[18F]FT8, a derivative of 1-(4-pyridyl)-4-piperazinyl arene ([18F]TPZA), exhibits high affinity for AL amyloid in myocardial tissue sections and shows no significant binding to transthyretin amyloid. By comparing its diagnostic performance against established clinical methods, including echocardiography, contrast-enhanced MRI, and relevant laboratory tests, this study aims to establish [18F]FT8 as the basis for a robust PET protocol for the direct visualization and differential diagnosis of AL amyloidosis . The study preimarily evaluates the safety and diagnostic efficacy of [18F]FT8 PET imaging in human subjects.

Subjects will undergo [18F]FT8 PET/CT scans for safety and diagnostic efficacy evaluation. Organ uptake will be quantified using the standard uptake value (SUV). Clinical assessments and laboratory tests, including baseline information collection, physical examination, cardiac function assessment, and hepatic and renal function tests, will be conducted before and after the scan.

1. Subject Recruitment Participants will be recruited from outpatients and/or inpatient populations of the Hematology Department at Tianjin Medical University General Hospital. The principal investigator and collaborating hematologists will ensure consistent application of diagnosis and enrollment criteria based on standardized guidelines. The planned enrollment includes 20 patients with systemic amyloidosis (including cardiac involvement) and 5 healthy volunteers.
2. Amyloidosis Patients:

2.1 Inclusion Criteria:

Subjects must meet all of the following criteria:

1. Adult patients (age ≥ 18 years);
2. Suspected, newly diagnosed, or previously diagnosed with cardiac amyloidosis, with supporting evidence from one or more of the following: cardiac MRI, contrast-enhanced CT, serum biomarkers (e.g., NT-proBNP, Troponin), or histopathological confirmation of amyloidosis.
3. Scheduled to undergo a clinical Pan-Amyloid PET/CT scan as part of standard care or clinical evaluation.
4. Able to understand the study procedures and provide written informed consent. 2.2 Exclusion Criteria

Subjects will be excluded based on any of the following:

1. Confirmed non-cardiac amyloidosis or other non-amyloid cardiac pathologies that could confound image interpretation.
2. Pregnancy or breastfeeding.
3. Any medical, psychological, or social condition that, in the opinion of the investigator, would compromise the subject's ability to participate fully or complete the study follow-up.

3. Healthy Volunteers: 3.1 Inclusion Criteria:

Subjects must meet all of the following criteria:

1. Adult subjects (age ≥ 18 years);
2. No clinical evidence of active cardiac or systemic disease, as confirmed by medical history review, physical examination, and electrocardiogram (ECG).
3. Able to understand the study procedures and provide written informed consent. 3.2 Exclusion Criteria:

Subjects will be excluded based on any of the following:

1. History or current diagnosis of any significant cardiac, hepatic, renal, or neurological disorder.
2. Pregnancy or breastfeeding.
3. Any condition that, in the opinion of the investigator, could pose an increased risk from the study procedure or interfere with the interpretation of study data.

Healthy volunteers and patients with confirmed or suspected systemic or cardiac amyloidosis, including cases secondary to hematologic disorders or genetic diseases.