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study guide
week 2 ch. 12&18
Question | Answer |
---|---|
PET is a unique, 3 dimensional tomographic imaging tech. capable of demonstrating what | the biochemical function of the body's organs and tissues |
PET is similar to nuc. med in what ways | that radioactive tracers are adminstered to the patient. |
PET scanner itself does'nt produce what | radiation |
PET primarily uses | oxygen, nitrogen, carbon & fluorine |
PET tracers have a very | short half-lives 2 min to 110 min |
Raiation oncology or therapy involves | ionizing radiation for treatment of cancer and some benign diseases |
2 types of radiation treatments | internal and external |
internal is | brachytherapy |
external is | teletherapy |
internal involves | teh insertiion of low intensity radioactive nuclides inside the body placed close to tumor |
external involves | the spplication of external beam radiation |
3 types of external beam radiation | xray type units, colbalt-60 gamma rays, & linear accelerators |
cobalt-60 emit | high energy gamma rays about 1.25mEv |
linear have | both low and high energy capabilities 4 mEv to as high as 30mEv |
what does quality assurance primarily deal with | people |
quality control ensures | instruments and equipment |
quality control begins with what | imaging systems used to produce the image |
what does it end with | |
typical time for monitoring equipment performance | annually |
the most important patient protection of imaging system is | filtration of x ray beam |
filtration is measured in | HVL half value layer |
the minimum total filtration level for genral purpose rooms is | 2.5 mmal |
the x ray film must coincide with what | the light field |
PBL is | positive beam limiting |
distance and centering must be accurate to what % of the SID | with in 2 -1% of the SID |
3 tools for measuring focal spot size | pin hole camera- star pattern-slit camera |
3 types of processor maintenance | scheduled-preventative-non scheduled |
the efficiency of x ray production increases with | increasing kvp |
discrete energies of characteristic x rays are characteristic of | the differences between electron binding energies in a particular element |
the result of added filtration is an | increase in energy of beam with accompanying reduction in quantity |
compensating filter is | a filter that compensates for differences in subject raiopacity |
2 compensting filter are | a wedge & a trough |
inherent filtration is | the glass or metal enclosure of an xray tube filters the emitted beam |
inherent filtration of a general purpose x ray tube is | 0.5 mm Al |
an ejected electron from a incident photon is called a | photoelecton |
in pair production the incident photon interacts with | the nuclear force field |
coherent scatter is | change in the direction of an incident x ray with out a loss of energy |
compton effect occurs when | incident x rays ionize atoms and teh xray then changes direction with a loss of energy |
photoelectric effect occurs when the | incident xray is absorbed into one of the inner electron shells and emits a photoelectron |
photodisintegration occurs when the incident xray is | directly absorbed by the nucleus |