Beta camera for static and dynamic imaging of charged-particle emitting radionuclides in biologic samples.

A detection system based on microchannel plates has been constructed to image charged particles emitted by radionuclides in biomedical samples. This technique has significant advantages over conventional film autoradiography for investigating the distribution of radiolabeled compounds: shorter acquisition times due to the high sensitivity, easier sample handling, direct quantification and the ability to perform dynamic studies. The detector performance shows a spatial resolution of 0.9 mm for carbon-14 (14C) (0.156 MeV), good linearity and homogeneity. The noise level is below 50/(cm2.sec). Successful imaging with this system has been performed with beta-emitters 14C, sulfur-35 (35S), iodine-131 (131I), yttrium-90 (90Y), and positron emitters gallium-68 (68Ga), and fluorine-18 (18F). Dynamic studies of axonal transport of 35S-methionine in a nerve, and static images of 90Y-labeled monoclonal antibodies in slices of tumors are presented. The system shows promise for rapid quantitative imaging of charged-particle emitting radionuclides in small biologic samples.