Hi, MinnieMia:
I completed 26 FSR treatments on October 16, 2006. They followed microsurgery in June, 2006 to reduce my 4.5 cm AN tumor down to about 2.3 cm, making it suitable for radiation. Unlike your situation, my surgery and FSR were planned, performed and followed up by my neurosurgeon and a radiation oncologist, working as a team.
I had a 'baseline' MRI scan in December (the beginnings of tumor necrosis was noted) and in April, I'm scheduled for a follow-up MRI scan so my doctors can monitor the tumor and see whether it continues to show necrosis (cell death) - or not. My neurosurgeon is confidently optimistic but he wants me to have an MRI scan every six months for the next few years, then once per year, probably for many years, if not the rest of my life (I'm 64).
You'll very likely want to connect with a doctor who will take you as a patient, order and read the MRI scans on either a six-month or annual basis. He'll look for signs of necrosis or growth and also evaluate any symptoms you may have or develop. As for 'standards', I don't believe there really are any in a specific sense. As you noted, so much about AN symptoms, even during recovery, is subjective as well as specific to each individual. I would expect, following radiation treatments, that any pre-FSR symptoms would lessen, as mine did. However, I had surgery first to relieve the pressure on my brain stem, which made my symptoms more intense. Ultimately, had the tumor not been reduced, it would have become life-threatening. The neurosurgeon also wanted to 'de-bulk' (hollow out) the tumor to make it more susceptible to radiation. So far, so good (as my signature says).
I suggest that you find a physician who has some experience with acoustic neuroma tumors and try to become his or her patient. Being independent is fine but in this situation, you need some professional assistance and certainly a semi-annual MRI, evaluated by a medical professional. As for insurance, it takes years for a radiated tumor to completely 'disappear', if it ever does. I would guess that after a few years, a physician might write a letter to an insurance company stating that your AN has been successfully treated and (hopefully) shows signs of necrosis. That is probably about the best you can do.. Re-growth from radiation does occur, it is relatively rare and long-term studies can verify that, should an insurer deny you coverage. However, some insurance companies will deny coverage for 'pre-existing' medical conditions, meaning that any AN-related medical problems will not be covered by your medical insurance policy. That is an issue you would have to discuss - in detail - with an insurance agent to have it clarified.
I wish you well.
Jim