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CT scans and risk of cancer

I recently had a DaT scan to check whether I have Parkinson's. The scan involves an injection with radioactive material that is then seen by using a CT-like method, only with higher radiation levels.

Don't get me wrong - I did my research into this scan before having it and everywhere I looked its said that it's safe. I was very reluctant to have it. Absolutely reluctant but like an idiot, I went and had it anyway.

I then saw a random clip on You Tube about the Fukushima nuclear plant disaster and its effects. The woman presenting, a doctor, started by saying that even the smallest XRay affects the DNA, causing cancer. CTs are even worse and PET scans even worse than that.

With that in mind I went back to my medical file and listed the occasions when I had Xrays and CT scans in the past 10 years.

In total I had 12 Xrays, 7 CT scans, a HIDA scan (with radioactive injection) and a DaT scan (with radioactive injection.

The radiation impact is cummulative - i.e. each time you have another, it adds up to the ones already had. It is sometimes referenced to the number of background radiation we receive through just living on this planet. To give an example, an X-ray of teeth equals about 1 day's worth of natural radiation, whereas a heart CT equals 3 years of natural radiation and a PET scan 8 years of natural radiation.

If I use these equivalent values cummulative for all the xrays and CTs I've had so far, I've been exposed to 27 years of background radiation in addition to the 10 years natural radiation that I've been living in. Add to that the risk is higher in women and even higher in immunosuppressed people, I'm now really freaking out!

Looking back to the list of scans, I could have avoided the vast majority of them. I could have said 'NO' to them, including the last one which I think was the worst.

In an effort to protect myself from the lupus impact, I ended up giving myself a very high risk of cancer.

How stupid is THAT?

I can't believe how many of these I've had - has anyone else had so many?

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About a million x-rays, 3 cat scans and 6 MRI's.

Have not mutated yet.

I actually thought that apart from lymphomas - etc, cancer wise, lupus people actually have an advantage over other people because of our over reactive immunity ?


My last MRI of the brain showed its about the size of a walnut. It was taken due to left sided knumbness & loss of some co - ordination. They say its due to Lupus (?) - 'question mark in notes' & age.

No strokes, no white matter damage, healthy vessels, not even a mico stroke. Just a case of mysterious shrinking brain.

Drs and a neuropsychologist have told me there's no way of predicting what may happen in the future and to try and think happy thoughts.

Needless to say I've been doing a lot of reading about cerebral lupus and have come to the conclusion that there has not been enough research on it for anybody to know anything concrete about what is going on inside our skulls.

(Apart from the most obvious facts like vasculitis/stroke etc.) The rest is just theory.

Reading you're post I would say your brain is considerably large.

How are you faring now with you're symptoms !

Sounds like you're still convinced its parkinsons ?


I don't know what to think, to be honest. I'm waiting to see what the neuro says on 15 Dec. But I'm angry with these doctors who are so laid back about the dangers of those highly radioactive tests. The MRIs are using magnetic fields, not radiation, so those don't worry me so much.

As lupus sufferers we are actually at a slightly increased risk of cancers because the immune system is so focused on fighting its own, it misses the abnormal cells that then accumulate and become cancers. And when you then add immunosuppressants, then the immune system's efficiency reduces even further, leaving us exposed to cancers.

I've never heard of shrinking brain - how do you feel about it?


To be more precise its mild frontal and temporal lobe atrophy. Mild enlargement of ventricles.

I'm a bit of a glass half empty person and fear its the start of a degenerative decline, perhaps even some nasty mental illness coming my way. But the proffessionals are trying to reassure me it may have been due to past flare/s some time ago, the effects of which takes time to present physically. They are trying to convince me that there's just as much chance of it staying the same as declining further. Since a last blast of immuno- suppression I've actually been feeling a lot of cognitive improvements.

I was genuinely dissconcerted when i saw the images. The atrophy was obvious. I thought that can't be the real me ! Its a wierd thing for your own still thinking brain (ie. me) to be looking at its slightly deflated self.

Im not horribly traumatized by it. Its just the uncertainty about the future that is a bit disconcerting.

How are you feeling about you're situation?


At the moment I can't think of anything else but the cancer risk from radiation. That's how I usually deal with stuff, focus on one thing at a time and deal with that, then absorb and move on. Parkinson's is a distant thing at the moment.

