radiation protection Flashcards
ionizing radiation
cosmic, gamma rays, x-rays, ultra voilet rays
non ionizing radiation
visible light, infrared, micro waves, radio waves
skin erythema dose
1900-1930 first unit used to measure radiation exposure
erythema
redness of the skin, irradiated area that had become inflamed
roengten / coulombs/kg
was accepted as the first unit of measure for exposure but was not adequately defined ; measures ionization occurring in the air ; coulombs/kg or air in SI units
rad / gray
radiation absorbed dose ; primarily used for patient dose 1 rad = .01 gray
rem / sivert
radiation equivalent man ; primarily used for radiation protection purposes ; film badges for radiation workers ; measure biological effects from radiation ; 1 rem = .01sv ; 1 rem = 10 mSv
occupational dose
5 rem or 50 msg of whole body effective dose per year
whole body dose
refers to the head, neck (thyroid), trunk, gonads
occupational cumulative dose
the lifetime effective dose limit for an occupationally exposed worker 1 rem or 10 msg times the years of age regardless of how many years that worker has been employed in field
occupational dose
dose received by any individual in the course of employment
pregnant technology exposure
0.05 rem, 50 mrem, or 0.5 msv, for any one month ; 0.5 rem, 500 rem or 5.0 msg for entire duration of pregnancy
general public exposure
0.1 rem ot 1 msv
personnel monitoring equipment
devices worn or carried by the individual for the purpose of measuring the dose equivalent received by that individual ; worn only on the job
personnel monitoring devices
film badges, TLD, OSL
film badges
a packaged film within a holder with a variety of filters ; sensitive to exposure equivalent doses as low as 10 milliards up to a high as 700 rads ; needs to be changed and read every month
TLD
thermoluminescent dosimeter ; common material used inside is lithium fluoride ; once the TLD has been read it cannot be read again ; can be changed and read every 3 months(may be changed every month)
OSL
optically stimulated luminescent dosimeter ; uses aluminum oxide crystals ; can bet read up to one year before reading
collimation
limiting the field size to the area of clinical interest only ; must be within +/- 2% of the SID used during an x-ray exposure
A.L.A.R.A.
as low as reasonably achievable ; close collimation, filtration of the primary beam, optimum kV techniques, high speed film/screen combinations, minimum repeat exams
entrance skin exposure (ESE)
patient dose in radiography is usually calculated according to the exposure level at the skin
law of bergonie and tribindeau
degree of sensitivity depends on - age of cell, differentiation or complexity of cell, metabolic rate or how much energy the cell uses, biotic rate or how quickly the cell produces
long term / latent
may not be observed for as long as 30 years ; greatest percentage occurs between 10 and 15 years ; effects are unpredictable ; severity of effects are unrelated to dose
somatic
occurring within the exposed individual
genetic
occurring within the children or grandchildren of the exposed individual
gonad shielding
prevents genetic effects from radiation, it used primarily with patients younger than age 55, must be 0.5 mm lead equivalent, is used when gonads are within 5cm of the margin of the radiation field, also used on all females of reproductive age ; shield should not obscure desired anatomy
personnel shielding
gloves - 0.25mm lead equ ; aprons - 0.5mm lead equ ;
what is the radiographic table made of
carbon fiber material
what is the name of the common collimator
light - localizing variable aperture rectangular collimators
who was the first american radiation worker to die from radiation induced cancer in October 1904
clarence madison dally
terrestrial radiation includes which of the following sources
long lived radioactive elements, such as uranium, radium and thorium that are present in variable quantities in the crust of the earth
cosmic radiation occurs in which two forms
solar and galactic
the first decay of radium is
radon
which of the following devices contains aluminum oxide detector
OSL dosimeter
stochastic effect
results of radiation exposure for which no threshold dose of radiation exists
non stochastic effect
characterized by a threshold dose below which they do not occur
non threshold dose
any amount of radiation may produce biological damages
threshold dose
the minimum dose of ionizing radiation , that will produce a detectable degree of any given effect
linear
an observed response is directly proportional to the dose
non linear
an observed response is not directly proportional to the dose
radio resistant cells
bone, liver, kidney, cartilage, muscle, nervous, tissue
radio sensitive cells
germinal cells, lymphoid tissue, basal cells, hematopoietic tissues, epithelium of the GI tract
primary barrier
located perpendicular to the line of travel, consist of 1/16 inch lead
secondary barrier
deflected from the primary beam, 1/32 inch lead
wall over lap of barrier
1/2 inch lead
lead glass window
1.5 mm lead eq
