ARRT SAFETY MID EXAMS ANSWERS AND
QUESTIONS SET A+
✔✔What traditional unit measures exposure in air? - ✔✔Roentgen
✔✔What does air kerma measure? - ✔✔Kinetic energy released per unit mass of air
✔✔What is the SI unit of air kerma? - ✔✔Gray
✔✔What does equivalent dose account for in addition to absorbed dose? - ✔✔Type of
radiation
✔✔How is equivalent dose calculated? - ✔✔Absorbed dose multiplied by radiation
weighting factor
✔✔What is the radiation weighting factor for x rays? - ✔✔1
✔✔What is the radiation weighting factor for gamma rays? - ✔✔1
✔✔For x rays how does equivalent dose numerically compare with absorbed dose? -
✔✔They are numerically equal when expressed in corresponding SI units because the
radiation weighting factor is 1
✔✔What does effective dose account for? - ✔✔Radiation type and radiosensitivity of
the exposed tissues
✔✔How is effective dose calculated? - ✔✔Absorbed dose multiplied by radiation
weighting factor and tissue weighting factor
✔✔What does the tissue weighting factor represent? - ✔✔Relative contribution of an
organ or tissue to the total risk of stochastic effects
✔✔What does LET stand for? - ✔✔Linear energy transfer
,✔✔What does LET describe? - ✔✔Amount of energy radiation deposits per unit length
of tissue traveled
✔✔Which is generally more biologically damaging high LET or low LET radiation? -
✔✔High LET radiation
✔✔Are diagnostic x rays considered high LET or low LET radiation? - ✔✔Low LET
radiation
✔✔What does RBE stand for? - ✔✔Relative biological effectiveness
✔✔What does RBE describe? - ✔✔Ability of a type of radiation to produce biological
damage compared with a reference radiation
✔✔What generally happens to biological damage as LET increases? - ✔✔Biological
damage increases
✔✔What generally happens to RBE as LET increases up to an optimal level? - ✔✔RBE
increases
✔✔What is radiosensitivity? - ✔✔Susceptibility of cells or tissues to radiation damage
✔✔According to the law of Bergonie and Tribondeau which cells are most
radiosensitive? - ✔✔Cells that divide rapidly are less differentiated and have a long
mitotic future
✔✔Are rapidly dividing cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are immature cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are highly specialized mature cells generally more or less radiosensitive? - ✔✔Less
radiosensitive
✔✔Which blood cell is highly radiosensitive? - ✔✔Lymphocyte
✔✔Which blood cell is among the most radiosensitive mature cells? - ✔✔Lymphocyte
✔✔Which cells are highly radiosensitive because of rapid division? - ✔✔Bone marrow
reproductive cells and gastrointestinal epithelial cells
✔✔Which tissues are relatively radiosensitive? - ✔✔Bone marrow gonads lymphatic
tissue intestinal epithelium and developing embryo or fetus
, ✔✔Which tissues have intermediate radiosensitivity? - ✔✔Skin lens of the eye thyroid
and other moderately proliferative tissues
✔✔Which cells are among the most radioresistant? - ✔✔Muscle cells and nerve cells
✔✔Why are muscle and nerve cells relatively radioresistant? - ✔✔They are highly
differentiated and divide very slowly or not at all
✔✔What is the oxygen effect? - ✔✔Cells are more sensitive to radiation when oxygen is
present
✔✔Why does oxygen increase radiation damage? - ✔✔Oxygen helps stabilize free
radical damage making it more permanent
✔✔Are well oxygenated cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are hypoxic cells more or less radiosensitive? - ✔✔Less radiosensitive
✔✔What is direct radiation action? - ✔✔Radiation directly damages a critical cellular
molecule such as DNA
✔✔What is indirect radiation action? - ✔✔Radiation interacts with water and produces
free radicals that then damage cellular structures
✔✔Which type of radiation action is most common with diagnostic x rays? - ✔✔Indirect
action
✔✔Why is indirect action common in the human body? - ✔✔The body contains a large
amount of water
✔✔What is radiolysis of water? - ✔✔Radiation induced breakdown of water molecules
producing ions and free radicals
✔✔What is a free radical? - ✔✔Highly reactive molecule or atom with an unpaired
electron
✔✔What cellular molecule is the most important target for radiation damage? - ✔✔DNA
✔✔What can radiation damage to DNA cause? - ✔✔Cell death mutation or abnormal
cell function
✔✔What is a somatic effect? - ✔✔Radiation effect occurring in the exposed individual
