Radiation CAT scan mapping: I’m... - Advanced Prostate...

Advanced Prostate Cancer

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Radiation CAT scan mapping

plato123 profile image
26 Replies

I’m starting radiation and scheduled for CAT scan mapping of pelvic floor. Any advice on how to ensure maximum accuracy of this process? The clinic wants me to take gas-x and milk of magnesia a week prior. Assume this is to prevent full bowels to ensure that the mapping is accurate and won’t affect other anatomy. Any tips to ensure maximum would be awesome.

26 Replies
Jancapper profile image

Yes, be certain rectum is empty before your mapping. The mapping process takes a limited look at both your bladder and rectum. If your bladder is not full or if your rectum indicates stool contents, you will be asked to disembark the table and either drink water or use the toilet, after which the mapping is attempted again. Once mapped, the same instructions hold true for your irradiation visits. I failed not only my mapping, but also my first two IMRT sessions due to stool in my rectum. In all situations, I had a pre session bowel movement. This is embarrassing as it really delays the process for not only yourself, but for all patients scheduled after you. Once you start reporting to your radiation center with a full bladder, you will come to appreciate being on schedule like never before! So I developed a routine that I have since followed that has worked well for me. Once I rise in the morning, I drink hot coffee, which for me, encourages a BM. To prevent the continuous movement of new stool into my rectum, I stop the coffee consumption just as soon as I have used the toilet. Sometimes, I need two full 12 oz cups of coffee while other times I need only a few sips. Additionally, I take a single Immodium pill after my early morning BM. Again, this is to slow the movement of new stool into my rectum. Since adopting this routine, I have not experienced a single preparedness failure. Next Tuesday, is my last day of IMRT!

After the BM, I super-hydrate by drinking 6 x 16 oz oz of straight water. I try to stop urinating 45 minutes prior to my scheduled scan time. This is overkill but once you experience a preparedness failure, you will understand. In the event that I should need to be removed from the table, to use the toilet, my bladder refilling time is minimal and will cause the least amount of disruption to all.

Best of luck.

maley2711 profile image
maley2711 in reply to Jancapper

I am VERY irregular, and sometimes miss days. I have no idea how I can fulfill the requirement of an empty rectum. Suggestions? also, mucho gas !!

Jancapper profile image
Jancapper in reply to maley2711

Try a hot beverage in the morning and continue until you poo. However, stop just as soon as you do. Otherwise, you will cause more stool to move into rectum. I too am normally very gassy myself. Follow the recommended diet of low to no fiber and you will reduce your gas.

maley2711 profile image
maley2711 in reply to Jancapper

Thanks.....often at least 6-8 hours after waking up. Cup after cup of hot tea?

dadsdrdawn profile image
dadsdrdawn in reply to Jancapper

A problem with having a "low or no fiber" diet, is associated with constipation. Fiber KEEPS you regular, and lessens bloating as it shuttles out impurities. Eat a diet rich in vegetables that have cancer killing and preventing properties. Fruits and vegetables are what nearly all medical, and holistic care practitioners recommend:) However, be sure to drink enough water to flush your body out and keep you hydrated.

Jancapper profile image
Jancapper in reply to dadsdrdawn

I agree 100%. However, we are talking just about a low fiber diet during IMRT sessions. The machines used to deliver the irradiation are so accurate now, when a patient experiences flatulence while the irradiation beam is on, thereby causing the rectum to distort, this will shut down the machine. Then that session has to be restarted and repeated from the beginning. Additionally, IMRT is bound to cause some looseness in stool hardness. You will want anything other than to be full of fiber and or regular when this happens. Not only did I receive an entire professional pamphlet on the importance of a low fiber diet while receiving IMRT, I also did an internet search. My brief investigation yielded the same results. I am not arguing that such a diet is healthy, it is not. However, it will facilitate a smooth and successful IMRT treatment.

dadsdrdawn profile image
dadsdrdawn in reply to Jancapper

Got it! I completely understand that this is necessary before the treatments! Wishing you stellar health and healing:)

Alturia profile image

What prep instructions did your RO provide? I was initially scheduled for radiation with an RO who wanted me to do 2 enemas before the mapping and each radiation session and drink a huge bottle of barium before the mapping. And have my bladder full. I switched to a different provider (not because of the prep, I just never felt comfortable with the first RO) and the new RO only wanted me to have a comfortably full bladder. No enemas and no barium. So there can be a big difference in prep depending on the RO and the machine that is used.

BTW, after experimenting a bit I would drink 400ml (about 14 ounces) of water about 15 minutes before my radiation session and that gave me a full bladder without it being hard to keep from peeing.

Mrtroxely profile image

There's CT guided radiotherapyAnd

MRI guided radiotherapy

My understanding MRI guided more is accurate?

There's also space oar hydrogel to help with side effects and possible damage to anal and ureatha!

Would tall Allen or other fact based advocates be able confirm this?

Tall_Allen profile image

I was told to not do anything out of the ordinary other than to take a shit before the CT and MRI. Some are instructed to do an enema or go on fiber-free diets - I wasn't because my RO feels that any extraordinary bowel prep or diet can cause excess motility. The lab techs will check to see if your rectum is free of shit.

Follow your RO's instructions.

plato123 profile image
plato123 in reply to Tall_Allen

you crack me up - take a shit. lol

Tall_Allen profile image
Tall_Allen in reply to plato123

I have potty mouth.💩😮

dadsdrdawn profile image
dadsdrdawn in reply to Tall_Allen

Fiber free BEFORE these procedures yes - but omitting fiber from your diet entirely can lead to constipation...

