Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique (‘MOST’). Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (<20% solid tissue within the volume of interest). Results Bipolar RFA resulted in a highly significant (p < 0.0001) decrease of nodule volume (ΔV), median 5.3 mL (range 0.13–43.1 mL), corresponding to a relative reduction in mean of 56 ± 17.9%. Median initial volume was 8 mL (range 0.48–62 mL); 3 months after ablation a median volume of 2.3 mL (range 0.3–32 mL) was measured. Nodule growth ≥50% occurred in 70% (14 nodules). At the follow-up no complications such as infections, persisting pain, nerve injuries or immunogen stimulation occurred. Patients with cold nodules (15) remained euthyroid, with hyperfunctioning nodules either euthyroid (2) or latent hypofunctional (1). Conclusion The use of bipolar RFA is an effective, safe and suitable thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.

High-intensity focused ultrasound (HIFU) is a promising, non-invasive technique in treating benign thyroid nodules (TNs). The aim of this study was to evaluate the efficacy of HIFU to induce clinically meaningful shrinkage in benign predominantly solid TNs and to identify variables that influence or predict the magnitude of TN volume reduction. For each of ten subjects, HIFU treatment was conducted on a single nodule. Nodular volume was measured sonographically at baseline and at 3 months post-procedure. Nodular function and early treatment assessment was done scintigraphically. Median nodular volume reduction was 0.7 ml absolute and 48.8% relative to pre-interventional size (p < 0.05). Absolute shrinkage was negatively correlated with the average treatment depth (τ = −0.61, p < 0.05). Absolute nodular volume was positively correlated with the scintigraphic nodular uptake reduction (τ = 0.66, p < 0.05). HIFU treatment of benign predominantly solid TNs appears to be safe and effective for inducing nodular shrinkage. Despite potential for improvement, a single treatment session with HIFU is already a viable alternative to more standard methods. The feasibility of multiple HIFU treatments requires further investigation. Due to the small sample size, the findings of this analysis need conformation by larger studies.

High-intensity focused ultrasound (HIFU) allows to inflict intracorporal thermal lesions without penetrating the skin or damaging the surrounding tissue. This analysis intends to assess the magnitude of HIFU-induced ablations within benign thyroid nodules using scintigraphic imaging with 99mTc.

Summary: Aim: Goiters and thyroid nodules are an ongoing problem in healthcare. There has not been any treatment of goiters and thyroid nodules based on the combined therapy of microwave ablation (MWA) and radioiodine therapy (RIT) until now. In this study the potential benefit of a combined therapy versus single RIT is evaluated in order to achieve improvements concerning 131I-dose and hospitalization time. Patients, material, methods: Ten patients with goiter and benign thyroid nodules or Graves' disease were included. Pre-ablation assessments included sonographical imaging, functional imaging with 99mTc and FNAB to collect data of nodules and total thyroid volume and to exclude malignancy. Prior to treatment, radioiodine uptake test was performed. MWA was operated under local anesthesia with a system working in a wavelength field 902–928 MHz. Post-MWA, thyroid volume was recalculated ultrasonically. Due to reduced vital volume, changes of 131I-dose and hospitalization time could be monitored. Results: Mean absolute thyroid volume reduction by MWA before applying RIT was 22 ± 11 ml, meaning a relative reduction of 24 ± 6% (p < 0.05). Thereby, administered activity could be reduced by 393 ± 188 MBq using the combined therapy, reflecting a relative reduction of 24 ± 6% (p < 0.05). Additionally, mean hospitalization time was decreased by 2.1 ± 0.8 days using MWA prior to RIT, implying a relative reduction of 28 ± 6% (p < 0.05). Conclusion: Depending on ablated volume by MWA, RITmonotherapy requires on average 31.2% more 131I-activity than the combined therapy. The combined therapy remarkably decreases 131I-dose and hospitalization time. The combined MWA and RIT therapy is a considerable, effective and safer alternative to surgery for the treatment of very large benign nodular goiters.

