OBJECTIVE: The present study was aimed at evaluating the viability of replacing ¹⁸F with ^99mTc in dose calibrator linearity testing. MATERIALS AND METHODS: The test was performed with sources of ^99mTc (62 GBq) and ¹⁸F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical ^99mTc and ¹⁸F sources activities were calculated and subsequently compared. RESULTS: Mean deviations between experimental and theoretical ^99mTc and ¹⁸F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the ^99mTc source as measured with the equipment pre-calibrated to measure ^99mTc and ¹⁸F was 3.42 (± 0.06), and for the ¹⁸F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. CONCLUSION: The results of the linearity test using ^99mTc were compatible with those obtained with the ¹⁸F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in ¹⁸F acquisition suggest ^99mTc as the element of choice to perform dose calibrator linearity tests in centers that use ¹⁸F, without any detriment to the procedure as well as to the quality of the nuclear medicine service.

Keywords: Nuclear medicine; Dose calibrator; Linearity test; Nuclear instrumentation.