The most frequent thyroid cancer is Differentiated Thyroid Cancer (DTC) representing more than 95% of cases. A suitable choice for the treatment of DTC is the systemic administration of 131-sodium or potassium iodide. It is an effective tool used for the irradiation of thyroid remnants, microscopic DTC, other nonresectable or incompletely resectable DTC, or all the cited purposes. Dosimetry represents a valid tool that permits a tailored therapy to be obtained, sparing healthy tissue and so minimizing potential damages to at-risk organs. Absorbed dose represents a reliable indicator of biological response due to its correlation to tissue irradiation effects. The present paper aims to focus attention on iodine therapy for DTC treatment and has developed due to the urgent need for standardization in procedures, since no unique approaches are available. This review aims to summarize new proposals for a dosimetry-based therapy and so explore new alternatives that could provide the possibility to achieve more tailored therapies, minimizing the possible side effects of radioiodine therapy for Differentiated Thyroid Cancer.

Purpose: We evaluate the ability of Artificial Intelligence with automatic classification methods applied to semi-quantitative data from brain 18F-FDG PET/CT to improve the differential diagnosis between Alzheimer Disease (AD) and Mild Cognitive Impairment (MCI). Procedures: We retrospectively analyzed a total of 150 consecutive patients who underwent diagnostic evaluation for suspected AD (n = 67) or MCI (n = 83). All patients received brain 18F-FDG PET/CT according to the international guidelines, and images were analyzed both Qualitatively (QL) and Quantitatively (QN), the latter by a fully automated post-processing software that produced a z score metabolic map of 25 anatomically different cortical regions. A subset of n = 122 cases with a confirmed diagnosis of AD (n = 53) or MDI (n = 69) by 18–24-month clinical follow-up was finally included in the study. Univariate analysis and three automated classification models (classification tree –ClT-, ridge classifier –RC- and linear Support Vector Machine –lSVM-) were considered to estimate the ability of the z scores to discriminate between AD and MCI cases in. Results: The univariate analysis returned 14 areas where the z scores were significantly different between AD and MCI groups, and the classification accuracy ranged between 74.59% and 76.23%, with ClT and RC providing the best results. The best classification strategy consisted of one single split with a cut-off value of ≈ −2.0 on the z score from temporal lateral left area: cases below this threshold were classified as AD and those above the threshold as MCI. Conclusions: Our findings confirm the usefulness of brain 18F-FDG PET/CT QL and QN analyses in differentiating AD from MCI. Moreover, the combined use of automated classifications models can improve the diagnostic process since its use allows identification of a specific hypometabolic area involved in AD cases in respect to MCI. This data improves the traditional 18F-FDG PET/CT image interpretation and the diagnostic assessment of cognitive disorders.

This study aims to evaluate the reliability of qualitative and semiquantitative parameters of 18F-FDG PET-CT, and eventually a correlation between them, in predicting the risk of malignancy in patients with solitary pulmonary nodules (SPNs) before the diagnosis of lung cancer. A total of 146 patients were retrospectively studied according to their pre-test probability of malignancy (all patients were intermediate risk), based on radiological features and risk factors, and qualitative and semiquantitative parameters, such as SUVmax, SUVmean, TLG, and MTV, which were obtained from the FDG PET-CT scan of such patients before diagnosis. It has been observed that visual analysis correlates well with the risk of malignancy in patients with SPN; indeed, only 20% of SPNs in which FDG uptake was low or absent were found to be malignant at the cytopathological examination, while 45.45% of SPNs in which FDG uptake was moderate and 90.24% in which FDG uptake was intense were found to be malignant. The same trend was observed evaluating semiquantitative parameters, since increasing values of SUVmax, SUVmean, TLG, and MTV were observed in patients whose cytopathological examination of SPN showed the presence of lung cancer. In particular, in patients whose SPN was neoplastic, we observed a median (MAD) SUVmax of 7.89 (±2.24), median (MAD) SUVmean of 3.76 (±2.59), median (MAD) TLG of 16.36 (±15.87), and a median (MAD) MTV of 3.39 (±2.86). In contrast, in patients whose SPN was non-neoplastic, the SUVmax was 2.24 (±1.73), SUVmean 1.67 (±1.15), TLG 1.63 (±2.33), and MTV 1.20 (±1.20). Optimal cut-offs were drawn for semiquantitative parameters considered predictors of malignancy. Nodule size correlated significantly with FDG uptake intensity and with SUVmax. Finally, age and nodule size proved significant predictors of malignancy. In conclusion, considering the pre-test probability of malignancy, qualitative and semiquantitative parameters can be considered reliable tools in patients with SPN, since cut-offs for SUVmax, SUVmean, TLG, and MTV showed good sensitivity and specificity in predicting malignancy.

Background: The prognostic importance of neck lymph node (LN) metastases in differentiated thyroid carcinoma (DTC) is controversial even if their presence at surgery often correlates with tumor recurrences that it is mandatory to identify. To this purpose, in the present study, we used 131 I-SPECT/CT as diagnostic imaging procedure.Methods: We retrospectively evaluated 224 consecutive DTC patients already submitted to total thyroidectomy and radioiodine therapy, all of them with ascertained neck radioiodine-avid foci at ¹³¹I-SPECT/CT during long-term follow-up; at surgery, 62 patients were classified at high risk (H), 64 at low risk (L), 98 at very low risk. All patients underwent ¹³¹I-Whole body scan (WBS) followed by SPECT/CT. Result: In the 224 patients, 449 neck iodine avid foci were ascertained at SPECT/CT, while 322 were evidenced at WBS in 165/224 patients. WBS classified as residues 263/322 foci and as unclear 59/322 foci; among the former foci SPECT/CT correctly characterized 8 LN metastases and 3 physiologic uptakes and among the latter it pinpointed 26 LN metastases, 18 residues and 15 physiologic uptakes. SPECT/CT also classified 127 foci occult at WBS as 59 LN metastases and 68 residues. Globally, SPECT/CT identified 93 LN metastases in 59 patients (26 H, 20 L, 13 VL), while WBS evidenced 34 in 25 cases. All 13 VL patients,T1aN0M0, 5 of whom with LN near sub-mandibular glands, had thyroglobulin undetectable or <2.5 ng/ml. Globally, SPECT/CT obtained an incremental value than WBS in 45.5 % of patients, a more correct patient classification changing therapeutic approach in 30.3 % of cases and identified WBS false positive findings in 8% of cases. Conclusion: ¹³¹I-SPECT/CT proved to correctly detect and characterize neck LN metastases in DTC patients in long-term follow-up, improving WBS performance. SPECT/CT routine use is suggested, its role being particularly significant in patients with WBS inconclusive, VL, T1aN0M0 and with undetectable or very low thyroglobulin levels.

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