Microwave ablation: a technical and clinical comparison to other thermal ablation modalities to treat benign and malignant thyroid nodules

Introduction

Thyroid nodules are common, and the incidence is rising due to the increased use of imaging that detects incidental nodules, which leads to further workup. Over 90% of the nodules are benign lesions (1). Malignant thyroid nodules, especially papillary thyroid cancer (PTC), are also common. PTC has a favorable 10-year survival rate, which led to the new development of active surveillance (2). Additionally, 15% to 20% of the benign nodules will grow significantly (at least 20%) over time, and up to 10% will develop additional nodules during surveillance (1). Furthermore, patients with PTC may not always be amenable to active surveillance due to psychological, time, travel, and other constraints. Traditionally, all malignant thyroid lesions and some larger benign lesions are treated with surgery, but the morbidity of surgery can be significant (3). A multicenter study of 3,660 patients showed re-bleeding, nerve paresis, and hypocalcemia rates of 2.10%, 0.97%, and 4.40%, respectively, 6 months after surgery (4). Percutaneous ethanol injection (PEI) and other chemical ablative techniques are proven to be effective and safe in cystic nodules; however, for solid and malignant nodules, thermal ablation (TA) is needed to treat the lesion effectively (5). Furthermore, TA techniques have shown effectiveness in cystic and predominantly cystic nodules (6). A recent paper also showed the cost-effectiveness of radiofrequency ablation (RFA) over lobectomy (7). Of all the TA modalities, RFA is the most used (8). More recently, in the early 2010s, microwave ablation (MWA) gained increasing attention (9), and in 2023, Food and Drug Administration (FDA) approved MWA use in the United States (US) (10).

Ablation is a technique for achieving cell necrosis using chemical, thermal, or cryogenic modalities. In TAs, hyperthermia is induced at 40–50 ℃ when enzymes, cell membranes, and molecular bonds are altered. At 60 ℃, protein and collagen denature, leading to tissue coagulation. At 100 ℃, water vaporizes, producing gas that alters cells and thermal decomposition of tissue. Over 100 ℃, carbonization occurs, leading to tissue charring. Sixty degrees is the critical temperature for most biological matters because, at that temperature, the effect is irreversible (11).

Most thermal ablative techniques can be performed under minimal sedation using real-time ultrasound guidance. Some techniques can be carried out using only local anesthetics combined with relaxation techniques, making performing in an office setting possible and further reducing costs (12). All thermal ablative techniques can employ the trans-isthmic approach and the moving shot technique with other advanced maneuvers such as hydro-dissection and vascular ablation to improve safety and efficacy and reduce complications such as skin burn and hematoma formation (13,14).

MWA technique

MWA is an indirect, energy-based hyperthermic reaction generated by the electric field using an antenna with frequencies between 900 and 2,450 MHz (15). It uses two electromagnetic theories to induce cell death: (I) dipole theory and (II) ionic theory. Dipole rotation theory states that the water molecule’s unequal charge rotates around the microwave’s oscillating charges, which generates friction and heat that causes coagulative necrosis of the cell. Ionic polarization theory states that the collision of ions by the electromagnetic field generates heat by kinetic energy (16,17).

The MWA system used for tissue ablation consists of a generator, a coaxial cable with a cooling component, and an antenna. The antenna is on a probe of between 14 and 17 gauge and has a sharp cutting tip that assists in placing it in the area to be ablated. There is a temperature sensor at the end of the antenna, and the shaft distal to the temperature sensor is often also cooled using water at 0 ℃ (10,18,19). The diameter of the coagulation zone can be changed by adjusting the frequency (MHz) or the power setting (W) (15).

Vital technical differences between different TA techniques

RFA

RFA uses electrical currents, the frequency of which typically falls between 200 and 1,200 kHz. The RF wave is passed between two electrodes and generates heat by ionic friction, producing kinetic heat. Over time, heat conduction can also damage the surrounding tissue. The temperature target of RFA is typically between 60 and 100 ℃, stopping the heating as soon as vaporization is achieved, revealed by a hypoechogenic cloud of gas bubbles seen on ultrasound. The charring of the tissue at over 100 ℃ can also increase the impedance and prevent the delivery of additional RFA. A cooled RFA system can be used by running cold water through the tip to lower the heat immediately next to the probe to prevent charring and enable the delivery of energy to a larger area (20). The RFA system uses a dispersive electrode (grounding pad) placed on the patient’s skin. It can generate up to 250 W of energy through the patient between the two electrodes. The probe has a sharp 18-gauge needle tip (21).

