My Experience with RAI (I-131) Therapy

This post will probably be most beneficial to someone who’s recently been told they need radioactive iodine (RAI or I-131) therapy. It’s pretty dry but hopefully someone will take comfort that the process isn’t as scary as it feels.


The internet is riddled with horror stories (vomiting for days! disappearing taste!) and simple two-liners (“Isolation not that big of a deal! It goes quickly!”) – so it’s hard to get a sense of exactly what to expect. So I thought I’d chronicle my experience, which is probably pretty average, and hope it helps someone else who is frantically Googling what to expect and how long they have to remain isolated.

(There’s about 62,450 people diagnosed with thyroid cancer each year. Not everyone is prescribed RAI therapy and it seems like every doctor has their own method for how to approach the process as well as how long you need to remain isolated and to what degree. What I mention below is what my nuclear medicine department at the local hospital sent me home with – by all means, please follow your own doctor’s orders!)

The process itself is very straight-forward: you will receive 2 injections of Thyrogen (unless you have a reason to need to go off your thyroid hormone replacement meds for 2-4 weeks and deal with severe hypothyroidism) in the two days before receiving your RAI therapy dose. If you are a female, you will need a blood test on the first day of Thyrogen to confirm you are not pregnant. Thyrogen has its own set of potential side effects, the most common being nausea and headaches. I was fortunate enough to have a supportive work environment and was able to work from home on the two Thyrogen days. I have a 90min commute between work and home and didn’t want to have to deal with possibly trying to get home with nausea on an hour-long train ride. Fortunately I did not experience any significant side effects although I noted I was a bit on the tired side.

The day of RAI treatment I had to get another blood test to confirm my severe hypothyroid levels (this is due to the Thyrogen injections) right before heading to the nuclear medicine department at the hospital. My hospital is one that allows you to convalesce at home (i.e., it does not admit you overnight).

I had to sign a bunch of paperwork. The nurse took me back and gave me everything I would need post-therapy, including validating my parking (how nice). This included specific written instructions for isolation, a Personal Disposal Kit (i.e., a kitchen trash bag), and a card for my wallet that confirms my I-131 therapy and that I am not a radiation hazard to the public.

Another nurse came in to talk to me about isolation – the biggest being Time and Distance. The first 3 days are the biggest concern because the radiation is literally emanating from you, not just being eliminated. He answered all of my questions and then took me back to the doctor who would administer the treatment.

My doctor had a Geiger counter on the table next to us; the pill was in a lead-lined cylinder. He explained the therapy to me again as he put on hospital gloves and used a pair of thongs to remove the pill from the cylinder. He gave it to me with a cup of water. My dose was a grey pill about the size of any other average prescription capsule. The doctor advised me to not eat anything spicy or that would upset my stomach for the next few hours to allow the I-131 to absorb into my body. He had me walk to the door of the room and back to show the amount of distance I needed to keep between myself and others for the first several days – and then sent me on my way.

In the few days before doing all this, I recommend doing the following:

* securing a beach house or lake house or other accommodations that have a private kitchen and bathroom. Convalesce in style!

* If you are like me and don’t have any of those available to you, kick your SO out of the master bedroom with attached bathroom and make it your Isolation Suite. Wash and clean everything before undergoing therapy. Yes you’ll have to rewash and clean everything again – but no one likes to wallow in filth.

* Stock up on foods you like, ginger ale (with real ginger), saltines and lemon hard candies. These help you feel moderately better and you’ll actually want to eat them. You may get nauseated for the first 3 days or so – the ginger ale and saltines will help you not feel totally wrecked and you can get some extra sleep. The hard candies are to keep your saliva production up to minimize the sore/swollen salivary glands that may happen. I chose sugar snap peas for my snack and they were super delicious! I also asked for water ice, which was also delicious.

* Find a way to keep your pet at bay. Buy a baby gate if you have to. My dog couldn’t understand why I couldn’t let him kiss me or snuggle up on my lap or sleep with me at night. It was horribly sad.

* Have young kids? Send them to Grandma’s for the week. Have older kids? Get them to make you meals and keep the dog happy. My teens were the best at making me food and leaving it at my door. They kept the dog happy. And in return they got a week of unencumbered video game time because Mom Can’t Do Anything About It.

* Cover your electronics for the first 5 days or so. A plastic sandwich bag over your smartphone is fine. You can get a keyboard cover relatively inexpensively online. Staying in touch with people through the internet or texting is a great way to keep your mind off the fact that you can’t be around anyone.

* Keep the door to your room open and the blinds drawn back if possible. This allows you to feel like you are still incorporated in family life – just make sure everyone is aware of the safety limitations.

