Nuclear Medicine Communications最新文献

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.

Background: The clinical utility of 18 F-fluorodeoxyglucose (FDG) PET/computed tomography (PET/CT) imaging in bladder cancer is often compromised by high urinary FDG accumulation, which can interfere with the accurate detection of primary tumors and metastatic sites. This study aimed to evaluate the added benefit of delayed PET/CT imaging after diuretic administration in patients with bladder cancer, focusing on its ability to overcome the limitations posed by high FDG excretion into the bladder.

Methods: This prospective study was conducted at the Sohag Oncology Center, Egypt, and included patients with pathologically confirmed bladder cancer between March 2022 and March 2024. All patients underwent dual-phase PET/CT imaging, with early-phase imaging performed 45-90 min after the 18 F-FDG injection, followed by delayed imaging 1 h later after administering intravenous furosemide (20 mg) and enhanced hydration. The PET/CT images were analyzed qualitatively and quantitatively, with a maximum standardized uptake value (SUV max ) used to assess tumor activity in both early and delayed phases. Results were validated through biopsy, a combination of MRI and clinical follow-up for at least 6 months, or both.

Results: A total of 39 patients were included in the study (33 males, 6 females, aged 42-80 years). Residual bladder lesions were observed in 12.8% of the early images and 58.9% of the delayed images, with a significant increase in SUV max ( P  = 0.018). Lymph node involvement was detected in 12 patients, showing a similar rise in SUVmax ( P  = 0.012). Also, delayed PET/CT imaging improved sensitivity for both bladder lesions and metastatic lymph nodes (92.6 and 93%, respectively), while maintaining specificity (100% for bladder lesions, 74% for lymph nodes).

Conclusion: Delayed PET/CT postdiuretic administration improves image quality in bladder cancer via reducing urinary radiotracer activity, thus minimizing bladder interference and improving lesion detectability and characterization.

Objectives: Using personalized treatment with Lu-177-labeled radiopharmaceuticals, rather than using a fixed activity of 7.4 GBq, the administered radioactivity is adjusted in each patient. Achieving precise control of the administered activity would be possible during Lu-177 infusion if real-time monitoring techniques were possible. However, these techniques are not currently available. In this study, we used Monte Carlo simulations to simulate imaging of the administration site in an arm phantom with a pinhole gamma camera to explore the feasibility of achieving real-time monitoring and control of the administered activity during infusion.

Methods: We used the Geant4 toolkit to simulate a compact gamma camera. We simulated the basic performance of the camera within an energy window of 208 keV ± 10% and the imaging of an arm phantom to evaluate the feasibility of visualizing and quantifying the inflow of Lu-177-labeled radiopharmaceutical activity.

Results: The spatial resolution with the 1.0-mm pinhole collimator for Lu-177 was 1.8 mm full width at half maximum (FWHM) at 50 mm, whereas it was 1.2 mm FWHM for the 0.5-mm pinhole collimator. Our gamma camera captured the activity of Lu-177 in a 3.0-mm diameter vessel within the arm phantom, achieving measurements in only 1 min. The maximum values among the mean estimation errors of the administered activity were 0.73% and -3.53% for the 1.0 and 0.5-mm pinhole collimators, respectively, both occurring within the initial 1 min.

Conclusion: Monte Carlo simulations demonstrated the feasibility of real-time monitoring of administered activity during Lu-177 infusion by imaging the administration site with our pinhole gamma camera.

Objectives: To evaluate the treatment patterns and outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with radium-223 dichloride in the UK.

Methods: Patients initiating treatment with radium-223 from 1 September 2017 to 1 September 2019 in 15 UK oncology centres were included. Demographics, treatment, clinical, biochemical, and outcome data were collected prospectively. Quality of life data were obtained using analgesic scores and components of the Functional Assessment Cancer Therapy - Prostate (FACT-P) questionnaire.

Results: A total of 550 consecutive, evaluable patients were included. The most common prior therapy for mCRPC was enzalutamide. At final analysis, after a median follow-up of 13.3 months, 55% of patients had completed six cycles of treatment. Median overall survival was 13.7 months (95% confidence interval, 12.6-14.8 months). Poor performance status, prior use of docetaxel in the metastatic hormone sensitive prostate cancer (mHSPC) setting, number of lines of prior treatment, and abnormal platelet count were independent variables associated with poor prognosis. Adverse events led to treatment discontinuation in 5.5% of patients. WHO analgesic scores and FACT-P questionnaire scores did not significantly change after treatment administration.

Conclusion: The National Radium-223 Dichloride Audit was the first and largest multicentre prospective analysis of treatment patterns, outcomes, and quality of life data in patients treated with radium-223 in the UK. Radium-223 can be administered safely to patients previously treated with other life-prolonging therapies. Efficacy and safety data compare favourably with clinical trial and other real-world data. Our results suggest that its use earlier in the treatment pathway is associated with longer survival.

