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.

Objective:To develop radiomics score (RS) based on 18F-FDG PET/CT, and construct the machine learning model combining clinical and other relevant factors for personalized prediction of 2-year event-free survival (2-EFS) in patients with diffuse large B-cell lymphoma (DLBCL), and to perform interpretability analysis of the model. Methods:A total of 91 patients (49 males, 42 females; age (57.8±12.8) years) with pathologically confirmed DLBCL from December 2017 to December 2020 at the First Hospital of Shanxi Medical University were retrospectively analyzed. According to the ratio of 7∶3, patients were randomly divided into training set ( n=63) and test set ( n=28), and divided into non-progression group and progression group according to the follow-up results. The whole-body PET semi-quantitative parameters were calculated from the PET/CT images before treatment, and 328 radiomics features were extracted from the largest target lesions of patients. The least absolute shrinkage and selection operator (LASSO) was used to develop the RS. Clinical and PET characteristic difference analysis was performed through χ2 test and Mann-Whitney U test. Extreme gradient boosting (XGBoost) models were constructed based on clinical, PET radiomics features and RS, and the prediction efficiency of each model was evaluated by ROC AUC. The model interpretability was analyzed by using shapely additive explanation (SHAP). Results:Of all patients, 32 had disease progression and 59 did not. There were no significant differences in baseline characteristics between the training set and the test set ( χ2 values: 0.06-1.84, U values: 665.00-763.00, all P>0.05). The comparison between the progression group and non-progression group in the training set showed statistical differences in the international prognostic index (IPI) score ( χ2=4.87, P=0.027), myelocytomatosis viral oncogene (MYC) protein expression ( χ2=4.29, P=0.038), and metabolic tumor volume (MTV; U=307.00, P=0.038). Seven radiomics features were screened by LASSO. Among XGBoost models with different feature combinations, IPI score, MYC protein expression, MTV combined with RS had the highest predictive efficiency (training set: AUC=0.73; test set: AUC=0.70). Through SHAP analysis, RS was the most predictive feature in the optimal model. Conclusion:The machine learning integrated model of IPI score, MYC protein expression and MTV combined with RS can effectively predict the prognosis of DLBCL patients, and baseline 18F-FDG PET/CT radiomics can be used as a potential means to evaluate the prognosis of DLBCL patients.

Objective:To investigate the value of tumor and adipose tissue metabolic parameters from baseline 18F-FDG PET/CT in predicting the efficacy and prognosis of immunotherapy in patients with advanced nasopharyngeal carcinoma (NPC). Methods:From February 2019 to February 2022, 112 patients (91 males, 21 females, age 21-73 years) with advanced NPC who were treated with programmed death-1 (PD-1) inhibitors at Sun Yat-Sen University Cancer Center were retrospectively included. All patients underwent baseline PET/CT examination. Tumor and adipose tissue metabolic parameters were measured and calculated. Patients were divided into clinical benefit and non-clinical benefit groups, and Mann-Whitney U test or χ2 test was used to assess the differences between groups. Prognostic analysis of progression-free survival (PFS) was performed using multivariate Cox proportional hazards regression model and a prognostic stratification system was constructed. Results:Of the 112 patients, 85 were in the clinical benefit group and 27 were in the non-clinical benefit group. In non-clinical benefit group and clinical benefit group, the metabolic tumor volume (MTV) of primary tumor (PT-MTV) were 47.7(7.7, 81.2) and 14.0(5.7, 27.1)cm 3, total lesion glycolysis (TLG) of primary tumor (PT-TLG) were 228.9(27.4, 492.8) and 72.7(20.4, 165.5)g, whole-body MTV (WB-MTV) were 94.2(45.9, 215.4) and 61.3(31.6, 104.3)cm 3, whole-body TLG (WB-TLG) were 605.5(214.1, 1 402.5) and 319.2(172.4, 632.8)g, SUV max of visceral adipose tissue (SUV max-VAT) were 0.77(0.55, 0.91) and 0.62(0.48, 0.76), respectively ( Z values: from -2.72 to -1.96, all P<0.05). The proportion of patients with lung metastasis in non-clinical benefit group was higher than that in clinical benefit group (44.4%(12/27) vs 23.5%(20/85); χ2=4.39, P=0.036). PT-MTV (hazard ratio ( HR)=2.807, 95% CI: 1.540-5.118, P=0.001) and the presence of lung metastases ( HR=1.691, 95% CI: 1.012-2.823, P=0.045) were independent predictive factors for PFS in multivariate analysis. The prognostic prediction model based on the two predictive factors was able to significantly differentiate the prognosis in patients. Conclusions:Baseline tumor metabolic parameters and SUV max-VAT are associated with the efficacy of immunotherapy in patients with advanced NPC. PT-MTV and lung metastasis can independently predict PFS. The constructed prediction model can stratify patients′ prognosis.

