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

Background: Local abla ve treatments play an important role for pa ents who cannot be treated surgically. Radiofrequency abla on is a well-established alterna ve to surgical treatment of thyroid nodules, however it also has disadvantages. Microwave abla on (MWA) is a new minimally invasive treatment promising several improvements. The aim of this retrospec ve study was to evaluate the effects of microwave abla on on thyroid nodules by 99m Tc-pertechnetate and 99m Tc-MIBI scin graphy. Materials and Methods: 30 pa ents with overall 40 nodules were treated. For the abla on of thyroid nodules, a microwave generator working with frequencies from 902 to 928 MHz was used. The abla on me ranged between 120 and 300 seconds per abla on zone. The target temperatures ranged between 60-80 °C. Preand postinterven onal, the radionuclide uptake was determined using a thyroid specific scin lla on camera. For 27 cold nodules 99m Tc-MIBI was used for evalua on; 13 indifferent nodules were measured with 99m Tc-pertechnetate. Results: The rela ve change of uptake was detected as a quo ent of preand posttherapeu c uptake. The sta s cal analysis of scin graphy data proved the efficacy of microwave abla on. 99m Tc-pertechnetate scin graphy showed an uptake reduc on of 39% (range 9 to 85%). 99m Tc-MIBI imaging showed a median reduc on of 40% (p<0.01) (range 7 to 100%). Conclusion: The determined results show the effec veness of MWA as a treatment op on for benign thyroid nodules. With func onal scin graphy a significant ac vity decrease could be detected in the abla on zone; hence a verifica on of affec vity was possible a=er a short