Upcoming Radiation: Any advice about process, prep, time commitment?

Hello - firstly, your physician should have given you ALL of the necessary information about radiation therapy, and had a discussion as to the advantages of Proton Beam Therapy. Your best source of "prep" info should come from your physician, not us.
Personally, I am with you regarding Proton Beam Therapy. Traditional Radiation Therapy goes "to", but also "through" the target tissue and has the potential to irreparably damage surrounding normal/healthy tissue. It can cause permanent urinary incontinence (something my radiation oncologist told me in a consultation just for knowledge sake). The advantage of Proton Beam is that it only goes "to" the target tissue...it does not travel through to potentially damage surrounding health tissue. That sounded like a winner to me.
I literally wrote something this morning as a reply to someone else's post, and it is a good lesson for us all as an example of the absolute worst thing that can happen resulting from traditional Radiation Therapy: Dilbert cartoon creator Scott Adams died of prostate cancer in January 2026. He had only been diagnosed the prior May 2025, but as a Gleason 9 and metastasis to his bones. He underwent traditional Radiation Therapy and it left him paralyzed below the waist...yep...paralyzed below the waist. He also considered assisted suicide because the pain from the bone metastases was unbearable (I can't imagine going through that).
So...that added, further evidence for me, that my personal choice would be Proton Beam Therapy if/when I ever might need it. The radiation oncologist with whom I met for a consult told me flat-out that I can pretty much count on having permanently urinary incontinence for the rest of my life following radiation therapy. I said "no thanks."
So...again...if/when I need it, I will find a place - even out of my insurance network - that does Proton Beam Therapy, and have that. My chances and outcomes will be far better. I am sure that many gents here will comment here that they had traditional Radiation Therapy and had no problems whatsoever. I am of the opinion that they are just the "lucky ones." When a radiation oncologist gives you the reality info of surrounding tissue damage and likely 100% probability of permanent urinary incontinence, they aren't saying that to entertain us...it is "fact." Let us know how you are doing once your Proton Beam Therapy is completed. Good luck to you.

Humans love novelty (protons), so do I, but don't dismiss photon technology which has 20 years of refinement in planning and delivery.
I took my rad onc's advice based on his experience with thousands of prostate cancer cases and had 28x IMRT/VMAT on a Varian Truebeam LINAC with spacer and markers. I'm two weeks post radiation. Mild urinary symptoms.

FORTY Ounces of bladder prep, you say? Shoot, for me
it was 16 oz. That's medieval
Age 70 4+3 local

@bob1955 Bob. I will be starting the exact
Same treatment (same machine) after getting the Barrigel and fiduciary.

My dr didn’t think I needed them but I requested them.

I just felt more more
comfortable with the 28 vs the 5. It is 22 miles away to distance not an issue.

I have 13 of 17 samples with 11 3+3, 1 3+4, and 1 3+5 (<5% of the 5). I thought the extra margins may help get anything near the edge. Very small 22 mL prostate.

Biggest concern is about rectal or urinary issues. Short and long term.

Any special diet?
Optimal time of day for treatment?
Any other tips or observations?

I underwent six weeks of daily radiation last July through the end of August, 2025 and my wife says, ever since, I have had this certain glow…
During the process, I had diarrhea the likes of which I hadn’t seen since I was a Peace Corps volunteer in Africa some forty years ago but it was manageable without medication.
I’m a cyclist, at 68, the most senior member of my team, and I had scheduled a century race - 100 miles - two weeks post radiation so I continued to train during the radiation period but it wasn’t pretty. I was fatigued and I planned a training route where there were evenly spaced public toilets. I was in the middle of one such ride, moving at about ten mph and feeling sorry for myself when a fellow cyclist, a man my age, passed me after politely calling out “on your left”. I let him pass but my competitive spirit engaged and I chased him down and we began talking. He, too, had undergone radiation therapy a decade ago and he assured me that this feeling of malaise was only temporary and I needed to continue my training even when my body wasn’t having it. That was the best advice I’ve received on this journey.
And, yes, I ran the race after getting permission from my oncologist. The diarrhea stopped a week post treatment and I was still careful to keep hydrated. Two of my teammates chaperoned me during the race, ready to flag down an official in the event that I suffered medical distress but, of course, I didn’t.
I haven’t experienced any of the physical symptoms about which others have complained - no hot flashes or urinary incontinence but I do have a certain urgency - when I have to go, I HAVE to go.
I have been training with my team for the past fifteen weekends in preparation for the season and will be riding the Horribly Hilly Hundreds endurance event on Saturday and I will be slower than last year but I fully intend to finish.

@madisonman0326 thanks much.

Are there meds that help preemptively or during that help with the diarrhea or urgent urination?

Are you on. ADT?

@darinlm1 X-ray guided radiation therapy (IGRT) and Intensity-Modulated Radiation Therapy (IMRT) are not competing technologies, but complementary approaches. IMRT shapes the precise dose of radiation to fit the tumor, while IGRT uses X-ray imaging during treatment to ensure the tumor is exactly in the targeted position.Intensity-Modulated Radiation Therapy (IMRT)What it is: An advanced, highly precise form of external radiation that uses computer-controlled X-ray accelerators to deliver customized radiation doses.How it works: The intensity of the radiation beam is varied—or modulated—to conform precisely to the three-dimensional shape of a tumor.The Benefit: It allows oncologists to deliver a highly lethal dose of radiation directly to the cancer while minimizing the exposure of surrounding healthy tissue and sensitive organs.X-Ray Guided Radiation (IGRT)What it is: Image-Guided Radiation Therapy uses imaging technologies (such as CT scans, X-rays, or cone-beam CT) immediately before or even during your radiation session.How it works: Because tumors and organs can shift slightly from day to day, IGRT takes real-time images to verify your exact positioning.The Benefit: It allows your treatment team to adjust the patient's position or the radiation beams on the fly. This ensures pinpoint accuracy, compensating for internal movement and protecting surrounding healthy tissue.

Basically, both are used in IMRT..from what I understand..whether you recieve proton or photon radiation. you will have slightly more radiation "splash" with photon but that can be useful when doing pelvic areas when not sure if cancer is present or not...the 'splash' knocks out small patches of cancer that may not have been seen by PETSCAN even