Fusion overlays two aligned series in a single viewport, typically PET on CT. The viewer supports standard fusion (MR, CT, NM), PET-CT fusion, and Advanced PET Fusion with multiple PET reconstructions.
Step 1: Load both series
Open a study that contains both modalities (for example, a PET/CT with attenuation-corrected CT and attenuation-corrected PET). Both series must share a frame of reference for automatic alignment.
Step 2: Enable Fusion
Click Fusion in the toolbar. The viewer overlays the second series on the first with a default opacity. A colour palette (typically Hot Metal or PET) applies to the overlay.
Step 3: Adjust blend and windowing
Use the blend slider to shift between 100% base and 100% overlay. Windowing the overlay changes the PET intensity mapping; windowing the base changes the CT anatomy. Each series has independent W/L.
Step 4: Use Advanced PET Fusion
For studies with multiple PET reconstructions (AC, NAC, CTAC-corrected), open Advanced PET Fusion. Switch between reconstructions without reloading the study.
Tips
- If alignment looks off, check that both series have matching frame-of-reference UIDs. Missing or mismatched UIDs force manual registration.
- SUV measurements require a correctly calibrated PET with decay-corrected injection time. Always verify the SUV label on the overlay matches what your protocol expects.
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