Safety (Radiation Physics and Radiobiology) for ARRT
Boards Questions and Answers| Latest Update
exposure when air is irradiated with x or gamma rays an interaction occurs between xray
atoms & air
SI unit for exposure Coulombs
Traditional unit for exposure Roentgen
effective dose estimates the risk present when various tissues are irradiated
air kerma used to define radiation exposure or radiation delivered to a specific point
radiosensitivity the relative susceptibility of cells, tissues, organs or organisms to the
harmful effect of radiation
dose-response relationships linear non-threshold
linear threshold
non-linear non-threshold
non-linear threshold
linear-nonthreshold indicates that no level of radiation can be considered completely
safe (a response occurs at every dose)
linear-threshold indicates that at a lower doses of radiation exposure (to the left of the
line intersecting the x-axis) no response is expected
, nonlinear-threshold indicates that at lower doses of radiation exposure (to the left of the
curve intersecting the x-axis) no response is expected
nonlinear-nonthreshold indicates that no level of radiation can be considered safe (A&B
in picture)
LET (Linear energy transfer)amount of energy deposited by radiation per unit length of
tissue
RBE (relative biological effectiveness) ability to produce biologic damage; varies with LET
cell survival the ability of the cell to live when effected by radiation
cell recovery ability of the cell repair itself after radiation and to continue to function
normally
oxygen effect (OER) Oxygen Enhancement Ratio - the ratio of radiation dose required to
cause a biologic response in cells without oxygen to the dose required to cause an identical
response with cells with oxygen
somatic effects effects of radiation on the body being irradiated
short term effects effects that happen over a short period of time
long term effects effects that happen over a long period time
acute effects symptoms develop rapidly
Boards Questions and Answers| Latest Update
exposure when air is irradiated with x or gamma rays an interaction occurs between xray
atoms & air
SI unit for exposure Coulombs
Traditional unit for exposure Roentgen
effective dose estimates the risk present when various tissues are irradiated
air kerma used to define radiation exposure or radiation delivered to a specific point
radiosensitivity the relative susceptibility of cells, tissues, organs or organisms to the
harmful effect of radiation
dose-response relationships linear non-threshold
linear threshold
non-linear non-threshold
non-linear threshold
linear-nonthreshold indicates that no level of radiation can be considered completely
safe (a response occurs at every dose)
linear-threshold indicates that at a lower doses of radiation exposure (to the left of the
line intersecting the x-axis) no response is expected
, nonlinear-threshold indicates that at lower doses of radiation exposure (to the left of the
curve intersecting the x-axis) no response is expected
nonlinear-nonthreshold indicates that no level of radiation can be considered safe (A&B
in picture)
LET (Linear energy transfer)amount of energy deposited by radiation per unit length of
tissue
RBE (relative biological effectiveness) ability to produce biologic damage; varies with LET
cell survival the ability of the cell to live when effected by radiation
cell recovery ability of the cell repair itself after radiation and to continue to function
normally
oxygen effect (OER) Oxygen Enhancement Ratio - the ratio of radiation dose required to
cause a biologic response in cells without oxygen to the dose required to cause an identical
response with cells with oxygen
somatic effects effects of radiation on the body being irradiated
short term effects effects that happen over a short period of time
long term effects effects that happen over a long period time
acute effects symptoms develop rapidly
