In-111 WBC labeling Flashcards
what is 8-hydroxyquinoline (oxine)
a weak organic chelate (-)
what happens when 8-hydroxyquinoline (oxine) bind with In-111(+3)
they bind in a 3:1 ratio and produce a large neutral molecule that can pass easily through cell membrane
In-111 mixed with WBC then the ______ passes through the _______ and into the ________ where _______ displaces In-111 from ______ and permanently bind the isotope.
chelate, cell membrane, cytoplasm, intracellular proteins, oxine
what does it mean that In-111 oxine is an indiscriminate label
WBC must be seperated from other cells to prevent cross labeling
because oxine is a weak chelate and easily displace by other materials, what iron binding proteins in plasma prevent mislabeling
lactoferrin and transferrin will bind to In-111 and make it incapable of labeling cells so they must be removed early on
what must be determined prior to in wbc labeling
pt wbc count
upper and lower limit allowed for wbc count
too low= <2,000 mm^3
too high= 40,000 mm^3
nothing higher than 25,000 pref
what do you do if pt wbc count too low
you can double amount of whole blood and combine with already drawn wbc or use donor matched wbc
what do you do if pt wbc count is too high
> 40,000 mm3 indicates leukemic patients whihc means poor functioning cells so poor locating and labeling
labeling % avg and what alters this
75% of indium binds to cells dependent on technique and pt status (75-80%)
how long can i delay wbc reinjection
4 hours max but reinject asap and invert gently to suspend cells. store in hard capped syringe.
when should we use PET or Ga-67
brain/transaxial system
what is the benefit of In
weak chelate so binds well and crosses cell membrane easier
what is tc exametazine
a lipophilic tc labeled material is introduced that penetrates the cell and energy of tc and has the ability to administer 10-15 times greater activity compared to In-111. This allows quicker and better imaging
what is tc hmpao good for
well suited bc of its ability to cross the cell membrane easily and wash out quickly
how to minimize cross cell labeling
WBC isolated from whole blood
why is the presence of plasma during labeling not an issue
because the tc is not bound by plasma ion binding protiens and other plasma proteins have no affinity for tc
practical considerations of tc
-wbc count
-labeling %
-reinject asap
labeling % of tc wbc
50-60% which is low and why we use In-111
In labeling procdures
7 mL of ACD (heparin) to 60 mL syringe>draw pt blood>invert syringe>position syringe in holder and remove needle and pull back plunger far as possible>add 6% hetastarch and attach needle and invert>position at 45 degree for 30 min> straighten syringe when 2 min left so solid sink to bottom>baxter tubing extension and centrifuge for 10 min @1000rpm>pippette plasma to new centrifuge tube to isolate wbc> button wash and spin 5 min @750 rpm>draw 650-680 uCi In-111 oxine>discard hot supernatant
while labeling with tc how old can tc be
less than 2 hours old and milked from gen that has been eluted in past 24 hours
how much activity used for Tc
12 mCi in 2 mL
incubate Tc labeled for how long
15 min
how long to incubate Tc kit
1-2 min
how long to incubate In
15 min
