Inclusion Criteria:

1. Patients with adrenal masses suspected to be aldosterone-producing adenomas based on routine imaging (e.g., CT scans), or clinically diagnosed primary aldosteronism patients requiring subtyping
2. Signed written informed consent, with willingness and ability to comply with study procedures.
3. Female participants must be surgically sterilized or postmenopausal for over a year; if not, reliable contraception is required.
4. Male participants must use reliable contraception during the study and refrain from sperm donation.

Exclusion Criteria:

1. Severe neurological disorders, or any significant diseases affecting the gastrointestinal, cardiovascular, hepatic, renal, hematological, oncological, endocrine, respiratory, or immune systems, or other serious illnesses.
2. Diagnosis of claustrophobia.
3. History of drug abuse or alcohol dependence.
4. Pregnant or breastfeeding women.
5. Poor venous access that would preclude repeated venipuncture.
6. Use of experimental drugs or devices within one month prior to the study, where the safety or efficacy has not been established.
7. Any condition that the study investigators deem could pose potential harm or jeopardize participant safety.