I'm a glass half empty too but only because the more I read about medicine, health (or lack of it), the ineptitude in dealing with patients, the general lack of knowledge, etc, etc, the more I wonder how on earth humankind managed to make it so far!

I agree with you that the doctors don't know much. And I agree that no one really knows how things will progress, if at all. The overwhelming anxiety that we need to deal with on a daily basis is staggering. How can we not be anxious when we're bombarded by all these bad messages, we're programmed to fight for survival and anxiety is the means by which our body tells us that we should pay attention.

Having said that - too much anxiety isn't good either. The cells are put in continuous state of alertness and they can't do their normal job of recovering, mending, killing cancer, etc.

Argh, we can't win.


I totally agree.

Just her theory -but my neuropsychologist even suggested that what has happened to my brain could even be the direct result of about 12 years of constant SLE hypervigelence and becoming deranged over the morality of Drs. As you say, the survival instinct on total over drive, all the time - with no easy way for the mind to feel things are ever safe.

The irony being the additional buden of knowing you have to reduce you're anxiety to stay healthy. An anxiety in of itself.

I was in a life threatening car accident once and I can tell you that was so much easier. Everything was black and white and the Drs did what they where meant to without me having to beg or do their job for them.

(Sorry, got to go to bed - from Australia) I'll check this post tomorrow - if you want to keep talking.

ps. I actually think the linking of anxiety and disease (especially with SLE is a bit over the top). I dont doubt there is a link, but I dont believe its as profound as we've been led to believe.

Anywhere where there is a mystery zone in medicine - the medical establishment likes to blame the victim. A bit of finger pointing at the hysterical neurotic. Rheumatologists have observed over the years that their lupus patients are anxious - and I'm willing to bet that connecting lupus flates with anxiety has not been proven via propper research.


I like that you haven't used the word "hypochondriac" because that's what doctors think of us. But hypochondria is now called "health anxiety" and it is well recognised by those who treat anxiety generally.

Am I anxious about my health? Hell yeah! Is that good for me - of course not. But as a doctor, don't sit there with a patronising smile on your face judging me, nor hand over some overpriced zombie-making pills. Teach me how to deal with it, get off your high horse and learn about nutrition, meditation, exercise, social support, whatever you can that helps. That's their role, a holistic role. Not just telling me what's wrong but how to deal with it.

Anyway, don't get me started on that! Check your messages, I'll continue ranting over there so that I don't clog the site here.

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Hi Purpletop

Good luck for your results on 15 th Dec. Let us know how you get on. Your worries about radiation exposure mean that we should only have these scans if absolutely necessary!. It's a frightening thought!. X


I have shrinking lungs from lupus....that much I know for sure. so now I feel better. I don't have shrinking brain. lol well...last I checked anyway. hmmmmmm, maybe my brain is shrinking too. I am running out of paper listing down all the symptoms and side effects lupus delivers. Im just amazed im still alive. actually really amazed. the body is a weird thing. I have this theory that lupus/autoimmine etc, is some type of human morphing thing. lets hope its evolutionary. some sort of change for the better. we are the warriors.



I read somewhere that an MRI actually causes the atoms to seperate and spin?

A bit like being beamed up in a star trek episode.

Philosophically speaking you may be a new person after getting out of those machines.

So many new scans and medicines without anybody knowing the long term effects.


Better start eating garlic and apples every day and walking in fresh air minimum one mile or the exit will be sad. Stay away from butchers with MD's unless you need necessary surgery. And don't forget to pray like hell.


Garlic is contraindicated for lupus patients.


The x-ray thing is scary, I've had about 10 chest x-rays alone in the last 7 years and working in dental and doing the x-rays didn't help much either, Then to add up the MRI and CT scans, I don't think I want to know how much is in me. But then you could start worrying about the amount of surgeries one has had and how many times you have gone under, I think I've been under at least 18 times since my 20's. Yah, sure just give me another pill and ok, lets up that one while where at it. I think we do pretty good counteracting all this stuff with the healthier lifestyles we have due to our illness!!


