Effect of different retention doses of ultrasound-guided polidocanol chemical ablation for benign cystic-solid thyroid nodules.

OBJECTIVE: To assess the influence of varying retention doses of ultrasound-guided polidocanol chemical ablation for benign cystic-solid thyroid nodules. METHODS: A retrospective study was conducted from December 2019 to January 2022, including 78 patients with benign cystic-solid thyroid nodules, of which 31 received polidocanol chemical ablation alone, 23 received polidocanol chemical plus thermal ablation, and 24 received open surgery. Patients who received polidocanol chemical ablation were assigned into groups based on the retention dose of polidocanol: 0 %, 10 %, 20 %, 30 %, and 50 %. Follow-ups were done at 1, 3, 6, and 12 months postoperatively. The volume of the nodules, postoperative complications, and recurrence of the nodules were examined before treatment and during follow-up visits. RESULTS: Total operation time and intraoperative bleeding volume for patients who received ablation were substantially lower than those for patients who received open surgery (P < 0.001). Among patients in the polidocanol chemical ablation group, volume shrinkage rate of thyroid nodules in the 10 % retention dose group was significantly lower than that in the 0 % retention dose group at 1, 3, and 6 months postoperatively (P < 0.05). The 30 % retention dose group had the highest nodule shrinkage rate (98.46 ± 1.55 %) at 12 months postoperatively, which was significantly higher than that in the 50 % retention dose group (P < 0.05). Among patients in the polidocanol chemical and thermal ablation group, the volume shrinkage rate of thyroid nodules in the 10 % and 30 % retention dose groups at 1 month postoperatively was significantly lower than that in the 0 % retention dose group (P < 0.05). Although volume shrinkage rate in the 20 % retention dose group after thermal ablation was higher than that in the 0 % retention dose group, the difference was not statistically significant (P > 0.05). In terms of adverse reactions, the incidence of hoarseness and coughing was higher in the open surgery group than in the polidocanol chemical ablation and polidocanol chemical and thermal ablation groups, but there was no significant difference (P > 0.05). CONCLUSION: Chemical ablation with polidocanol was safe and effective for therapy of benign cystic-solid thyroid nodules, and the optimal retention dose may be between 20 % and 30 %. Patients with poor efficacy from chemical ablation alone can receive safe and effective treatment through thermal ablation.

High-resolution real-time Fourier transform based on optical frequency comb injected frequency shifting loop.

A high-resolution real-time Fourier transform scheme is proposed and demonstrated based on injecting an optical frequency comb (OFC) into a frequency shifting loop (FSL). Through setting the frequency interval between neighboring teeth in the coherent OFC to be equal to an integer multiple of the frequency shift and also the free spectral range of the FSL, the number of the effective signal replicas from the FSL is increased by M times, where M is the tooth number of the OFC. Hence, it breaks the limitation on the number of round trips due to the gain saturation effect and the cumulative amplified spontaneous emission noise in the FSL under a single optical carrier injection, which greatly enhances the frequency resolution. In the experiment, a coherent three-tone optical carrier is injected into an FSL to realize real-time spectrum analysis, where the frequency resolution is enhanced by three times compared with that by using a single-tone optical carrier injection, i.e., from 60 kHz to 20 kHz.