Quantification of thallium myocardial studies affords the advantage of objectivity over visual analysis. Moreover, comparison of patient profiles to normal limits gives nonexpert readers a sense of confidence for interpreting these studies. Quantification of the washout rate from planar scintigrams aids in overcoming any lack of contrast. Tomography has excellent contrast resolution and identifies most stress perfusion defects without the need for washout calculations. Moreover, with the use of polar displays such as the Bullseye map, the perfusion defect is better characterized by tomography in terms of its location, shape, and size. The main caveat in the use of tomography is that it is technically demanding. The decision as to which method to use depends largely on the application and on the instrumentation and technical expertise available.