radionuclide angiography (rna) gated equilibrium method (eqrna) first-pass method (fprna)
TRANSCRIPT
Radionuclide angiography (RNA)
Gated equilibrium method (EqRNA)
First-pass method (FPRNA)
Gated equilibrium method (EqRNA)
Tc-99m labeled RBCs:
in vivo, in vitro, and modified in vivo approach
Tc-99m human serum albumin
Comparison of First-pass & Gated perfusion methods for evaluation of ventricular function
First-pass Needs 99mTc based agents as compact bolus injection Needs high sensitivity detectors, programs May be performed with rest and stress LV & RV wall motion, volumes, and ejection fraction
Gated May be performed with 201Tl or 99mTc based agents Uses conventional cameras May be performed with rest and stress Only LV wall motion, volumes, and ejection fraction Provides LV wall thickening Accuracy dependent on endothelial border definition
Dosimetry for Tc-99m Red Blood Cells
Organ Tc-99m Red Blood Cellsrad/mCi
Blood 0.04Liver 0.03Spleen 0.11Bladder Wall 0.02Testes 0.01Ovaries 0.02Heaart Wall 0.10Total Body 0.015
Drug interfering with Tc-99m RBC labeling
Drug Mechanisms
Heparin Formation of labeled heparin
Methyldopa, hydralazine Oxidation of stannous ion
Digoxin, prazosin, propranolol unknown
Iodinated contrast media Competitionn with anion transport system
First-pass method (FPRNA)
Tc-99m pertechnetate Tc-99m DTPA or Tc-99m sulfur
colloid Short-lived agents:
Au-195m, Ir-191m, Ta-178
Infarction-avid imaging
Radiopharmaceuticals:
Tc-99m Pyrophosphate, 20 mCi, i.v. Time of imaging:
3-4 hours after injection