Nuclear Medicine Communications最新文献

Marine-Lenhart syndrome (MLS) is a rare variant of hyperthyroidism characterized by the coexistence of Graves' disease and autonomously functioning thyroid nodules. This comprehensive literature review aims to synthesize current knowledge regarding the pathophysiology, diagnostic approach, and management of MLS, with a particular focus on the role of nuclear medicine. A structured review of relevant literature-including clinical studies, case reports, and international guidelines-was conducted to explore thyroid anatomy, mechanisms of nodule formation, imaging findings, and therapeutic strategies. Thyroid scintigraphy using radiotracers such as 99m Tc-pertechnetate remains central to the diagnosis of MLS, enabling functional distinction between diffusely hyperactive tissue and coexisting nodules. Despite advances in ultrasonography and fine-needle aspiration biopsy, nuclear imaging continues to offer unique functional insights. Treatment typically involves antithyroid drugs and radioiodine (¹³¹I) therapy; however, higher radioiodine doses may be necessary due to the relative resistance of autonomously functioning nodules. Newer imaging modalities, such as ¹⁸F-fluorodeoxyglucose PET/computed tomography (CT), are not useful for primary nodule characterization but may detect incidental fluorodeoxyglucose-avid nodules that warrant further evaluation. MLS poses a diagnostic challenge due to its overlapping features with other thyroid disorders and the potential for malignancy within cold nodules. This review highlights the indispensable role of nuclear medicine in diagnosing and tailoring treatment for MLS, ultimately promoting better outcomes through precise functional assessment.

Background: Radioembolization is classically used in patients with hepatocellular carcinoma and secondary hepatic malignancies like colorectal cancer and neuroendocrine tumors. Up to now, data for other hepatic metastasized tumor entities are rare, and it is not clear which clinical and imaging features could predict the outcome.

Methods: Data of 60 patients exceptionally treated with radioembolization through the decision of an interdisciplinary board with tumor entities usually not treated by radioembolization were retrospectively analyzed. Hepatic features on cross-sectional preprocedural imaging, for example, like hypervascularization, hepatic tumor burden, maximum diameter, and clinical data, were also analyzed during follow-up. Predictive factors were calculated.

Results: Univariate Cox regression showed a significant impact of different features on overall survival, for example, primary malignancy histology in the case of sarcoma, with 25 months median vs. 6 months median overall survival ( P  = 0.015). Multivariate Cox regression revealed the two key factors for overall survival: arterial hypervascularization more than rim enhancement (15 vs. 6 months, P  = 0.011, hazard ratio: 0.339) and hepatic tumor burden below 10% (18 vs. 5 months, P  < 0.001, hazard ratio: 1.04).

Conclusion: Preprocedural hypervascularization of liver malignancies and hepatic tumor burden are overall survival predicting factors in tumor entities rarely treated by radioembolization. Consideration of these factors can help to carry out suitable patient selection in the interdisciplinary board for radioembolization.

Objective: Pheochromocytoma is an intra-adrenal sympathetic paraganglioma that carries an inherent potential for metastasis, although such events are seldom encountered. Its clinical symptoms and signs are nonspecific. Early and precise identification is essential for effective clinical management and treatment; however, the diagnostic accuracy of pheochromocytoma is influenced by multiple factors, and studies addressing these influences remain limited. This study aimed to investigate the impact of different imaging backgrounds and acquisition times on the diagnostic performance of [ 131 I]meta-iodobenzylguanidine ([ 131 I]MIBG) single-photon emission computed tomography (SPECT)/computed tomography (CT) in differentiating pheochromocytoma from adrenocortical adenoma.

Methods: This retrospective study included 67 patients who had not undergone adrenal surgery before enrollment, underwent [ 131 I]MIBG SPECT/CT, and subsequently received surgical treatment within 2-5 months after imaging, with all lesions histopathologically confirmed. [ 131 I]MIBG SPECT/CT scans were acquired for each patient at different acquisition time points and under varying imaging conditions. Clinical characteristics and imaging data were collected and analyzed to evaluate the diagnostic performance of [ 131 I]MIBG SPECT/CT in differentiating pheochromocytoma.

