Spatial calibration of digital scintigraphic images: work in progress.
Accurate scintigraphic determination of organ dimensions is often difficult because of the wide variety of camera-collimator combinations and display formats used for imaging. An algorithm (SPACE-CAL) was developed for digital spatial calibration of up to six large- or small-field gamma cameras using various collimators and magnification factors. The algorithm employs a master calibration file that can be used at multiple terminals. An interactive subroutine permits the operator to measure distances and areas directly from the images. Evaluation of three operators' measurements of a pine-tree phantom acquired at various magnifications showed that distances could be measured with a high degree of accuracy. Calculation of ejection fraction from end-diastolic and end-systolic areas determined by SPACE-CAL showed a high correlation with automatic count determinations (r = 0.96) and angiographic calculations (r = 0.93) of ejection fraction in 12 patients. SPACE-CAL provides an easily implemented, reproducible, and rapid method for accurate analysis of organ dimensions in digital images.
D003201:Computers; D003626:Data Display; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008961:Models, Structural; D011877:Radionuclide Imaging; D013318:Stroke Volume