Radiopharmaceuticals are the cornerstone of molecular imaging and precision medicine, which play a huge role in the diagnosis and treatment of malignant tumors, central nervous system diseases, cardiovascular and other diseases. On the basis of summarizing the advantages of radiopharmaceuticals and analyzing the development status at home and abroad, this article specifically introduces the general process of radiopharmaceutical research and development, and analyzes the key points of research and development. Finally, the future development of radiopharmaceuticals is prospected, with a view to providing reference for practitioners in fields related to the creation of new radiopharmaceuticals and accelerating the radiopharmaceutical development in China.

Objective: To investigate the characteristics of primary mediastinal large B-cell lymphoma (PMBL) in ¹⁸F-fluorodeoxyglucose (FDG) PET/CT imaging. Methods: From July 2010 to April 2019, ¹⁸F-FDG PET/CT images of 27 patients (10 males, 17 females, median age 31 (19-57) years) with pathologically confirmed PMBL from the First Affiliated Hospital of Nanjing Medical University were retrospectively analyzed. The location, shape, density, presence of necrosis and calcification, and invasion around or beyond the lesions were observed. The maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured by automatic segmentation algorithm method. Spearman correlation analysis was used to evaluate the correlation between SUV_max or MTV or TLG and the maximum diameter or Ann Arbor staging. Results: The lesions appeared as anterior mediastinal huge masses in 27 patients, and grew in the anterior mediastinal cross-regionally in 25 patients, lobulated at the edge in 24 patients. Low-density necrosis lesions were found in 18 patients. The lesions were surrounded by large blood vessels in 15 patients and tracheae were compressed in 12 patients. Lung tissues were invaded in 3 patients, abdominal lymph nodes and bone marrow were invaded in 1 patient, and no splenomegaly was found in 27 patients. The maximum diameter, SUV_max, MTV and TLG were (11.6±3.7) cm, 21.07 (15.78, 25.09), 190.43 (130.14, 350.75) cm³ and 2 165.54 (1 465.86, 4 185.21) g, respectively. There was no correlation between SUV_max and the maximum diameter of lesions (r_s=-0.305, P=0.122), while MTV and TLG were positively correlated with the maximum diameter (r_s values: 0.741, 0.532, both P<0.05). The maximum diameter, MTV and TLG were positively correlated with Ann Arbor staging (r_s values: 0.394, 0.413, 0.422, all P<0.05), while SUV_max was not (r_s=0.031, P>0.05). Conclusions PMBL mostly presents as large anterior mediastinal mass with the high ¹⁸F-FDG uptake in ¹⁸F-FDG PET/CT imaging, and the focal necrosis is common, while abdominal lymph nodes, spleen and bone marrow invasion are rare. MTV and TLG of lesions positively correlate with Ann Arbor staging.

Objective: To investigate the prognostic value of metabolic parameters calculated from pretreatment ¹⁸F-fluorodeoxyglucose (FDG) PET/CT images in patients with extranodal natural killer/T cell lymphoma (ENKTL) of stage Ⅰ-Ⅱ. Methods: From August 2010 to April 2018, 67 patients with ENKTL of stage Ⅰ-Ⅱ disease (47 males, 20 females; median age 57 years) in the First Affiliated Hospital of Nanjing Medical University were enrolled, and the clinic data and pretreatment ¹⁸F-FDG PET/CT imaging data were retrospectively analyzed. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of tumor tissue were calculated from PET/CT images with the threshold value of 40% of maximum standardized uptake value (SUV_max). The optimal cut-off values of progression-free survival (PFS) and overall survival (OS) of SUV_max, MTV and TLG were investigated by using receiver operating characteristic (ROC) curve analysis. Kaplan-Meier method, log-rank test and Cox proportional hazards model were used for data analysis. Results: SUV_max, MTV and TLG of 67 patients were 12.32(8.65, 16.96), 13.13(7.37, 22.74) ml, 92.17(46.54, 198.46), respectively. ROC curve analysis showed that the cut-off values of SUV_max, MTV and TLG were 13.09, 18.05 ml and 152.81, respectively. Univariate analysis showed that B symptoms, lactate dehydrogenase (LDH) level, β₂-microglobulin, Eastern Cooperative Oncology Group (ECOG) score, Korean prognostic index (KPI), SUV_max, MTV, TLG and treatment mode (chemotherapy or chemoradiotherapy) were relative factors affecting PFS (χ²: 5.466-27.163, all P<0.05). B symptoms, LDH level, β₂-microglobulin, EB virus (EBV)-DNA, extra-cavitary extension, ECOG score, KPI, MTV, TLG and treatment mode were relative factors affecting OS (χ²: 4.022-34.774, all P<0.05). SUV_max was not the influencing factor of OS(χ²=2.766, P>0.05). Multivariate analysis showed that ECOG score, MTV and TLG were independent prognostic predictors of PFS (relative ratio (RR): 5.107-6.802, all P<0.05), and ECOG score, MTV, TLG and treatment mode were independent prognostic predictors of OS (RR: 0.221-9.106, all P<0.05). Conclusions MTV and TLG from pretreatment ¹⁸F-FDG PET/CT images are independent prognostic factors for PFS and OS in patients with ENKTL of stage Ⅰ-Ⅱ. MTV and TLG may be more useful than SUV_max for prognosis.

