Since I have been here, this has been almost as controversial as to PEG or not. Allow me to fine tune the discussion a little with a few facts (I basically agree with Charm and here are some additional perspectives):

1. PET/CT has a substantially higher accuracy than PET alone. This is because of the fusion between the PET and CT images. Points of reference within the anatomy are more clearly defined and hence interpretation of the images more accurate (note that I said "interpretation"). I have read studies that PET/CT can be as accurate as 98% - less for straight PET (80% or so). No doubt that this will be dependant on the skill set of the reading radiologist.

2. PET or PET/CT is most likely used as part of validation of the tumor site (in the initial triage of the cancer site) and to closer identify/examine any additional regions of interest, such as nodal involvement or distant mets. They are also typically a full body type of scan.

3. PET and/or PET/CT work through a process of cooncentration of a radioisotope laced glucose (sugar) solution (administered by IV prior to the scan) that concentrates itself in tissues that are cancerous or healing (AKA as "uptake"). This is what acoounts for many false positives, especially in the case of healing tissue. This is why doctors typically wait before ordering one after a surgery for example (if one is ordered at all).

4. Reimbusrement. What does money have to do with this? A LOT - since a PET or PET/CT is not on the list of standard NCCN, Oncology Practice Guidelines, follow-up protocols, many doctors and institutions will not perform them. Consequently, most patients coming here never have a follow-up PET or PET/CT and some seem to have one every 6 months. Certainly your health care provider will ultimately have the final decision on whether you get one or not. It is the singlemost expensive scan you can get. It is costly for multiple reasons: Low throughput - For each patient, the scan takes an hour or so. The radioisotope has a very short half life and must be prepared, to order (in a cyclotron), and couriered to the institution in a relatively fast time frame (say an hour or so before use). As you can imagine, some insurers and even Medicare may be reluctant to pay for them.

5. Alternative scan modalities: Many CCC's prefer annual MRI's vs. a PET or PET/CT, at least during the first several years post Tx. Assuming there are no metal implants in your body, this is a safest scan you can get (although a few have reactions to MRI's that are performed with a contrast agent). MRI's are very accurate and display soft tissue anomalies very well and in great detail. They typically cover the lower part of the brain to the top of the lungs so local metastesis areas may be revealed as well.

6. NCCN guidance protocol for follow up: Annual chest x-rays are in the NCCN followup protocols but IMHO, I doubt that, after several years post Tx, there is a diminishing return on the risk/benefit for the radiation from them. Chest x-rays use relatively little radiation anyway.

Last edited by Gary; 01-26-2011 09:14 AM.
Gary Allsebrook
***********************************
Dx 11/22/02, SCC, 6 x 3 cm Polypoid tumor, rt tonsil, Stage III/IVA, T3N0M0 G1/2
Tx 1/28/03 - 3/19/03, Cisplatin ct x2, IMRT, bilateral, with boost, x35(69.96Gy)
________________________________________________________
"You are a mist that appears for a little while and then vanishes" (James 4:14 NIV)