Light amplification stimulated emission of radiation (LASER) ablation

Laser ablation (LA) uses light energy generated by different excited states of photons the target absorbs. This transfer of energy state produces heat in the surrounding area, causing coagulation. Relaxation time between each light wave is crucial in achieving penetration depth. The relaxation time differs between target materials, which makes laser setting effective on specific tissues and harmless on others. Blood perfusion of various tissues also plays a role in heat convection generated by light energy (11,22). The LA system uses hollow needles to deliver a fiberoptic probe to the target tissue, delivering light energy for 5 to 15 min to achieve the total target energy (21).

Key differences between MWA, RFA, and LA are summarized in Table 1.

Key technical advantages and disadvantages of MWA

MWA does not use dispersive electrodes and can be effective at lower power inputs, making it safe for patients with implants and cardiac defibrillators. The heat delivered by MWA is more uniform because it produces less of a “heat sink” effect, where electrical currents of RFA travel down the path of least resistance when they are near a vessel. MWA can be faster than RFA and LA (16,18).

However, because MWA is affected less by the “heat sink” effect, it will ablate through vessels, making it theoretically less safe around major vessels. However, there are very few reported major vessel complications, and some cases of internal jugular thrombosis are reported to be attributed to hypothyroidism, cancer status, or extended compression (23). Because RFA relies more on heat conduction which results in relatively slower damage of tumor beyond the radius of the electrode. Its effect could potentially be detected months after the initial procedure, which could give it a theoretical advantage to tumor volume reduction over MWA in the long-term (16,20). MWA also uses a larger probe than both RFA and LA.

Outcomes

Benign thyroid nodules (BTNs)

The American Thyroid Association recommends surgical resection (SR) of nodules larger than 4 cm, associated with many risks. Furthermore, there are significant cost and psychosocial burdens associated with the diagnosis and surveillance of those smaller nodules (24). Ablation is a minimally invasive technique used to shrink those BTNs successfully. Traditionally, LA and RFA are some of the more established tools used for TA, and recently, MWA has also been shown to be effective with minimal adverse effects.

MWA has significant volume reduction ratios (VRRs) at follow-up. A large single-center cohort study with 1,180 thyroid nodules showed significant VRR at 6-, 9-, 12-, and 15-month follow-ups (81.4%, 89.8%, 92.9%, and 93.3%, respectively) (25). Other studies show similar results with VRR of over 90% at 12-month (4). However, some studies demonstrate lower VRR at around 50% at 6- to 12-month (26-28).

MWA can significantly affect thyroid function tests and thyroglobulin levels in 24 hours, with sustained effects after 3 and 6 months, signifying damage to surrounding healthy thyroid tissue. The thermal spread is more pronounced in MWA than in RFA (29). TSH decreased from 0.72 to 0.49, free T3 increased from 4.62 to 5.64, free T4 increased from 10.81 to 12.29, and thyroglobulin increased from 44.8 to 1,205.3 (all P<0.001) (30). However, in other study, the effect on thyroid functions is not significant (27).

A recent meta-analysis of patients >50 years old compared the efficacy and complication rate of MWA, RFA, and LA for BTN. The VRR 6 months after treatment between MWA and RFA is not significantly different (8). The ablative time (193 vs. 209 s, P<0.001) and energy (50.8 vs. 32.2 W, P<0.001) used between RFA and MWA differ significantly (31). The average procedure time for MWA was less than that of LA (21.1 vs. 47.9 min, P<0.01) at similar energy for BTN of all sizes (32).

