REAL-TIME, IN-VIVO MEASUREMENT OF RADIATION-DOSE DURING RADIOIMMUNOTHERAPY IN MICE USING A MINIATURE MOSFET DOSIMETER PROBE

This report presents the first real-time measurement of absorbed radiation dose during radioimmunotherapy in mice. Dose rate and total dose at the center of the tumor were measured after administration of Y-90-labeled antibodies using a miniature metal oxide semiconductor field-effect transistor radiation dosimeter probe which was inserted into the center of the tumor volume. Continuous real-time measurements were made for as long as 23 h after injection of the radiolabeled antibodies. Comparison of the real-time dose-rate measurements with estimates based on the MIRD formalism indicates good agreement. The real-time measurements are further compared to measurements made in a second experiment in which groups of mice were sacrificed at individual times after injection of the same radiolabeled antibodies. The real-time measurements agree well with the measurements in excised tumors. The real-time measurements have greater time resolution and are much more efficient than traditional uptake measurements. (C) 1995 by Radiation Research Society