Hybrid 18F-FDG PET with low- and high-dose CT for malignancy screening.

The primary objectives of this retrospective study were to determine the cancer detection rate of PET/CT in this institution and to compare the sensitivity and specificity of low-dose PET/CT to that of PET with high-dose CT. Three hundred sixty-seven (367) patients with unremarkable history, family history of cancer, symptoms or abnormal diagnostic tests, and with follow-up studies were included. PET/CT and histopathology results were noted. Individual and overall cancer detection rates, as well as sensitivities and specificities for each subgroup, were computed. Overall cancer detection rates was 22.3%, for low-dose PET/CT was 17.9%, and for high-dose PET/CT was 24.4%. Using the chi squared test of independence, no statistically significant difference was found between the calculated sensitivities and specificities of low- and high-dose PET/CT across all patient groups. Using the Mantel-Haeaszel chi squared test, a statistically significant association between the subindication for malignancy screening and PET/CT results was established with subindications pointing to a higher suspicion for malignancy having a higher probability of detecting a malignancy. Therefore, high-dose PET/CT as a screening test would be advised for high-risk patients and low-dose PET/CT would be recommended because of its similar accuracy but lower radiation exposure.