Chapter 9 Key Terms Flashcards
Activity
describes the quantity of radioactive material; expressed as the number of radioactive atoms that undergo decay per unit time
Air kerma
the kinetic energy released per unit of mass air
Alpha particle
contains two protons and two neutrons, is equivalent to a helium nucleus, and is emitted from the nuclei of heavy elements as they undergo radioactive decay; it has a great mass and a positive charge
Becquerel (Bq)
the SI unit for activity
Beta particle
identical to an electron, except it is emitted from the nuclei of radioactive materials; it is very light and negatively charged
Compton scattering (Compton effect)
an interaction between x-rays and matter characterized by an incident x-ray photon interacting with a loosely bound outer-shell electron, resulting in removal of the electron from the shell, which then proceeds in a different direction as a scattered photon
Curie (Ci)
the unit of activity
Dosimeter
a mechanism that can measure amounts of radiation
Effective dose
the sum of the weighed equivalent doses for all irradiated tissues and organs; used to measure the radiation and organ-system-specific damage in humans
Electromagnetic radiation
a form of energy that is the result of electric and magnetic disturbances in space
Field survey instrument
portable device used to measure radiation in a given location
Film badge dosimeter
two pieces of film having different sensitivities to x-rays contained within a light, tight envelope; the film emulsion darkens in response to the radiation exposure received
Genetic
describes the effects of radiation that appear in the descendants of the individual being irradiated
Gray (Gy)
unit of absorbed energy or dose; 1 joule of energy absorbed in each kilogram of absorbing material
Integral dose
the total amount of energy imparted to matter; the product of dose and the mass over which the energy is imparted
Kerma
kinetic energy released in matter, the energy imparted directly to electrons per unit mass
Optically stimulated luminescence (OSL) dosimeter
measures radiation that passes through a thin strip of aluminum oxide; a laser light stimulates the aluminum oxide, which becomes luminescent in proportion to the amount of radiation exposure
Particulate radiation
high-energy electrons, neutrons, and protons that produce ionization in matter by direct atomic collisions
Personnel monitoring device
instrument worn by health-care workers who work regularly in radiation-exposed environments
Photoelectric absorption
an interaction between x-rays and matter characterized by an incident electron with slightly greater energy than the binding energy of the electrons in the inner shells, ejecting an electron from the inner shell while being absorbed in the reaction, resulting in an ionized atom
Pocket dosimeter
a personal-use ionization chamber; when exposed to radiation, ionization occurs in the chamber, which neutralizes
Quality factor
radiation weighting factor, specific to specific types of radiation; accounts for the biologic effectiveness of the specific radiation
Rad
term used to describe the measurement related to the absorbed dose of radiation; unit of absorbed energy or dose applicable to any material; 100 ergs of energy absorbed in 1 gram of absorbing material
Rem
term used to describe the measurement of the biologically equivalent dose
Roentgen (R)
term used to describe the measurement related to exposure; the unit of exposure in air; the quantity
Sievert (Sv)
the product of the absorbed dose in gray and the radiation weighting factor
Somatic
describes the effects of radiation that appear in the individual who was irradiated
Systeme Internationale d’Unites (SI units)
an international system of units based on the metric system
Thermoluminescent dosimeter (TLD)
small chips of thermoluminescent material, usually lithium fluoride; when exposed to radiation, the chips enter a metastable state; when exposed to heat they give off visible light
