PET vs. CT

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rogina2336
rogina2336 Member Posts: 188
in Colorectal Cancer #1
Someone asked me if a PET scan is for certain cancers and a CT for certain cancers my husband has only had CT scans so I didn't have an answer. I am not much for research, but I know alot of you are and maybe you could answer this question for me. Much thanks Kim

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  • John23
    John23 Member Posts: 2,122 Member
    #2
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    Kim -

    To make it simple:

    A pet scan uses radioactive glucose, with assumption that cancer
    cells use glucose faster than normal cells. Any area that indicates
    a high concentration of glucose is assumed to be cancer.

    CT and MRI scans indicate all types of masses; bone, tissue, fat....

    The problem with a pet scan, is:
    1. Not all cancers use glucose faster than the cells around it.
    2. PET scans taken too soon after surgery (or illness), usually will
    give false positives; when good cells are attempting to recover
    and heal, they use more glucose than other cells.
    3. The PET is not as accurate as CT or MRI scans for surgical
    purposes; most surgeons prefer CT or MRI, rather than a PET.

    Although the PET is -not- designed to locate individual cancer
    cells, only cancer cell clusters, the PET remains preferred by
    most Oncologists. They apparently feel that it will indicate how
    extensive the spread of cancer is, to help them determine how
    much chemotherapy and/or radiation you will require in an
    attempt to get rid of the cancer.

    An Oncologist assigned to my case during my last operation,
    scheduled a PET for me while I was in ICU, with my surgical
    wound still wide open and unhealed. I cancelled the scan, and
    my surgeon concurred. The scan would have indicated wide
    spread cancer, since my entire abdominal cavity was in a
    healing state. I was not operated on for cancer, I had to have a
    resection to remove an intestinal obstruction due to an adhesion.

    I don't know if all that helped you in any way, Kim?

    Personally, I do not care to be subjected to a radioactive PET
    scan, for the purpose of helping a physician sell me treatments
    I may not need or require.

    I hate to sound cynical, but money is a major part of the cancer
    industry, and if there's a way to make more, they will find that way.

    I try to listen to the surgeon rather than an Oncologist, but I
    am wary of them all.

    Stay well,

    John
  • rogina2336
    rogina2336 Member Posts: 188
    #3
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    John23 said:

    Kim -

    To make it simple:

    A pet scan uses radioactive glucose, with assumption that cancer
    cells use glucose faster than normal cells. Any area that indicates
    a high concentration of glucose is assumed to be cancer.

    CT and MRI scans indicate all types of masses; bone, tissue, fat....

    The problem with a pet scan, is:
    1. Not all cancers use glucose faster than the cells around it.
    2. PET scans taken too soon after surgery (or illness), usually will
    give false positives; when good cells are attempting to recover
    and heal, they use more glucose than other cells.
    3. The PET is not as accurate as CT or MRI scans for surgical
    purposes; most surgeons prefer CT or MRI, rather than a PET.

    Although the PET is -not- designed to locate individual cancer
    cells, only cancer cell clusters, the PET remains preferred by
    most Oncologists. They apparently feel that it will indicate how
    extensive the spread of cancer is, to help them determine how
    much chemotherapy and/or radiation you will require in an
    attempt to get rid of the cancer.

    An Oncologist assigned to my case during my last operation,
    scheduled a PET for me while I was in ICU, with my surgical
    wound still wide open and unhealed. I cancelled the scan, and
    my surgeon concurred. The scan would have indicated wide
    spread cancer, since my entire abdominal cavity was in a
    healing state. I was not operated on for cancer, I had to have a
    resection to remove an intestinal obstruction due to an adhesion.

    I don't know if all that helped you in any way, Kim?

    Personally, I do not care to be subjected to a radioactive PET
    scan, for the purpose of helping a physician sell me treatments
    I may not need or require.

    I hate to sound cynical, but money is a major part of the cancer
    industry, and if there's a way to make more, they will find that way.

    I try to listen to the surgeon rather than an Oncologist, but I
    am wary of them all.

    Stay well,

    John

    Thanks
    Thank you soooooo much. After asked that question I was starting to have second thoughts about what is or isn't happening for my husband. Very much appreciated. Thanks again Kim
  • Betsydoglover
    Betsydoglover Member Posts: 1,248 Member
    #4
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    John23 said:

    Kim -

    To make it simple:

    A pet scan uses radioactive glucose, with assumption that cancer
    cells use glucose faster than normal cells. Any area that indicates
    a high concentration of glucose is assumed to be cancer.

