PET scans can show solid tumors in the brain, prostate, thyroid, lungs, and cervix. The scans can also evaluate the occurrence of colorectal, lymphoma, melanoma, and pancreatic tumors. They are also used to assess if treatment is being effective in eliminating cancer.
PET scans must be interpreted carefully because noncancerous conditions can look like cancer, and some cancers do not appear on PET scans.
Though most cancers are picked up on PET CT, there are a few which do not. The most important of these would be cancer of stomach (signet cell type). In such cases performing this test would be waste. However, there are cancers which are very sensitively detected which include lymphoma, GIST, etc.
PET/CT is the most useful test for determining the stage of cancer. It is more accurate than any other test in finding local or metastatic tumors. Although PET can't detect microscopic cells, it can detect clusters of tumor cells that metastasized, or spread, to other tissues or organs.
Discussion: The detection limit of PET is in the magnitude of 10(5) to 10(6) malignant cells.
Not all that lights up on a PET scan can or should be considered malignancy, and clinical context can become even more pertinent. Inflammatory cells, sarcoidosis, and other thoracic etiologies such as silicone-induced granuloma, can cause PET scans to light up, giving false positives [3,4,5].
In general, PET scans may be used to evaluate organs and/or tissues for the presence of disease or other conditions. PET may also be used to evaluate the function of organs, such as the heart or brain. The most common use of PET is in the detection of cancer and the evaluation of cancer treatment.
The diagnostic accuracy of PET-CT was 93.5%, and the false positive rate was 6.50%.
Benign tumors and tumor-like conditions are often incidentally detected on FDG PET/CT in serial follow-up studies of cancer patients and should be differentiated from metastasis.
A CT scan (also known as a computed tomography scan, CAT scan, and spiral or helical CT) can help doctors find cancer and show things like a tumor's shape and size. CT scans are most often an outpatient procedure. The scan is painless and takes about 10 to 30 minutes.
PET/CT-guided biopsies may help in difficult situations, especially when it is important to know which part of the tumor is active or which lesion is active in patients with multiple, widespread lesions.
PET scans detect the rate at which cells are using sugar. When the scan lights up brightly, it means there is metabolic activity. Most aggressive cancers light up brightly, but the caveat is inflammation in the body also lights up because inflammatory cells are also metabolically active.
MRI scans, note that both can detect diseases and abnormalities. However, PET scans can show how your body performs at the cellular level. On the other hand, PET scans include radiation. MRI scans don't expose you to harmful radiation, which can be preferable for certain patients and annual scans.
Compared with CT-guided percutaneous bone biopsy, PET/CT-guided percutaneous bone biopsy is an effective and safe alternative with high diagnostic performance in the evaluation of hypermetabolic bone lesions to diagnose bone tumors and tumor-like lesions.
PET scans can show solid tumors in the brain, prostate, thyroid, lungs, and cervix. The scans can also evaluate the occurrence of colorectal, lymphoma, melanoma, and pancreatic tumors. They are also used to assess if treatment is being effective in eliminating cancer.
PET scans may play a role in determining whether a mass is cancerous. However, PET scans are more accurate in detecting larger and more aggressive tumors than they are in locating tumors that are smaller than 8 mm a pinky nail (or half of a thumb nail) and/or less aggressive cancers.
FDG-positive lesions often mean cancer, but not always. A variety of lesions have increased FDG radiotracer including infection, inflammation, autoimmune processes, sarcoidosis, and benign tumors. If such conditions are not identified accurately and in a timely manner, misdiagnosis can lead to inadequate therapies.
Multiple nonspecific infectious/ inflammatory processes can cause increased FDG uptake and result in a false positive diagnosis for malignancy on PET/CT.
PET scans are sometimes used to look for cancer in the lymph nodes in the centre of the chest.
The PET scan accurately determined the outcome of 90% patients, while the combination of all the conventional images accurately determined the outcome of only 75% of patients.
Physicians should disclose a cancer diagnosis in a personal setting, discussing the diagnosis and treatment options for a substantial period of time whenever possible.
CT and PET Scan Comparison
PET scans show metabolic changes occurring at the cellular level in an organ or tissue. This is important because disease often begins at the cellular level. CT scans (and MRIs) can't reveal problems at the cellular level. PET scans can detect very early changes in a patient's cells.
Do I have to pay for a PET scan? There is no cost for most PET scans if you are a citizen or permanent resident of Australia and covered by Medicare. For a limited number of indications that are not approved by Medicare, there can be a charge to the patient.
F-FDG PET/CT can be useful in diagnosing leukemia, mainly in patients with fever and anemia of unknown origin. Moreover, it is of great value for detecting extramedullary disease, monitoring extramedullary relapse and evaluating treatment response.