood count is not recommended as a method for monitoring occupational radiation exposure because

Both B and C

Based on current data, which of the following would be considered a safe radiation dose for the gonads of both males and females?

0 Gyt

The term apoptosis is synonymous with

programmed cell death

Which of the following finals radiation doses may cause permanent sterility in a male human?

5.0 or 6.0 Gyt

Which of the following groups of cells is most radiosensitive?

Lymphocytes

Direct action may occur after exposure to any type of radiation, but it is much more likely to occur after exposure to

high LET radiation such as alpha particles

When LET increases, the chance of significant biologic response in the radiosensitive DNA macro molecule

also increases

Neutrophils play an essential role in

fighting infection

radio sensitivity of ova

varies considerably throughout the lifetime of the germ cell

Which of the following tissue contain cells that do not divide?

1. Epithelial tissue

2. Muscle tissue

3. Nervous tissue in an adult

2 and 3 only

Which of the following is a category of white blood cell that is essential in fighting infections?

Granulocytes

If bone marrow cells have not been destroyed by exposure to ionizing radiation, they can

repopulate after a period of recovery

Which of the following statements is true concerning patients who receive radiation exposure from a routine radiographic procedure such as a chest x ray?

Patients are not expected to sustain appreciable damage to either the blood or the blood forming organs as a consequence of the examination