    CT and MRI scans indicate all types of masses; bone, tissue, fat....

    The problem with a pet scan, is:
    1. Not all cancers use glucose faster than the cells around it.
    2. PET scans taken too soon after surgery (or illness), usually will
    give false positives; when good cells are attempting to recover
    and heal, they use more glucose than other cells.
    3. The PET is not as accurate as CT or MRI scans for surgical
    purposes; most surgeons prefer CT or MRI, rather than a PET.

    Although the PET is -not- designed to locate individual cancer
    cells, only cancer cell clusters, the PET remains preferred by
    most Oncologists. They apparently feel that it will indicate how
    extensive the spread of cancer is, to help them determine how
    much chemotherapy and/or radiation you will require in an
    attempt to get rid of the cancer.

    An Oncologist assigned to my case during my last operation,
    scheduled a PET for me while I was in ICU, with my surgical
    wound still wide open and unhealed. I cancelled the scan, and
    my surgeon concurred. The scan would have indicated wide
    spread cancer, since my entire abdominal cavity was in a
    healing state. I was not operated on for cancer, I had to have a
    resection to remove an intestinal obstruction due to an adhesion.

    I don't know if all that helped you in any way, Kim?

    Personally, I do not care to be subjected to a radioactive PET
    scan, for the purpose of helping a physician sell me treatments
    I may not need or require.

    I hate to sound cynical, but money is a major part of the cancer
    industry, and if there's a way to make more, they will find that way.

    I try to listen to the surgeon rather than an Oncologist, but I
    am wary of them all.

    Stay well,

    John

    PET vs CT
    John makes good points. I am Stage IV - 6+ years from diagnosis - and currently being monitored with PET scans only.

    Regarding John's good points, a good radiologist will take surgeries / joint problems / bruises from recent falls etc into consideration and will not automatically tag every uptake as cancer.

    In addition a good PET specialist will detect very subtle changes. For example, in 2008 I had a PET that showed a tiny lung nodule (9x11mm). SUV was < 1.0, BUT my wonderful radiologist could see that it was subtly brighter than surrounding tissue. We followed it with CT for 4 months - no change - then did VATS. Turned out to be a met. Wouldn't have worked this out if not for the PET and a great radiologist who specializes in PET.

    Take care (and consider searching for a radiologist who specializes in PET scans).
  • taraHK
    taraHK Member Posts: 1,952 Member
    #5
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    another way of looking at it
    I like to think of it as: CT scans (and MRI) show 'structure' (anatomy) and PET scans show 'activity' (physiology). Sometimes a CT is given first and if anything suspicious, it is followed up with a PET

    Tara
  • rogina2336
    rogina2336 Member Posts: 188
    #6
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    Betsydoglover said:

    PET vs CT
    John makes good points. I am Stage IV - 6+ years from diagnosis - and currently being monitored with PET scans only.

    Regarding John's good points, a good radiologist will take surgeries / joint problems / bruises from recent falls etc into consideration and will not automatically tag every uptake as cancer.

    In addition a good PET specialist will detect very subtle changes. For example, in 2008 I had a PET that showed a tiny lung nodule (9x11mm). SUV was < 1.0, BUT my wonderful radiologist could see that it was subtly brighter than surrounding tissue. We followed it with CT for 4 months - no change - then did VATS. Turned out to be a met. Wouldn't have worked this out if not for the PET and a great radiologist who specializes in PET.

    Take care (and consider searching for a radiologist who specializes in PET scans).

    Thanks
    Very helpful info thank you. So what is your secret for 6+ years ?? My husband has been taking treatments for 7 1/2 months, however no talk as of yet about any surgery. CT tomorrow 7/14 and results on 7/15. Thinking nothing but happy thoughts!!!!! (at least trying to, big case of scanxiety) Thanks again for the info very helpful. Kim
  • rogina2336
    rogina2336 Member Posts: 188
    #7
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    taraHK said:

    another way of looking at it
    I like to think of it as: CT scans (and MRI) show 'structure' (anatomy) and PET scans show 'activity' (physiology). Sometimes a CT is given first and if anything suspicious, it is followed up with a PET

    Tara

    Thanks
    Thanks Tara, all of your info is so very helpful. Thanks again Kim

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