Comparisons of animal-human translated and human 18F-BAY94-9172 amyloid radiation dosimetry

Objectives Animal based radiation-dosimetry analyses form the basis of radiation safety assessment prior to the use of new radio-labelled agents in humans. This work reports a comparison of radiation-dosimetry for animal-translated and human measurements of the novel amyloid tracer ¹⁸F-BAY94-9172.

Methods Three NMRI mice per time point were injected with 112.6 kBq ¹⁸F-BAY94-9172 and sacrificed at time points of 2, 5, 15, 30, 60, 120 and 240 mins. Resected organs were weighed and counted for radioactivity. The resultant %ID/g Time Activity Curves were scaled to adjust for metabolic and organ differences between mouse and human.Human radiation dosimetry was determined from three human subjects injected with ¹⁸F-BAY94-9172 and scanned on a Philips Gemini PET/CT camera. Five Sequential wholebody PET images were acquired over a period of three hours. Organs of interest were defined from the CT and applied as Volumes-Of-Interest to the PET image data.The scaled-mouse and the human cumulated activities for organs were determined and OLINDA/EXM was used to calculate the effective dose for each organ.

Results The major discrepancy between the two models is the factor of 5-times lower estimated Liver ED from the mouse-translated compared to human-measured data. There is, however, good overall agreement for individual organs and the resultant wholebody ED's.

Conclusions The human wholebody ED of ¹⁸F-BAY94-9172 determined from mouse-translated data is in good agreement with human measurements and demonstrates the utility of animal-based models in the assessment of human radiation dosimetry for the development of novel radio-labeled tracers.