My dose was 150 millicurries. I was told I would need to enact radiation safety protocol for 10 days – but the most stringent portions were lifted within about 3-7 days. Keep in mind radioiodine will exit the body through fluids (urine, stool, perspiration, and saliva) – water dilutes the radiation.

For the first 3-5 days and nights:

* sleep completely separate from any other family member.

* have sole use of a bathroom – toilet, shower, sink. Don’t share towels.

* keep as great a distance as possible from others, minimum of 9′ (first 3 days) to 3′ (days 4-7). No hugs, kisses, snuggles, or sex.

* do not travel by plane or mass transit and do not take prolonged car trips.

* drink a minimum of 64oz of fluids each day to encourage unabsorbed radioiodine to leave your system as quickly as possible. Pee a lot.

* use a laxative or eat high-fiber foods to encourage your digestive tract to keep things moving along and minimize any GI issues.

* Use regular plates and utensils. Wash them separately in the dishwasher (2 cycles) to reduce the chance of contaminating the rest of your family for the first 3-5 days.

For the full 10 days and nights:

* Flush the toilet 2 or 3 times after use. If you’re a dude, you have to sit to pee to avoid splashback. If you do splash, wet a tissue to clean it up and then flush the tissue.

* Wash your hands with plenty of soap and water.

* Rinse the sink, shower, and tub with plenty of water to reduce the chance of others becoming contaminated that is being excreted through your bodily fluids.

* Do not exercise for the first 7 days. Radioiodine is excreted in your sweat, which means lots of stuff would be contaminated.

* Do not have any lab tests done unless it’s an emergency through Day 7, in which case have someone call the Radiation Safety Officer at the hospital. Your blood may contain radioactive material!

* Avoid prolonged contact with pregnant women, babies and children. Their thyroids are more susceptible than adults.

* Put all of your trash into the Personal Disposal Kit. You will need to hold onto this bag in your garage until the safe disposal date, which is 75 days after your treatment dose. Write that date on the bag so you don’t accidentally toss it too soon and contaminate the garbage trucks and landfill. Eat an apple? Core goes in the PDK bag.

* wash your towels, sheets, and clothing separately and run the washer on a rinse cycle twice after the final load to minimize any potential contamination.


On Day 10 you will most likely get a whole body scan to see where the radioiodine was absorbed. This is a baseline to see where the potential stray thyroid cells are located. The idea is that over time the radioiodine will destroy these cells and reduce the chance of cancer recurring. It also helps to see if there is any metastatic cancer.  This is basically the beginning of a lifelong monitoring of the cancer to ensure if it comes back we can act quickly. The downside is the slight increase in secondary cancers from this treatment. Something we always have to be mindful of and enjoy the time we have and treat anything that comes up as it does.


I’m only on Day 7 right now and looking forward to finishing out my isolation time very soon. I miss being with my family and yelling that I love them from my room as they get ready to go to bed or leave for work is kinda sad. I ate my meals in my room for the first 5 days, which is also weird and sad. But necessary! I’d rather be alone and sad for a week than put any of my children or husband or pets at risk.

I tentatively booked a bike ride for this weekend, which I am so looking forward to. Provided the weather cooperates – see you on the road!

Edit to add: My experience included mild nausea and sleepiness for the first 3-4 days. I slept around 14 hours a day! My salivary glands at the back of my jaw became tender on Day 2 so I used hard candy to keep saliva production going and gentle massage of the area. My taste has altered slightly, as things don’t taste as fully flavorful right now. My understanding is this is temporary for the next several weeks and should return. Around Day 5 I started to feel more normal and now at Day 7 I feel mostly like myself again.

Author: Laura

wife. mother. kick-ass girl. all mountain, all road adventurer by bike.

17 thoughts on “My Experience with RAI (I-131) Therapy”

  1. I went through this as well, knowing I might have to do it again in six months cause I had a lot of disease. What I wasn’t told was there was a possibility it wouldn’t work. I came back in 6 months for a scan and most of my tumors were still there. The theory being the tumors no longer took up iodine, so couldn’t uptake radiation. This was the scariest time in my cancer journey. If interested check out

  2. This is a very helpful post. I had the same treatment, but a lower dose, because I had Graves Disease. That was about two years ago and now I’m healthier than I have been for almost ten years! You’re right, there are a lot of horror stories on the inter webs about RAI treatment. It also motivated me to write about my experience on my blog. I wish I’d read your post before my treatment. All the best on your journey forward!

  3. Thank you for such a detailed account of your treatment. I really couldn’t find much online about what to expect, so this is so helpful. Question: did you have to do the low-iodine diet before and during your treatment? I’m seeing my endocrinologist on Thursday to make plans for getting my treatment, and I’m now wondering how much longer I’ll have to wait to get the treatment. I stopped using iodized salt a month ago and I’ve been avoiding any type of fish, but I had no idea that there was iodine in eggs and dairy products.