Atdabeach profile image

I was told I needed my rectum to be "mostly empty" and my bladder "mostly full" for each session. I was instructed to take Miralax every day, starting a few days before simulation, and continuing all the way through my 44 proton sessions. That would presumably make sure that I remained regular throughout the period. As for water, it's just a matter of timing my drinking and peeing ahead of each session.

In addition, I was told I would have a rectal balloon inserted for each session, to minimize rectal damage by moving my rectum slightly away from my prostate (in lieu of SpaceOar, because of the "unique characteristics of my cancer"). I assume it has to do with my lymph node involvement. I understand that in some cases, doctors are concerned that SpaceOar could actually shield some cancer cells from radiation.

I had my simulation this past Wednesday, and will start proton therapy on 2/2. My simulation appointment included both a CT and an MRI, back to back. The only problem was that I had hydrated well, and by the end of the second scan, had to pee like a racehorse. For the actual treatment sessions I'll plan more carefully, but thankfully the sessions will be shorter.

plato123 profile image
plato123 in reply to Atdabeach

thank you sir

London441 profile image

instructions vary. Full bladder, empty bowel are pretty ubiquitous. How you are supposed to get there is the difference. I was told enema only as last resort, and the ensuing zero fiber diet they recommended constipated me so I refused it. They said okay and it was fine.

IMO what matters most is that they care enough to be accurate. Truly a matter of faith-no shit😀

plato123 profile image
plato123 in reply to London441

well said.

Drandma profile image

My husband’s radiation was scheduled for 2 pm every day. He would hold off eating anything until after radiation and would drink a bottle of water on the way there. Never had any problems

warrior22 profile image

miralax each evening before tx. : empty bowels in am

2 bottles of water one hour prior to fill bladder

Eliminate gas producing food on days before treatments. ( greens etc )

hfl20 profile image

My experience has been pretty rocky... Before treatment, I ate a primarily plant based diet heavy on legumes with a bit of dairy (yogurt and ice cream) and occasionally chicken or salmon. Extremely regular bowel movements after a cup or 2 of coffee in the morning and perhaps again after lunch. I was told not to change my diet for my 38 proton treatments. I do have the spaceoar and am getting radiation for part of the treatment also to the pelvic bed and seminal vesicles (which with proton beam patterns I think radiates more of the bowel than prostate alone).

For simulation (CT then MRI) for planning prior to treatment, I was told to drink 128 oz water the day before and on the day of my simulation give myself a fleet enema (in my hotel room) then arrive at 7am an hour before simulation and drink 32 ounces prior to the CT/MRI.

I complied and simulation went fairly quickly after measuring how much liquid was in the bladder on the CT table. After the 1st CT I was told I had a gas bubble and could I push it out. I could not and they used a rectal catheter to release the gas. The next CT went fine, the Dr. came down, approved, and the MRI proceeded with no problem. It is important to note (at least at MD Anderson) that whatever is measured in your bladder at simulation becomes the minimum standard required for all of your following treatments.

I arrived for my 1st treatment after driving about 5 hours and thought I was hydrated enough after drinking water throughout the day and 32 ounces within the hour prior to treatment. No so - I was measured at about 50 ml and could not be treated until my bladder was holding 200 ml. I drank 5 more 500 ml bottles over the next 4 hours and my bladder never filled enough for treatment so that day was scrapped and 1 more added to the end of my schedule.

Each day before treatment we are measured and either told to drink more or release a prescribed amount. It really screws up the schedule, usually with whoever is ready goes next. My general method now (at 31 of 38 late afternoon treatments) is to eat nothing and set 6 500ml bottles of water on the counter and consume prior to treatment and clamp off (ask for a penile clamp at your first treatment) 2 hours prior to treatment. Between feeling the need to pee and mashing on my bladder with my hand I can usually tell when I am full enough. I have had some rough days when short and also when way too full. If I don't think I can hold it, I will go early to treatment, ask to be taken back and measured so I don't let out too much.

As for bowels, I oscillate between diarrhea and constipation and have lost about 20 lbs. I've tried the FODMAP, BART, and low residue diets and now mainly eat canned soup and boost (only after treatment) and use Colace, Senokot (stool softeners), Metamucil, or Miralax (fiber) and the occasional fleet enema to crap and 1 to 3 Imodium to stop. The suggestion to take 1/2 tablet of Imodium every morning doesn't work for me... Gas has been released via catheter 3 or 4 times on the treatment table. They may proceed if you have gas that is not in the treatment field in certain situations. After this next 10 days, I plan to return to my super high fiber diet and never use Imodium the rest of my life. My singular goal every day, through hell or high water, is simply to get on that table, receive my treatment, and get through this.

louschu profile image

Vanderbilt is using PSMA to guide. Both Vanderbilt (IMRT) and our Proton Center are using Space Oar. My personal experience was do nothing but that was 2010.

Teacherdude72 profile image

Start a Low Residue diet.

Stevecavill profile image

you REALLY need to get this advice from the RO nurses. If their instructions s weren’t clear, ring and ask again. Getting conflicting advice from people who don’t know your exact situation is unhelpful and possibly harmful

runtrails profile image

My RO had me take Colace and metamucil twice a day. Never failed a treatment. Drank 12 oz water 45 min before

pcmyway profile image

IMRT & fiber during treatment? I eat a high fiber diet like most but now have already failed my first 2 IMRT sessions due to full bowel and some gas. If I shouldn’t eat fiber what should you eat for 8 weeks of treatment to not end up with constipation and other issues?

plato123 profile image
plato123 in reply to pcmyway

my medical team recommend gas-x night before and milk of magnesia

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