Patient description: The patient is a 41-year-old man and a known case of Acromegaly who underwent transsphenoidal surgery 4 months ago. He came to the clinic for the follow up lab studies after his primary resection surgery. His lab study shows the IGF-1 level of 4.5 ULN adjusted by sex and age. His random GH level is 4 ug/L. The recent brain MRI confirmed the residual pituitary tumor. His past medical history is only significant for acromegaly due to pituitary adenoma and the recent surgery. After his surgery he takes only vitamin D and multivitamins.

Clinical trial eligibility criteria: eligible ages (years): 8.0-999.0,  Cushing's Disease Pituitary Adenoma In order to be eligible to participate in this study, an individual must meet all of the following 1. Patients aged 8 or older with biochemical evidence of Cushing s disease and a clinical MRI pituitary neuroradiology result of negative or possible adenoma (e.g. 'no tumor' or 'possible tumor' around) 2. MRI of the Pituitary gland with and without contrast obtained within 9 months of screening 3. Ability to undergo PET-imaging without general anesthesia 4. Ability to provide informed consent for study participation (parents or guardians in the case of minors) 5. Clinical diagnosis of Cushing s disease based on documented medical records 6. Surgical candidate for resection of ACTH producing pituitary adenoma within 1 weeks of PET-imaging 7. Normal liver function as evidenced by liver enzyme tests completed within 14 days before injection of radiopharmaceutical: SGOT, SGPT <= 5 x upper limit of normal; bilirubin <= 2 x upper limit of normal 8. Enrolled in 03-N-0164, Evaluation of Neurosurgical Disorders  An individual who meets any of the following will be excluded from participation in this study: 1. Pregnancy or lactation 2. Severe chronic renal insufficiency (glomerular filtration rate < 30 mL/min/1.73 m squared), hepatorenal syndrome or post-liver transplantation. 3. Elevated blood glucose level above 200 mg/dL on the day of the scan prior to 18F-FDG administration. 4. Known intolerance to CRH OF Children: Children age 8 and older are included in this protocol. More than half of the patients with CD requiring transsphenoidal surgery at the NIH are children. Furthermore, the knowledge gained by the use of CRH PET imaging in children with MR-invisible tumors will provide direct benefit to the individual child and will provide generalizable knowledge in the treatment of CD in this population. Children under the age of 8 usually require anesthesia for a PET scan, which involves greater risk. Therefore, children under the age of 8 will be excluded from participation NIH Employees: Protections for employees and staff participating in this study 1) assuring that the participation or refusal to participate will have no effect, either beneficial or adverse, on the subject s employment or position at the NIH, 2) giving employees and staff who are interested in participating the 'NIH Information Sheet on Employee Research Participation' prior to obtaining consent, and 3) assuring that there will be no direct solicitation of employees or staff. 4) Independent consent monitoring will be provided by the NIH HSPU. 5) The PI will train study staff regarding obtaining and handling potentially sensitive and private information about co-workers through staff discussions and written branch/section procedures. No compensation will be provided for this protocol Pregnant or lactating women: Pregnant and lactating women will be excluded from participation. The PET radiopharmaceutical used in this study can be harmful to a developing fetus. Therefore women who are able to become pregnant will have a pregnancy test performed within 24 hours before PET-imaging. Individuals will not be able to participate in PET scanning if the pregnancy test results positive