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CAT or PET?

Skagway Jack's picture
Skagway Jack
Posts: 205
Joined: Oct 2013

During the Super Bowl I was visiting with a friend who was formerly a Xray Technician.  He had not heard about my RCC, so as I was filling him in on the details I mentioned that I have my first scan since my surgery coming up.  He asked if it was a PET scan, and I replied that as far as I was aware it was just a CAT scan.  He recommended strongly that I advocate for a PET scan, but suggested against the facility i was planning to use.  Being familiar with their specific equipment he advised other facilities instead.

In anycase he stated that the PET scan required a glucose free diet for a period of time prior to the procedure, then the radio tagged glucose was given which goes then to the cancerous sites....since we know that cancer loves sugar.  Seems logical to me that a PET Scan would be the way to go and would be a "standard of care".  I am still new to this game, however and could be missing something.  Any comments from the good folks on the forum would be welcome.  Thanks

Darron's picture
Darron
Posts: 291
Joined: Jun 2013

My Dr has indicated to me that the glucose take rate in my type of RCC wouldn't show well in a PET scan. I have never had one. 

I did have a full body bone sca, a brain MRI, chest, and abdominal CT with and without contrast.

thaxter's picture
thaxter
Posts: 124
Joined: Jan 2014

I had my first post-op scan on 1/6.  It was billed as a PET scan and some folks on this board or at Smart Patients were wondering why it wasn't a CT scan.  Actually it turned out to be both it was a PET/CT scan without contrast--quoting from the report, "The CT and PET images were fused and evaluated concurrently"

NanoSecond's picture
NanoSecond
Posts: 653
Joined: Oct 2012

No, your former Xray Technician is mistaken.  A PET scan is not "the standard of care" for most forms of RCC.  That is because most RCC is not very aggressive and therefore the tumors do not "drink" up a lot of glucose.  In addition, many of them "run" on other nutrients such as the amino acid Glutamine.

PET scans are based on the Nobel prize winning research of Dr. Otto Warburg who demonstrated starting in the 1920's that all tumors have disfunctional metabolism.  They cannot derive sufficient energy by the normal oxidation of nutrients (oxidative phosphorylation) but instead revert to a primative form of metabolism that does not require any molecular oxygen to work called glycolysis (fermentation of glucose).  Glycolysis is highly inefficient so tumors end up consumming high levels of glucose just to be able to derive the same amount of energy as normal cells running on oxidation.

To rely solely on a PET scan to reveal the presence of RCC is a bit foolhardy.

a_oaklee
Posts: 293
Joined: Nov 2013

My husband had a CT/PET scan done as a diagnostic tool after the 5 cm renal tumor was found via CT scan.  We were encouraged to have the PET/CT in order to find out if anything else showed up by way of metastatic sites.  The surgeon, oncologist, and primary care doctor all wanted that test.  It turned out that there were multiple metastatic sites to bone.  Then MRI's were done to those areas.  Surgery to remove the primary tumor happened.  Since then PET/CTs are done every 3 months.  The PET portion helps show functional data of tumor sites.  The CT portion helps show the anatomical portion.  It monitors the effectiveness of the targeted therapy by being able to measure the size of a tumor and also the metabolic activity of the tumor. 

I agree with Nano that it is not the "standard of care".  I think of it as another diagnostic test that hopefully helps tell the whole picture of what is going on.  If I had cancer (like my husband), I would want to know whether it had metastasized anywhere else.  I think I would want it done once.  If it was negative, I wouldn't want it again unless I had symptoms that warranted it.  That's just my lay person opinion of what my personal desire would be.  I also believe that insurance companies have alot to do with whether or not certain optional tests get performed.  I have often wondered how a person can be told "we got it all", when the patient hasn't had an exam/test to look for cancer anywhere else.  I just don't get it, and please forgive me for making that comment.  I've always been the kind of person that I want to know everything...the good and the bad. 

Regarding preparation for the PET...they tell my husband to not eat anything after midnight.  They check his fasting glucose level prior to the test, and also renal function.

Skagway Jack's picture
Skagway Jack
Posts: 205
Joined: Oct 2013

I appreciate the answers.  I will bring it up with the doctor, but perhaps the thing that has me bothered is mostly "mental" where any other aches and pains are viewed now within the context of my RCC experience.  For example I started back to running and my hip joints are killing me. Granted I hadnt run consistently in about 2 years, but I never had issues with my hips before, and only 6 years ago I was doing triathlons.

It was interesting hearing my technician friends opinion of different imaging machines....he mentioned that some machines have great capability but lack ease of operation.  More automation is easier and provides more consistency.  The differences in the quality of imaging was made recently when at a doctors appoint for my wife.  The doctor complained about the quality of the imagery from another clinic.  He specified that he recommended future imagery be done at his clinic.

I guess the first scan out of the chute is perhaps a bit stressful.

Galrim's picture
Galrim
Posts: 305
Joined: Apr 2013

CT scan

PET/CT scan 

MR scan

Is usually the scanning buffet we have in this club.

/G

 

 

donna_lee's picture
donna_lee
Posts: 758
Joined: Feb 2009

I've had a lot of CT scans.  They are generally used for a comparison - previous scan(s) to the new one; or to monitor a specific area in the body for any change.

The PET was used as a confirmatory diagnostic.  The CT comparisons showed an enlargement of a node in the lower abdomen, but in a location that could not be biopsied.  The PET scan was then performed to see if the node "lit up", which it did.  Then I had the surgery to remove it.

And if you have metal in your body, as I do, they won't do an MRI.

Donna

Your advisor, was mostly correct.  And I'd also take his recommendations of test location under consideration.

donna_lee's picture
donna_lee
Posts: 758
Joined: Feb 2009

I got good advice from my brother in the early stages of this game.  He was a professor of radiology for 35 years.

Donna

Eliezer2
Posts: 85
Joined: Aug 2012

!

Billy's Wife's picture
Billy's Wife
Posts: 51
Joined: Jan 2014

My husbands oncologist is an RCC specialist in NYC.  She never sent him for a Pet scan because she said they are not reliable for RCC, too many false positives.   He always had CT's of the abdomen chest and pelvis and MRI's.  We were also told to stick to the same radiaolgy facility for the same reasons you and others have stated.  Different facilities have different machines and different technicians doing the readings too.  If the same radilogist continues to do a patients scans they are reviewing their own work again and thus are more accurate.

I am sure your xray tech friend is knowledgeable about radiology but maybe not as well versed in RCC and how it is detected as opposed to other cancers etc...I would ask around to others too about the facility he recommended against as that might be valuable information but I would try to coorborate that too.

Best of Luck to you!

Arleen 

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