This is one of those cases where with such a low PSA (0.24), a PSMA PET scan will miss cancers about half the time (even though you know there’s likely recurrence due to the rising PSA).
> how did they know where to target the radiation if the PSMA PET scan showed nothing?
> in conjunction with the salvage radiation, did they include hormone therapy (ADT)?

In Dr. Kwon’s (of Mayo Clinic) presentation about recurrence and salvage radiation, they always include ADT:

Again, with such a low PSA now (0.11), will the PSMA PET scan see nothing again?

Have you asked about using an older PET scan (called Axumin)? It doesn’t rely on PSMA so, it might show something. (Usually PSMA PET is better than the older PET scans; but, with PSA that low, there’s no telling……
> Mayo Clinic uses an older PET scan called Choline C11 if the PSMA PET scan shows nothing. Ask them about that PET scan option.

Also, since your husband had his prostatectomy in 2014 - long before PSMA PET scans came out, he’s never had a positive one, has he? (They say that about 15% of prostate cancers don’t even express PSMA so, the scan would never show anything. He may be one of those 15%.)