Most partial volume correction (PVC) methods are ROI-based, and assume uniform activity within each ROI. Here, we extended a PVC method, developed by Rousset et al (JNM, 1998) called geometric transfer matrix (GTM), to a voxel-based PVC approach called v-GTM which accounts non-uniform activity within each ROI. The v-GTM method was evaluated using simulated data (perfect co-registered MRIs). We investigated the influence of noise, the effect of compensating detector response during iterative reconstruction methods and the effect of non-uniform activity. For simulated data, noise did not affect the accuracy of v-GTM method seriously. When detector response compensation was applied in iterative reconstruction, both PVC methods did not improve the recovery values. In the non-uniform experiment, v-GTM had slightly better recovery values and less bias than those of GTM. Conclusion: v-GTM resulted better recovery values, and might be useful for PVC in small regions of interest.