Not feasible at this time.

This is a Phase III study to evaluate 68Ga Citrate PET/MRI for detection of origin of fever of unknown origin.

The purpose of this research study is to evaluate a PET tracer (68Ga-Citrate) that can localize the origin of patients diagnosed with fever of unknown origin (FUO) using a PET/MRI scanner. We hope to learn if this can detect FUO better than with the present nuclear imaging standard of care (67Ga SPECT).

We propose the following aim:

• To evaluate 68Ga Citrate PET/MRI for detection of origin of fever in patients with fever of unknown origin.

Patients disgnosed with fever of unknown origin are injected intravenously (IV) with 370 MBq of 68Ga Citrate. 45-60 minutes later, a whole body PET/MRI images are obtained.

Inclusion Criteria:

• Patient is >/=18 years old at the time of the scan.
• Patient with diagnosis of FUO.
• Patient is capable of complying with study procedures.
• Patient can remain still for duration of imaging procedure.
• Able to provide written consent.

Exclusion Criteria:

• Patient is pregnant or nursing.
• Metallic implants (contraindicated for MRI).
• History of renal insufficiency (only for MRI contrast administration).
• Inability to lie still for the entire imaging time.
• Inability to complete the needed investigational and standard of care imaging examinations due to other reasons (severe claustrophobia, radiation phobia, etc.).
• Any additional medical condition, serious intercurrent illness, or other extenuating circumstance that, in the opinion of the investigator, may significantly interfere with study compliance.
• Known allergy, hypersensitivity, or intolerance to the investigational product or its excipients.