Bone RP's Flashcards
what principle do bone RP’s use for localization?
ion exchange where radioactive material subs biologic material.
-increased blood flow and metabolic activity lead to incr uptake of RP in area of interest
what early imaging isotope subbed for Ca?
strontium-89 (Sr-89)
what did F-18 sodium fluoride sub?
F ion subs for hydroxide ion in bone matrix
what 2 tracers were high energy gamma emitters suitable for use with rectilinear scanners (rip)?
F-18 and Sr-89
what did the incr of gamma cam production and Tc generators results in?
new traces that are Tc based
what analog is Tc attached to?
phosphate ion (PO4-2)
how does Tc bone imaging localize?
by passive ion exchange with phosphate ions in bone
-excretes quick and doesn’t go to much other tissue
polyphosphonate
long chain linked phosphate groups
pyrophosphonate
2 phophate groups linked by O2 atom which leads to more stable labelling and rapid excretion
phosphonate
2 phosphate ions linked by C atom= better bone retention, more stable, better labeling and widely used in general medicine
what two phosphonates are used?
MDP (methylene diphosphonate)
HDP (hydroxymethylene diphosphonate)
what brand name of MDP is the standard?
medronate
T/F: MDP clearence and uptake is quick compared to other bone imaging agents
Trueat
what % of tracer is left in blood 3 hours after injection?
5-10%
at 24 hours what percent of MDP is in bones? How does this benefit reimaging?
50%
-allows for later delays
