New PET scan warning -- to stay warm?

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  • zarovka
    zarovka Member Posts: 3,607
    edited March 2017

    Michelle - Scans generally are not as accurate in determining the size of the lesions then radiologists imply and doctors communicate. PET scans in particular pick up inflammation that mimicks cancer, so that is an issue. Brown fat and other tissue can absorb the radioactive glucose and also cause false positives. Finally, the SUV's are highly dependent on glucose levels and the time between the injection and the scan as well as other factors. I think the SUV level is the most variable, so comparing subtle differences in SUV levels between scans should take that into consideration.

    The short answer is yes. Sometimes it is hard to watch people torture themselves over small changes in the scan.

    >Z<

  • ShetlandPony
    ShetlandPony Member Posts: 4,924
    edited March 2017

    And yet, the subtle changes in SUV in my liver did turn out to represent progression, though the radiologist and my onc would not call it until it reached a certain level. We watched it slowly rise over the course of several scans. It seems reasonable to expect that an effort to be consistent with pre-scan diet, refraining from exercise, and staying warm would help ensure accuracy. And it must also be important for the techs to time the injection well and consistently (don't be late), and the radiologist and oncologist to interpret the scan well. Notice the word interpret. Someone once said to me something to the effect that when it comes to biological processes, things are often not simple yes-no, black or white. This fits with Zarovka's caution about how we think about scans.

  • zarovka
    zarovka Member Posts: 3,607
    edited March 2017

    Shetland - I did so want subtle changes in scans and TM's to be wrong in your case, but they were not.

    I've seen people who were forced to delay treatment after a bad scan for various reasons, only to find that the next scan showed improvement.

    You felt the change in your body as well, that seems the most reliable indicator sometimes. And you have ILC, which is notorious for being difficult to track in scans.

    Wish this were simple. We can certainly improve the reliability of PET scans by prepping for the scans consistently.

    >Z<

  • ShetlandPony
    ShetlandPony Member Posts: 4,924
    edited March 2017

    Yes, I don't mean my post to scare people, but to show that often one scan is inconclusive. I agree with your advice, which I think is saying not to panic over a scan that shows a small change. It could just be a different "slice" on the imaging or something. Scans need expert interpretation and sometimes waiting to see what consecutive scans show. In my case, no decisions were made based on just one or two scans. I look at the waiting and watching period I had as getting a longer time out of a treatment which must have been partly working still. And yes, I knew exactly when things started waking up. By the way, in my case, ILC has been visible on all imaging, which isn't true for everyone.

  • TarheelMichelle
    TarheelMichelle Member Posts: 871
    edited March 2017

    key word = interpretation. I've learned a lot here. Thanks, everyone.

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