The accuracy of target delineation in radiation treatment (RT) planning of cerebral gliomas is crucial to achieve high tumor control, while minimizing treatment-related toxicity. Conventional magnetic resonance imaging (MRI), including contrast-enhanced T1-weighted and fluid-attenuated inversion recovery (FLAIR) sequences, represents the current standard imaging modality for target volume delineation of gliomas. However, conventional sequences have limited capability to discriminate treatment-related changes from viable tumors, owing to the low specificity of increased blood-brain barrier permeability and peritumoral edema. Advanced physiology-based MRI techniques, such as MR spectroscopy, diffusion MRI and perfusion MRI, have been developed for the biological characterization of gliomas and may circumvent these limitations, providing additional metabolic, structural, and hemodynamic information for treatment planning and monitoring. Radionuclide imaging techniques, such as positron emission tomography (PET) with amino acid radiopharmaceuticals, are also increasingly used in the workup of primary brain tumors, and their integration in RT planning is being evaluated in specialized centers. This review focuses on the basic principles and clinical results of advanced MRI and PET imaging techniques that have promise as a complement to RT planning of gliomas.

The aim of this work is to compare [⁶⁸Ga]Ga-PSMA-11 and [¹⁸F]PSMA-1007 PET/CT as imaging agents in patients with prostate cancer (PCa). Comparisons were made by evaluating times and costs of the radiolabeling process, imaging features including pharmacokinetics, and impact on patient management. The analysis of advantages and drawbacks of both radioligands might help to make a better choice based on firm data. For [⁶⁸Ga]Ga-PSMA-11, the radiochemical yield (RCY) using a low starting activity (L, average activity of 596.55 ± 37.97 MBq) was of 80.98 ± 0.05%, while using a high one (H, average activity of 1436.27 ± 68.68 MBq), the RCY was 71.48 ± 0.04%. Thus, increased starting activities of [⁶⁸Ga]-chloride negatively influenced the RCY. A similar scenario occurred for [¹⁸F]PSMA-1007. The rate of detection of PCa lesions by Positron Emission Tomography/Computed Tomography (PET/CT) was similar for both radioligands, while their distribution in normal organs significantly differed. Furthermore, similar patterns of biodistribution were found among [¹⁸F]PSMA-1007, [⁶⁸Ga]Ga-PSMA-11, and [¹⁷⁷Lu]Lu-PSMA-617, the most used agent for RLT. Moreover, the analysis of economical aspects for each single batch of production corrected for the number of allowed PET/CT examinations suggested major advantages of [¹⁸F]PSMA-1007 compared with [⁶⁸Ga]Ga-PSMA-11. Data from this study should support the proper choice in the selection of the PSMA PET radioligand to use on the basis of the cases to study.

Pulmonary carcinoids (PCs) are part of a spectrum of well-differentiated neuroendocrine neoplasms (NENs) and are classified as typical carcinoid (TC) and atypical carcinoid (AC). TC differ from AC not only for its histopathological features but also for its “functional imaging pattern” and prognosis. ACs are more undifferentiated and characterized by higher aggressiveness. Positron emission tomography/computed tomography (PET/CT) with somatostatin analogs (SSA) labeled with Gallium-68 (⁶⁸Ga-DOTA-TOC, ⁶⁸Ga-DOTA-NOC, ⁶⁸Ga-DOTA-TATE) has widely replaced conventional imaging with gamma camera using ¹¹¹In- or ^99mTc-labelled compounds and represents now the gold standard for diagnosis and management of NENs. In this setting, as already described for gastro-entero-pancreatic NENs, ¹⁸F-Fluorodeoxiglucose ([¹⁸F]FDG) in addition to ⁶⁸Ga-SSA can play an important role in clinical practice, particularly for ACs that show a more aggressive behavior compared to TCs. The aim of this systematic review is to analyze all original studies collected from the PubMed and Scopus databases regarding PCs in which both ⁶⁸Ga-SSA PET/CT and [¹⁸F]FDG PET/CT were performed in order to evaluate the clinical impact of each imaging modality. The following keywords were used for the research: “¹⁸F, ⁶⁸Ga and (bronchial carcinoid or carcinoid lung)”. A total of 57 papers were found, of which 17 were duplicates, 8 were reviews, 10 were case reports, and 1 was an editorial. Of the remaining 21 papers, 12 were ineligible because they did not focus on PC or did not compare ⁶⁸Ga-SSA and [¹⁸F]FDG. We finally retrieved and analyzed nine papers (245 patients with TCs and 110 patients with ACs), and the results highlight the importance of the combined use of ⁶⁸Ga-SSA and [¹⁸F]FDG PET/CT for the correct management of these neoplasms.