Objective: To explore the imaging presentation of ¹⁸F-FDG PET-CT and clinical characteristics of the patients with lymphoblastic lymphoma (LBL). Methods: The clinical and imaging data of 18 patients with newly diagnosed LBL in the First Affiliated Hospital with Nanjing Medical University from July 2009 to June 2017 were retrospectively analyzed. The sensitivity, specificity and accuracy of ¹⁸F-FDG PET-CT to diagnose bone marrow involvement (BMI) was calculated respectively. Results: There were 18 LBL patients, including 12 male and 6 female with median age of 24.5 (14-51) years old. Eleven patients were T-LBL, and 7 patients were B-LBL. All lesions were presented with high ¹⁸F-FDG uptake on ¹⁸F-FDG PET-CT imaging, with a median SUV_max of 14.3 (10.6, 16.8). The most frequent lymph node involvement site was mediastinal lymph nodes, and 7 T-LBL cases had jugular node involvement. The most frequent extranodal involvement site was bone marrow, with multifocal FDG accumulation in bone marrow on ¹⁸F-FDG PET-CT imaging in 8 cases. The median SUV_max of node and extranodal involvement were 15.0 (9.0, 18.2), 12.3 (8.4, 15.3), and there was no significant difference (Z=-0.867, P= 0.386). The median SUV_max of T-LBL and B-LBL patients was 14.1 (9.2, 15.9), 14.5 (12.1, 19.5) respectively, and there was no significant difference (Z=-0.679, P= 0.497). According to clinical features, ¹⁸F-FDG PET-CT and bone marrow biopsy (BMB), 12 patients were diagnosed as BMI. If multifocal FDG accumulation and diffuse hypermetabolism of FDG in bone marrow were considered as the diagnosis criteria, the sensitivity, specificity and accuracy of PET-CT was 91.7% (11/12), 66.7% (4/6), 83.3% (15/18), respectively. The parameters in BMB were 50.0% (6/12), 100.0% (6/6), 66.7% (12/18), respectively. Conclusions LBL mostly occurs in young men and its clinical manifestations include lymphadenectasis and invasion of bone marrow. ¹⁸F-FDG PET-CT has certain characteristics which are helpful to diagnose and staging.

Objective To validate the value of 18F-fluorodeoxyglucose (FDG) uptake on PET/CT and thyroid transcription factor-1 (TTF-1) expression to predict the epidermal growth factor receptor (EGFR)mutations in lung adenocarcinoma.Methods From May 2012 to May 2016,a total of 137 lung adenocarcinoma patients (89 males,48 females,age range 33-84 years) pathologically proved were reviewed retrospectively.EGFR mutation testing,TTF-1 expression and PET/CT scan were performed for all patients.x2test was used to assess the differences of EGFR mutation in different groups.Two-sample t test was used to compare the differences of maximum standardized uptake value (SUVmax) between EGFR mutation type and EGFR wild type,TTF-1 positive and negative expression.Multivariate logistic regression analysis was used to test the univariate models that yielded the best predictors of EGFR mutation receiver operating characteristic (ROC) curve analysis was performed to quantify the predictive value of those factors.Results EGFR mutation was identified in 53 patients,including 2 cases in exon 18,19 cases in exon 19,3 cases in exon 20 and 29 cases in exon 21.The high risk factors of EGFR mutation were female (x2=7.465,P=0.006),non-smoking (x2=7.193,P=0.007) and positive expression of TTF-1 (x2=9.104,P＜0.05).The SUVmax of EGFR mutation type was significantly lower than that of EGFR wild type (8.76±4.59 and 11.20±5.09;t =2.832,P =0.005).Multivariate analysis showed that the lower SUVmax (SUVmax ＜8.65) and positive expression of TTF-1 were the independent risk factors for EGFR mutation (P=0.032,P=0.018).The combined use of SUVmax and TrF-1 yielded a higher area under the ROC curve (area under curve=0.697),suggesting a good discrimination.Conclusion The combined evaluation of 18F-FDG uptake and expression of TTF-1 may be helpful in predicting EGFR mutation status in patients with lung adenocarcinoma,especially when the genetic testing is not available,and can provide meaningful clues for clinical treatment.

