- The effects of FLT on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. A screening urine hCG will be administered in the Nuclear Medicine to women of childbearing potential before each FLT scan and pregnant women will not be accepted as subjects in this study.