The object of this study was to evaluate the effect of gender, age and anthropometric data on regional isotope uptake in myocardial perfusion scintigraphy using 99mTc-MIBI-SPECT (myocardial sestamibi single-photon emission technique). Seventy-one healthy, non-smoking subjects, 42 men and 29 women between 40 and 80 years of age, with less than 5% likelihood of having coronary artery disease were studied. All subjects underwent a maximal exercise and rest MIBI-SPECT using a 2-day protocol and a 180 degrees anterior circular rotation. No correction for scatter or attenuation was made. Normalized regional activity was different in men and women in the anterior and inferior regions, with higher values anteriorly in men and inferiorly in women. Regional activity also differed with age in both women and men with higher relative activity in the anterior regions in the oldest age groups. Higher activities were seen in the basal parts of the left ventricle at rest compared with stress in both men and women. Regional isotope uptake was significantly affected by habitus expressed as body mass index (BMI) and thoracic circumference. Different protocols for stress and rest seem to be needed for men and women in different age groups, and for stress and rest when performing semiquantitative MIBI-SPECT and comparing data with a normal file of healthy subjects. Furthermore, such anthropometric data as BMI and/or thoracic circumference should be considered in order to minimize the risk for false-positive or false-negative scintigraphic results.