Diagnostic Validity of [18F]FSPG PET for the Assessment of Acute Rejection After Heart or Liver Transplantation

Inclusion Criteria: * Subject is aged between 19 and 79 years and male or female of any race/ethnicity. * Subject received heart transplantation or liver transplantation at least 30 days prior to screening * Subject underwent or is scheduled to undergo biopsy for histologic diagnosis of acute rejection within 7 days prior to or after the planned \[18F\]FSPG PET/CT administration. Exclusion Criteria: * Subject or subject's legally acceptable representative does not provide written informed consent. * Dose escalation of the current immunosuppressant drugs or starting a new immunosuppressant is scheduled from the study enrollment to the scheduled day of biopsy, or 24 hours after \[18F\]FSPG administration * Female subject is pregnant or nursing. Exclusion of the possibility of pregnancy is made by one of the following: 1) Woman is physiologically post-menopausal (cessation of menses for more than 2 years), 2) woman is surgically sterile (has had a documented bilateral oophorectomy and/or documented hysterectomy, or 3) if the woman is of childbearing potential, a serum or urine pregnancy test performed within 24 hours immediately prior to administration of \[18F\]FSPG has to be negative and the women is advised to apply contraceptive measures during her participation in this study. * Subject has concurrent severe and/or uncontrolled and/or unstable medical disease (e.g. congestive heart failure, acute myocardial infarction, severe pulmonary disease, chronic renal or hepatic di…