- Patients of childbearing potential must have a negative urine or serum pregnancy test within 7 days prior to FLT (or FDG if for research) PET/CT imaging per institution's standard of care; A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria; Has not undergone a hysterectomy or bilateral oophorectomy; or Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).