Baseline uptake on prostate-specific membrane antigen (PSMA)-targeted imaging is a prerequisite for radioligand therapy (RLT) with [¹⁷⁷Lu]Lu-PSMA-617. This study aims to quantify lesion-based response to RLT in relation to pretreatment standard molecular imaging metrics derived from [⁶⁸Ga]Ga-PSMA-11 PET/CT. Sixty-one patients with mCRPC underwent [⁶⁸Ga]Ga-PSMA-11 PET/CT imaging before and after a median of 4 (IQR 2–6) RLT cycles. Maximum and mean standardized uptake values (SUV_max, SUV_mean), as well as tumor-to-liver ratio (TLR), were assessed. A median of 12 (IQR 7–17) lesions was analyzed per patient, resulting in a total of 718 lesions. Lesions with ≥30% SUV_max decline or falling below the blood pool uptake were considered responsive; ≥30% SUV_max increase marked lesion progression. Additionally, 4-point visual scoring was performed according to E-PSMA consensus. In total, 550/718 (76.6%) lesions responded to RLT, including 389/507 (76.7%) bone metastases and 143/181 (79.0%) lymph node metastases. Baseline SUV_max, SUV_mean, and TLR values were associated with lesion response by a moderate but significant correlation (r_s = 0.33, p < 0.001, r_s = 0.32, p < 0.001, and r_s = 0.31, p < 0.001, respectively). For the classification of lesion progression based on baseline PSMA uptake, receiver operating characteristics (ROC) found SUV_max, SUV_mean, and TLR to have comparable discriminatory value (AUC 0.85, 0.87, and 0.83). Of 42 tumor sites with baseline uptake below the liver (V-score < 2), 19/42 (45.2%) were responsive, 9/42 (21.4%) were stable, and 14/42 (33.3%) showed progression, leaving liver uptake a threshold with low prognostic value for the identification of RLT-refractory lesions (PPV 33%). This was observed accordingly for various liver uptake-based thresholds, including TLR < 1.5, <2.0 with a PPV at 24%, 20%, respectively. Standard uptake parameters quantified by routine baseline [⁶⁸Ga]Ga-PSMA-11 PET/CT are moderately associated with post-treatment lesion response to [¹⁷⁷Lu]Lu-PSMA-617. Commonly applied liver-based uptake thresholds have limited value in predicting refractory lesions at individual tumor sites.

Bone-seeking ²²³Radium-dichloride (²²³Ra) is an established treatment prolonging survival and reducing morbidity in selected patients with metastatic castration-resistant prostate cancer (mCRPC) with skeletal involvement. Radioligand therapy with ¹⁷⁷Lutetium-PSMA-617 (¹⁷⁷Lu-PSMA-617) has been increasingly implemented in patients with mCRPC failing conventional treatment options. In this study, the safety and efficacy of ¹⁷⁷Lu-PSMA-617 in patients with progressive bone involvement under treatment with ²²³Ra was assessed. Twenty-eight men (median age 73 years, range 63–89 years) with progressive mCRPC, who started ¹⁷⁷Lu-PSMA-617 within 8 weeks after the last ²²³Ra administration, received a median of 4 (IQR 3–6) and a total of 120 cycles of ²²³Ra and a median of 4 (IQR 2–7) cycles ¹⁷⁷Lu-PSMA-617 with a mean treatment activity of 6.5 ± 1.2 GBq per cycle, reaching a mean cumulative activity of 30.7 ± 23.4 GBq. A PSA response (≥50% PSA decline 12 weeks after the first ¹⁷⁷Lu-PSMA-617 cycle) was observed in 18/28 (64.3%) patients and imaging-based partial remission (PR) was observed in 11/28 (39.3%) patients. Median imaging-based progression-free survival (PFS) was 10 (95% CI, 6–14) months and median overall survival (OS) was 18 (95% CI, 14–22) months. Patients with low bone tumor burden (2–20 lesions) had a significantly longer OS (28 vs. 14 months, p < 0.045) compared to patients with a high tumor burden (>20 lesions). Grade ≥ 3 hematological toxicity was observed in six patients after their last treatment cycle with anemia, leukopenia and thrombocytopenia in 5/28 (17.9%), 4/28 (14.3%) and 6/28 (21.4%) patients, respectively. In progressive bone-metastatic mCRPC patients, prompt initiation of ¹⁷⁷Lu-PSMA-617 after failing ²²³Ra is effective with an acceptable toxicity profile.