Another meta-analysis of 9 studies of all age groups comparing only RFA and MWA showed significantly higher VRR in the RFA group at 6 months [standardized mean difference (SMD): −0.05; 95% confidence interval (CI): −0.15 to 0.04; P=0.29; I²=0%] and 12 months (SMD: −0.07; 95% CI: −0.17 to 0.03; P=0.17; I²=0%) (33). A recent small single-center RCT of 36 patients who underwent RFA and MWA detected a larger VRR at 3 months for the RFA group (62.08% vs. 46.90%, P=0.021); however, there was no significant difference at 1 and 6 months. The complication rates between the groups were similar. In this study, the RFA group showed slightly more favorable cosmetic improvement (34). The theoretical VRR of MWA and RFA has been tested in a laboratory setting. One study demonstrates that 10 min after ablation of ex vivo bovine liver tissue, MWA demonstrated greater contraction than RFA with similar energy delivery (35). However, it is difficult to replicate these studies in live human subjects with diseased organs (34).

PTC

More centers have been using TA to treat PTC in recent years. Many techniques, including MWA, have demonstrated excellent VRR (over 98%), resolution (over 95%), and comparable recurrence and survival rates to those who underwent SR (36-38). A study that analyzed the pathological outcomes of patients who underwent SR after MWA demonstrated that all the post-ablation lesions showed no residual carcinomas, cases of detected PTCs were outside the ablation zones, and all the patients who underwent surgery due to uncertainty about the efficacy of MWA (25%) were completely disease free (39).

A 10-center retrospective study from China published in 2024 collected 775 patients with T1N0M0 multifocal PTC, based on pre-treatment imaging, who underwent MWA and SR from May 2015 to December 2021 using propensity score matching. All patients in the SR group underwent central neck dissection, and 35.5% were detected to have micro-metastasis to the lymph node (LN) at the time of treatment. Subgroup analysis of the post-operative T1N1M0 was also performed. There was no difference in tumor progression rate (4.8% MWA vs. 3.5% SR, P=0.42), progression-free survival (log-rank P=0.19), and over survival (log-rank P=0.15) at 1, 3, and 5 years between all groups. The LN metastasis rate during follow-up was lower in the MWA group (0.4%) than in the SR group (1.3%), indicating that omission of prophylactic LN ablation during MWA does not elevate post-treatment LN metastasis rates compared with routine LN dissection during SR (40).

Another large 12-center prospective cohort study with 461 participants compared the outcomes of using MWA to treat papillary thyroid microcarcinoma (PTMC), defined as biopsy-confirmed PTC of less than 1cm, with and without capsular invasion seen on pre-treatment ultrasound. No differences were observed in VRR (mean: 97% vs. 96%, P=0.58) or disease progression (2% vs. 1%, P=0.82); comparable technical success rates were achieved (99% vs. 100%, P=0.18), with a similar incidence of complications (1% vs. 3%, P=0.38) (41).

Pediatric population

A single-center study of 25 pediatric patients (mean age: 9.8 years) with 34 symptomatic BTNs who underwent MWA between 2018 and 2021 demonstrated VRRs after 3, 6, and 12 months, and at the last follow-up assessment were 49.8%±33.7%, 74.1%±17.0%, 82.4%±19.0%, and 85.0%±17.0%, respectively and 17.6% of nodules completely disappeared at last visit. The symptom score decreased from 5.56±1.85 to 2.47±1.08 (P<0.001), and the cosmetic score improved from 3.26±0.79 to 1.82±0.63 (P<0.001). There were two cases of subcapsular hemorrhage during the procedure resolved with 30 min compression, and the thyroid function was not affected after MWA. This study demonstrated that MWA can be a safe and effective way to treat the pediatric population (42).

Different studies comparing outcomes between MWA, RFA, and LA are summarized in Tables 2,3.

Factors that influence and predict outcome

Several factors influence the success of MWA. Multivariate analysis has identified the internal component of nodules (solid or solid predominant), enhancement mode (hypo- or iso-echoic), and immediate volume after the procedure as independent factors affecting ablation efficacy (43). Moreover, the procedure appears to have a better effect on smaller nodules, with 10 mL or less initial volumes showing a more significant reduction. The energy per 1 mL reduction in nodular volume has been suggested as a potential risk factor for nodule recurrence (44). A similar effect is seen in RFA in a large multi-institutional North American study on the efficacy of RFA, where the paper demonstrated that RFA might be associated with a lower rate of successful reduction for nodules over 20 mL (45). Another multi-institutional study showed that stiff nodules were more likely to have a lower VRR than soft nodules in RFA [odds ratio (OR): 11.64; P<0.05], demonstrating the importance of assessing tumor characteristics when deciding treatment (46).

