The pathogenesis of ovarian cancer is concealed, which is prone to recurrence and metastasis and carries a very poor prognosis. The precise imaging assessment of abdominopelvic tumor burden is crucial for debulking surgery decision in patients with ovarian cancer. Fibroblast activation protein inhibitor (FAPI) PET imaging has shown a great prospect of clinical application, which provides a new imaging technique for the diagnosis and staging of ovarian cancer. This review summarizes the clinical value and research progress of 68Ga-FAPI PET in the diagnosis and treatment of ovarian cancer.

In recent years, targeted PET imaging of chemokine CXC subfamily receptor 4 (CXCR4) has become a prominent area of research, offering considerable potential for precise diagnosis, tracking disease progression noninvasively, guiding therapeutic strategies, and monitoring treatment responses. This article reviews recent achievements in noninvasive molecular imaging techniques targeting CXCR4 expression, with a particular focus on the pathophysiological mechanisms underlying CXCR4 and the clinical utility of the molecular probe 68Ga-pentixafor PET for diagnosis and treatment. Furthermore, the paper discusses the clinical translation of CXCR4 molecular imaging and highlights prospective research directions.

Objective:To compare the value of different imaging modalities in evaluating early efficacy of 90Y-selective internal radiation therapy (SIRT) for liver malignant tumors. Methods:From September 2021 to December 2023, a retrospective analysis was conducted on 43 patients (32 males, 11 females; age (55.8±14.7) years) with liver malignant tumors who received 90Y-SIRT at Hainan Cancer Hospital and Boao Super Hospital. The injection dosage of 90Y was 1.5(1.2, 2.4)GBq. Clinical and imaging data of patients before and after treatment for multimodal evaluation were collected, including MRI plain and enhanced scans, as well as diffusion weighted imaging (DWI). Plain scan images were evaluated for the treatment efficacy by response evaluation criteria in solid tumors (RECIST) 1.1 version, while enhanced MRI was scored into 1-5 based on changes in the target area, including increased low-density range, necrotic features, and decreased enhancement. The minimum apparent diffusion coefficient (ADC min) of DWI increased by 20% compared to baseline was determined to be responsive. Wilcoxon signed rank test was used to analyze data, and ROC curve analysis was used to analyze the diagnostic efficacy of different imaging modalities (Delong test). Results:All patients had baseline MRI data, 39 underwent MRI at 1-month after treatment, and 22 underwent MRI at 3-month after treatment. Based on MRI plain scan images, the target lesions showed partial remission (PR) in 10.26%(4/39) of patients, progressive disease (PD) in 5.13%(2/39) of patients, and stable disease (SD) in 84.61%(33/39) of patients at 1-month after treatment; while there were 40.91%(9/22) PR, 9.09%(2/22) PD and 50.00%(11/22) SD at 3-month after treatment. Based on DWI images, 35.90%(14/39) and 68.18%(15/22) of patients were considered responsive at 1-month and 3-month after treatment, respectively. Compared with baseline, the differences of tumor sizes, enhancement degree of target lesions and ADC min at 1-month and 3-month after treatment were statistically significant ( Z values: from -3.88 to -2.39, all P<0.05). Compared with the tumor size and enhancement degree, the AUCs of ADC min were the highest at 1-month (0.701) and 3-month (0.953) after treatment ( Z values: 0.40-2.29, all P<0.05). Conclusions:MRI plain scan, MRI enhancement and DWI are effective in the evaluation the efficacy of 90Y-SIRT for liver malignant tumors at 1-month and 3-month after treatment. ADC min is superior to tumor size and enhancement degree in diagnostic efficacy.

