Cancer cells consume sugar (glucose) at a much higher rate than normal cells. PET contrast agent is kind of like glucose. It has similar molecular structure.
When you get an injection of PET contrast agent, cancer cells consume the agent faster than normal cells.
SUV = Standard Uptake Value. It measures the uptake of the contrast agent by the tumors.
High SUV: bad
Low SUV: good
Your SUV went down. This is GOOD! Lower SUV is the reason they wrote “locally positive response to therapy”.
>>> “No other foci of abnormal F-18 uptake.”
They didn’t see any other places where the contrast agent was consumed at abnormally high rate. This is GOOD! That’s why they wrote: “no PET/CT evidence of nodal or distant metastases”.
DISCLAIMER: I’m not a doctor.