Recent advancements in PET/CT, including the emergence of long axial field-of-view (LAFOV) PET/CT scanners, have increased PET sensitivity substantially. Consequently, there has been a significant reduction in the required tracer activity, shifting the primary source of patient radiation dose exposure to the attenuation correction (AC) CT scan during PET imaging. This study proposes a parameter-transferred conditional generative adversarial network (PT-cGAN) architecture to generate synthetic CT (sCT) images from non-attenuation corrected (NAC) PET images, with separate networks for [¹⁸F]FDG and [¹⁵O]H₂O tracers. The study includes a total of 1018 subjects (n = 972 [¹⁸F]FDG, n = 46 [¹⁵O]H₂O). Testing was performed on the LAFOV scanner for both datasets. Qualitative analysis found no differences in image quality in 30 out of 36 cases in FDG patients, with minor insignificant differences in the remaining 6 cases. Reduced artifacts due to motion between NAC PET and CT were found. For the selected organs, a mean average error of 0.45% was found for the FDG cohort, and that of 3.12% was found for the H₂O cohort. Simulated low-count images were included in testing, which demonstrated good performance down to 45 s scans. These findings show that the AC of total-body PET is feasible across tracers and in low-count studies and might reduce the artifacts due to motion and metal implants.

Background: Evidence of the efficacy of laser thermal ablation (LTA) in benign thyroid nodules is abundant. However, little is known about the effect on quality of life (QoL) of this treatment. Methods: Prospective cohort study investigating the effect of LTA before, three, and six months after LTA on QoL using the thyroid-specific patient-reported outcome (ThyPRO) measure. Patients receiving LTA (laser group [LG]) was compared with a well-characterized control group (CG) from the Danish civil registry. Results: The LG comprised 54 patients, with no age or sex differences compared with the CG ( n = 739). Sixty-nine percent of the patients had a recurrent cystic thyroid nodule, 6% had a solid nodule, while the remaining 25% were of mixed character. The median nodule volume was 6.8 mL (interquartile range [IQR]: 4.0–11.1) before LTA, and 1.8 mL (IQR: 0.6–4.1) at 6 months post-LTA ( p < 0.001), corresponding to a median reduction of 78%. All cystic fluid (median: 6 mL; IQR: 2.0–9.0) was aspirated before LTA. Median treatment time was 400 seconds (IQR: 300–600), applying a median energy of 823 J (IQR: 600–1200). At baseline and according to the ThyPRO scales, the LG differed significantly from the CG by having more goiter symptoms, hyperthyroid symptoms, tiredness, and cognitive complaints ( p < 0.05 for all variables), but only the difference in the goiter symptom scale was of a clinically important magnitude. At three months, the LG experienced a large improvement in goiter symptoms (effect size [ES] = 1.05), a moderate improvement in cosmetic complaints (ES = 0.50), and a moderate improvement in the overall QoL (ES = 0.64). Only the improvements in the goiter symptom and the cosmetic complaint scales were clinically important. Six months after LTA, the anxiety scale showed further improvement of moderate size (ES = 0.52). At 6 months, the results above were maintained, and 79% of patients experienced a large and clinically important improvement in the goiter symptom scale and no clinically important differences were found between the LG and the CG. Conclusions: In this unblinded, prospective observational study, measures of disease-specific QoL were significantly improved compared with preprocedure levels, in patients with solid-cystic nodules.

Purpose: We examined the effect of selenium vs placebo on remission rate and quality of life (QoL) in the Graves’ selenium supplementation (GRASS) trial (ID: NCT01611896). Methods: Double-blinded, placebo-controlled, multi-centre trial in individuals with newly diagnosed Graves’ hyperthyroidism randomised to daily supplementation with 200 μg selenium or placebo tablets during 24–30 months, depending on the timing of antithyroid drug (ATD) withdrawal. The primary outcome was the proportion of participants with non-remission, defined as receiving ATD or remaining hyperthyroid (thyroid stimulating hormone <0.1 mIU/L) during the last 12 months of the intervention period or referral to ablative therapy (radioactive iodine or surgery). QoL was serially assessed by the thyroid-related patient-reported outcome ThyPRO and compared with previously collected norm data. Results: Between Dec 7th 2012 and Dec 3rd 2018, 430 participants with Graves’ hyperthyroidism were recruited. Non-remission was observed in 114 (53.3%) participants in the placebo group and 118 (54.6%) in the selenium group (OR = 1.0 (95% CI: 0.7–1.5); P = 0.98). There was no beneficial effect of selenium, as compared with placebo, on any ThyPRO scale. The participants’ QoL at the end of the study was comparable to that of the general population sample. Thyrotropin receptor antibody levels were similar in the groups at the 18-month and end-of-study follow-up visits. Conclusion: In individuals with newly diagnosed Graves’ hyperthyroidism, daily supplementation with selenium did not have any effects compared with placebo as add-on to standard antithyroid drugs. The GRASS trial findings do not support the use of selenium supplementation in Graves’ hyperthyroidism.

Introduction: Incidental uptake within or adjacent to the thyroid gland is occasionally observed on somatostatin receptor-targeted PET imaging in patients with neuroendocrine neoplasms (NENs). The reported prevalence and clinical relevance of such findings are not well established. Materials and methods: We reviewed PET scan reports for all patients undergoing [⁶⁸Ga]Ga-DOTA-TOC PET/CT or [⁶⁴Cu]Cu-DOTA-TATE PET/CT in our department from 2018 to 2022. Scans reporting incidental uptake within or adjacent to the thyroid gland were reviewed post hoc to extract semi-quantitative scores of tracer uptake for the incidental lesions. We further extracted data from electronic patient charts, including cytology and histology. Results: A total of 3692 PET scans were performed on 1808 unique patients. Incidental abnormal thyroid uptake was reported in 42 of the 1808 patients, with thyroid malignancy identified in five of these 42 patients. Two patients had medullary thyroid cancers, two had neuroendocrine tumor metastases, and one had a renal clear cell carcinoma metastasis. Focal uptake in close relation to the thyroid gland, suggestive of parathyroid adenoma, was reported in another 13 of the 1808 patients, with biochemical hyperparathyroidism found in six of these 13 patients. Conclusion: In patients undergoing somatostatin receptor-targeted PET scans for evaluation of NENs, the prevalence of reported abnormal uptake within or adjacent to the thyroid gland was low. However, the rates of thyroid malignancy and parathyroid adenomas were substantial. Prospective studies are needed to determine the optimal diagnostic and therapeutic strategies for these incidental findings.