Development of multispectral autoradiography with solid state detector.

Abstract

Autoradiography is a useful imaging technique to understand biological function by using radio isotopes (RIs). However, conventional autoradiography using X-ray film or Imaging Plate can not easily image distributions of different RIs simultaneously. Each tracers describes each biological functions, therefore we constructed here a multispectral autoradiography. The system consists of a solid state detector (SSD) with high energy-resolution to acquire multispectral information, a collimator with small aperture to restrict the region of observing area, and a translational stage to scan the specimen. The distribution of the RI of interest agent can be obtained by mapping spectrum intensity within the energy-window to corresponding observed points. We confirmed the validity of this method by experiments with physical phantoms and tissues of rat's hearts. First, we imaged the phantom with 201Tl and 99mTc, and could specify the individual RIs. Next, from rectangular paper phantom soaked in 99mTc-labeled tracer, the spatial resolution of experimental system was estimated on about magnitude of x mm2. Finally, the sliced tissue of rat's heart was imaged. Here, we also propose a new imaging method to improve the spatial resolution and reduce data-acquisition time. It is based on reconstruction from projections like X-ray CT.