My situation was and is similar to yours. Had brachytherapy, and external beam Radiation little over seven years ago. My PSA started to rise several years ago in very small increments. Had psma pet scan twice . Almost 12 months apart. Showed PC had metastasized to the sternum in the first one and the second one a year later when my PSA was 2.8. The sternum , thoracic region t7, and 2 lymph nodes. To make a long story short, I had a biopsy done in the first one on the sternum showed negative for prostate cancer. On the second one we didn’t do any biopsies. The second PSMA pet scan and two CT scans, I had completed for other reasons confirmed the sternum lesion was stable and there were no more lesions attribute to growth confirming a negative biopsy.Assumption was this has been a reoccurrence, and I just completed SBRT on 4 spots. Of which I feel only two to be possibly cancerous. on the second PSA pet scan the pathologist didn’t list SUV numbers, but did say there mild uptake in the T7 and one of the lymph nodes. The other one just said there was uptake. If your using an F 18 tracer, it has a significantly higher false positive in the bones then the 68 tracer. Also,for prostate cancer to metastasize to the sternum is very very rare.so if it was me. I would do a biopsy to confirm especially in the bones. Since you’ve already had prostate cancer, and a few of these spots are shown up on a PSA pet scan your physician is going to assume recurrent anyway so do your homework as many questions and best of luck and may God bless you in your journey.