We plan to enroll up to 25 (target of 20 fully evaluable) adult subjects in this study who have an established diagnosis of advanced cardiac amyloidosis (AL). Subjects will be included in 2 subject cohorts of approximately 10 subjects each. In one cohort positron emission tomography/computed tomography (PET/CT) imaging will be used to measure inducible nitric oxide synthase (NOS) expression in the heart as a marker oxidative stress and inflammation using an investigational radiotracer called 18F-NOS. In the other cohort PET/CT imaging will be used to measure amyloid deposition as an estimate of the actual AL load in the heart using an approved radiotracer called [18F]Florbetaben. Subjects in both cohorts will have two PET/CT scans performed, before therapy and 3-6 months after initiation of therapy. The 18F-NOS scans will include approximately 60 minutes of dynamic scanning over the chest starting at the time of injection of 18F-NOS. This will be followed by a skull base to thigh scan. 18F-NOS imaging sessions will include an injection of 6.5 mCi (approximate range for most studies is anticipated to be 3.5-6.5 mCi) of 18F-NOS. Immediately following the dynamic chest imaging, patients will undergo a skull base to thigh scan. Blood samples will be drawn during the dynamic portion of the scan to measure radioactive counts and/or biometabolites of the tracer. The Florbetaben scans will include approximately 60 minutes of dynamic scanning over the chest starting at the time of injection of Florbetaben. This will be followed by a skull base to thigh scan. Florbetaben imaging sessions will include an injection of approximately 8.1 mCi (approximate range for most studies is anticipated to be 6.4 9.7 mCi) of Florbetaben. Following the dynamic chest imaging, patients will undergo a skull base to thigh scan. Blood samples will be drawn during the dynamic portion of the scan to measure radioactive counts and/or biometabolites of the tracers. Data will be collected to evaluate uptake of each radiotracer in the heart and peripheral tissues, measurements will be compared between cohorts.

You may be eligible for this study if you meet the following criteria:

• Conditions: advanced cardiac amyloidosis
• Age: 99 years or below
• Gender: All