الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
PET/CT is superior to PET and CT alone, and/or magnetic resonance imaging (MRI), in the diagnosis and treatment of various primary or metastatic cancers. Thus, PET/CT is a more accurate test than either of its individual components.
PET/CT has advantages over other imaging methods; it can differentiate benign from malignant lesions, staging and restaging tumors, detect functional changes before there is any change in clinical or radiological size of a mass, better in identify cancer that has spread, making up treatment plane and monitoring tumor response, detect tumor recurrence early and distinguish viable metabolically active tissue from scars.
18F-FDG PET has advantages over conventional imaging techniques in designing and evaluating managements of hepatic malignancies. PET/CT is more and more widely applied in clinical practice. It is more sensitive and specific than PET, with a lower false positive and false negative rate.
The ability of PET and PET/CT with 18F-FDG to enhance the diagnosis algorithm of hepatic malignancies, which can benefit the patients suffering from hepatic metastases, HCC and CC by more accurate diagnosis, staging, restaging and further evaluation of their biologic characteristics.
Whole body positron emission tomography with (18)F-fluoro-deoxy-glucose (FDG) in combination with CT scanning (PET/CT) represents one of the most sensitive imaging modalities for the detection of hepatic metastases and extrahepatic tumor manifestations. For the staging and follow up of colorectal cancer, FDG-PET/CT represents a standard imaging modality.
(18)F-FDG PET/CT is useful in the evaluation of HCC metastasis, although its role in the diagnosis of primary HCC is more limited. Dual tracer PET/CT had an incremental value and complementary advantage when compared with single tracer imaging in the evaluation of HCC metastasis.
The ability of FDG-PET quantitatively to estimate metabolic rates makes it an important tool for monitoring. With increasingly broad indications for FDG-PET imaging, it is expected that FDG-PET (and PET/CT) of the liver will play a growing and increasingly important role in detecting and monitoring treatment of tumors involving the liver .
Conventional imaging modalities have limitations in discriminating portal vein tumor thrombus.
18F-FDG PET/CT was more sensitive than conventional CT and MRI in detecting suspected vein tumor thrombus in patients with HCC. Tumor thrombus differentiates it self from blood thrombus by its intense uptake of 18F-FDG as a result of its high metabolic neoplastic activity.
PET and PET/CT is very important in patients with unexplained high levels of tumor markers.
Limitation of PET/CT includes the following:
• Cost.
• Motion artifact.
• Attenuation correction artifact.
• CT truncation artifact.
• Radiation exposure.
• Highly trained personnel to generate the radiopharmaceuticals used for PET imaging.