The quantification of technetium in generator-derived pertechnetate using ICP-MS.

Area of Science:

• Radiochemistry
• Analytical Chemistry
• Nuclear Medicine

Background:

• Chromatographic technetium-99m (99mTc) generators, crucial for medical imaging, are derived from molybdenum-99 (99Mo).
• Accurate measurement of the 99Tc:99mTc ratio is vital for regulatory compliance and ensuring generator performance.
• Existing analytical methods struggle to accurately quantify this ratio in low-activity generator eluates throughout their elution cycle.

Purpose of the Study:

• To develop and validate a sensitive analytical method for measuring 99Tc:99mTc ratios in 99mTc generator eluates.
• To address the limitations of previous methods in monitoring low-activity generators.
• To provide a reliable method for regulatory assessment of generator eluates.

Main Methods:

• Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was utilized to measure total technetium concentrations.
• The method achieved a detection limit of 200 pg mL−1 (200 parts per trillion) for technetium in generator eluates.
• 99Tc:99mTc ratios were determined and compared with theoretically computed values.

Main Results:

• The ICP-MS method demonstrated high sensitivity, capable of measuring technetium down to 200 pg mL−1.
• Measured 99Tc:99mTc ratios showed excellent agreement with theoretically calculated values across various elution stages.
• Ratios varied from 47:1 for initial elutions of generators with long ingrowth times to 1.4:1 for later elutions of generators with short ingrowth times.

Conclusions:

• ICP-MS provides a robust and sensitive analytical technique for determining 99Tc:99mTc ratios in 99mTc generator eluates.
• This method overcomes previous limitations in monitoring low-activity generators and meets regulatory requirements.
• The validated method ensures accurate assessment of generator quality and performance for nuclear medicine applications.