Objective:To compare the lung shunt fraction (LSF) of 90Y imaging after 90Y-selective internal radiation therapy (SIRT) and preoperative 99Tc m-macroaggregated albumin (MAA) imaging in patients with liver malignant tumors, and compare the volume and visual score of intrahepatic distribution of both nucleins on SPECT/CT images. Methods:A total of 91 patients with liver malignant tumors (78 males, 13 females; age (56.7±13.7)years; 99 cases) who underwent 90Y-SIRT in the Second Affiliated Hospital of Guangzhou Medical University from November 2022 to June 2024 were retrospectively collected. All patients underwent preoperative 99Tc m-MAA simulation and postoperative 90Y distribution verification by whole-body planar scintigraphy and hepatic SPECT/CT imaging. ROIs of the liver and lungs under the anterior-posterior position were delineated on the planar scintigraphy and LSF of 99Tc m-MAA and 90Y were calculated. The volume of interest (VOI) was drawn on the SPECT/CT images to calculate the nuclide distribution volume of both 99Tc m-MAA and 90Y within the liver. Wilcoxon signed rank test was used to compare the difference between two groups. In addition, the liver was divided into five lobes, namely left lateral lobe, left medial lobe, caudate lobe, right anterior lobe and right posterior lobe. Visual assessment of 90Y and 99Tc m-MAA radioactive distribution was performed ( 90Y and 99Tc m-MAA uptakes were graded on a scale of 0-3, where 0 indicated no nuclide accumulation and 3 indicated heavy accumulation). Kappa consistency test was used to analyze the scores of the corresponding lobes between two groups. Results:LSF for 99Tc m-MAA was 11.60%(4.27%, 15.03%), and LSF for 90Y was 11.80%(9.70%, 13.30%), without significant difference ( Z=-1.50, P=0.134). The distribution volume of 99Tc m-MAA within the liver was 542.63(204.00, 818.00)ml, which was significantly different from that of 90Y (688.69(287.00, 954.00)ml; Z=-7.37, P<0.001). Kappa values of the score of each lobe between 99Tc m-MAA imaging and 90Y imaging were 0.469-0.740 (all P<0.001). Conclusions:99Tc m-MAA simulation is reliable for assessing LSF for 90Y-SIRT. The distribution volume of 99Tc m-MAA is generally smaller than that of 90Y, but the consistency of the visual score of radioactive distribution is high. Overall, 99Tc m-MAA may well simulate the distribution pattern of 90Y-SIRT.

Objective:To optimize the image quality of PET/CT following 90Y-selective internal radiation therapy ( 90Y-SIRT) using block-sequential regularized expectation maximization (BSREM) reconstruction algorithm, and to evaluate its impact of different β values on image quality and quantitative analysis. Methods:A retrospective study was conducted on 8 male patients with hepatic tumors (age: 62(52, 71) years) treated at Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua Medicine Tsinghua University, between June 2024 and January 2025. All patients were treated with 90Y resin microspheres (2.6(0.9, 3.6)GBq) and underwent post-treatment 90Y PET/CT liver imaging. Imaging data were reconstructed using BSREM with different noise penalty weighting factors ( β values: 0, 300, 1000, 1500, 2500, 3500, 4000, 6000, 8000, 10000). Visual assessment was independently performed by two nuclear medicine physicians, using a 4-point scale (1=worst, 4=best). The mean score was considered as the final score. The consistency of the 2 reviewers was calculated and analyzed by Kappa test. Visual scores of different β value groups were compared by Friedman test. The β value demonstrating highest mean score and optimal consistency was selected as the optimal. Quantitative analysis was performed using MIM software to calculate the maximum absorbed dose ( Dmax) and the mean absorbed dose ( Dmean) for tumor, normal liver, and whole liver regions, and the CV was used to evaluate the impact of β values. Results:The visual assessment consistency of reviewers in 3 β value groups (0, 3500, 6000) were the highest (7/8) (all kappa=0.88, all P<0.05). Visual scores of the 10 β value groups were significantly different ( χ2=28.74, P<0.001), and the visual scores of 2 β value groups (3500, 4000) were the highest, both of which were 4.0(4.0, 4.0). Overall, visual assessment identified β=3500 as the optimal. Quantitative analysis revealed that, (1) Dmax in all regions (tumor, normal liver, whole liver) decreased with the increasing β values, stabilizing when β>1000 ( CV 56%-67%); (2) Dmean remained stable across different β values ( CV 0.04%-5.00%). Conclusions:In BSREM reconstruction, β=3500 is the optimal parameter for improving 90Y-PET image quality. β values significantly affect Dmax (stabilizing at β > 1000), but have no significant impact on Dmean, suggesting that reconstruction parameters primarily influence dose distribution morphology rather than average dose assessments.