Psychological factors such as anxiety and depression can also influence the outcome of MWA. In a study, 238 patients who underwent MWA were given Self-Rating Depression and Anxiety Scales at follow-up visits. The results demonstrated that the VRR of patients without negative emotions in the first month, the third month, and the sixth month was significantly more than that of patients with negative emotions (P<0.05). Patients with a history of hypertension and hyperglycemia are more prone to these negative emotions, which can impact their prognosis (38).

Utilization of real-time ultrasonography is essential in TA of thyroid nodules (47). Specialized contrast enhancing ultrasound (CEUS) is used to evaluate the microvasculature and used to predict VRR (48). Several other imaging techniques have been used to predict post-MWA effectiveness. A German study of 36 thyroid nodules found that technetium-99m (^99mTc) pertechnetate scintigraphy imaging could detect a change in all thyroid nodules 24 hours after MWA. The standard B-mode sonography was only able to detect changes in 80.6% and color-coded Doppler in 86.1% (49). Scintigraphy findings using ^99mTc-MIBI and ^99mTc-pertechnetate at 24 hours post-ablation also had a significant correlation with VRR at 3-month (50). Although real-time imaging using sonography cannot be replaced for the MWA procedure, other less user-dependent imaging techniques may be able to predict MWA efficacy.

Safety of MWA

MWA is a minimally invasive approach to treating thyroid diseases that offers numerous benefits over traditional surgery. It is associated with less pain, shorter recovery time, reduced risk of scarring, and a lower chance of vocal cord injury (4). Less blood loss, shorter incision length, and shorter procedure and hospitalization durations (all P<0.001), permanent hoarseness (2.2%, P=0.05), and hypoparathyroidism (4.0%, P=0.005) were encountered only in the SR group (40). Complications of MWA are low overall, with transient voice change being the most common adverse effect after MWA (30) and most studies report no major complications—permanent voice change, nodule rupture, sympathetic nerve injury (26-28). The median line approach to MWA has higher transient hoarseness than the lateral cervical approach (51).

Many studies demonstrated that there was no statistical difference in the complications and cosmetic and pain scores between RFA and MWA (31,33,51). The complication rates between LA and MWA are also similar (8). In one meta-analysis, MWA is more likely to cause major complications when compared to RFA (P=0.002; 95% CI: 1.11, 4.718). One study noted a better cosmetic outcome with RFA than MWA (34).

Different studies comparing the safety profile between MWA, RFA, and LA are summarized in Table 4.

Conclusions

MWA is effective and safe in BTNs in adults and pediatric populations and PTC compared to other TA techniques. However, some key technical differences between MWA and other methods could influence the selection of patients and nodules. Most studies on the efficacy and safety of MWA are from retrospective review or prospective cohort studies. There is a lack of large, randomized control trials comparing TA techniques. This could be due to the lack of equipment available at the same center. It is important to directly compare different techniques as the effect of these techniques can be different with various nodule characteristics, such as size and cystic content. At the time this article was published, there was one study found on the outcome of MWA on pediatric patients with a median follow-up of 12 [6–48] months (42). Longer follow-up would help assess the long-term endocrine effect of MWA in the developmental ages. MWA can also be a cost-effective and fast procedure performed under minimal sedation or local anesthetic. Further studies can evaluate the effect of relaxation techniques in reducing sedation. Although more studies are to be conducted comparing various TA techniques, to date, there is no consensus that any of these techniques are superior to others. The decision on which technique to use largely depends on the availability of the technology and familiarity of the operator with the equipment.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Gland Surgery for the series “RFA and Recent Innovations in Endocrine Surgery”. The article has undergone external peer review.

