Percutaneous microwave ablation of thyroid nodules: efficacy evaluation with 99m Tc - pertechnetate and 99mTc-MIBI functional imaging

Background : Local ablave treatments play an important role for paents who cannot be treated surgically. Radiofrequency ablaon is a well-established alternave to surgical treatment of thyroid nodules, however it also has disadvantages. Microwave ablaon (MWA) is a new minimally invasive treatment promising several improvements. The aim of this retrospecve study was to evaluate the effects of microwave ablaon on thyroid nodules by 99m Tc-pertechnetate and 99m Tc-MIBI scingraphy. Materials and Methods : 30 paents with overall 40 nodules were treated. For the ablaon of thyroid nodules, a microwave generator working with frequencies from 902 to 928 MHz was used. The ablaonme ranged between 120 and 300 seconds per ablaon zone. The target temperatures ranged between 60-80 °C. Pre- and post- intervenonal, the radionuclide uptake was determined using a thyroid specific scinllaon camera. For 27 cold nodules 99m Tc-MIBI was used for evaluaon; 13 indifferent nodules were measured with 99m Tc-pertechnetate. Results: The relave change of uptake was detected as a quoent of pre- and post- therapeuc uptake. The stascal analysis of scingraphy data proved the e fficacy of microwave ablaon. 99m Tc-pertechnetate scingraphy showed an uptake reducon of 39% (range 9 to 85%). 99m Tc-MIBI imaging showed a median reducon of 40% (p<0.01) (range 7 to 100%). Conclusion: The determined results show the effecveness of MWA as a treatment opon for benign thyroid nodules. With funconal scingraphy a significant acvity decrease could be detected in the ablaon zone; hence a verificaon of affecvity was p ossible a=er a short period ofme.