Efficacy of [18F]Florbetaben PET for Diagnosis of Cardiac AL Amyloidosis

This study is testing a PET scan imaging agent called [18F]Florbetaben to see whether it can accurately detect cardiac AL amyloidosis — a dangerous condition where abnormal proteins called amyloids build up in the heart muscle, stiffening it and causing heart failure. Currently, diagnosing this condition often requires an invasive heart biopsy; this study aims to see if a PET scan can be just as accurate without the need for surgery. You may be eligible if: - You are 18 years or older - You are being evaluated for possible cardiac amyloidosis - You have at least one of the following: established systemic amyloidosis, known plasma cell dyscrasia (such as MGUS or myeloma), abnormal free light chains in urine or blood, or heart failure with preserved ejection fraction - AND at least one cardiac sign: thickened heart walls on echocardiogram or elevated NT-proBNP/BNP levels - You are scheduled for a diagnostic procedure to confirm the diagnosis You may NOT be eligible if: - You have a known allergy to the study drug - You have severe liver disease - You are unable to lie flat for up to 60 minutes - You are pregnant, breastfeeding, or lactating - You have had a radiopharmaceutical injection within the past 10 half-lives Talk to your doctor to see if this trial is right for you.