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-24-221/prf

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-24-221/coif). The series “RFA and Recent Innovations in Endocrine Surgery” was commissioned by the editorial office without any funding or sponsorship. E.K. serves as an Editor-in-Chief of Gland Surgery from May 2024 to April 2026 and served as the unpaid Guest Editor of the series. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Durante C, Costante G, Lucisano G, et al. The natural history of benign thyroid nodules. JAMA 2015;313:926-35. [Crossref] [PubMed]
2. Ding W, Ruan G, Lin Y, et al. Survival outcomes of low-risk papillary thyroid carcinoma at different risk levels: a corollary for active surveillance. Front Endocrinol (Lausanne) 2023;14:1235006. [Crossref] [PubMed]
3. Luo X, Kandil E. Advancements in thyroid surgery: enhancing safety and efficacy through technological and clinical innovations. Gland Surg 2024;13:1-3. [Crossref] [PubMed]
4. Li S, Yang M, Guo H, et al. Microwave Ablation Vs Traditional Thyroidectomy for Benign Thyroid Nodules: A Prospective, Non-Randomized Cohort Study. Acad Radiol 2022;29:871-9. [Crossref] [PubMed]
5. Clark RDE, Luo X, Issa PP, et al. A clinical practice review of percutaneous ethanol injection for thyroid nodules: state of the art for benign, cystic lesions. Gland Surg 2024;13:108-16. [Crossref] [PubMed]
6. Papini E, Monpeyssen H, Frasoldati A, et al. 2020 European Thyroid Association Clinical Practice Guideline for the Use of Image-Guided Ablation in Benign Thyroid Nodules. Eur Thyroid J 2020;9:172-85. [Crossref] [PubMed]
7. Kuo EJ, Oh A, Hu Y, et al. If the price is right: Cost-effectiveness of radiofrequency ablation versus thyroidectomy in the treatment of benign thyroid nodules. Surgery 2023;173:201-6. [Crossref] [PubMed]
8. Qian Y, Li Z, Fan C, et al. Comparison of ultrasound-guided microwave ablation, laser ablation, and radiofrequency ablation for the treatment of elderly patients with benign thyroid nodules: A meta-analysis. Exp Gerontol 2024;191:112425. [Crossref] [PubMed]
9. Morelli F, Sacrini A, Pompili G, et al. Microwave ablation for thyroid nodules: a new string to the bow for percutaneous treatments? Gland Surg 2016;5:553-8. [Crossref] [PubMed]
10. Young S, Walker L, Huber T. Thermal Ablation of Thyroid Nodules, From the AJR "How We Do It" Special Series. AJR Am J Roentgenol 2024; Epub ahead of print. [Crossref]
11. Ansari MA, Erfanzadeh M, Mohajerani E. Mechanisms of Laser-Tissue Interaction: II. Tissue Thermal Properties. J Lasers Med Sci 2013;4:99-106.
12. Bertrand AS, Iannessi A, Buteau S, et al. Effects of relaxing therapies on patient's pain during percutaneous interventional radiology procedures. Ann Palliat Med 2018;7:455-62. [Crossref] [PubMed]
13. Chan WK, Sun JH, Liou MJ, et al. Novel and Advanced Ultrasound Techniques for Thyroid Thermal Ablation. Endocrinol Metab (Seoul) 2024;39:40-6. [Crossref] [PubMed]
14. Marcy PY. Editorial Comment: Percutaneous Thermal Ablation of Thyroid Nodules-Where Do We Stand, Where Shall We Go? AJR Am J Roentgenol 2024; Epub ahead of print. [Crossref]
15. Sun Y, Wang Y, Ni X, et al. Comparison of ablation zone between 915- and 2,450-MHz cooled-shaft microwave antenna: results in in vivo porcine livers. AJR Am J Roentgenol 2009;192:511-4. [Crossref] [PubMed]
16. Skinner MG, Iizuka MN, Kolios MC, et al. A theoretical comparison of energy sources--microwave, ultrasound and laser--for interstitial thermal therapy. Phys Med Biol 1998;43:3535-47. [Crossref] [PubMed]
