GENERATION OF MYOCARDIAL FACTOR IMAGES DIRECTLY FROM THE DYNAMIC OXYGEN-15-WATER SCAN WITHOUT USE OF AN O-15 CARBON-MONOXIDE BLOOD-POOL SCAN

The measurement of regional myocardial blood flow (MBF) with (H2O)-O-1 5 and PET requires an additional (CO)-O-15 blood-pool scan for the pur pose of region of interest (ROI) definition. This additional scan resu lts in a substantially increased radiation dose, study duration and ri sk of movement artifacts. Therefore, a method was developed to generat e myocardial factor images directly from the dynamic (H2O)-O-15 study without the need for a (CO)-O-15 scan. Methods: The factor sinograms w ere generated by means of linear dimension reduction of the dynamic si nograms, where the required variate and covariate factors (myocardial and blood time-activity curves) were modeled from the lung time-activi ty curve. The factor images were generated by iterative reconstruction . Results: No significant difference was found between MBF values from ROls drawn on the traditional images (using the (CO)-O-15 scan) and t hose drawn on the factor images. Conclusion: It is possible to generat e myocardial images directly from the dynamic (H2O)-O-15 study, so tha t the (CO)-O-15 scan can be omitted from MBF studies. The proposed met hod is robust and results in nearly optimal signal-to-noise ratios in the factor images.