Notes on Radiation Biology

Stochastic Effects: Random probability of effects occurring; no threshold dose. For example, cancer development may occur after exposure without a defined minimum dose.
Non-Stochastic Effects: Require a threshold level of exposure; the severity of these effects increases with the total dose. Examples include hair loss and cataracts.

Absorbed Dose: The amount of radiation energy absorbed per unit mass of tissue, which is a crucial measure in assessing radiation exposure.
Total Dose: Refers to the cumulative amount of radiation energy absorbed by tissues over time, with higher doses leading to greater damage.
Dose Rate: The speed at which radiation is delivered. Higher dose rates can lead to increased injury because there is less time for cellular repair.
Film Speed: Faster films lead to less radiation exposure for imaging purposes, thus minimizing client exposure during dental radiographs.

Roentgen (R): A unit of measurement for radiation exposure that quantifies the amount of ionization produced in air.
Rad: A unit that measures the absorbed dose of radiation, representing 100 ergs of radiation energy absorbed per gram of tissue.
Rem: A unit that measures the biological effect of radiation, accounting for the type of radiation and its effectiveness in causing biological damage.

Latent Period: The time lapse between exposure to radiation and the observable effects of injury.
Period of Injury: The phase during which the damaging effects of radiation manifest.
Period of Recovery: After the period of injury, cellular repair may occur; not all damage is permanent, and low-level radiation effects can be repaired.