17. Tanaka M, Sato M. Microwave heating of water, ice, and saline solution: molecular dynamics study. J Chem Phys 2007;126:034509. [Crossref] [PubMed]
18. Gala KB, Shetty NS, Patel P, et al. Microwave ablation: How we do it? Indian J Radiol Imaging 2020;30:206-13. [Crossref] [PubMed]
19. Zheng BW, Wang JF, Ju JX, et al. Efficacy and safety of cooled and uncooled microwave ablation for the treatment of benign thyroid nodules: a systematic review and meta-analysis. Endocrine 2018;62:307-17. [Crossref] [PubMed]
20. Shin JH, Baek JH, Ha EJ, et al. Radiofrequency ablation of thyroid nodules: basic principles and clinical application. Int J Endocrinol 2012;2012:919650. [Crossref] [PubMed]
21. Papini E, Gugliemi R, Pacella CM. Laser, radiofrequency, and ethanol ablation for the management of thyroid nodules. Curr Opin Endocrinol Diabetes Obes 2016;23:400-6. [Crossref] [PubMed]
22. Heisterkamp J, van Hillegersberg R, IJzermans JN. Critical temperature and heating time for coagulation damage: implications for interstitial laser coagulation (ILC) of tumors. Lasers Surg Med 1999;25:257-62. [Crossref] [PubMed]
23. Liu Y, Wang XJ, Wang JL, et al. Internal Jugular Vein Thrombosis After Microwave Ablation of Cervical Lymph Node Metastasis in Papillary Thyroid Microcarcinoma: A Case Report. Front Endocrinol (Lausanne) 2022;13:792715. [Crossref] [PubMed]
24. Uppal N, Collins R, James B. Thyroid nodules: Global, economic, and personal burdens. Front Endocrinol (Lausanne) 2023;14:1113977. [Crossref] [PubMed]
25. Honglei G, Shahbaz M, Farhaj Z, et al. Ultrasound guided microwave ablation of thyroid nodular goiter and cystadenoma: A single center, large cohort study. Medicine (Baltimore) 2021;100:e26943. [Crossref] [PubMed]
26. Yue W, Wang S, Wang B, et al. Ultrasound guided percutaneous microwave ablation of benign thyroid nodules: safety and imaging follow-up in 222 patients. Eur J Radiol 2013;82:e11-6. [Crossref] [PubMed]
27. Heck K, Happel C, Grünwald F, et al. Percutaneous microwave ablation of thyroid nodules: effects on thyroid function and antibodies. Int J Hyperthermia 2015;31:560-7. [Crossref] [PubMed]
28. Feng B, Liang P, Cheng Z, et al. Ultrasound-guided percutaneous microwave ablation of benign thyroid nodules: experimental and clinical studies. Eur J Endocrinol 2012;166:1031-7. [Crossref] [PubMed]
29. Chu KF, Dupuy DE. Thermal ablation of tumours: biological mechanisms and advances in therapy. Nat Rev Cancer 2014;14:199-208. [Crossref] [PubMed]
30. Erturk MS, Cekic B, Celik M, et al. Microwave ablation of symptomatic benign thyroid nodules: Short- and long-term effects on thyroid function tests, thyroglobulin and thyroid autoantibodies. Clin Endocrinol (Oxf) 2021;94:677-83. [Crossref] [PubMed]
31. Cheng Z, Che Y, Yu S, et al. US-Guided Percutaneous Radiofrequency versus Microwave Ablation for Benign Thyroid Nodules: A Prospective Multicenter Study. Sci Rep 2017;7:9554. [Crossref] [PubMed]
32. Shi YF, Zhou P, Zhao YF, et al. Microwave Ablation Compared With Laser Ablation for Treating Benign Thyroid Nodules in a Propensity-Score Matching Study. Front Endocrinol (Lausanne) 2019;10:874. [Crossref] [PubMed]
33. Zufry H, Hariyanto TI. Comparative Efficacy and Safety of Radiofrequency Ablation and Microwave Ablation in the Treatment of Benign Thyroid Nodules: A Systematic Review and Meta-Analysis. Korean J Radiol 2024;25:301-13. [Crossref] [PubMed]
34. Zhang Y, Han X, Ren YJ, et al. Microwave ablation versus radiofrequency ablation for solid or predominantly solid benign thyroid nodules: a randomized controlled clinical trial. Zhonghua Nei Ke Za Zhi 2024;63:74-80. [Crossref] [PubMed]
