Chapter 23 Flashcards
acid group
contains carbon double bonded to an oxygen, single bonded to another oxygen, and a negative charge at the pH of the body
what does hydrophilic mean and why is it an advantage of lower osmolality contrast media?
water soluble
less likely to be reactive with the cells that trigger allergic reactions
amine group
contains nitrogen bonded to two hydrogen atoms
barium peritonitis
BaSO4, extravates and causes inflammation of the abdominal cavity
what is barium sulfate?
powder composed of crystals, BaSO4
anaphylactoid
resembling an immune system response to foreign material
what are the ways negative contrast agents are administered? do they have a high or low atomic number?
gas (air), tablets, crystals, soda water (carbon dioxide)
low atomic number
why are most adverse reactions to contrast media related to the osmolality of the media?
the osmolality determines osmotic pressure, which controls the movement of water in the body
atomic numbers
numbers of protons in the nuclei of the different elements
blood urea nitrogen (BUN)
reveals whether the urea nitrogen levels are higher than normal, suggesting that the kidneys or liver may not be working properly
bronchospasm
involuntary constriction of the bronchial tubes usually resulting from an immune system reaction to a foreign particle or molecule
creatinine
nitrogen containing waste products of metabolism excreted by the kidneys filtration system; high blood plasma levels indicate poor filtration by kidneys
dimer
compound formed by bonding of two identical similar molecules
histamine
molecular substance containing an amine group; causes bronchial constriction and a decrease in blood pressure
ionic
atom or molecule having a negative (anion) or positive (cation) charge
what are the two molecular particles ionic media dissociates to, in water or blood plasma? which is negative and positive?
anion = negative
cation = positive
most ionic iodine contrast media are identified as what?
lower osmolality contrast media
why is it important for patients to drink fluids after receiving barium sulfate?
residue can dry and cause obstruction
monomers
simple molecules of a compound of relatively low molecular weight
radiopharmaceutical
pharmaceutical compound that is attached to a radioisotope
suspension
nonuniform mixture of two or more substances, one of which is composed of larger than molecule size particles that have a tendency to cluster together
what are factors that affect the degree of radiographic density differences?
absorption of the tissues, technical factors used, characteristics of the IR, image processing, use of contrast
the body absorbs x-ray photons according to what? which absorbs more x-ray photons?
various tissue atomic numbers and amount of matter per volume of tissue
tissues with high atomic number absorb more
which radiographic images result in few density differences and are difficult to visualize?
anatomic areas classified as low in subject contrast
how is contrast media classified?
negative/positive agents
ionic/non-ionic agents
areas filled with negative contrast agents appear __________ and have an _________density.
dark, increased
contrast media
diagnostic agents that are instilled into the body to enhance subject contrast in anatomic areas where low subject contrast exists
solution
uniform mixture of two or more substances composed of molecule sized particles that do not react together chemically
osmosis
movement of water from an area of high concentration to low concentration through a semipermeable membrane such as blood vessels and cell membranes
osmolality
measurement of the number of particles (molecules/ions/cations) that can crowd out water molecules in a measured mass (kg) of water
methyl groups
common biochemical groups containing one carbon atom and 3 hydrogen atoms
areas filed with positive contrast agents appear ___________ and have ____________density.
light, decreased
flocculation
formation of flaky masses resulting from precipitation or coming out of a suspension or solution
why is barium sulfate contraindicated if a patient is thought to have a perforation in the digestive tract?
the body does not absorb BaSO4 naturally
what is another name for viscosity and what can be done to reduce it and facilitate the ability for rapid injection?
viscosity = friction
heating the medium to body temperature
osmotic diuresis
increased secretion of urine
increased ____________ and ____________ levels indicate the patient may have renal disease and are good indicators for possible contrast medium renal effects.
BUN, creatinine
what are two issues that could occur with a rapid injection for a pediatric through a small angiocath with a high viscosity agent?
proper injection may not be possible, catheter could burst
what is the primary concern when working with short-lived unsealed radiation sources?
contamination
examples of external and internal contamination of radiopharmaceuticals
external = dropped, spilled, splashed
internal = inhalation, ingestion, absorption
in patient prep, the general considerations for the patient have two aims. what are they and how are they performed?
contrast media reaction prevention
preparedness in the event of adverse reaction
what is the most important patient care aspect before administration of water-soluble iodine contrast media?
patient history
NSF
nephrogenic systemic fibrosis