Background/Objectives: Lutathera^® ([¹⁷⁷Lu]Lu-DOTA-TATE) is the first radiolabelled somatostatin (SST) analog approved for the treatment of patients with well-differentiated (G1 and G2) unresectable or metastatic gastro-entero-pancreatic neuro-endocrine-neoplasms (GEP-NENs). The bone marrow and kidneys are critical organs for RLT with [¹⁷⁷Lu]Lu-DOTA-TATE. Our purpose was to evaluate hematological and renal toxicity in 29 patients (18 males, 11 females) treated with Lutathera^®. Methods: According to standard protocols, four cycles of (¹⁷⁷Lu)Lu-DOTA-TATE were administered every eight/nine weeks. Patients received pre-medication with anti-emetic and anti-acid drugs and a slow amino acid infusion for renal protection. Blood count and serum creatinine data were collected at three time points: before the first cycle, after the second cycle, and at the end of treatment. Results: We found that almost all hematological parameters significantly decreased between the baseline and/or interim and post-therapy evaluation, although without a clinical impact. The presence of total tumor load or bone metastases had no influence on these findings, while male patients showed less hematological toxicity than females. Conversely, creatinine levels did not vary during treatment. Conclusions: Our study confirms that [¹⁷⁷Lu]Lu-DOTATATE RLT is safe and well tolerated despite some minor (grade 1) hematological toxicity.

Background/Objectives: The purpose of this study was to compare [¹⁸F]Fluorocholine (FCH) PET/CT, ultrasound (US) and dual-phase scintigraphy with [^99mTc]Tc-methoxyisobutylisonitrile (MIBI) and [^99mTc]Tc-pertechnetate (TcO₄-) ([^99mTc]Tc-MIBI/[^99mTc]TcO₄) in the preoperative detection of hyperfunctioning parathyroid glands. Secondary aims were to determine the optimal scanning time of [¹⁸F]FCH PET/CT while investigating the correlation between [¹⁸F]FCH PET/CT parameters and PTH, calcium levels, lesions size, histopathology, and immunohistochemical analysis. Methods: Patients with primary hyperparathyroidism who underwent US, [^99mTc]Tc-MIBI/[^99mTc]TcO₄ scintigraphy, [¹⁸F]FCH PET/CT and parathyroid surgery were retrospectively evaluated. The following PET parameters were calculated: SUVmax and SUVmean, parathyroid retention index (RI) and lesion contrast (LC). Lesions were classified as parathyroid adenomas (PA), hyperplastic parathyroid glands (HP) or parathyroid carcinoma (PC) according to histology. Results: Forty-nine patients were evaluated and 55 lesions were removed at surgery (8 normal glands, 33 PAs, 12 HP glands, 2 PCs). In a lesion-based analysis, the sensitivity and specificity were 68.9% and 28.6% for US, 65.7% and 40.0% for [^99mTc]Tc-MIBI/[^99mTc]TcO₄, 97.8% and 14.3% for early-phase [¹⁸F]FCH PET/CT and 95.7% and 12.5% for late-phase [¹⁸F]FCH PET/CT. The sensitivity of both early and late [¹⁸F]FCH PET/CT acquisitions was statistically higher than that of US and [^99mTc]Tc-MIBI/[^99mTc]TcO₄ scintigraphy. SUVs were statistically higher in PA than in HP, and RI was significantly lower in HP compared with PC, although this difference was based only on two PC cases. Therefore, this result must be considered preliminary and interpreted with caution. Conclusions: [¹⁸F]FCH PET/CT performed better than US and [^99mTc]Tc-MIBI/[^99mTc]TcO₄ scan for the detection of hyperfunctioning lesions. The most favorable time point to assess parathyroid lesions appears to be 60 min after injection. However, due to the possible rapid washout of some lesions, a supplementary early acquisition is advisable. SUVmax, SUVmean and RI may predict the histological nature of a parathyroid lesion, but larger studies are needed to confirm these findings.

Background: Pulmonary neuroendocrine tumors (lung NETs) comprise a biologically heterogeneous group of neoplasms ranging from indolent typical carcinoids to more aggressive atypical carcinoids. Accurate characterization of tumor biology is essential for optimizing staging, prognostic stratification, and treatment selection. Beyond conventional cross-sectional imaging, functional imaging and emerging quantitative imaging techniques are progressively redefining the diagnostic pathway. Methods: We performed a comprehensive narrative review of the current evidence regarding conventional radiological imaging, somatostatin receptor (SSTR) PET/CT, ¹⁸F-FDG PET/CT, dual-tracer imaging, and radiomics in lung NETs, integrating recent international recommendations from ENETS, ESMO, AIOM, and other major societies. Results: Contrast-enhanced CT remains the cornerstone of anatomical staging, whereas ⁶⁸Ga-labelled somatostatin analogue (SSA) PET/CT provides highly sensitive assessment of receptor expression and patient eligibility for somatostatin analogue therapy and peptide receptor radionuclide therapy (PRRT). Conversely, ¹⁸F-FDG PET/CT identifies metabolically active and biologically aggressive disease, particularly in atypical carcinoids and tumors showing dedifferentiation. Increasing evidence supports the complementary role of dual-tracer PET/CT for non-invasive characterization of tumor heterogeneity, prognostic stratification, and treatment planning. Radiomics further expands this paradigm by extracting quantitative imaging biomarkers that may improve histological prediction, recurrence risk assessment, and individualized management. Although promising, radiomics remains limited by methodological heterogeneity and the lack of prospective validation. Conclusions: The integration of conventional imaging, molecular imaging, and quantitative radiomics supports a shift from lesion detection toward biologically driven precision imaging. Future prospective multicenter studies incorporating imaging biomarkers, artificial intelligence, and clinical-pathological variables may further support personalized management of patients with lung NETs.