Radiography Flashcards
What were past uses of radiation?
Shoe fitting
What type of radiation are x-rays?
Ionizing radiation
What two ways does ionizing radiation damage and what do they damage?
DNA; direct and indirect action
What is direct action?
direct damage to DNA (ie. altered base pairs and breaks bonds)
What are deterministic effects?
What is indirect action?
forms free radicals from water molecules adjacent to DNA
What are stochastic effects? Example?
no threshold of exposure below which effects won’t happen
probability of effect is proportional to dose
severity is not proportional to dose
Ex. CANCER
What is the ALARA principle and why was it created?
The ALARA principle stands for as low as reasonably achievable and it was created because stochastic effects have no threshold.
What are the 3 components of radiation safety?
Distance, Shielding, Time
X-ray beam intensity ________ as the distance from the beam ____________
decreases; increases
Explain the inverse square law
Double the distance, quarters the exposure
Triple the distance, ninths the exposure
Give examples of shield protection.
Lead protection including aprons, gloves, thyroid shields
What are the limitations of shielding?
Protects only from scatter radiation AND not allowed in the primary beam
What is the golden rule of MRI?
The magnet is ALWAYS on
Does MRI have ionizing radiation?
NO