Objective:To establish criteria for diagnosing lymph node metastasis (LNM) in newly diagnosed papillary thyroid cancer (PTC) patients based on 18F-FDG PET/MR and evaluate its diagnostic efficiency. Methods:The data of 14 patients with PTC (all females, age (38.8±13.5) years) who underwent 18F-FDG PET/MR and ultrasound sequentially 2 weeks before surgery at the First Affiliated Hospital of the Air Force Medical University from May 2021 to August 2023 were retrospectively analyzed. Visual and semi-quantitative assessments were performed on all patients step by step (Ⅱ-Ⅵ area) and neck by neck (left, right, and central area). The dimensions of all suspected lymph nodes were measured on T 2 weighted imaging (WI)-MRI and SUV max was measured on PET. Taking postoperative pathology as the reference standard, the independent risk factors for predicting LNM were determined by multivariate logistic regression analysis, and the diagnostic efficiency of each model was evaluated by ROC curve analysis. Results:A total of 21 macroscopic regions of lymph nodes(15 were malignant, 6 were benign) and 178 lymph nodes (120 were malignant, 58 were benign) were cleared by surgery. Multivariate logistic regression analysis showed that SUV max (odds ratio ( OR)=1.865, 95% CI: 1.323-2.630, P<0.001) and short diameter on MRI (SD-MRI) ( OR=1.752, 95% CI: 1.189-2.580, P=0.005) were independent predictors of LNM. The cut-off value of SD-MRI in predicting LNM was 5.7mm (AUC=0.812, Youden index (YI)=0.463). For the SD-MRI cut-off values ≥5.7 or <5.7mm, the corresponding SUV max cut-off values were 1.6 and 1.8, respectively. When " dual threshold" quantitative criteria (SD-MRI≥5.7mm + SUV max≥1.6 or SD-MRI<5.7mm + SUV max≥1.8) was used as the diagnostic criteria of 18F-FDG PET/MR, the AUC and YI could be improved to 0.909 and 0.818. Based on the regional level analysis, sensitivity, specificity, and accuracy of LNM diagnosis by ultrasound, MRI, and 18F-FDG PET/MR " dual threshold" criteria were 11/15 vs 12/15 vs 13/15, 5/6 vs 3/6 vs 5/6, 76.2%(16/21) vs 71.4%(15/21) vs 85.7%(18/21), respectively. Conclusion:Compared with the ultrasound and MRI, the 18F-FDG PET/MR " dual threshold" criteria exhibits higher sensitivity and accuracy in determining the scope of LNM clearance for PTC patients.

