A great explaination of a PET scan

[Guest guest]

A PET scan is a very sensitive test for any rapidly growing tissue.

That could be either a tumor or any healing taking place after an

injury.

In that cancer LOVES sugar, a PET scan works in the following

manner. The patient restricts food of any kind for at least 12 hours

or longer, thereby driving down the blood glucose level to about 105

to 110. (That's the " G " in FDG.)

Next, a sugary substance tagged with a fluorine radioisotope (that's

the " F " in FDG) is injected while the patient sits immobile for

about an hour.

With the body (and cancer) starved for sugar, any actively growing

cancer cells will preferentially gobble up the sugary substance

tagged with the positron emitting radioisotope.

When the positive electron (positron) ejected at a tumor site, meets

a normal negatively charged electron, a huge burst of energy is

released, thereby locating a tumor.

This burst is detected by sensors, shown on a monitor and printed on

a film.

This may be far more than you wish to know. However, the good news

is that the technique is so sensitive that it can detect any further

spread while still too small to reliably detect with either an MRI

or a CT scan.