Cushing s Syndrome

Background: The adrenal glands are 2 small organs that sit on top of each kidney. They release hormones; these are chemicals that control how the body works. Tumors on or outside the adrenal glands are called functional if they release hormones; they are called nonfunctional if they do not. Doctors who treat adrenal tumors need to know which type a person has. Researchers want to find better ways to learn whether an adrenal tumor is functional. Objective: To see if a new radioactive tracer (\[68Ga\]Ga-PentixaFor) can make it easier to identify functional adrenal tumors with positron emission tomography (PET) scans. Eligibility: People aged 18 years and older with 1 or more adrenal tumors. They must have increased levels of the hormones aldosterone or cortisol. They must also be enrolled in at least 1 other related NIH study (protocols 19-DK-0066, 18-CH-0031, or 09-C-0242). Design: Participants will be screened. They may have imaging scans. Their ability to perform normal activities will be reviewed. Participants will have one PET scan with the study tracer. The tracer will be given through a tube attached to a needle inserted into a vein. Participants will receive the tracer 1 hour before the scan. They will lie still on a bed while a machine captures images of the inside of their body. The scan will take 45 to 90 minutes. Participants heart rate, blood pressure, and rate of breathing will be checked before, during, and after the scan. Participants will have a follow-up visit 3 days after their scan. This visit can be by phone, email, or in person.

In previous clinical practice, 68Ga-Pentixafor PET/CT has demonstrated promising diagnostic utility in various neuroendocrine tumors by targeting CXCR4, a chemokine receptor overexpressed in several ACTH-secreting neoplasms. Building on this, and leveraging the Nuclear Medicine expertise at Peking Union Medical College Hospital, we aim to conduct a prospective observational study investigating the role of CXCR4-targeted PET/CT imaging in patients with confirmed or suspected Cushing's syndrome. This study will focus on evaluating the capability of \^68Ga-Pentixafor PET/CT to assist in the differential diagnosis of ACTH-dependent and ACTH-independent subtypes, as well as in the localization of primary lesions in challenging cases. Imaging performance will be assessed in comparison with conventional modalities and/or 68Ga-DOTATATE PET/CT when available.