Good point, PT! Too true! Great discussion! Yes, I've been regularly having X-rays etc of bits all over my bod for decades...often several of each every year. And I can totally understand & share this anxiety & the extent that I won't torture myself by trying to count these exposures to radioactivity etc...they're bound to be in high double figures

But, the only full on cancer I've been treated for over the decades was spotted 17 years ago thanks to X-ray: it's a rare chondrosarcoma (malignant tumour of the cartilage (a connective tissue)) in my hand which went misdiagnosed as arthritis for 14 years while it grew & grew to the point of actually breaking up & dispersing its malignancy into my blood stream. Plus, I'm a DES daughter, which means I'm highly prone to both rare vaginal/cervix & breast cance.....and, what's more, I have considerable close family history of GI cancers & skin cancers. So, I need X-rays, scans etc at reasonable intervals to catch these early. This is a Catch 22 thing, no?

Then there is the fact I've had infant onset lupus go without daily systemic treatment until 5 years ago when I was in my late 50s. So, I'm being actively monitored for cancers by a bunch of multisystem NHS clinics: my GP and my consultants have all confirmed these cancer checks/scans etc are totally necessary in my case because those decades of uncontrolled lupus inflammation all over my bod means I'm highly at risk.

Meanwhile immunology has discovered I have also got early onset immunodeficiencies (started decades before daily treatment with immunosuppression) which make bone & lymph cancer good possibilities. So fatal infection is as likely as cancer to do me in - as much as anything due to frequent antibiotic-taking predisposing me to resistance

Yet, thanks partly to all my treatment plans & monitoring/X-rays + scans etc + lifestyle management, I'm bewildered to be feeling better physically, emotionally & spiritually than I have since my 20s...although I'm also a depressive, who has spent years being a glass empty I'm more of a glass full person...this shift is largely thanks to the solidarity & info sharing here on our wonderful forum....yes I do still have flaring anxiety, but I tend to be able to cope...I know this is down to everyone here: the knowledge sharing, the friendship &, yes, the joking too

Am v much feeling for you never fail to inspire, inform and interest so glad you posted about this: it's often the elephant in the room...this discussion has helped me a lot...I hope it's helped sure you can tell from the length of my reply that this risk/benefit problem is close to my feeling is: it's better to face all this together, to openly share + understand the threat & our anxiety...and learn to keep calm & carry on with due vigilance and joy, making the very most of the life we do have right now

XO🍀🌻 coco


Hi, the scans you had would only been done if they were required. The results are very important to your health now. If you don't sort your health out now what future do you have? The risk is low, but of course not to be ignored. Most things we do carry risk. We weigh up the pros and cons . Don't spend time worrying about what has passed, be informed for the future.

Good luck.


Thank you, everyone, for your kind words.

I agree that at the time of having the scans, I thought they were necessary. But I didn't know any better. My mistake was to rely on the doctor. But had the doctor considered whether a less risky scan would have done the job? An ultrasound or an MRI for example? Had the doctor warned me about the risk of cancer against the risk of not having the scan? It may be that, indeed, I would have chosen to go ahead with most of these, but I would have liked to have had the choice.

No one had asked how many CT scans I've had so far - no one. Why not? These things accumulate in the body, for goodness sake, they don't go away.

My point in all this is to raise awareness - if I wasn't sufficiently aware of the risk to ask the questions, maybe you will be.

Ask what will happen if the test isn't done. Ask if a less risky scan could show the same. Ask whether a lower intensity could be used, for example when the quality of images is not critical. Tell them of how many CTs you've had already and ask whether THEY are comfortable to take the risk of causing YOU cancer.

Because I can assure you - once a doctor has the onus of risk put on him/her, he/she won't be so laid back about it.

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GRRRREAT points, well made, PT❗️👏👏👏👏

Thanks again for this discussion: will be following it as more replies come in


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anyone out there ever met a rheumatologist with an autoimmune disease??? I haven't...

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Like Barnclown says great discussion!! I have had umpteen X Ray's and a good few Ct's.

I am afraid I have just become a bit fatalistic in my older age now, 62.

My systemic Sjogrens has been following me like a hungry wolf for most of my life and has become pretty bad in the last fifteen, mostly with pancreatic and biliary symptoms as the worst.

But now every thing is jumping in and it is affecting almost all my body systems.

