Terms

Question 1

Therapeutic Index

Answer 1

Ratio - toxic concentration : effective concentration in the blood

Question 2

Grays (Gy)

Answer 2

Energy absorbed per unit of mass (J·kg−1)

Question 3

DAP

Answer 3

Dose area product

Quantity used in assessing the radiation risk

Absorbed dose x the area irradiated (Gy·cm2)

Question 4

DLP

Answer 4

Dose length product

Parameter used as a surrogate measure for patient dose

Energy deposited in single slice x scan length (mGy x cm)

Question 5

Equivalent Dose

Answer 5

Probability of radiation-induced cancer and genetic damage (Sievert (Sv))

Mean dose to organ by radiation type, multiplied by a weighting factor

Takes into account the biological effectiveness of the radiation type

Question 6

Effective Dose

Answer 6

Tissue-weighted sum of the equivalent doses in all specified tissues and organs of the human body

Question 7

Specific Activity

Answer 7

Activity per quantity of a radionuclide

Represents a physical property of the radionuclide

Remember: the probability of radioactive decay for a given radionuclide is a fixed physical quantity –> the number of decays that occur in a given time of a specific number of atoms of that radionuclide is also a fixed physical quantity

Measured in Bq/kg or Ci/g

Question 8

Becquerel (Bq)

Answer 8

Number of radioactive transformations per second that occur in a particular radionuclide

Question 9

Absorbed Dose

Answer 9

Dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass

Used in the calculation of dose uptake in living tissue

Measured in Gy

Question 10

Curie (Cu)

Answer 10

1 Ci = 3.7×1010 decays per second