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define the acronym ALARA
as low as reasonably achievable- having to do with radiation exposure
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how are filters used in basic radiation protection?
absorb low energy x-rays before reaching pt
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how are collimators used in radiation protection?
restricts x-ray beam to the area to be viewed
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how are intensifying screens used in rad protection?
reduce x-ray exposure by 95%
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what are the 3 guidelines for x-ray exposure for women of childbearing age?
elective booking, patient questionarre, postings
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1st commandment of radiology
time, distance and shielding
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2nd commandment
don't let familiarity result in false security
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3rd commandment
never stand in primary beam
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what is radiobiology?
the study of the effects of ionizing radiation on the biologic tissue
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state the 50/60 lethal dose principle
the lethal dose of radiation to the whole body that will result in death within 60 days to 50% of irradiated subjects
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direct effect of radiation
if the initial ionizing event occurs on the most radiosensitive molecule, dna, the effect is direst
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effects of direct radiation
molecular alteration, biochemical lesion, cell death, death, organ damage, tissue damage
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indirect effect of radiation
ex- water is ionized, then transferred to dna
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effects of indirect radiation
molecular alteration, biochemical lesions, point mutations, genetic damage
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define doubling dose
dose of radiation that will produce twice the frequency of genetic mutations as would have been observed without radiation
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define roentgen
unit of radiation intensity
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roentgen absorbed dose
measures radiation absorbed by pt
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roentgen equivalent man
measures radiation absorbed by tech
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