I Also now have had multiple new Neuro symptoms and they are now thinking MS again and suggesting more investigation before they will begin me on Myco as planned for this week.

I am really interested in your investigation for Parkinson's, thing is , if those scans will hopefully alert them , you can then go on more appropriate drugs which will hold back the disease.

I suppose as others have said it is all a weighing up business. I just think now that years ago I would probably be dead now, in fact about ten years ago, with no drugs to hold back the pancreatic inflammation and the various surgeries to widen pancreatic and bile duct.

But yes I do agree we should be told the risks, it is our body and our decision . They are too clever at playing God sometimes.

At last it is done and dusted now, and you will know in the future. I would try not to worry and just hope they get to the right answer for you soon.

This no mans land is a bleak place for us all.

All the best, C xx


The thing with Parkinson's is that there is no drug that stops it. It isn't like lupus that if you control the inflammation, then you slow down the damage and the progression rate. Oh no. With PD you only get drugs to make you able to move and live some life, go to the loo, swallow, even smile - people seem to think that PD is all about tremors but it is much more than that. Imagine your face being too rigid to smile or show emotion. Dreadful.

In my case I have some weird neuro symptoms since last year when I changed from myco to ciclosporin. The latter being the drug that absolutely fried my brain in this way, I.e. Giving me all these neuro symptoms. The symptoms are not bang on PD and the neuro specialist believes that it is early PD, I.e. Not yet fully developed.

If the scan shows PD or other related diseases (the scan only shows levels of dopamine and doesn't differentiate between PD or Lewes BOdies Dementia or MuLti System Atrophy, all sharing a low level of dopamine) - but if does show it, I doubt I'd be taking the drugs just yet, as the symptoms are not yet sufficiently debilitating.

Bottom line for me is - if the scan doesn't help the illness, why the hell is it given??

Anyway, I'm going around in circles, so I'll stop.

Thank you for your input and I so hope that you get to the bottom of your neuro symptoms.

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Sorry , did not realise there was no drug for Parkinson's. As you say what was the point of the scan if they can do nothing.

An awful situation too for you with the second drug they tried affecting your brain like that. I have had MS like symptoms for over ten years and four brain scans. Nothing has came up ,so they keep saying it is Sjogrens related.

I have had recent new bouts of optic neuritis, and numb foot so they are testing again.

Like you I am seronegative so diagnosis has taken decades, but even when you get there there seem to be no easy answers. I can take the steroid injections but oral steroids upset me due to the liver problem and I am so hoping I will tolerate the Myco when I eventually get to try it!

Understand your alarm and frustration, hope they can rule out the Parkinsons at least. X


There are drugs for Parkinson's but their side effects are sadly notorious.


I totally understand the aaaarrgghhh rock or hard place issues with the necessary test v more radiation. I do think medical folk should give us the information first but I suppose they don't want to scare us away from possibly life saving tests and results. I personally have had so many xrays ct scans etc plus massive dose of internal radiation to kill off cancerous cells which had escaped from my cancerous thyroid and gone holidaying elsewhere around my system ( darn sneaky cells) .Then thinking I could outdo the readybrek advert they send me for further and ongoing scans. Damned or lucky if I do and damned or lucky if I don't? Hmm not sure and then they add the carcenogenic immune suppressants to stop the lupus and RA doing there thing. Ha have to laugh or give up and to be honest we all want to look after ourselves and get second opinions of the imortant stuff when given by err the more questionable of professionals but without the medical professional and there weird and sometimes wonderful science and tests etc some of us like me would not still be here.

Wishing you all the best results with the least effects.

Happy hugs to all x


This is interesting - the DaT scan uses a radioactive iodine injection to go to the brain and make it visible on the PET scan. To protect the thyroid against that, I've been given the stable form of potassium iodide first - the idea being that the thyroid absorbs the stable form, then it can't absorb the radioactive substance.

If there is too much radiation as a result of this scan (whether it hasn't been eliminated by the kidneys, etc) then the thyroid becomes cancerous.

In my case - I took the protective pills as instructed, then had the scan, two days after that, my thyroid swelled. I spoke to the nuclear medicine people about it and they put it down to the thyroid being irritated because of the stable form. GP saw it and said to come back if not gone away in 2-3 weeks. It hadn't.

