Nuclear Cardiology: Nuclear Cardiology:

62 Nuclear Cardiology, The BasicsTable 6-1Acquisition ParametersTc-99mTl-201Dose 10–30 mCi 3.5–4.5 mCiCollimator High resolution Low energy all-purposeMatrix parallel holeparallel hole64 × 64 64 × 64Peak 140 keV,78 keV 30% centered20% centeredGating 8 or 16 frames/cycle 8 frames/cycleNo. of projections 64 32Orbit 180° 180°Orbit type Circular CircularAcquisition type Step and shoot/continuous Step and shoot /continuousPixel size 6.4 ± 0.2 mm 6.4 ± 0.2 mmTime/projection 25 s for low doses 40 s (at least)20 s for high dosesAttenuation Different for different Different for differentcorrection vendors vendorsdards). Additional information on accepted standards for performingmyocardial perfusion imaging can be found in the Society of NuclearMedicine Procedure Guidelines for Myocardial Perfusion Imaging (online: www.snm.org/policy/new_guidelines_1. html).A review of clinical indications for myocardial perfusion imagingcan be found on line: www.acc.org/clinical/radio/57252.pdf and in:Guidelines for clinical use of cardiac radionuclide imaging 2 (theseGuidelines are currently under revision).The time interval from injection of radiopharmaceutical to the start of imaging is:Exercise PharmStress RestT1-201 10 min 10 min 30 minTc-99m-agent 15 min 45 min 45 minACQUISITION PARAMETERSThe acquisition parameters are listed in Table 6-1. In this and followingtables doses are given in mCi. Note: 1 mCi = 37 MBq. The followingsubsections are comments on the individual parameters listed.DoseIt is prudent to institute weight criteria for the choice of imagingagents, Tl-201 or Tc-99m-agent, and imaging protocols, one-day or two-