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 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 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 investigate the prognostic value of SUVmax , SUVmean , MTV and TLG cal-culated from 18 F-FDG PET/CT in patients with postoperative esophageal cancer. Methods Sixty-one pa-tients ( 51 males, 10 females;age ranged 50-81 ( median:64) years) with esophageal cancer who under-went preoperative 18 F-FDG PET/CT from October 2007 to November 2015 were retrospectively analyzed. The relation of SUVmax , SUVmean , MTV and TLG in primary lesions with clinic pathological factors was ana-lyzed. Differences of metabolic parameters were compared with two-sample t test, one-way analysis of vari-ance, Mann-Whitney u test or Kruskal-Wallis H test. The optimal cutoff points of SUVmax , SUVmean , MTV and TLG for predicting overall survival ( OS) were investigated by ROC curve analysis. The Kaplan-Meier method and log-rank test were used to perform univariate survival analysis, and Cox proportional hazards model was used for multivariate analysis. Results MTV and TLG were associated with tumor length, N stage and clinical stage, while SUVmax and SUVmean were only associated with tumor length ( t=-2.396, F=4.206, 4. 471;z=-3.051,χ2=8.908, 9.796;t=-2.417,-2.423;all P<0. 05) . The optimal cutoff points of SUVmax, SUVmean, MTV and TLG were 11.76, 7.06, 24.35 cm3 and 166. 84 g, respectively. Univariate analysis of OS showed that the lymphatic metastasis, clinical stage and TLG were all significantly associated with the patient outcome (χ2=14.683, 7.139, 11.669, all P<0.05) . Multivariate analysis showed that lym-phatic metastasis and TLG were the independent predictors for OS (β=-1. 472, -1. 223; Wald=5. 224, 4. 668;both P<0.05) . Conclusion For predicting the prognosis of esophageal cancer after operation, TLG of the primary tumor may be more valuable than SUVmax , SUVmean and MTV.

Objective To investigate the prognostic value of 18F-FDG PET-CT in patients with diffuse large B-cell lymphoma(DLBCL).Methods The clinical data of 130 DLBCL patients from June 2009 to May 2015 and pretreatment 18F-FDG PET-CT were retrospectively analyzed.Results The 130 DLBCL patients' median of maximal standard uptake value(SUVmax),metabolic tumor volume(MTV)and total lesion glycolysis(TLG)was 19.93,34.45 cm3,459.92 respectively.Univariate analysis showed that the affecting factors of progression-free survival(PFS)and overall survival(OS)rate included Eastern Cooperative Oncology Group(ECOG)grade,Ann Arbor stage,β2-MG,lactate dehydrogenase level,tumor diameter,bone marrow involvement,National Comprehensive Cancer Network International Prognostic Index(NCCN-IPI),MTV and TLG(all P <0.05),while age was related with PFS rate(P<0.05).As MTV and TLG were strongly correlated,only TLG measure was used for multivariate analysis.The result showed that ECOG grade,Ann Arbor stage,NCCN-IPI and TLG were statistically significant predictors of PFS rate,and NCCN-IPI and TLG were independent factors of OS rate(all P<0.05).According to TLG and NCCN-IPI,the patients were divided into three groups: low risk group,mediate risk group and high risk group.The 3-year PFS rates of these groups were 66.0%,36.8% and 26.1% respectively(P< 0.05),and the 3-year OS rates of these groups were 70.0%,49.1% and 39.1% respectively(P < 0.05).Conclusion TLG in 18F-FDG PET-CT is an independent prognostic factor for PFS and OS in patients with DLBCL,which has a reference value for prognosis of DLBCL.

Objective To investigated the prognostic value of 18 F-FDG PET/CT in patients with limited-stage small cell lung cancer (LS-SCLC). Methods Sixty-six patients (58 males, 8 females;median age 65 years) with LS-SCLC who underwent pretreatment 18 F-FDG PET/CT from April 2009 to December 2015 were included in this retrospective study. The relations between the SUVmax , the sum of MTV ( MTVsum ) , the sum of TLG ( TLGsum ) and clinical factors were analyzed. ROC curve was plotted to estimate the most discrimination threshold ( cutoff point) for each parameter to maximize the sensitivity and specifici-ty in predicting the progression or recurrence. Kaplan-Meier method and log-rank test were used to perform univariate survival analysis and Cox proportional hazards model for multivariate analysis. Results The SUVmax, MTVsum and TLGsum of 66 patients were 10.57±3.27, 38.71(2.89, 221.68) cm3 and 267.04 (1167, 1684.13), respectively. SUVmax, MTVsum and TLGsum were all associated with hydrothorax, the maximum diameter of tumor, clinical stage and LDH. MTVsum and TLGsum were also associated with tumor type and NSE. During the median 33 months of follow-up, 4 patients were lost to follow-up, 43 patients were progressive or recurrent with the median PFS of 12.30 months, and 38 patients died with the median OS of 15.75 months. The optimal cutoff point of SUVmax, MTVsum and TLGsum were 10.08, 16.18 cm3, 209.14, re-spectively. Univariate analysis showed that hydrothorax, the maximum diameter of tumor, clinical stage, NSE, LDH, surgery, MTVsum and TLGsum were all associated with PFS and OS. SUVmax was associated with PFS, but not with OS. Multivariate analysis demonstrated that NSE, LDH, MTVsum and TLGsum were the in-dependent predictors of PFS ( HR:3.83, 4.46, 9.26, 3.87, all P<0.05) , and LDH, MTVsum were also the independent predictors of OS ( HR:2.77, 6.83, both P<0.05) . However, SUVmax was not the independent predictor of PFS(HR=1.47, P>0.05). Conclusions 18F-FDG PET/CT can predict the prognosis of pa-tients with LS-SCLC. SUVmax is correlated with PFS, MTVsum and TLGsum are independent predictors of PFS, and MTVsum is also an independent predictor of OS.