Objective To investigate the relationship between metabolic parameters of 18F-FDG PET-CT and cilinicopathological features of patients with lung squamous cell carcinoma. Methods The study comprised 118 patients with lung squamous cell carcinoma. All patients undergone 18F-FDG PET-CT before surgery. Maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) were measured, and total lesion glycolysis (TLG) was calculated. Relationship between metabolic parameters and clinicopathological factors was analyzed. Results SUVmax, MTV and TLG of 118 primary lesions were 11.93 (3.12-41.46), 27.71 cm3 (0.54-347.10 cm3) and 153.13 (1.65-2219.37), respectively. SUVmax was related to tumor differentiation degree and pleural invasion (χ2= 15.358, P= 0.000; Z= -2.875, P= 0.004); MTV was related to tumor differentiation degree, pleural invasion, vascular invasion and lymphatic metastasis (χ2= 13.341, P= 0.001; Z= -2.855, P= 0.004; Z= -2.683, P= 0.008; Z= -3.951, P= 0.000), TLG was also related to these clinicopathological factors (χ2= 15.609, P= 0.001;Z= -3.901, P= 0.002;Z= -2.311, P=0.021;Z= -3.721, P= 0.000). T stage and TNM stage had positive correlation with all metabolic parameters (r= 0.326, 0.794, 0.732;r= 0.358, 0.718, 0.668; all P< 0.05). And for N stage, SUVmax was no correlative (r=0.125, P=0.107), but MTV and TLG were positively correlative (r=0.399, 0.371, both P< 0.05). According the MTV or TLG and tumor size, patiens were divided into three groups: low-risk group, moderate-risk group and high-risk group. Significant differences were found among the three groups not even in MTV model, but also in TLG model (χ2= 20.800, P= 0.000; χ2= 20.069, P= 0.000). Conclusions Metabolic parameters of lung squamous cell carcinoma primary lesion have good correlation with clinicopathological factors, and can reflect partial characteristics of the tumor pathology in a certain extent. Furthermore, the probability of lymphatic metastasis could be predicted by MTV or TLG combined with tumor size.

Objective To assess the role of 68Ga-N,N′-bis(2-hydroxy-5-(carboxyethyl)benzyl) ethylenediamine-N,N′-diacetic acid(HBED-CC)-(Ahx)Lys-CO-Glu(PSMA-11) PET/CT on the detection of metastatic lesions from castration-resistant prostate cancer (CRPC).Methods Sixteen patients with CRPC who underwent 68Ga-PSMA-11 PET/CT between January 2015 and November 2015 were recruited in this study.Mean age of patients was (72±9) years.The PSA levels were 4-12 356 μg/L, Gleason score was 7-10.PET/CT was performed at 1 h postinjection of 68Ga-PSMA-11.Patient-based analysis and lesion-based analysis were performed.ROI analysis was used to calculate the tumor uptake (SUVmax).Final diagnosis was based on histopathology and results of other imaging examinations(99Tcm-MDP imaging, MRI).χ2 test was used to compare the diagnostic efficiencies of PET and CT.Results No adverse effects were observed in patients.68Ga-PSMA-11 PET/CT showed moderate physiologic uptake in salivary glands and proximal small intestine, with predominant tracer clearance by the kidneys.All patients were positive on 68Ga-PSMA-11 PET/CT.Bone metastasis was found in 16 patients, liver metastasis in 2 patients (5 lesions), and lymph node metastasis in 4 patients (26 lesions).The SUVmax of liver, lymph node and bone metastases were 15.06±2.77, 7.54±5.20, 19.01±16.96, respectively.The diagnostic sensitivity, specificity and accuracy on bone metastasis with 68Ga-PSMA-11 PET and CT were 96.30%(52/54) vs 61.11%(33/54), 3/3 vs 1/3, 96.49%(55/57) vs 59.65%(34/57).The sensitivities and accuracies of the two modalities were significantly different(χ2=19.943, 22.593, both P<0.01).Conclusions 68Ga-PSMA-11 PET/CT could precisely detect both primary and metastatic lesions of CRPC, suggesting that it is of great value for the clinical management and treatment.