Purpose: COVID-19 vaccine-induced reactive axillary lymph nodes (RAL) on fluorodeoxyglucose (FDG) PET/computed tomography (CT) imaging can mimic malignant lymphadenopathy, leading to diagnostic errors. Reported RAL prevalence varies widely in the literature, and factors contributing to its development remain poorly understood. This meta-analysis aims to evaluate vaccine-induced RAL observed on FDG PET/CT imaging and consolidate evidence from multiple studies to assess its prevalence, duration, and associations with vaccine-related factors and demographic characteristics.

Method: Using multiple databases, a systematic review and meta-analysis was conducted on studies reporting RAL on FDG PET/CT following COVID-19 vaccination. The primary outcome was RAL prevalence, while the secondary outcomes were maximum standardized uptake value (SUV max ), vaccine-to-scan interval, and associations with vaccine type and demographics.

Results: A total of 25 studies comprising of 5010 subjects were included. Mean SUV max of reactive nodes was 2.8 ± 1.2. Overall, RAL prevalence was 38.6% ± 17.6, higher in females (58.1% versus 41.9%, P  = 0.02) and younger individuals (mean age 63.3 versus 70.7 years, P  = 0.03). The RAL rate was not statistically different between mRNA (39.9% ± 16.9) and non-mRNA vaccines (26.3% ± 30.9). However, subanalysis showed about 40% RAL with Pfizer and Moderna mRNA vaccines and AstraZeneca non-mRNA vaccine, versus much lower, below 20%, RAL with Sinovac and Johnson & Johnson non-mRNA vaccines. Stricter PET/CT interpretation criteria using blood pool threshold reduced RAL prevalence to <20%. RAL rate declined with time but was still present after 1 month.

Conclusion: Low activity RAL is common on FDG PET/CT after COVID-19 vaccination, while higher activity RAL (above blood pool) that can lead to clinical errors is less frequent. The frequency of RAL is affected by expected factors, such as age, gender, vaccine type, and time after vaccination, which indirectly suggest the link between RAL and COVID-19 postvaccinal immunity.

Objective: The primary treatments for Graves' disease include antithyroid drugs (ATD), thyroidectomy, and iodine-131 (I-131) therapy. This study aimed to identify factors predicting treatment outcomes and the treatment period required to achieve euthyroidism after I-131 administration.

Methods: This study included 109 patients with Graves' disease who underwent I-131 therapy. Patients achieving euthyroidism or hypothyroidism within 1 year were classified as the success group, whereas those with remaining hyperthyroidism were classified as the failure group. Thyroid volume, computed tomography (CT) values, 24-h radioiodine uptake, effective half-life, the levels of free triiodothyronine, free thyroxine, thyroid-stimulating hormone, and thyrotropin receptor antibody, history of I-131 therapy, history of ATD use, history of potassium iodide use, and thyroid absorbed dose were analysed.

Results: Larger thyroid volume [odds ratio = 0.982, 95% confidence interval (CI): 0.967-0.998, P  < 0.05] was identified as a predictive factor for treatment failure, as determined by multivariable logistic regression. In contrast, a shorter treatment period was associated with lower thyroid volume (hazard ratio = 0.990, 95% CI: 0.982-0.999, P  < 0.05), higher thyroid absorbed dose (hazard ratio = 1.007, 95% CI: 1.002-1.011, P  < 0.01), and lower thyroid CT values (hazard ratio = 0.963, 95% CI: 0.939-0.987, P  < 0.01), as identified by multivariable Cox regression.

Conclusion: Larger thyroid volume was associated with treatment failure. Smaller thyroid volume, higher thyroid absorbed dose, and lower thyroid CT values were significant predictors of the treatment period required to achieve euthyroidism after I-131 administration.

As a promising approach, in vivo pretargeting can leverage the unique tumor-targeting properties of antibodies for nuclear imaging and therapy while bypassing their pharmacokinetic limitations. The core premise of pretargeting is that targeted vectors and radioisotopes are administered separately, leading to a higher target background ratio than traditional imaging methods using long-lived radionuclides. This strategy directly relies on chemical reactions, namely bioorthogonal reactions. The inverse electron-demand Diels-Alder (IEDDA) cycloaddition between 1, 2, 4, 5-tetrazine and strained alkene dienophile is an emerging catalyst-free 'click' chemistry. The IEDDA reaction has been used in various chemical environments because of its selectivity, efficiency, cleanliness, biocompatibility, and bioorthogonality. In the present review, we briefly focused on the IEDDA reaction in pretargeted nuclear imaging and radioimmunotherapy and discussed the common bioorthogonal click reactions in vivo systems.