PSMA pet scan

[lewicki]

Will dead cancer show alive or dead on the scan?

[tango65]

It will not show in the PET , it could show in the CT. I had several lymph nodes PSMA positive in 2016, After 1 Lu 177 PSMA treatment the nodes become PSMA negative but they had and have the same size in the CT scans.

[Dban]

Good question - I've just had a PET PSMA scan after Cyberknife/ADT a year ago. The single met on the iliac crest is 'half as avid' as it was last year. SUV has gone down from 7 to 3. MRI shows it is inactive as far as it can see. Consultant mentioned 'zombie' cells may still be existing and that 'who knows how long it takes cancer cells to die off fully after treatment'. Be interested to know if anyone can add their knowledge.

[GP24 in reply to Dban]

The Cyberknife radiation - how many sessions and what was the dose in Gy? The met should not be visible on a PSMA PET/CT after a successful radiation.

[Dban in reply to GP24]

3 hits. Not sure of dose. That’s what I would have thought. Time will tell.

[GP24 in reply to Dban]

The dose will be specified in the final report of the radiation therapy. I had three sessions with 10 Gy each. The mets and the recurrence in the seminal vesicle did not appear again on subsequent PSMA PET/CTs. I got new ones at different locations though.

[Tall_Allen]

Dead cancer cells are quickly cleared away. Only cells that express PSMA show up on the PSMA PET scan. The CT part of the scan will pick up bone overgrowth.

[lewicki in reply to Tall_Allen]

Thanks.