Objective:To evaluate the application potential of the bimodal ultrasound/near-infrared (NIR) composite nanoscale probe Arg-Gly-Asp (RGD)/Ag 2Te/perfluoropentane (PFP) @ mesoporous silica nanoparticles (MSN) in the diagnosis and treatment of microvascular diseases. Methods:Nanoprobes loaded with RGD, PFP and Ag 2Te were prepared by ultrasound sonication and carbodiimide method. The characterization of the nanoprobes was determined. The imaging performance, photothermal response, and target-seeking ability of the nanoprobes under NIR irradiation were verified. The biosafety of the nanoprobes was examined, and the thrombolytic ability of the nanoprobes was evaluated. The mice were observed to visualize microvessels of the abdominal wall under the NIR-Ⅱ imaging, and the microvascular visualization ability of the nanoprobes was evaluated. Results:The particle size of nanoprobes was (205.3±2.9) nm and the potential was (2.05±0.58) mV. The coupling rate of the RGD was (82.27±0.36)%, the encapsulation rate of the quantum dots was (80.80±3.26)%, and the photostability of the quantum dots was good. The fluorescence intensity was enhanced with the increase of the mass concentration of RGD/Ag 2Te/PFP@MSN, and the warming effect was more obvious. After ultrasound and NIR irradiation, the thrombolysis rate was significantly increased. RGD/Ag 2Te/PFP@MSN successfully realized NIR-Ⅱ fluorescence imaging of mice microvessels. The cytotoxicity assay and hemolysis assay showed that the probe had a good biosafety. Conclusion:The RGD/Ag 2Te/PFP@MSN nanoprobe is a potential strategy for targeted therapy of thrombotic diseases, combining dual-modality therapy of ultrasound and NIR to offer new possibilities for non-invasive and visual diagnosis and treatment of microvascular embolism.

SPECT myocardial perfusion imaging (MPI) can obtain many parameters such as myocardial perfusion, morphology, function and mechanical synchronization in one stop, which has become an essential non-invasive examination technique in the diagnosis and treatment of various cardiovascular diseases (CVD). With the continuous development of cardiac SPECT instrument, imaging scheme and image reconstruction algorithm, its application in the diagnosis and treatment of CVD is expanding. This paper reviews the research progress of qualitative, semi-quantitative and quantitative parameters of SPECT MPI in recent years, and expounds the threshold, influencing factors and application value of various parameters.

Due to the specificity of radiopharmaceuticals for targeted α radionuclide therapy, such as radioactivity and radiation damage risk, it is necessary to estimate the internal radiation dose in preclinical evaluation to correctly evaluate the efficacy and safety of the drug, as well as in subsequent clinical studies. This review illustrates current research status of estimating internal radiation dose of targeted α radionuclide therapeutic radiopharmaceuticals based on preclinical studies, in order to add insights for understanding estimation of radiopharmaceuticals internal radiation dose and provide reference for the preclinical evaluation of radiopharmaceuticals.

Radiomics technology extracts high-dimensional quantitative radiomics features from medical imaging to achieve intelligent analysis of nuclear medicine and other medical imaging, which has important application value on improving the diagnostic performance of imaging. However, it has been demonstrated that variability in image acquisition, reconstruction settings, and technological differences can affect the reproducibility of radiomics features, which may lead to variability in the calculations of radiomics models across different centers or scanners, affecting the stability of the performance of radiomics models (i.e., generalizability) in the clinical translation of radiomics models. For this reason, researchers at home and abroad have conducted extensive studies on the influencing factors of radiomics features and harmonization strategies for heterogeneous imaging data in recent years to improve the reproducibility of radiomics features and the generalizability of radiomics models. This paper reviews the above research progress mainly from the aspect of PET imaging in nuclear medicine.