Results: Significant differences in semiquantitative values of [ 131 I]MIBG SPECT/CT were observed for the same lesion across different imaging backgrounds and acquisition times ( P < 0.0001). The highest diagnostic performance for pheochromocytoma was achieved when the liver was used as the imaging background and images were acquired 48 h postinjection, yielding an area under the curve greater than 0.95. In addition, other imaging parameters also contributed to improving diagnostic accuracy.

Conclusion: Optimizing imaging background and acquisition time significantly enhances the diagnostic performance of [ 131 I]MIBG SPECT/CT for pheochromocytoma, facilitating timely and effective patient management.

Background: Technetium-99m (Tc-99m)-labeled cefixime, ceftriaxone, and ciprofloxacin are explored for stable, effective radiopharmaceutical infection imaging agents.

Objective: This study optimizes Tc-99m labeling of antibiotics, evaluating stability, effectiveness, and infection imaging suitability.

Methods: TcO₄⁻ was reduced with stannous chloride to label antibiotics; scanning electron microscope, ITLC, Fourier transform infrared spectroscopy, HPLC, and biodistribution studies confirmed purity, labeling efficacy, and infection specificity.

Results: Tc-99m labeling of cefixime was performed at a concentration of 5 mg/ml, using 120 µl of SnCl₂ solution (96 µg) as the reducing agent, with the pH adjusted to 4.34 using 1N NaOH. For ciprofloxacin, the concentration was 7.5 mg/ml, with 120 µl of SnCl₂ solution (96 µg) and a pH of 4.5. Ceftriaxone was radiolabeled at 5 mg/ml, using 120 µl of SnCl₂·2H₂O (50 µg) and a pH of 6.8. Radiochemical binding was monitored for 3 h to assess stability. The labeled drugs were administered to mice for SPECT scintigraphy to assess biodistribution, confirm infection imaging, and evaluate their diagnostic potential.

Conclusion: This study examines 99mTc labeling of cefixime, ceftriaxone, and ciprofloxacin, achieving high binding efficiency. It compares their potential in infection imaging, distinguishing infections from inflammation, and exploring therapeutic applications.

Objective: Prostate cancer is one of the most common malignancies in men. While multiparametric MRI is the gold standard for local staging of prostate cancer, accessibility may be limited. The same is true for Prostate Specific Membrane Antigen (PSMA) PET/computed tomography (CT). This study evaluates the diagnostic performance of [ 99m Tc]Tc-PSMA single photon emission computed tomography (SPECT) as an alternative molecular imaging modality.

Methods: This retrospective study of 82 patients with newly diagnosed prostate cancer compares the performance of [ 99m Tc]Tc-PSMA SPECT/CT with multiple readers, with MRI, and with respect to histopathological correlation from biopsies. SPECT/CT findings were evaluated both locally, using a standardised 12-segment prostate model, and with respect to metastases. Agreement between modalities and readers was measured using intraclass correlation and Cohen's kappa.

Results: PSMA SPECT/CT identified clinically relevant prostate lesions with the best interreader agreement for bone metastases and laterality, and poorest agreement for extraprostatic extension and seminal vesicle invasion. Sector-based comparison showed PSMA SPECT/CT to have comparable detection rates to MRI. Higher SPECT standardised uptake values (SUV) were associated with stronger concordance with biopsy results, higher than both the low SPECT SUV group and clinical MRI readings.

Conclusion: [ 99m Tc]Tc-PSMA SPECT/CT demonstrates promise as an alternative to MRI in the primary staging of prostate cancer, particularly in high SPECT SUV settings. While MRI remains more sensitive for local extension, PSMA SPECT may offer complementary value in comprehensive staging, especially in a resource-limited setting.

Background: Classical Hodgkin's lymphoma (cHL) is a largely curable cancer, although a percentage of patients experience recurrence or treatment failure. Interim PET(iPET)/computed tomography (CT) scanning after 2-4 rounds of adriamycin, bleomycin, vinblastine, and dacarbazine chemotherapy has emerged as a useful predictor of treatment response and survival. The current study aimed to assess the prognostic significance of iPET/CT in patients with cHL treated at Azadi Hematology Oncology Center in Duhok Province, Kurdistan Region, and compare the results to worldwide data.

