Backgrounds: Myocardial single-photon emission computerized tomography (SPECT) with the patient in the prone position has recently been applied to improve the percentage uptake (%uptake) in the inferior wall by reducing diaphragmatic attenuation. We hypothesized that the type of stress might cause a difference in the %uptake improvement in inferior regions in the prone position. The purpose of this study was to compare the %uptake improvement between exercise and pharmacological vasodilator stress in prone myocardial SPECT.