Objective:To investigate the predictive value of 18F-FDG PET related metabolic parameters on microsatellite instability-high (MSI-H) and human epidermal growth factor receptor-2(HER2) expression in colorectal cancer (CRC). Methods:The 18F-FDG PET imaging, clinical and pathological data of 101 CRC patients (58 males, 43 females; age 68.0(58.0, 75.0) years) admitted to Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2016 to March 2024 were retrospectively collected, including 17 cases in MSI-H group, 84 cases in microsatellite stability/microsatellite instability-low (MSS/MSI-L) group, 23 cases in HER2 expression group, 34 cases in non-HER2 expression group, and 44 patients without HER2 detection. Univariate analyses (independent-sample t test, Mann-Whitney U test, χ2 test) and multivariate logistic regression analysis were used to screen out independent risk factors, and ROC curve was used to evaluate the predictive efficacy. Bootstrap method was used to verify the model internally. Results:There were significant differences in metabolic tumor volume (MTV) 80% between MSI-H group and MSS/MSI-L group (2.1(1.6, 4.0) vs 1.4(1.0, 2.7) cm 3;Z=-2.10, P=0.036), and total lesion glycolysis (TLG) 80% and carcinoembryonic antigen (CEA) were significantly different between those 2 groups ( Z=-2.27, χ2=6.40, both P<0.05). There were significant differences in TLG 80% (29.0(16.1, 41.0) vs 14.3(9.4, 22.9) g; Z=-2.80, P=0.005) between HER2 expression group and non-HER2 expression group, and significant differences were also found in MTV 80%, heterogeneity index (HI) and CV ( Z=-2.24, t values: -2.26, 2.54, all P<0.05). The independent risk factors for MSI-H were MTV 80% (odds ratio ( OR)=1.326, 95% CI: 1.015-1.733, P=0.038) and CEA ( OR=0.200, 95% CI: 0.056-0.706, P=0.012), with the AUC for the combined model of 0.730 (95% CI: 0.605-0.856), and the concordance index (C-index) of 0.716. The independent risk factors for HER2 expression were TLG 80% ( OR=1.037, 95% CI: 1.001-1.073, P=0.041) and CV ( OR=1.467, 95% CI: 1.073-2.005, P=0.016), with the AUC for the combined model of 0.775 (95% CI: 0.645-0.875), and the C-index of 0.757. Conclusions:18F-FDG PET can be used as a noninvasive tool to evaluate CRC microsatellite status and HER2 gene amplification. MTV 80% and CEA are independent risk factors for MSI-H; TLG 80% and CV are independent risk factors for HER2 expression.

Objective:To investigate the additional value of 99Tc m-hydrazinonicotinamide (HYNIC)-Tyr3-octreotide (TOC) SPECT/CT imaging in the diagnosis and treatment of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Methods:A total of 54 patients (28 males and 26 females, age: (52.6±11.7) years) who underwent enhanced CT (MR) and 99Tc m-HYNIC-TOC SPECT/CT in People′s Hospital of Zhengzhou University between December 2017 and June 2023 were analyzed retrospectively. Surgical pathology or biopsy was the gold standard of patients′ diagnosis (primary tumors), and comprehensive evaluation based on pathology, imaging and follow-up results was used as the diagnostic criteria of lesions. McNemar χ2 test was used to compare the diagnostic efficacy of different imaging methods. Results:Pathological results showed that 43 of the 54 patients were with GEP-NETs and 11 were with non-neuroendocrine tumors (NETs). The sensitivities of enhanced CT and enhanced MR in the diagnosis of patients with GEP-NETs were 65.1%(28/43) and 60.0%(15/25) respectively, which increased to 93.0%(40/43) and 92.0%(23/25) with the addition of 99Tc m-HYNIC-TOC imaging ( χ2 values: 8.64, 4.90, P values: 0.002, 0.021). There were 22 and 15 patients showing atypical enhancement on enhanced CT and enhanced MR respectively. The sensitivities of these two methods for GEP-NETs in patients with atypical enhancement were 54.5%(12/22) and 8/15 respectively, which increased to 95.5%(21/22) and 14/15 with the addition of 99Tc m-HYNIC-TOC imaging ( χ2 values: 5.82, 4.17, P values: 0.012, 0.031). Compared with enhanced CT, the detection rates of liver and bone metastatic lesions were improved significantly from 90.8%(158/174) and 55.2%(32/58) to 96.6%(168/174) and 87.9%(51/58) with the addition of 99Tc m-HYNIC-TOC imaging ( χ2 values: 5.79, 9.82, P values: 0.013, 0.001). Compared with enhanced MR, the detection rate of bone metastases was improved significantly from 56.0%(14/25) to 88.0%(22/25) with the addition of 99Tc m-HYNIC-TOC imaging ( χ2=4.08, P=0.039). After 99Tc m-HYNIC-TOC imaging, stages were changed in 7.0%(3/43) of patients and a greater number or extent of metastases were detected in 11.6%(5/43) of patients. 99Tc m-HYNIC-TOC imaging detected additional recurrent or metastatic lesions in 40.0%(8/20) of patients during follow-up compared to enhanced CT. Conclusion:99Tc m-HYNIC-TOC imaging can provide an added value for diagnosing GEP-NETs with atypically enhanced CT(MR), and in the detection of liver metastasis and early bone metastasis, thus helping the optimization of clinical treatment strategies.

