I find that using GOOGLE (www.google.com) then typing in  "Definition
PET"   or whatever you are looking for usually does the trick.  Lots of
info appears.  Leads to understanding.

CEA - carcinoembryonic antigen

CT scan or CAT scan - computed tomography or computed axial tomography
( means the same thing)
MRI - magnetic resonance imaging
PET - positron emission tomography

thank you all for your replies...very helpful and informative...will ask
about CEA markers when I go.......Not a good time for my friend,  Mary. in
hospital with mets  and feeling very poorly....Please pray for her, or
whatever your beliefs.....good vibes  much appreciated

Thanks   Pam xx

These definitions as well as comprehensive explanations can be found by
going to www.Google.com . Enter the word, abbreviation or phrase. This
should help. . .Bob

CAT scan or CT scan (Computed Tomography) is basically a 3-dimensional
X-ray using a computer rather than photographic film to convert the
x-ray data into an image.  This is commonly used to check for any spread
of the cancer to other parts of the body, and will be done routinely if
there is a significant risk that the cancer has spread.

PET scan (Positron Emission Tomography) is an isotope scan, a
radioactive-tagged sugar is injected into the bloodstream, and the
scanner detects its specific emissions, thus highlighting the areas
where the sugar is taken up, which generally correlates to areas of high
biological activity, including cancers.  It can detect smaller tumours
than a CAT scan, but is a lot more expensive and not available everywhere.

There is also a bone scan, which is similar to a PET scan but uses a
compound which specifically attaches to areas of bone growth, which is
very useful for looking for bone mets, but also can light up for areas
of arthritis.

Both types of scan also inevitably detect a lot of other things going on
in the body which are mildly abnormal but harmless, and so have a
tendency toward "false positives".  They also involve exposing the body
to radiation, and so carry a small risk of causing cancers themselves.

CEA and other markers are blood tests for compounds which are commonly
present in larger quantities when cancer is present.  These are
generally not very helpful for detecting the occurrence of metastases
for two reasons.  Firstly the baseline levels of most markers vary quite
a lot between individuals, and secondly, they tend to lag behind the
development of the tumour, so often metastases will become symptomatic
before any significant marker rise is seen.  What they are good for is
assessing the reaction of a cancer to a particular treatment, A *fall*
in the marker is a lot more meaningful than a rise.

As to what tests she should ask for, it depends what stage her cancer
was treated at.  If it was stage II or less, probably none of these
would be of much benefit.  If it was a stage III, then a CAT scan and
bone scan would normally be done.

It must be understood that the benefits of early detection of metastases
are much less than the benefits of early detection of primary cancer,
and so consequently the benefit of aggressively searching for metastases
is limited, especially in patients at relatively low risk.

Tim Jackson