PSME3 and neoplasm: However, the Ki parametric map revealed higher (p < 0.001) tumor to tissue contrast ratio (for MDA-MB-435: 75.4 ± 8.5 at 1 h post PDT, 81.2 ± 7.8 at 24 h post PDT; for U87MG: 69 ± 15.5 at 1 h post PDT, 78.2 ± 10.8 at 24 h post PDT) than static PET image at 2 h post tracer injection (for MDA-MB-435: 3.78 ± 1.25 at 1 h post PDT, 3.25 ± 1.87 at 24 h post PDT; for U87MG: 3.25 ± 2.5 at 1 h post PDT, 3.54 ± 1.85 at 24 h post PDT) for both tumor models.