Description
Sodium Iodide I 123 (Na123I) for diagnostic use is supplied in capsules for oral administration. The capsules are available in strengths of 3.7 and 7.4 megabecquerels (MBq) (100 and 200 μCi) I-123 at time of calibration.
The radionuclidic composition at calibration is not less than 97.0 percent I-123, not more than 2.9 percent I-125 and not more than 0.1 percent Te-121. The radionuclidic composition at expiration time is not less than 87.2 percent I-123, not more than 12.4 percent I-125 and not more than 0.4 percent Te-121. The ratio of the concentration of I-123 and I-125 changes with time. Graph 1 shows the minimum concentration of I-123 as a function of time and Graph 2 shows the maximum concentration of I-125 as a function of time.
Graph 1. Radionuclidic Concentration of I-123
PERCENT OF TOTAL RADIOACTIVITY:
IODINE-123
Graph 2. Radionuclidic Concentration of I-125
PERCENT OF TOTAL RADIOACTIVITY:
IODINE-125