@hanscasteels Below are a few lines (3 paragraphs) from your post above. I wish to add my experience today (parenthetical notes after the lines from your post).

a. Yesterday marked the end of my EBRT pilgrimage. Twenty-one precision-guided rituals at the Chernobyl Spa,
(This afternoon was my second SBRT treatment. Three more treatments to go.)

b. Your carefully measured bladder? A green check mark. Your heroic bowel prep? A polite nod.

(As I was getting off from the "treatment bed," one of the techs said, "Everything was according to the textbook. That's why we finished early."
(But in fact, we finished late. My schedule was for 1:30 p.m., Radiation Unit 9. Initially, I was told to wait 10 more minutes, then it would be my turn. Then I was told, Unit 9 is behind schedule, we will ask the RO to see you first, then you'll be in to Unit 9. After the RO had seen me, I was told that Unit 9 wasn't ready, I would be treated at Unit 6. My treatment started at 2:15 p.m.
(I was told that the cancer center has several Elekta MRI guided machines, the one at unit 6 is a sister of unit 9's. I guessed that the patient ahead of me at unit 9 (where I was the last time) had his treatment delayed. Maybe he had gas or his rectum wasn't empty? I understand that treatments do not proceed until the patient has passed the gas or emptied the rectum, and his bladder is almost full? [drink 500 ml water 30 to 40 minutes before, don't pee before treatment], else organs at risk. I think it is a good thing. Better late than sorry.)

c. The technicians re-enter. “All done,” they say, as if you’ve just renewed your driver's license.
You nod, grateful to leave.

(Then I heard the unexpected. I was about to ask, but the technician was ahead of me. She said, "Your bladder is perfect. As well as your rectum. Everything was according to the textbook. That's why we finished early."
(Event "c" is actually before "b," but I put it last because it was then that I said, "Oh, thank you. I'm happy to know.)

In conclusion, I think that each of us may have our own unique experience that we can share in this Support Group, and hopefully help others. Hans, you are a writer. Your posts are somewhat long, but I have read them all. I wish you the best!