Had chemo and radiation therapy April-May for CA, lung
Chem doctor scheduled a CAT Scan for 9/5, Rad doctor scheduled a PET SCan for 9/9.
Do you think I need both?
I know you’re not my doctor, so I’m just asking.
I really don’t have the answer to your question, but my thought would be to call the Chem doctor and ask them if a PET scan would work, and/or call the rad doctor and ask them if a CAT scan would work. Which ever one says it would work, I would make sure they make any adjustments to the order so they can see what they need to see.
They are different types of scans and image different things. There is no reason to think one is superfluous.
Actually, superfluous scans can potentially be a problem. Since both CAT and PET have a radiological aspect, and this person has already had radiation therapy this year, both doctors should be informed of both scheduled scans. There is probably not a problem, but there have been a few cases where people got more radiation than they should have. Can’t hurt to tell the docs, and it might be a good thing you did.
The health risk of PET and CT radiation doses is miniscule in comparison to radiation therapy, and is far outweighed by the benefit the scans provide. There is really no rational reason for concern.
In any event, I’ll call my chemo doctor on Monday.
Thanks for your inputs.
It’s not so much the individual tests but the cumulative doses. Enough scans in a short enough period of time can be of concern, which is precisely why all doctors should be made aware of all exposure to radiation (be it x-ray or other).
CAT scans expose people to less radiation than radiotherapy, but the dose with a CAT scan is still considerable in comparison to, say, normal background radiation or a single chest x-ray. Better safe than sorry.
The CAT scan, like an X-ray in three dimensions, will show volume and position of the structures (e.g. a tumor). The PET is measuring cellular activity, by intake and use of radiolabeled glucose molecules. They’re not the same, but comparing the two would give the added benefit of distinguishing active tissue from “dead” tissue.
Meanwhile, the MRI scan measures tissue density and might be used to demonstrate what type is being imaged. If they need that information, they would order MRI also.
(Take-home message from a continuing education course “Imaging for Psychiatrists” that I took last year. I’ll take the updated course in November. It’s always interesting.)
All of you were kind enough to advise me, so I’l let you know what happens when I call my doctors tomorrow.
Indeed.
I’ve inserted a table that gives typical expsoures for common imaging procedures. Note that a CT of the chest gives the equivalent exposure as about 400 chest x-rays or almost four years of natural background radiation - impressive figures, but still considered safe.
Diagnostic Typical effective Equiv. no. of Approx. equiv. period
procedure dose (mSv) chest x-rays of natural background
radiation
single arm, leg, hand, or foot
less than 0.01 less than 0.5 less than 1.5 days
Chest
(single PA film)
0.02 1 3 days
Skull
0.06 3 9 days
Thoracic spine
0.07 35 4 months
Lumbar spine
1.0 50 5 months
Hip
0.4 20 2 months
Pelvis
0.7 35 4 months
Abdomen
0.7 35 4 months
IVU/IVP
2.4 120 14 months
Barium swallow
1.5 75 8 months
Barium meal
2.6 130 15 months
Bariumfollow-through
3 150 16 months
Barium enema
7.2 360 3.2 years
CT head
2.0 100 10 months
CT chest
8 400 3.6 years
CT abdomen or pelvis
10 500 4.5 years
How many superfluous CTs of cancer patients do you suppose are ordered?
KG can probably provide actual data on the topic, but as a doctor who has many patients getting treated for cancer, I can say that it does happen.
Usually when multiple doctors are involved, and they’re not always fully aware of what the other doc has ordered, frankly.
I’ve seen CT scans ordered and performed on more than one occasion because the ordering MD didn’t have the access to or knowledge of a scan done just days ago.
Coordination of care can be a challenge, especially in the setting I practice in.
Prior to my lumpectomy, my chemo doctor ordered a whole slew of scans…a PET scan, a CAT scan, a bone scan, and a Muga scan. He wanted to make sure the rest of my body was healthy before he started chemo.
How have you fared - from the radiation and the surgery? Well, I hope!