Patient 23. (a) Multifocal HCC seen on catheter-directed CT angiogram of the replaced left hepatic artery, arising from the left gastric artery. Four small tumors are indicated by arrows. (b) Enlarged view of segment IV shows the larger central tumor being flanked by two smaller, closely adjacent tumors separated by approximately 3 mm. (c) Post-radioembolization 90Y PET/CT confirms focal activity within the four small tumors, depicted in high resolution. (d)90Y bremsstrahlung SPECT/CT was barely able to detect subtle activity in the larger (arrow) of the four small tumors, but was unable to confirm any focal activity within the other three small tumors due to its low resolution.