The aim of this study is to evaluate the potential of Al18F-1,4,7-triazacyclononane-1,4,7-triacetate-octreotide (Al18F-NOTA-octreotide) as a positron emission tomography (PET) somatostatin receptor imaging agent in patients with neuroendocrine tumors.

In the first part of the study, six healthy volunteers will undergo several sequential whole-body PET/CT scans starting from the moment of tracer injection up to six hours post injection for an initial safety assessment and dosimetry study of Al18F-NOTA-octreotide in humans.

In the second part of the study, six neuroendocrine tumor patients, with at least five positive lesions on routine clinical 68Ga-DOTA-peptide PET, will undergo a dynamic PET scan for the first 45 minutes, followed by three single static whole-body PET/CTs up to three hours post injection for an initial efficacy assessment (evaluation of the lesion detection rate) and pharmacokinetics study of Al18F-NOTA-octreotide in humans. Furthermore a first comparison with 68Ga-DOTA peptide PET will be performed.

Inclusion Criteria:

Part 1: Healthy volunteers:

• Age between 18 and 65 years
• Signed Informed Consent
• Subject is judged to be in good health by the investigator on the basis of medical history, physical examination including vital signs and clinical laboratory tests
• Female subjects should be post-menopausal or surgically sterile or using effective contraceptive with negative urinary pregnancy test

Part 2: Neuroendocrine tumor patients:

• Age between 18 and 75 years
• Signed Informed Consent
• Subject is diagnosed with a neuroendocrine tumor of gastroenteropancreatic, pulmonary, neural crest or unknown primary origin
• Subject is judged to be in good general condition by the investigator on the basis of medical history, physical examination including vital signs and clinical laboratory tests, besides the diagnosis of neuroendocrine tumor.
• Subject should have at least 5 positive lesions on routine clinical 68Ga-DOTA-peptide PET performed within 6 months prior to the inclusion visit. A positive lesion is defined as tracer uptake above background deemed to be caused by the presence of NET cells by an experienced nuclear medicine physician
• Female subjects should be post-menopausal or surgically sterile or using effective contraceptive with negative pregnancy test

Exclusion Criteria:

Part 1: Healthy volunteers:

• Subject has a previous or ongoing recurrent or chronic disease able to interfere with the evaluation of the trial according to the judgement of the investigator, especially a known gastro-intestinal, hepatic, renal, cardiovascular, metabolic or hormonal disease, cancer, major neurological or convulsive disorder or any psychiatric disease
• Subject is currently a user (including ''recreational use'') of any illicit drugs, including cannabis, or has a history of drug or alcohol abuse
• Subject takes concomitant medication, except for oral contraceptives, sporadic paracetamol, or low-dose and limited in time non-steroidal antiinflammatory drugs
• Subject is unable to refrain from smoking more than 10 cigarettes per day during the study
• Subject has had exposure to ionizing radiation (> 1 mSv) in other research studies within the last 12 months
• Subject suffers from claustrophobia or cannot tolerate confinement during PET/CT scanning procedures; subject cannot lie still for 90 minutes inside the scanner
• Subject is unwilling to avoid unusual, unaccustomed, or strenuous physical activity (i.e. weight lifting, running, bicycling) from the time of the selection visit until the safety visit
• Subject does not understand the study procedure
• Subject is unwilling or unable to perform all of the study procedures, or is considered unsuitable in any way by the principal investigator
• Subject is potentially pregnant (urinary hCG test will be performed in women where pregnancy is not excluded), wishes to become pregnant up to 3 months after administration of Al18F-NOTA-octreotide or is breast-feeding
• Subject has recently (< 30 days) participated or is simultaneously participating in another prospective interventional clinical trial
• Subject has a history of multiple and/or severe allergies to drugs or food
• Subject underwent surgery between the selection and inclusion visit
• Subject is mentally or legally incapacitated

Part 2: Neuroendocrine tumor patients:

• Subject has a previous or ongoing recurrent or chronic disease, other than a neuroendocrine tumor, at high risk to interfere with the evaluation of the trial according to the judgement of the investigator, e.g. known gastro-intestinal, hepatic, renal, cardiovascular, metabolic or hormonal disease, cancer, major neurological or convulsive disorder or any psychiatric disease
• Subject is currently a user (including ''recreational use'') of any illicit drugs, including cannabis, or has a history of drug or alcohol abuse
• Subject is unable to refrain from smoking more than 10 cigarettes per day during the study
• Subject has had exposure to ionizing radiation (> 1 mSv) in other research studies within the last 12 months
• Subject suffers from claustrophobia or cannot tolerate confinement during PET/CT scanning procedures; subject cannot lie still for 60 minutes inside the scanner
• Subject is unwilling to avoid unusual, unaccustomed, or strenuous physical activity (i.e. weight lifting, running, bicycling) from the time of the selection visit until the telephone follow-up interview.
• Subject does not understand the study procedure
• Subject is unwilling or unable to perform all of the study procedures, or is considered unsuitable in any way by the principal investigator
• Subject is potentially pregnant (urinary hCG test will be performed in women where pregnancy is not excluded), wishes to become pregnant up to 3 months after administration of Al18F-NOTA-octreotide or is breast-feeding
• Subject has recently (< 30 days) participated or is simultaneously participating in another prospective interventional clinical trial
• Subject has a history of multiple and/or severe allergies to drugs or food
• Subject underwent surgery between the selection and inclusion visit
• Subject is mentally or legally incapacitated