How many CTs are safe per year / in a lifetime?

Hi there

I was wondering if anyone has had any problems as a result of CT scans (I appreciate it may be difficult to prove a connection between multiple scans and any subsequent issues but I thought I'd ask anyway) and how many CT scans your doctors or you believe are safe to undertake per year or per lifetime?

Thanks in advance
ADC

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My view on this is that I would rather take the risk of possibly developing another cancer 20 odd years down the line, than not having the scans and using the results to help plan and treat my current cancer.
I already have cancer, and in reality it is doubtful I'll still be alive in however many years it would take for the theoretical cancer (caused by x rays and scans) to develop and present symptoms.
But, that's just me. I'm sure there are many people who are uneasy about the amount of radiation they are exposed to. I guess it's yet another balancing act: enough scans necessary to benefit the patient in terms of treatment etc, but not too many that would then cause more harm than good in the long term.
With love and best wishes, Carolyn

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Hi Carolyn

Thanks for your response, I don't disagree, I was just wondering if there was a tipping point whereby one was in dangerous territory of developing another cancer relatively soon from the CT especially if one has had treatment and has a compromised immune system that cannot fight any new cancer cells created by the exposure to the radiation.

Best wishes
Katerina

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Hi Katerina
This might be a good question to ask at

http://cancergrace.org/

Grace is run by oncologists and a very useful site to visit. The doctors are usually very quick at responding to questions posted, and they are qualified to answer medical points raised.
Hopefully others from here will chime in soon, although I suspect this may be a question without a concrete answer. There must be guidelines somewhere listing recommended maximum exposures per year, in a lifetime etc, as you asked. Good luck, with love and best wishes, Carolyn

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In the first study of its kind, physicians at hospitals in Florida and Washington, D.C., evaluated the medical-imaging records of 1,243 randomly selected patients to calculate just how much radiation each patient had sustained in the past five years. CT scans were the biggest source of radiation.

The results of the study, presented at an annual conference of the Society for Academic Emergency Medicine: the average patient had received 45 millisieverts (mSv) of radiation. The typical chest X-ray dispatches 0.02 mSv of radiation. And 12% of patients had gotten more than twice that amount, 100 mSv or more. A CT scan packs a mega-dose of radiation, as much as 500 times that of a conventional X-ray.

What the results of the study suggest is to use the technology appropriately. It's not about its use during cancer treatment, radiation-induced cancer takes roughly 20 years to develop, it's about its use during the lifetime of a person. Long term studies of CT scans and cancer are still ongoing, but scientists are already anticipating future health implications.

Researchers found a population of 25,000 Japanese post-atomic-bomb survivors who were exposed to roughly the same amount of radiation as two CT scans. Based in part on those studies, the FDA estimates that an adult's lifetime risk of developing radiation-induced cancer from a CT scan is roughly 1 in 2,000. The question is, how many people have cancer today because of CT scans they received over the years?

CT scans came into use in the 1980s and how many adults of today were children back then? Children are more senstive to radiation because they have long life expectancies and because their cells divide more rapidly, making their DNA more vulnerable to damage.

Although newer machines can be adjusted to deliver up to 50% less radiation, a 2001 study in the American Journal of Radiation showed that radiologic technologists rarely make those adjustments.

An issue of Oncology News International quotes a Duke University study of the use of high-tech cancer imaging, with one representative finding being that the average Medicare lung cancer patient receives 11 radiographs, 6 CT scans, a PET scan, and MRI, two echocardiograms, and an ultrasound, all within two years of diagnosis. A study co-author asks are all these imaging studies essential? Are they all of value? Is the information really meaningful? What is changing as a result of all this imaging?

What is so nice about the circulating tumor cell (CTC) technique is the blood test could obiate the need for repeatedly doing CT scans and biopsies to measure disease, the extent of disease and new mutations in people undergoing cancer treatment.

Greg

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i'm sure i don't know - but lets just say that I don't plan on having any babies...

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So far for me I have had one million of them and counting and I am still blessed!
LOL,Sorry I had to find a little humor in something today.
Seriously I was told you can have them, and never show any problems from them for many years later, but it was never mentioned exactly how many.
I imagine it is like anything else, and we all are different and will react differently to the amount of them we have.
I agree not to have anymore children also like Karen.
I think I am safe since i am not only a celibate individual, but 57 years old too.
LOL..
I ma in a chipper mood today for a change.
God bless,
Sandy

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I also wondered how frequent PET/CT scans could possibly be good for cancer patients who have gone through radiation treatments and frequent chest x-rays. But unless they do go thru them, how else would they know if they are working? It's scary. If the disease doesn't get you, the treatments may!
Bonnie

