4.4+ 4.3 Flashcards
half life
length of time it takes for one half of a radioactive sample to decay
decay curve
shows the decay of radioactive isotopes
carbon dating
technique used to date ancient specimen
what formula do you use to date the age of a specimen using carbon
(1/2)^n x 100
why are radioactive isotopes used in medicine?
short half lives
they have the same chemistry in the body as the nonradioactive atoms
scan
image of site in body created by detection of radiation from radioactive isotopes that accumulated in that site
How do radiologists know if there is a problem when examining scans?
areas of decreased or increased radiation may indicate problem
what can radioactive particle can provide images of an organ? how?
gamma rays from organ can be used to expose a photographic plate providing an image of the organ
Positron Emission Tomograpghy (PET)
uses which radiation particle? and how
positron,
they combine with electrons to produce gamma rays that will be detected
examples of positrons for PET
carbon-11
oxygen-15
nitrogen-13
fluorine-18
Which positron is used for brain study function, blood flow or metabolism?
fluorine-18
Magnetic Resonance Imaging (MRI)
how is it done?
based on absorption of energy when protons in Hydrogen are places in a strong magnetic field.
which type of scans do not involve x-ray radiation?
MRI
which scan is the least invasive?
MRI
what aligns hydrogen against magnetic field? (MRI)
short pulses of energy aligns them
