• Biodistribution of [C-11]PBR28
  

Drug: [11C]PRB28
N/A

The peripheral benzodiazepine receptor (PBR) is distinct from central benzodiazepine receptors associated with GABAA receptors. Although PBR was initially identified in peripheral organs such as kidneys, endocrine glands and lungs, later studies identified PBR in the central nervous system. In normal conditions, PBR is expressed in low levels in some neurons and glial cells. PBR can be a clinically useful marker to detect neuroinflammation because activated microglial cells in inflammatory areas express much greater levels of PBR than in microglial cells in resting conditions.

PBR has been imaged with positron emission tomography (PET) using [11C]1-(2-chlorophenyl-N-methylpropyl)-3-isoquinoline carboxamide (PK11195). However, this classical ligand provides only low levels of specific signals and is not sensitive to detect changes that occurred in vivo. Recently we developed a new ligand, N-acetyl-N-(2-[11C]methoxybenzyl)-2-phenoxy-5-pyridinamine ([11C]PBR28), which showed much greater specific signals than [11C]PK11195 in non-human primates. Therefore, [11C]PBR28 is a promising PET ligand. However, radiation absorbed doses have not been estimated from human whole body imaging.

The purpose of this protocol is to estimate radiation absorbed doses of [11C]PBR28 by performing whole body imaging studies on healthy human subjects. The results of this overall study are required to apply this PET ligand in various neurological and psychiatric disorders in the future.

• INCLUSION CRITERIA:

All subjects must be healthy and aged 18-65 years.

EXCLUSION CRITERIA:

The exclusion criteria are shown below:

• Current psychiatric disease, substance abuse or severe systemic disease based on history and physical exam.
• Laboratory tests with clinically significant abnormalities.
• Prior participation in other research protocols or clinical care in the last year such that radiation exposure including that from this protocol would exceed the guidelines set by the Radiation Safety Committee (RSC).
• Pregnancy and breast feeding.
• Positive HIV test.
• Cannot lie flat for 2 - 3 h.
• Taking benzodiazepines.