Application of PET and PEt/CT imaging for cancer screening.

The aim of this study was to evaluate the potential application of 18-fluorodeoxyglucose positron emission tomography (FDG PET) and PET/CT for cancer screening in asymptomatic individuals. The subjects consisted of 3631 physical check-up examinees (1947 men, 1684 women; mean age +/- SD, 52.1 +/- 8.2 y) with non-specific medical histories. Whole-body FDG PET (or PET/CT), ultrasound and tumor markers were performed on all patients. Focal hypermetabolic areas with intensities equal to or exceeding the level of FDG uptake in the brain were considered abnormal and interpreted as neoplasia. Follow-up periods were longer than one year. Among the 3631 FDG PET (including 1687 PET/CT), ultrasound and tumor markers examinations, malignant tumors were discovered in 47 examinees (1.29%). PET findings were true-positive in 38 of the 47 cancers (80.9%). In addition, 32 of the 47 cancers were screened with the PET/CT scan. PET detected cancer lesions in 28 of the 32 examinees. However, the CT detected cancer lesions in only 15 out of 32 examinees. The sensitivity of FDG PET in the detection of a wide variety of cancers is high. Most cancer can be detected with FDG PET at a resectable stage. CT of the PET/CT for localization and characteristics of the lesion showed an increased specificity of the PET scan. The use of ultrasound and tumor markers may complement the PET scan in cancer screening for hepatic and urologic neoplasms.