Imaging Properties of PET Radiotracer [18F]3F-PHPG in Patients With Neuroendocrine Tumors

An Exploratory Study of 3-[18F]Fluoro-para-hydroxyphenethylguanidine ([18F]3F-PHPG) in Patients With Neuroendocrine Tumors

The goal of this exploratory study is to test whether [18F]3F-PHPG can be used reliably to map the locations of tumors in patients with neuroendocrine tumors. If so, the results of this study will be used to support further development of [18F]3F-PHPG as a clinical tool for neuroendocrine tumor localization and staging.

Subjects enrolled in this study will be recruited from the population of adult patients with neuroendocrine tumors, including pheochromocytoma and paraganglioma, being treated at the University of Michigan Hospital.

The primary objective of the study is to obtain basic information on the biodistribution and pharmacokinetics of [18F]3F-PHPG in cancer patients with neuroendocrine tumors.

The secondary objective of the study is to compare the diagnostic performance of [18F]3F-PHPG in cancer patients with neuroendocrine tumors with the FDA approved radiopharmaceuticals [123I]metaiodobenzylguanidine ([123I]MIBG) and [68Ga]DOTA-TATE in the same patients. A group of approximately 12 of the subjects scanned with [18F]3F-PHPG will be recruited to undergo a whole-body [123I]MIBG scan using planar scintigraphy with a gamma camera, following the standard clinical protocol used at the University of Michigan. In addition, a single SPECT/CT scan of the primary neuroendocrine tumor will be acquired after the whole-body scan to provide a tomographic image for comparison with the positron emission tomography (PET) image acquired using [18F]3F-PHPG. Several subjects enrolled on this study will undergo [68Ga]DOTA-TATE scans off-study, as part of routine clinical management. Existing [68Ga]DOTA-TATE scans will be obtained from consenting subjects' medical records.

This is an exploratory study and thus all statistical data analyses will be exploratory in nature.

Inclusion Criteria:

• Current neuroendocrine tumor diagnosis
• Able to lie flat for 60 minutes
• Provision of informed consent

Exclusion Criteria:

• Pregnancy or lactation

• Claustrophobia

• Inability to lie flat for 60 minutes

• Currently taking medications that may alter PET scans of neuroendocrine tumors with these tracers, including any of the following:

  • Tricyclic antidepressants, which inhibit the norepinephrine transporter: desipramine, amitriptyline, imipramine
  • Cold medications containing the sympathomimetic amines: phenylephrine, phenylpropanolamine, pseudoephedrine
  • Nasal decongestants (some use phenylephrine as the active agent)
  • Cocaine (which inhibits the norepinephrine transporter)
  • Tetrabenazine (Xenazine), which inhibits the VMAT2 transporter
  • Monoamine oxidase inhibitors (MAOI)
  • Some antihypertensive drugs: reserpine, labetalol, α-methyldopa, clonidine