So then I start reading about swollen thyroid - apparently the best way to control a swollen thyroid is to apply radioactive iodine. What? So you give me pills to protect against the radioactive substance, pills that make the thyroid swell, and then you radiate the thyroid directly to make it go down? Bonkers or what?

Have you managed to control your thyroid cancer in the end? How long did it take?


Hi again

They do seemed to have done a confusing way about with you. I had to ,four years ago have total thyroidectomy as well as ablation and radiation again now on levothyroxine for life

Just been sent new scan from oncology to have Dec 16 th to see why slight swelling in neck has appeared.

I do hope they sort you out as throid disfunction/ irritation will really mess with your health and mood.

All the best x

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I agree about radiation risks. Hate to tell you but these Drs will probably tell their family members about the risks whilst offering dirt cheap X-rays to their patients as if "no risks". You need to educate yourself to protect harms coming in your way. If you passively accept these things from Drs, you will die quicker. Be a discerning patient, who can see through what drs are thinking, but not telling you! Sorry for being so blunt.


I think if I had Parkinson's looming I would want to know - even if it is not a disease that can be modified because it's not an autoimmune disease.

And if it turns out to be a cerebral aspect of your seronegative Lupus then presumably there may be drugs that might slow it down? So worth knowing even if the risks were too high perhaps? It's too late to go there now and cancer is only one of many diseases to fear. So please try not to focus only on the negative aspects of having had this CT done as good may yet come of it. I'm a great believer in not crying over spilt milk -after a few days of frothing my essential optimism usually prevails. None of us are immortal.

Personally I fear other diseases more because there is far less protocol for treating them and far less support. I fear diseases which would slowly but surely ruin my quality of life by causing much pain or neurological damage.

While it's great that you've reminded us all to be vigililent and check with doctors what the risks of X-Ray's and CTs are - (I've had two chest x-Ray's and plus both hands and feet and breasts and teeth this year and no one has asked about my radiation quota) for most of us here life is chocked full of medical risks.

For me personally uncertainty and the resulting anxiety it creates are higher risks than cancer because my parents and grandparents all had cardiovascular disease and died prematurely. So persuading doctors to treat my borderline hypertension has been very important - but I'm definitely down as a patient with "health related anxiety" now because one new GP showed me this on my notes! Why on earth did he want me to see this?? I am starting to dislike the medical profession rather a lot just now I admit. Spilt milk is one thing but being a patronising jerk to a patient is another.

And as you've said - what is not to be anxious about? But anxiety in itself can kill or lead to strokes - so why don't they take the trouble to reassure us properly and explain the risks of all treatments before signing us up. How do we place our trust in these all too human people and why should we? Increasingly I don't. So I'm very glad you've posted this thanks PT - and will defintely not allow my new rheumy or others to X-Ray or CT scan me without doing a risk assessment in future.

Thanks and best of luck for the 15th. Tx


My point here is precisely that we have enough to worry about and enough lack of support, understanding of the disease etc from the medical profession - the least they can do is try and prevent those things that can be prevented.

I know what you mean about not trusting doctors anymore. It's so upsetting not to, though. Because if we don't trust them, then who do we have to trust when it comes to our health? We are left on our own, to scour the Internet for answers, to constantly asses the viability of what we read, to panic unnecessarily, and to contemplate an uncertain future because the people who have spent years learning about medicine actually realise they cannot help because they don't know enough.

Anyway - enough time on the soap box for me. I love your analogy to the few days of frothing, certainly applies to me too:)

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Sitting waiting for my double appt with new GP right now. She's as cold as ice but did request that I come back with a list of pain drugs I've tried to date so she can put me down for pain meds that are okay with my BP med. Also the pee sample she requested I bring to nurse. I made it double because I was expecting to have my rheumy letter to speak with her about and want my CRP checking before next rheumy appt on 7th January. Why I'm bothering, since no letter, I don't know but thanks to you I'm frothy enough and busy enough to hold my own this time - I hope!! Xx


So, how did it go in the end? Has she thawed a little?


Yes she's totally thawed and was actually kind and attentive for once! I credit you for waking me up a bit.

