in vitro labeling

Question 1

explain in vitro labeling

Answer 1

withdraw 1-3 mL of anticoagulated blood (using heparin lined syringe) then incubate this blood with a stannous ion source for 5 min. Make sure to inactivate the extracellular stannous ion to prevent pertechnetate from binding to the extracellular proteins or the surface of RBC
-we use syringe 1 and 2 for this so we combine tinned RBC with Tc and mix and incubate for 20 min. draw final dose in syringe and assay and inject

Question 2

how much activity for a MUGA/ GI bleed?

Answer 2

MUGA=20 mCi
GI bleed=25 mCih

Question 3

what % of RBC get labeled

Answer 3

> 95%

Question 4

why is labeling % so high for in vitro

Answer 4

because it happens outside of the body therefore allowing as much of the activity to go to the blood pool and not get stuck along the way.

Question 5

what is a higher labeling % good for

Answer 5

increased resolution/ sensitivity/image quality

Question 6

whats the downside for in vitro

Answer 6

takes longer and more hands on so incr rad exposure and potential for blood exposure

Question 7

when do we use a LEAP collimatro

Answer 7

if <10 mCi

Question 8

when do we use a HiRes collimator

Answer 8

> 10 mCi

Question 9

who makes ultratag kit for RBC

Answer 9

mallinckrodt

Question 10

3 components to an ultra tag kit

Answer 10

1-10 ml vial contaning stannous ion, sodiym citrate, and dextrose
2- syringe 1 contains dilute sodium hypochlorite that oxidizes extracellular tin which keeps SnCl2 from interferring
3- syringe 2 ocntains a citrate buffer to neutralize effects of sodium hypochlorite which stabilizes b4 adding Tc