Functional neuroinflammatory- and serotonergic imaging in Alzheimer's disease: validation and preliminary clinical findings
Year: 2003
Type: dissertation
Abstract: The peripheral benzodiazepine receptor (PBR) is found in highest concentrations in kidneys and heart. In addition, it was reported to reflect neuro-inflammatory damage by a colocalisation with activated microglia. PK 11195 is a high affinity ligand for the PBR. The aim of the present study was to investigate in humans the biodistribution and dosimetry of [I]iodo-PK 11195, a potential SPET tracer for the PBR. Five healthy volunteers were injected with 112 MBq of I labelled iodo-PK 11195. Sequential whole body scans were performed up to 72 hours post-injection. Multiple blood samples were taken, and urine was collected to measure the fraction voided by the renal system. Decay corrected ROIs of the whole-body images were analysed, and geometric mean count rates were used to determine organ activity. Organ absorbed doses and effective dose were calculated using the MIRD method. [I]iodo-PK 11195 was rapidly cleared from the blood, mainly by the hepatobiliary system. Approximately 22% was voided in urine after 48 hours. Average organ residence times were 0.74, 0.44, and 0.29 hrs for the liver, upper large intestine, and lower large intestine respectively. The testes received the highest dose, 109.4 μGy/MBq. All other organs investigated received doses of less than 50 μGy/MBq. The effective dose was 40.3 μSv/MBq. In conclusion, I labelled iodo-PK 11195 can be used for the visualisation of the PBR and indirectly for the imaging of neuroinflammatory lesions. Taking into account the radiation burden of 7.46 mSv following an administration of 185 MBq, a I labelled iodo-PK 11195 investigation has to be considered as an ICRP risk category IIb investigation.
Author: Jan Versijpt
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1602142943