الفهرس 
EMBRYOLOGIC DEVELOPMENTOnly 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.
Dual modality PET/CT scanning provides accurately fused morphologic (CT) and functional (PET) data sets. A very small tumor is well detected by PET but can be missed by CT. On the other hand, a large tumor with minimal functional deviations may be seen on a CT image, but may not be detected by PET. In both situations, PET/CT would localize the tumor accurately. 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 identifying cancer that has spread, making up treatment plan and monitoring tumor response, distinguish viable metabolically active tissue from scars, and it is indicated for restaging in patients with suspected recurrent and metastatic disease.
(18) F- FDG PET/CT is useful in the evaluation of metastasis and poorly differentiated HCC although its role in the diagnosis of well differentiated 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.
PET/CT was more sensitive than conventional CT and MRI in detecting suspected vein tumor thrombus in patients with HCC. Tumor thrombus differentiates itself from blood thrombus by its intense uptake of the tracer 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.
It is expected that PET/CT of the liver will play a growing and increasingly important role in detecting and monitoring treatment of tumors involving the liver as well as the assessment of liver that prepared for transplantation in hand with assessment and follow up of liver after transplantation.
The main drawbacks of PET/CT in management of HCC include the following:
- High cost.
- Motion artifact.
- Attenuation correction artifact.
- Radiation exposure.
- Needs highly trained personnel to generate the radiopharmaceuticals used for PET imaging.
In conclusion, PET/CT offers a promising imaging tool for evaluation of HCC and needs further evaluation studies.