Methods: This retrospective analysis comprised 53 patients who had histologically proven cHL treatment between January 2020 and March 2024. PET/CT scans were performed on all patients at the intermediate and end of therapy stages. Deauville scoring was used to categorize the replies. Kaplan-Meier analysis was used to determine survival results.

Results: Interim complete metabolic response (iCR, Deauville 1-3) was observed in 83% of patients, with a corresponding end-of-treatment complete response rate of 93.2%. Patients with iCR had significantly improved overall survival (OS) and progression-free survival (PFS) compared to those with partial response or no response/progression (OS: P  = 0.001; PFS: P  < 0.001). The concordance rate between iPET/CT and final response was 90.6%.

Conclusion: iPET/CT is a reliable prognostic indicator in cHL and significantly correlates with OS and PFS. The findings support its use in response-adapted therapy in resource-limited settings like Duhok. These results align with international studies, reinforcing the utility of iPET/CT in guiding treatment modifications.

Objective: We aimed to create a new combined left ventricular (LV) systolic function index (left ventricular systolic workload index: LEVESWI-1 and LEVESWI-2) in a gated single-photon emission computed tomography (gSPECT) study to estimate major adverse cardiovascular events (MACE: nonfatal myocardial infarction or cardiac death).

Methods: We analyzed 2727 consecutive patients with suspected coronary artery disease who underwent gSPECT (age 63.82 ± 11, male 60.73%). LEVESWI was obtained through the relationship between LV end-systolic volume (ESV), noninvasive SBP measurement, body surface area, approximate noninvasive LV systolic pressure, and stress heart rate (stress-HR). (LEVESWI-1 = ESV-index × 8.5/stress-HR; LEVESWI-2 = SBP × 0.9/stress-HR). During a follow-up of 3.85 ± 2.7 years, MACE were evaluated. Multivariate Cox regression analysis (MCRA) and receiver operating characteristic curve analysis were used.

Results: In MCRA age greater than 66 years (hazard ratio: 3.29, P  < 0.001); diabetes (hazard ratio: 1.86, P  = 0.008), ST-segment depression greater than or equal to 1 mm (hazard ratio : 1.95, P  = 0.005), METs less than 6.08 (hazard ratio: 1.85, P  = 0.029), LV ejection fraction less than or equal to 57% (hazard ratio: 2.4, P  = 0.005), summed stress score greater than 6 (hazard ratio: 2.32, P  = 0.002), LEVESWI-1 greater than 1.46 mmHg/ml/m²/bpm (hazard ratio: 2.18, P  = 0.017) and LEVESWI-2 greater than 1.34 mmHg/m²/bpm (hazard ratio: 1.98, P  = 0.01) were the independent predictors of MACE (Harell's C -statistic: 0.85; Akaike information criterion: 1003.64). The index LEVESWI was the principal predictor of MACE and improved the stratification of Vall-d'Hebron-Risk-Score-II for detecting MACE (net reclassification improvement: 85.5%; P  < 0.001).

Conclusions: LEVESWI is a new tool that incorporates key hemodynamic variables and offers a better perspective of ventricular systolic function as an independent predictor of MACE.

Objective: To assess the false positive gallium-68-labeled urea-based prostate-specific membrane antigen ( 68 Ga-PSMA) uptake rate in the prostate gland in patients with primary prostate cancer (PCa), and determine whether multiparametric prostate MRI (mpMRI) within hybrid PET/MRI can reduce false positives.

Methods: Fifty-one treatment-naive patients with PCa undergoing radical prostatectomy were prospectively recruited. All underwent 68 Ga-PSMA-11 PET/MRI with mpMRI. Images were assessed independently by the nuclear medicine physicians and radiologist using PRIMARY score and PIRADS v2.1, then jointly as fused PET/MRI. Radical prostatectomy followed imaging after a mean interval of 46 ± 32 days. Imaging findings were compared with postoperative histological mapping. Prostate was divided into sextants for lesion localization, and false positive uptake was recorded. Diagnostic performance metrics were calculated.