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Greg,
Can you elaborate on the "Blood Test" that could remove the need for CT and Pet scans? I would like to ask my Onc about it since I am due for a visit in a week.
Thanks,
Marylou

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Marylou

It would be important to label tumor cells in the circulation and to monitor their trafficking and homing to other sites. If these cells are viable and therefore able to disseminate, I think the most robust test to this end is to document their ability to metastasize. Using Circulating Tumor Cell (CTC) technology to capture, count and characterize circulating tumor cells in a patient's blood, is a way to find out from a few cells how much a cancer has spread or not and monitor progress. CTCs are cells that have come away from a primary tumor, are circulating in the bloodstream and have the potential to seed secondary tumors in another part of the body. The number of cells discovered in the CTC technique has turned out to be a good prognosticator of how well empiric or even assay-directed treatments are working. Recently, Veridex, who markets the CellSearch blood test and Massachusetts General Hospital are involved in a collaboration to exploit the latest CTC technology. Perhaps your oncologist can contact MGH for more information about the testing.

Greg

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Over the past 18 yrs. I've had a sarcoma, then 3 NSCLC's at a roughly 6 yr. cycle. I've taken out my calculator & my best estimate is that I've had 62 CT, PET & needle biopsy's as I start my 19th year. I'll tell you this, with out them I wouldn't be here.

Andy

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Hi everyone and thank you so much for your responses, I won't respond to them all individually but will reply here to you all:

Carolyn - I will look into the other site, thanks for the tip!!

Greg - I follow your posts closely and you always have somethng new and interesting to add, not to mention important, I'm not sure if you are medically trained but you are certainly on the ball, thanks for your invaluable tips and guidance.

Peyx 33 and cuddles - thanks for the smile, I can't say I managed a laugh, not today, I'm a little flat but I'm so glad you have both retained a sense of humour and your sanity - very inspirational.

Bonnie - that is what scares me too, dad may have had many more years but for the scary side effects that treatment now has him battling, he may yet bounce back but words can't describe my fear.

Marylou thank you for asking the question I was just about to get to...

AND FINALLY Apat, you have given me some hope and faith, both of which I seem to lose at the first sign of trouble and then recover with the smallest sign of recovery, I think I need to find some strength because I know my dad and mum will need it...

Thanks again EVERYONE!

Best wishes
Katerina

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THE HEMATOLOGY ONCOLOGIST SAID 'no more radiation' SINCE THEN I HAVE HAD 6 CHEST FILMS, 5 PETS AND 4 CT.

RADIATION ONCOLOGIST SAID ONE CT EQUALS 40 CHEST FILMS.

OF COURSE, CHANGING PULMONOLOGISTS CAUSES CREATION OF MORE CHEST FILMS AND CT'S BECAUSE THEY WANT THEIR OWN TO LOOK AT. YES,I TAKE IN COPIES OF EVERYTHING BUT THEY DO NOT WANT TO KEEP IT.

I WAS PERTURBED TO DISCOVER THAT I HAVE A SURGICAL CLIP IN MY CHEST WHICH HAS LOITERED AROUND FOR 27 YEARS, BELIEVE I COULD HAVE HAD IT MENTIONED BEFORE BUT NO ONE NOTICED IT UNTIL TWO TIMES AGO. INASMUCH AS IT IS NO LONGER VISIBLE 6 MONTHS LATER, WHAT HAPPENED TO IT? NOW THIS SCARES ME ABOUT RADIOLOGISTS. NOW I THINK RADIOLOGISTS SHOULD REVIEW AND DISCUSS THEIR FINDINGS BEFORE COMPARING THEM TO OTHERS BECAUSE THEY THEN APPEAR TO ZERO IN ON THE LATEST EVEN EXCEPT FOR SURGICAL CLIP GUY. YIKES

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Thanks Desertdweller, I agree, but I suppose there's no money in ordering and reviewing the same set of films....

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Doctors want their own machine to take images and do not want to use old images from foreign machines because of their calibration. Seems there is no absolute common calibration technique that they trust, even if the data was taken by machines of the same brand. So they all repeat CTs, PET scans, and X-rays. Waste of health-care money, our health and time. There needs to be a Government-mandated common calibration technique with electronic transfer of data between Labs and Docs. Until the medical community comes into the 21st century, it's going to cost millions in wasted health care funds.

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I AGREE......THE GOVT CAN CALIBRATE HOW TO BAKE CHOC CHIP, P'BUTTER AN SUGAR COOKIES. THEIR INSTRUCTIONS FOR THESE COOKIES ARE 16 PAGES LONG.

A SIMPLE, SQUARE COVER FOR A TANK CUSHION TAKES 72 PAGES...........WE HAD TO FOLLOW IT IN OUR BUSINESS SO I SAW IT FOR MYSELF.

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