Nuclear Cardiology: Nuclear Cardiology:

74 Nuclear Cardiology, The BasicsTable 7-1Acquisition ParametersTc-99mTl-201Dose 10–30 mCi 3.5–4.5 mCiCollimator High resolution Low energy, mediumresolutionZoom No zoom 10 in. FOV or No zoom 10 in. FOV or1.2–1.5 zoom LFOV 1.2–1.5 zoom LFOVMatrix 128 × 128 128 × 128Peak 140 keV 20% centered 78 keV 30% centeredGating 8 or 16 frames/cardiac cycle 8 frames/cardiac cycleImaging time 5 min 8–10(10 min ECG-gated) (10 min ECG-gated)Imaging counts At least 10 6 At least 600,000–800,000PositioningView Detector Position Patient PositionLAO Best septal SupineAnterior Best septal minus 45° SupineLeft lateral 0° Right decubitusKey factors to ensure optimal quality planar myocardial perfusionimaging are:1. Adhere to the acquisition parameters listed in Table 7-1.2. Bring the camera head as close to the patient’s chest as possible.3. Acquire adequate counts.4. Reproduce exactly stress and rest patient positioning.Soft Tissue Attenuation in Planar ImagingBREAST (FIG. 7-1)Soft tissue attenuation, in particular by breasts, is an important problemwith planar imaging. In order to recognize breast attenuation, onecan acquire in addition to the conventional three-view planar image,low-count images—without moving the patient—with a line source inthe FOV that outlines the outer contour of the breast.