Results: Seven of 51 patients (13.7%) exhibited false positive PSMA uptake because of benign findings - asymmetrical central zone thickening, benign prostatic hyperplasia, or prostatitis. mpMRI was true negative in all. PET/MRI showed higher sensitivity and accuracy (74.9 and 83.0%) than PET (65.0 and 74.5%) and mpMRI (66.5 and 77.5%). For index lesion detection, PET/MRI had 92.2% sensitivity, outperforming PET (80.4%) and mpMRI (86.3%). PET/MRI was significantly more accurate than mpMRI ( P  < 0.001) and PET ( P  = 0.014), while PET and mpMRI were similar ( P  = 0.770).

Conclusion: False positive 68 Ga-PSMA uptake is common and can affect clinical decisions, including focal therapy or recurrence assessment after radiotherapy. mpMRI helps clarify benign mimics, improving diagnostic accuracy. PET/MRI may offer more reliable assessment of PCa, potentially aiding focal therapy planning and posttreatment evaluation.

Purpose: This study aimed to evaluate the influence of silicon photomultiplier PET (SiPM-PET) and the Bayesian penalized-likelihood (BPL) reconstruction algorithm on the measurement of metabolic tumor volume (MTV), in comparison with conventional photomultiplier tube PET (PMT-PET).

Materials and methods: Six phantoms of varying shapes and volumes (1.2 to 20 ml) were prepared using an agar-based fluorodeoxyglucose F-18 mixture with a background-to-lesion activity ratio of 1 : 4 and placed in a 5-L water tank. Each phantom was scanned using PMT-PET and SiPM-PET systems. PMT-PET images were reconstructed with conventional ordered-subset expectation maximization (OSEM), whereas SiPM-PET data were reconstructed using both OSEM and BPL. MTV was calculated using relative threshold-based segmentation [30, 40, 42, and 50% of maximum standardized uptake value (SUVmax)] and a gradient-based method with weight coefficients of 0.3, 0.4, 0.5, and 0.6. Measured MTVs were compared with true phantom volumes to assess accuracy.

Results: SiPM-PET provided a more accurate geometric representation of phantom contours than PMT-PET. Across all conditions, a 40% SUVmax threshold and a weight coefficient of 0.4 yielded MTVs closest to the true volumes. When SiPM-PET was combined with BPL, gradient-based segmentation produced MTVs with the smallest deviation from the known volumes, particularly for irregularly shaped phantoms.

Conclusion: SiPM-PET using BPL facilitated clearer delineation of phantom boundaries compared with PMT-PET and SiPM-PET with OSEM. Under the present experimental conditions, MTVs obtained from SiPM-PET with BPL, especially when using the gradient-based method, showed improved agreement with true phantom volumes, suggesting potential advantages for volumetric assessment in oncologic PET imaging.

Objective: The objective of this study is to evaluate the combined prognostic values of 18F-fluorodeoxyglucose (18F-FDG) PET and computed tomography (CT)-derived entropy-based heterogeneity features from hybrid PET/CT scanner using machine learning in patients with lung adenocarcinoma undergoing curative surgery.

Methods: Presurgical 18F-FDG PET/CT from 131 patients with lung adenocarcinoma were divided into training (n = 92) and temporal validation (n = 39) cohorts. In the training cohort, we integrated entropy-based heterogeneity features from 18F-FDG PET/CT for disease-free survival (DFS) prediction using machine learning approach. The predictive value of clinical variables and 18F-FDG PET/CT-based machine learning for DFS was examined using Cox regression analyses, and independent prognosticators were used to develop the survival prediction model. The model was then tested in the temporal validation cohort.

Results: In the training cohort, 18F-FDG PET/CT-based machine learning, female sex, and pN status independently predicted DFS. The model, incorporating these predictors significantly predicted DFS in the training (hazard ratio = 1.483, P < 0.001) and validation cohorts (hazard ratio = 1.753, P < 0.001). This model outperformed traditional staging system in both cohorts (c-indices = 0.717 vs. 0.621 in training; and 0.728 vs. 0.644 in validation). The model also predicted overall survival in both cohorts (hazard ratio = 1.370, P < 0.001 in training; hazard ratio = 1.574, P = 0.017 in validation).

Conclusion: Our preliminary results suggest that integrating prognostic values from 18F-FDG PET and CT-based heterogeneity features with clinical prognosticators is feasible and may support personalized treatment strategies for patients with resectable lung adenocarcinoma.