Camera Setup Parameters
| Parameter | Setup details |
| Collimator | Collimator-specific properties such as thickness (depth), width (bore), and angulation (diverging/converging) affect sensitivity and resolution of acquisition. Collimator selection (e.g., low, medium, and high energy; low or high resolution; or high sensitivity) depending on isotope used and administered dose should be stated. Proper collimator selection can enhance quality of images and data collected, as is so when high-sensitivity collimator is used to increase counting rate during first-pass study. |
| Energy setting and window | Correct photopeak and energy window setting should be used. |
| Acquisition type | Whether study is static, dynamic, planar, or SPECT should be described. |
| Orbit, orbit type, and number of projections | For SPECT studies, protocol should state whether 180° (as is common in cardiac studies) or 360° orbit is used. Orbit type, such as circular or body contouring, along with number of stops or projections should also be stated. |
| Acquisition time or counts | Because count density directly affects diagnostic quality, acquisition time or minimum counts should be specified. There may be instances (e.g., with bone scanning) in which counts are obtained in one view, and time for that image is used for remaining views. |
| Matrix, pixel size, and zoom | For most nuclear medicine studies, matrix and pixel size are relatively standard. Dynamic studies are often acquired using 64 × 64 or 128 × 128 matrix, whereas static images commonly use 254 × 254 matrix. However, for myocardial perfusion imaging, pixel size (smallest discrete unit of image matrix) and matrix size play direct role in count statistics and resolution. Smaller pixel size required for large-field-of-view cameras is accomplished by adjusting camera zoom to be able to detect perfusion defects. |
| Gating | For cardiac gated studies, number of frames per cardiac cycle should be stated. Ejection fraction calculated from study acquired using 8 frames per cycle vs. 16 frames per cycle will result in different values. R-R acceptance window, which is particularly important in patients with irregular heart rates, should also be stated. Wide R-R window used for myocardial perfusion study results in count statistics different from narrow R-R window used for equilibrium radionuclide studies. |