I assume with 28 sessions, your husband will get the moderate-hypofractionation treatment. My husband had 25 sessions and completed it in mid May. At the first appointment, I asked several questions including these following;
1. Are the sessions traditional radiation therapy or moderate-hypofractionation radiation therapy (higher dose but less time)?
2. What locations will be treated? And what are the dosage (GY) use at each location?
3. What machine will be used? and why they use this specific machine with my husband? I needed to know then so that I could look up the pros and the cons. In my husband case, they used Elekta with Monaco treatment planning system. The three centers we went for consultation have combination of Elekta Synergy, Elekta Versa HD, Elekta Unity (MRI-guided), Varian Trubeam, and Siemen Ethos (similar to the LINAC but not using MRI).
4. Do they have "in-house" physicists?
5. Will my husband need to be on strict diets? Ask for recommendations. Some RO do but some don't.
6. Will my husband need to do the protocol "empty bowel, full bladder"? If he does, will he be allowed to use enema on the treatment day.
7. I asked them to explain clearly how the planning day will be like and specifically asked them for the protocol before we coming in.
8. In case of emergency or sudden side-effect symptoms, who should we contact?
9. Will bloodwork be done half-way through and at the end of the treatments?
10. What are the possible side effects that you should be aware of?
11. What is the plan for post-radiation?

Depending on how large is the treatment area, the MRI guided radiation therapy machine (Elekta Linac) may not be good options. In my husband's case, he was not a candidate for both Elekta Unity (MRI-guided) and Siemen Ethos (similar to Linac but not MRI) because his treatment area was vast and needed shorter time to avoid his movement. Both Elekta Unity and Siemen Ethos required longer time for his treatments (20-35 minutes of laying still per session) whereas the VMAT system only took (less than 10 minutes of laying still per session). Two centers decided to offer the treatments with either Elekta Versa or Elekta Synergy (both with Monaco treatment planning system) that could use VMAT system to do the job mainly because my husband needed Simultaneous Integrated Boost (SIB) to one PSMA-positive lymph node. Another one center offered SBRT which was not approved by our insurance due to my husband's biological history. My husband got 25 sessions of the moderate-hypofractionation to his prostate bed and whole pelvic lymph nodes, plus the SIB to prostate bed and the one PSMA-positive lymph node.