QUESTIONS SET A+
✔✔What traditional unit measures exposure in air? - ✔✔Roentgen
✔✔What does air kerma measure? - ✔✔Kinetic energy released per unit mass of air
✔✔What is the SI unit of air kerma? - ✔✔Gray
✔✔What does equivalent dose account for in addition to absorbed dose? - ✔✔Type of
radiation
✔✔How is equivalent dose calculated? - ✔✔Absorbed dose multiplied by radiation
weighting factor
✔✔What is the radiation weighting factor for x rays? - ✔✔1
✔✔What is the radiation weighting factor for gamma rays? - ✔✔1
✔✔For x rays how does equivalent dose numerically compare with absorbed dose? -
✔✔They are numerically equal when expressed in corresponding SI units because the
radiation weighting factor is 1
✔✔What does effective dose account for? - ✔✔Radiation type and radiosensitivity of
the exposed tissues
✔✔How is effective dose calculated? - ✔✔Absorbed dose multiplied by radiation
weighting factor and tissue weighting factor
✔✔What does the tissue weighting factor represent? - ✔✔Relative contribution of an
organ or tissue to the total risk of stochastic effects
✔✔What does LET stand for? - ✔✔Linear energy transfer
,✔✔What does LET describe? - ✔✔Amount of energy radiation deposits per unit length
of tissue traveled
✔✔Which is generally more biologically damaging high LET or low LET radiation? -
✔✔High LET radiation
✔✔Are diagnostic x rays considered high LET or low LET radiation? - ✔✔Low LET
radiation
✔✔What does RBE stand for? - ✔✔Relative biological effectiveness
✔✔What does RBE describe? - ✔✔Ability of a type of radiation to produce biological
damage compared with a reference radiation
✔✔What generally happens to biological damage as LET increases? - ✔✔Biological
damage increases
✔✔What generally happens to RBE as LET increases up to an optimal level? - ✔✔RBE
increases
✔✔What is radiosensitivity? - ✔✔Susceptibility of cells or tissues to radiation damage
✔✔According to the law of Bergonie and Tribondeau which cells are most
radiosensitive? - ✔✔Cells that divide rapidly are less differentiated and have a long
mitotic future
✔✔Are rapidly dividing cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are immature cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are highly specialized mature cells generally more or less radiosensitive? - ✔✔Less
radiosensitive
✔✔Which blood cell is highly radiosensitive? - ✔✔Lymphocyte
✔✔Which blood cell is among the most radiosensitive mature cells? - ✔✔Lymphocyte
✔✔Which cells are highly radiosensitive because of rapid division? - ✔✔Bone marrow
reproductive cells and gastrointestinal epithelial cells
✔✔Which tissues are relatively radiosensitive? - ✔✔Bone marrow gonads lymphatic
tissue intestinal epithelium and developing embryo or fetus
, ✔✔Which tissues have intermediate radiosensitivity? - ✔✔Skin lens of the eye thyroid
and other moderately proliferative tissues
✔✔Which cells are among the most radioresistant? - ✔✔Muscle cells and nerve cells
✔✔Why are muscle and nerve cells relatively radioresistant? - ✔✔They are highly
differentiated and divide very slowly or not at all
✔✔What is the oxygen effect? - ✔✔Cells are more sensitive to radiation when oxygen is
present
✔✔Why does oxygen increase radiation damage? - ✔✔Oxygen helps stabilize free
radical damage making it more permanent
✔✔Are well oxygenated cells more or less radiosensitive? - ✔✔More radiosensitive
✔✔Are hypoxic cells more or less radiosensitive? - ✔✔Less radiosensitive
✔✔What is direct radiation action? - ✔✔Radiation directly damages a critical cellular
molecule such as DNA
✔✔What is indirect radiation action? - ✔✔Radiation interacts with water and produces
free radicals that then damage cellular structures
✔✔Which type of radiation action is most common with diagnostic x rays? - ✔✔Indirect
action
✔✔Why is indirect action common in the human body? - ✔✔The body contains a large
amount of water
✔✔What is radiolysis of water? - ✔✔Radiation induced breakdown of water molecules
producing ions and free radicals
✔✔What is a free radical? - ✔✔Highly reactive molecule or atom with an unpaired
electron
✔✔What cellular molecule is the most important target for radiation damage? - ✔✔DNA
✔✔What can radiation damage to DNA cause? - ✔✔Cell death mutation or abnormal
cell function
✔✔What is a somatic effect? - ✔✔Radiation effect occurring in the exposed individual