Objective:To quantitatively evaluate the impact of hypothyroidism on renal function and address its underlying mechanisms using 99Tc m-diethylene triamine pentaacetic acid (DTPA) renal dynamic imaging. Methods:A total of 35 patients with differentiated thyroid cancer (12 males, 23 females, age (44.8±10.7) years), who were referred for radioiodine remnant ablation, were consecutively enrolled prospectively from October 2022 to October 2023 in Shanghai Sixth People′s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. Serum examinations of thyroid- and renal function-relevant parameters and 99Tc m-DTPA renal dynamic imaging were performed before and 4 weeks after stopping taking levothyroxine ( L-T 4). Paired t test, Wilcoxon signed rank test and Wilcoxon rank sum test were used to analyze data. Results:After L-T 4 withdrawal, glomerular filtration rate (GFR) derived from renal dynamic imaging, estimated GFR (eGFR), and cystatin C level significantly decreased ((95.80±18.09) vs (89.86±15.58) ml/min; t=4.83, P<0.001; (108.27±18.39) vs (87.97±16.24) ml·min -1·1.73 m -2;t=9.37, P<0.001; (0.72±0.12) vs (0.64±0.15) mg/L; t=3.73, P=0.001). GFR decreased more robustly in male patients than in females (6.16(3.62, 14.89) vs 3.83(0.57, 8.25) ml/min; Z=-1.98, P=0.048). Additionally, 99Tc m-DTPA renal dynamic imaging revealed that the peak times of both left and right kidneys were significantly prolonged (3.03(2.53, 3.78) vs 3.04(2.53, 4.13) min; Z=-3.85, P<0.001; 3.14(2.46, 4.20) vs 3.50(2.74, 4.50) min; Z=-3.44, P=0.001), but the left and right renal half-excretion times remained stable ( Z values: -0.88, -0.48, P values: 0.381, 0.634). Conclusion:Based on the 99Tc m-DTPA renal dynamic imaging results, it can be demonstrated that hypothyroidism can lead to a significant decrease in renal function, and the possible reason might be the reduction in the blood perfusion of kidneys.

Objective:To investigate the factors affecting the efficacy of 131I treatment for Graves′ disease (GD) and to construct a predictive model for the treatment outcomes of 131I therapy. Methods:Retrospective analysis of the treatment efficacy was performed on 2 190 patients (547 males, 1 643 females, age (42.9±12.4) years) with GD, who received initial 131I treatment in Tianjin Medical University General Hospital between October 2013 and May 2018. Univariate analysis ( χ2 test, et al) and logistic regression were performed to analyze the possible factors affecting the efficacy of 131I treatment. An efficacy prediction model for 131I treatment of GD was constructed, and decision curve analysis (DCA) was used to evaluate the clinical utility of the prediction model. Results:The overall effectiveness rate of 131I treatment for GD patients was 99.95%(2 189/2 190), with a total cure rate of 83.74%(1 834/2 190), among which 94.11%(1 726/1 834) were cured after a single treatment. Pre-treatment thyroid mass was identified as an independent risk factor affecting the efficacy of initial 131I treatment (odds ratio ( OR)=0.983(95% CI: 0.977-0.989), P<0.001). The clinical cure rate was higher in patients who received an adequate dose of 131I compared with that in patients who didn′t receive an adequate dose (79.97%(1 537/1 922) vs 70.52%(189/268); χ2=12.57, P<0.001), but it did not increase the incidence of hypothyroidism within one year. A predictive model was constructed, and it was found that thyroid mass and disease duration had a relatively high impact on the clinical cure rate. The concordance index (C-index) of the predictive model was 0.623(95% CI: 0.593-0.654). DCA indicated that the predictive model offered substantial net benefits across a wide range of probability thresholds. Conclusions:131I treatment is effective in most patients with GD. The predictive model for efficacy of initial 131I treatment developed in this study can assist in evaluating treatment outcomes and help clinicians select the most suitable 131I treatment dose, enhancing clinical decision-making.