Dose calibrator linearity test: (99m)Tc versus (18)F radioisotopes.

Area of Science:

• Nuclear Medicine Physics
• Radiopharmaceutical Quality Control

Background:

• Dose calibrator linearity testing is crucial for accurate radiopharmaceutical quantification in nuclear medicine.
• Fluorine-18 (18F) is commonly used but presents challenges due to high radiation exposure and acquisition costs.
• Technetium-99m (99mTc) is a widely available and lower-energy alternative isotope.

Purpose of the Study:

• To evaluate the feasibility of using 99mTc as a substitute for 18F in dose calibrator linearity assessments.
• To compare the performance of dose calibrator linearity tests using both 18F and 99mTc.

Main Methods:

• Performed linearity tests using 62 GBq of 99mTc and 12 GBq of 18F sources, measuring activities down to 1 MBq.
• Calculated and compared the ratios and deviations between experimental and theoretical activities for both isotopes.
• Assessed the constancy of the activity ratio over the measurement period.

Main Results:

• Mean deviations between experimental and theoretical activities were 0.56 (± 1.79)% for 99mTc and 0.92 (± 1.19)% for 18F.
• The mean ratio of indicated activity to true activity was consistently around 3.42 for 99mTc and 3.39 for 18F, remaining stable over time.
• Results indicated compatibility between the linearity test performance using 99mTc and 18F.

Conclusions:

• 99mTc is a viable radioisotope for dose calibrator linearity testing, yielding results comparable to 18F.
• Utilizing 99mTc can reduce radiation exposure and costs associated with 18F acquisition.
• 99mTc is recommended as the preferred isotope for dose calibrator linearity tests in nuclear medicine facilities using 18F, ensuring procedural quality and service integrity.