PET-CT is a systemic whole-body examination with positron emission imaging combined with CT scanning that is more accurate in the diagnosis and localization of malignant tumors. However, because it is expensive, it is generally used only when the primary lesion of a malignant tumor cannot be detected by conventional examination.
Malignant tumors often show nuclear uptake concentration in the area of the tumor lesion on the imaging picture. The most commonly used nuclide in PET-CT is 18F-FDG. The uptake of 18F-FDG by kidney cancer is related to the rate of tumor cell growth, with high uptake by fast-growing kidney cancer cells and low uptake by slow-growing kidney cancer cells. However, PET-CT imaging using 18F-FDG nuclide is not very sensitive in detecting kidney cancer, about 70%, and because 18F-FDG is mainly excreted by the urinary tract, more radioactivity can remain in the kidney, which has an impact on the diagnosis of intrarenal tumors and should be carefully differentiated when judging the results.
Therefore, PET-CT is not currently required for the diagnosis of kidney cancer, and only a few patients with diagnostic difficulties require PET-CT scanning as a diagnostic reference. On the other hand, whole-body PET-CT does help to exclude distant metastases and still has great application in determining the biology of kidney cancer as well as its prognosis.
In addition, the use of the newest 11C-acetate nuclide instead of 18F-FDG may help improve the detection rate of kidney cancer.