35. Liu D, Brace CL. Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery. Med Phys 2019;46:4127-34. [Crossref] [PubMed]
36. Bo XW, Lu F, Xu HX, et al. Thermal Ablation of Benign Thyroid Nodules and Papillary Thyroid Microcarcinoma. Front Oncol 2020;10:580431. [Crossref] [PubMed]
37. Gao X, Yang Y, Wang Y, et al. Efficacy and safety of ultrasound-guided radiofrequency, microwave and laser ablation for the treatment of T1N0M0 papillary thyroid carcinoma on a large scale: a systematic review and meta-analysis. Int J Hyperthermia 2023;40:2244713. [Crossref] [PubMed]
38. Zhang Y, Mao J, Zhao X, et al. Analysis of the risk factors of negative emotions in patients undergoing microwave ablation of thyroid nodules during the perioperative period and its impact on prognosis: a prospective cohort study. Gland Surg 2023;12:81-92. [Crossref] [PubMed]
39. Ding M, Wu GS, Gu JH, et al. Pathology confirmation of the efficacy and safety of microwave ablation in papillary thyroid carcinoma. Front Endocrinol (Lausanne) 2022;13:929651. [Crossref] [PubMed]
40. Zhao ZL, Wang SR, Dong G, et al. Microwave Ablation versus Surgical Resection for US-detected Multifocal T1N0M0 Papillary Thyroid Carcinoma: A 10-Center Study. Radiology 2024;311:e230459. [Crossref] [PubMed]
41. Zheng L, Dou JP, Han ZY, et al. Microwave Ablation for Papillary Thyroid Microcarcinoma with and without US-detected Capsule Invasion: A Multicenter Prospective Cohort Study. Radiology 2023;307:e220661. [Crossref] [PubMed]
42. Shi W, Cai W, Wang S, et al. Safety and efficacy of microwave ablation for symptomatic benign thyroid nodules in children. Eur Radiol 2024;34:3851-60. [Crossref] [PubMed]
43. Fu QQ, Kang S, Wu CP, et al. A study on the efficacy of microwave ablation for benign thyroid nodules and related influencing factors. Int J Hyperthermia 2021;38:1469-75. [Crossref] [PubMed]
44. Xia B, Yu B, Wang X, et al. Conspicuousness and recurrence related factors of ultrasound-guided microwave ablation in the treatment of benign thyroid nodules. BMC Surg 2021;21:317. [Crossref] [PubMed]
45. Russell JO, Desai DD, Noel JE, et al. Radiofrequency ablation of benign thyroid nodules: A prospective, multi-institutional North American experience. Surgery 2024;175:139-45. [Crossref] [PubMed]
46. Kandil E, Omar M, Aboueisha M, et al. Efficacy and Safety of Radiofrequency Ablation of Thyroid Nodules: A Multi-institutional Prospective Cohort Study. Ann Surg 2022;276:589-96. [Crossref] [PubMed]
47. Andrioli M, Valcavi R. Ultrasound B-flow imaging in the evaluation of thermal ablation of thyroid nodules. Endocrine 2015;48:1013-5. [Crossref] [PubMed]
48. Cao J, Fan P, Wang F, et al. Application of contrast-enhanced ultrasound in minimally invasive ablation of benign thyroid nodules. J Interv Med 2022;5:32-6. [Crossref] [PubMed]
49. Klebe J, Happel C, Grünwald F, et al. Visualization of tissue alterations in thyroid nodules after microwave ablation: sonographic versus scintigraphic imaging. Nucl Med Commun 2015;36:260-7. [Crossref] [PubMed]
50. Korkusuz H, Nimsdorf F, Happel C, et al. Percutaneous microwave ablation of benign thyroid nodules. Functional imaging in comparison to nodular volume reduction at a 3-month follow-up. Nuklearmedizin 2015;54:13-9. [Crossref] [PubMed]
51. Yue WW, Wang SR, Lu F, et al. Radiofrequency ablation vs. microwave ablation for patients with benign thyroid nodules: a propensity score matching study. Endocrine 2017;55:485-95. [Crossref] [PubMed]