Cumulative radiation from Mammograms, PET, CT scans, etc.

Holga · February 2016

I've been trying to research the various levels of "effective" radiation from Mammograms, PET, CT and Bone scans and External Beam radiation (including palliative), Xrays (including dental) and am having trouble getting some answers, most especially about External Beam Radiation (measured in Gray units) and how that Gray units convert to mSVs (mili Sieverts).

I want to reduce my overall exposure to radiation while not under-monitoring my cancer. In other words, I want to choose carefully and thoughtfully which scans I should have and how often and which I can probably safely skip.

My breast surgeons sends me to yearly mammograms. I think that's kind of silly since my cancer is already metastatic so what real difference in treatment would I have if I have another primary breast cancer? Or, if I have PET scans now and then, why bother with a mammogram?

I asked these questions and was told mammograms can detect microcalcifications, early signs of cancer. But again, so what? Why difference would it make to my survival / prognosis, if a new primary cancer was found in my breast in a PET scan and not in a mammogram? Surgery would be the likely treatment in both cases and would yield the same result, I would think.

Maybe it's best to give up the mammogram and "spend" those mSVs in a PET scan, which reads the entire body.

I think it's ridiculous that none of my doctors ever talk about this.

My surgeon sends me to mammograms because my prognosis is good enough for a second primary cancer to be a concern. At least, that's how I interpreted it.Which means that my prognosis is good enough to get a secondary cancer as a result from too much radiation from scans and treatment.

Which is why I should be tracking my exposure and reducing my exposure without compromising too much the monitoring of the cancer.

Anyone else concerned about this or have this discussion with one's oncologist?

This is what I mean by "effective" mSVs:

https://en.wikipedia.org/wiki/Effective_dose_%28ra...

Here is what I have found so far about "effective" mSVs but would like to have confirmed by other sources / professionals (like my oncologist, for one):

Here is a link to a chart:

Also, this:

http://www.informationisbeautiful.net/visualizatio...

If I understand correctly:

1 Gy (Gray) = 1Sv (or 1,000 mSvs)

1 Micro- (µ) = 0.001 mSvs (milli Sievert) or 1mSv = 1,000 µSv

So, if a single dose of 8 gray of external beam radiation = 8,000 mSvs or 8,000,000 (8 million µSvs) would make it just under fatal according to the second chart (link above in purple).

Does this make sense?

This is an ENORMOUS DOSE, if my calculations are correct.

Holga · February 2016

and this:

http://www.radiologyinfo.org/en/info.cfm?pg=safety-xray

KBeee · February 2016

I am not sure anyone knows exactly when the risk benefit swings in your direction. I do think mammograms have less radiation than pet scans, and show things quite a bit sooner. I read a study recently that women who are stage 4 who have surgery to remove their breast tumor live longer. I cannot remember the name of the study. That could be why they want to try to catch it early. Ultimately, it is your decision though... But it is hard to wade through all of the recommendation

marijen · February 2016

Trying to figure that out would make me nuts

lintrollerderby · February 2016

I get it. There's a bit of research that those of us with BRCA mutations are more sensitive to the negative effects of radiation. Being a BRCA1 mutation carrier, I feel that I now have to be selective in my exposure and choose the screening that will give me the most bang for my buck. Prior to both my breast cancer diagnosis or of learning of my BRCA status, I had 8 years of kidney issues that included uric acid kidney stones. That type of stone is radio-translucent and does not show up on x-rays and therefore, requires a CT scan. Due to this, I had 25 CT scans in the 8 years leading up to diagnosis. I now wonder if the cumulative effect of those CT scans spurred the loss of my only functioning BRCA1 copy and allowed the breast tumor to develop.

I understand your hesitation on the screening mammogram issue with regards to having a Stage IV diagnosis. I think if I were in your shoes, I'd question their necessity and utility as well.

I just wanted to post my support. All the best to you.

Holga · February 2016

Thank you all for your responses. It IS driving me crazy seeking these answers!!

Anonymous · February 2016

I came across your post and I wanted to tell you about my mostly bad experiences with mammograms. About 5 years ago I went in for a routine mammo at a facility I hadn't been to before. At the time I had a cluster of cysts and very dense breasts so I would usually follow with an ultrasound. That day the technician couldn't get a good picture of that area of the breast so she took 8 (!) pictures of one breast. I was stupid enough to let her but when I got home I was furious and called corporate. They apologized and called me back personally to tell me they would be having a talk with that technician. Anyway, 5 years later, here I am. I'll never know if that caused damage to my breast tissue which turned into a tumor. A genetic test I did after my diagnosis showed I have a variance in the BARD1 gene and that couldn't help either. And the most recent mammograms I had didn't even show a tumor. So I don't like mammograms at all and I wish my oncologist would agree with me and let me skip them since I'm getting an MRI and US every year anyway.

Wishing you the best.

Cumulative radiation from Mammograms, PET, CT scans, etc.

Comments

Categories