I phoned the practice secretary this time last week to chase the letter. She was shocked at the wait I've had. Then I asked for an appt with GP and she said none was it urgent? I said about blood in pee and how I'm worried because it's microscopic, no UTI but I'm in pain around my kidneys and bladder and peeing like a tap on full! She said "oh I have RA and microscopic haematuria - and I'm not worried and nor should you be!" Turns out her RA disappeared five years ago after trying every DMARD and then an anti tnf. I asked about all this on the RA HU and not common at all as she seemed to assume.

So I think she told my GP about all this because GP said she's been chasing letter. She said "you poor thing that's horrible" when I described pain at night, mouth problems and now this bladder stuff too. But I said I'm fine really - so busy I haven't time to think about my health much so just being business like about it with Xmas coming, change of address etc.

She prescribed more Tramadol and said blood in my pee still so referring me to urology now. Says she thinks rheumy's longstanding rumination about me are probably a good thing if infuriating. Hoped I have a very good Xmas and don't register with new GP until I've moved in end of January. Xxxx


Ive been dealing with about a year of trying to keep my kidneys in tact. The damage done to them was entirely preventable and was not due ignorance or lack of effort on my part to get help. I've since gutted my medical records and found out I was 'just anxious' propper term: diagnostic overshadowing. (I really really hate the word hypercondriac too) I've heard it for 33 years.

I don't know how to assimilate what has happened to me as this is a repeated experience.

Logically I know most of this was down to an overly respected, fibromyalgia fixated Rheumatologist and every second GP was actually trained by him, so his word was worshiped like that of an uber prat dieaty.

Emotionally it makes no sense whatsoever.

Lupus is kind of like PTSD, without the luxury of it ever being in the past.

I don't know how we can keep constantly absorbing and re absorbing these kinds of large and small injustices while simultaneously dealing with contant grinding uncertainty.

Almost impossible to try and connect the thinking part of our minds to the rampaging, primitive emotional - survival instinct bits of our brains.

No person in their right minds could control this kind brain spazm when we face what we have to face.

I think the survival instinct is the strongest force of the human mind.

I met mine directly - face to face in the nasty car accident I was in - and although it was 13 years ago now - I have not forgotten its really ugly overwealming power.

I wish I could squash mine down to the primative bug it is - and spend more time living in the ' it will be all right' brain space that other people (even other sick people) seem to just naturally posess.


yup... and the dentist is the cherry on top. all those years your thyroid was supposed to be covered up but wasn't. now I sit in the dental chair holding that apron up around my ears during xrays! but anyway, I love your math! I love the research you did on all that radiation. thanks for that. don't be too too hard on yourself. we all live in a world now that (and especially to sensitive autoimmunes like us) is not too healthy. no one is guaranteed to live forever anyway, even if we lived in the garden of eden all our lives! we could walk out and get hit by a bus and die tomorrow, not even of radiation or lupus for that matter lol. which win a point. just kidding. I still only wanted to say, I love your math. Im a math geek. a lupus math geek. how geeky is that? Oh, and I want to add, that I have a great GP and love her, but I see her limits totally. I also have a great rheumatologist and thank god for her, but my favorite doctors are my nephrologist team and lab. those guys are so geeky, but a good geeky. they are so focused on my tests and results its amazing to watch them in action. and my lung specialist is really really cool. he is more than a doctor. he has some kind of insight that was god gifted to him. most doctors are limited. GPs especially. im suggesting that we keep looking for new 'specialists'. I feel like ive got a huge team of doctors. different specialists. that alone relaxes me and makes me feel content. if I only had one doctor, that would irritate me. cause a flare up lol!


A good doctor is gold! I have a good rheumatologist but the others are just ok. The rheumatologist looks at me as a whole and is also a stickler for their first rule "do no damage". He's cautious with dosage, meds, scans, everything. He is my age and treats me as a colleague. He takes each of my questions seriously, although I can tell you, I've asked some stupid ones since I've started with him.

It's interesting that there is a hierarchy of specialisation - the ophthalmologists consider rheumatology as being superior and everyone else thinks neurology is top. But I haven't been impressed by neurologists at all - and I've seen 6 in the past 2 years. The greatest gap in knowledge seems to be in neurology, there is so much still unknown about our brain.

Actually, since struggling with lupus I came to the conclusion that there is very little known about the body. I long for the days when I was going to the GP for something as simple as a smear test.

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