Health Physics Ch 37 Flashcards
(27 cards)
Concerned with providing occupational
radiation protection & minimizing radiation
dose to the public
Health Physics
A radiation scientist who is concerned with
the research, teaching or operational aspects
of radiation safety
Health Physicist
Cardinal Principles of Radiation Protection
Purpose, Time, Distance, Shielding
The time of exposure should be kept to a
minimum
Minimize Time
Sequencing on-off rather than continuous on
during examination
Fluoroscopic Footswitch
It reminds the radiologist that a considerable
amount of fluoroscopic time has elapsed
5-Minute Reset Timer
It takes less than 5 minutes
Fluoroscopic Procedure
It takes more than 5 minutes
Interventional Radiology Procedure
Radiation dose is inversely related to the
distance between the source & the patient
Maximize Distance
It states that the intensity of radiation at a
location is inversely proportional to the
square of its distance from the source of
radiation
Inverse Square Law
Inverse Square Law Formula
I1/I2 = (d2/d1)squares
What distance from the sourcr is treated as a point source
Five times the source diameter
It states that one can compensate for a
change in the source-to-object dstance by
changing the mAs by the factor SID squared
Square Law
Square Law Formula
I1/I2 = (D1/D2) squared
A point source of radiation
X-ray Tube Target
Lines that represent positions of equal
radiation exposure in the fluoroscopy room
Isoexposure Lines
It greatly reduces the level of radiation
exposure
Shielding
The thickness of absorber necessary to
reduce radiation intensity to half its original
value
Half-Value Layer (HVL)
The thickness of absorber necessary to
reduce radiation intensity to one-tenth its
original value
Tenth-Value Layer (TVL)
Based on total body radiation exposure
Radiation Risk Coefficient
The equivalent whole-body dose
Effective Dose
The weighted average of the radiation dose
to various organs & tissues
Equivalent Whole-Body Dose
Those individuals who must make the first
decisions & take the first steps in the early
stages of such an event
Emergency Responder
Radiologic Devices
- Radiation Exposure Device (RED)
- Radiologic Dispersal Device (RDD)
- Improvised Nuclear Device (IND)
