Indications for PET/CT

Detecting Malignancy:

Although PET/CT is not typically utilized as a screening exam for cancer, it is routinely used to evaluate whether a previously noted abnormality (imaged or palpable) represents a malignancy — Does this patient have cancer? [Fig. 1]

Staging of Malignancy:

PET/CT is a powerful tool for the staging of most cancers, and helps answer several essential inquiries — all of which directly influence treatment and patient management: [Fig. 2]

• Where is the primary cancer?
• How large is the tumor burden?
• Is there local, regional, or distant metastatic disease?
• Where is the best site for biopsy?

Evaluating Response to Therapy/ Prognosis:

• Early Response: In clinical situations where there is more than one available treatment option, it is often useful to image a patient soon after initiation of therapy.  If improvement is noted, the treatment is deemed useful and can be continued. If, however, early imaging demonstrates little or no improvement, the initial treatment plan can be altered or completely replaced. [Fig. 3]
• Late Response: After completion of treatment, imaging can determine interim success or failure of therapy, as well as predicting ultimate patient outcome. Perhaps most powerfully, PET/CT offers the unique advantage of distinguishing residual active disease versus post-therapeutic scar tissue/fibrosis.

Detecting Recurrence:

PET/CT is an extremely useful tool for detecting recurrent disease. Even in cases where a presumed area of post-therapeutic scarring is unchanged in size and CT appearance, a significant associated interval increase in its metabolic activity will indicate recurrent disease. [Fig. 4]