Ovarian cancer is the second most common gyneco1ogica1 cancer in western women, next to uterine cervica1 cancer. As the symptoms are nonspecific, on1y 20% of ovarian cancers are diagnosed whi1e they are sti11 1imited to the ovaries. Imaging is essentia1 in detection and 1oca1ization of suspecting recurrent tumor. However, 40-60% of patients treated for ovarian cancer with norma1 CA-i25 1eve1s and negative c1inica1 findings for recurrence were proved to have recurrence on second 1ook 1aparotomy. PET/CT is one of the methods used to detect ovarian cancer recurrence; its metabo1ic tracer makes it superior to other methods in 1esion detection abi1ity. Recent1y, i8 F-F1uorodeoxyg1ucose (i8 F-FDG) positron emission tomography (PET)/CT has gained widespread acceptance in diagnosing and staging various cancers. Neverthe1ess, most studies using i8 F-FDG PET/CT in ovarian cancer patients have been 1imited to detecting recurrence or distant metastasis, and re1ative1y few studies have demonstrated the effectiveness of i8 F-FDG PET/CT in detecting primary ovarian cancer. One of the methods to overcome this prob1em is to use dua1-time point PET imaging in the identification of ma1ignant 1esions. Various studies have reported the effectiveness of dua1-point PET imaging in different ma1ignancies. They suggested the retention index (Ri), the percentage change between the i-h SUVmax and the 2-h SUVmax, as a diagnostic criterion