    1. Hi Caprice – No, I opted for Thyrogen (2 shots over 2 days). If it’s an option for you, discuss this with your doctor as it’s significantly less impactful to your well-being leading up to RAI treatment. Wishing you all the best for a successful treatment!

  4. Hi Laura, Great post! This was helpful. Following a diagnosis of Thyroid Papillary carcinoma which had metastasized to lymph node, I just had a total thyroidectomy, and RAI done, with the same dosage of 150 MCI. It’s early days for me, but I was wondering if you could elaborate on how it impacted the fitness side of things. You seem to be an avid cyclist, and this is a great data point for me! 🙂 How long after RAI did you resume fitness activities? Did you significantly alter your diet or diet schedule? How long did it take to find the right dosage of Thyroid supplements? What advice would you give to someone who is starting out now looking to become fit again?

    1. Hi! Thanks for reaching out! Most of my adjustments were to align myself more closely to generally accepted nutritional guidelines and then see what worked best for me.

      The first area to adjust was nutrition. I found I couldn’t eat carbs as easily as I had before. I now focus on having protein, whole and sprouted grains, and more fresh fruits and veggies. I’ve cut sodas and replaced it with water or tea. And of course, coffee in the morning.

      For finding the right medications, it took 2.5 years. I stayed with an endo too long that wasn’t truly addressing my concerns and symptoms. Once I found an endo who listened and wanted to try new medication combinations (I now take T4 and T3), most of my issues went away. I still have occasional days where I am more symptomatic but overall I am much closer to normal than I was before. I have not lost any weight I gained but I’m not gaining anymore either when I stick to my nutrition guidelines.

      For fitness, I make sure to walk, hike, or ride my bike as much as possible. I restarted my bike routine 2 weeks after RAI (to make sure I wasn’t going to sweat radiation on anyone) with slow, gentle rides on a bike path and built up from there. I found I was sweating more profusely than before so I’ve had to adjust my hydration and on-bike nutrition strategies to accommodate – how often I drink, which electrolyte beverages work for me, etc. I also prioritize sleep and true rest days.

      Good luck on your journey!

      1. Hi Laura,

        Thanks a lot for your reply, and elaborating on the nutrition, medication aspects! That was helpful!

        If I may ask, apart from the process of finding a helpful/considerate doctor, could you elaborate a bit more on the data-points that I could potentially bring up in my discussions with my doctor, to converge on the right dosage of medication, as fast as possible?

        As in – to drive a discussion along the lines – “Hey Doc,I am guessing I might need a combination of T4 and T3 because I have been observing X,Y, Z symptoms for ‘T’ duration of time. What is your opinion?’

        Any non-obvious observations/ experiences you might have encountered in the 2.5 years duration, would also probably incredibly useful both to me, and anyone new to this side of the journey.

        Best Wishes,

      2. Hi!

        I kept a copy of my results and tracked them on a spreadsheet to see any trends to match my symptoms. While my numbers were “good” according to my endo, I still had symptoms and my TSH was not stable from check to check. My endo didn’t necessarily change my dose right away either.

        My new endo started requesting consistent data (TSH, Free T4, Free T3) from check to check, which helped tremendously. She listened to my symptoms and then adjusted both my Synthroid dose and added Cytomel. It took a few checks to dial in the right levels of each but it was worth it. Some of the wait time is simply because T4 takes longer to build up (6-8 weeks) than T3 (quick-acting).

        I also developed a routine and made sure to take my medications at the same time every day. I have 4 different alarms on my phone to remind me to take my meds at the right time (otherwise I forget). Doing that has helped eliminate a variable in why I wouldn’t be feeling optimal.

        I don’t think anything was out of the ordinary other than experiencing brain fog, extreme fatigue, and hair coming out more than normal. As long as I stick to my routine, I tend to be OK.


  5. I have a doctor’s appointment on Thursday, symptoms and lab results indicate Graves Disease. Your story is really encouraging, so thank you. I am a runner, I run 4 days a week, I’m wondering if you feel like you could do the same amount of exercise post RAI as you did pre RAI? And once your RAI took place did you feel better, and hair return to normal?

    1. Hi Faith! Yes, I eventually got back to a normal energy level once my meds were dialed in. That took about 2.5 years and a change of doctors. I still sometimes have random days of brain fog and hair loss is still a Thing … but overall I’m about as close to pre-ThyCa normal as can be expected. Good luck at your appointment!

  6. Glad to hear all of the success stories, Caprice, I hope yours went well? I would love to hear about it. Great to hear that this treatment is so effective! If anyone is looking for more information on this procedure, please go to Bind-it hand soap, the only radioactive hand soap for home use!

  7. Thank you so much for sharing your experience. I just had a thyroidectomy and will be going through RAI. I needed as much information as possible.

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