Sub-millimeter technetium-99m calibration sources.

PURPOSE: Small animal radioscintigraphic imaging systems aim to achieve sub-millimeter resolution. At the present time, sub-millimeter calibration sources that can be placed at will within an imaged volume are not readily available. We have developed a method for producing technetium-99m (Tc-99m) sources in less than 15 minutes with readily available reagents. PROCEDURES: Tc-99m pertechnetate TcO(4)](-) was incubated with 45 microm to 106 microm diameter spherical anion exchange beads, washed, and mounted as desired for instrument calibration. RESULTS: The procedure yields spherical sources having between 6.8 microCi to 11.1 microCi of Tc-99m per source. This work shows that dual imaging of these sources using white light and radioscintigraphy permits measurement of system performance with high precision. CONCLUSION: Easily prepared, sub-millimeter Tc-99m spherical calibration sources are described, and it is demonstrated that such sources are useful for measuring the resolution and sensitivity of radioscintigraphic systems, such as those designed for small animal imaging.