Objective:To prepare a 177Lu labeled human epidermal growth factor receptor 2 (HER2) affibody 177Lu-1, 4, 7-triazacyclononane-1, 4, 7-triacetic acid (NOTA)-maleimide (Mal)-cysteine (Cys)-ZHER 2: 342 ( 177Lu-NOTA-MZHER2 for short), and investigate its labeling process and anti-tumor properties. Methods:Two kinds of buffer systems (sodium acetate buffer system and sodium ascorbate buffer system) were investigated. The effects of pH value, precursor mass and reaction temperature on 177Lu labeling NOTA-MZHER2 were compared to obtain optimal labeling conditions. The radiochemical purity of labeled product was determined by instant thin-layer chromatography (ITLC), and its stabilities in PBS and plasma were observed. Human ovarian cancer cell line SKOV-3 was selected for cell internalization and cytotoxicity test to evaluate cell uptake and killing effect of 177Lu-NOTA-MZHER2. SKOV-3 tumor-bearing mice( n=3) were injected with 177Lu-NOTA-MZHER2, and microSPECT/CT imaging was performed. Another 40 tumor-bearing mice were divided into 22.2 MBq group (tail vein injection with probe of 22.2 MBq), control group (tail vein injection with PBS), low-dose group (tumor injection with probe of 3.7 MBq) and high-dose group (tumor injection with probe of 7.4 MBq). Tumor volume and mass of tumor-bearing mice were monitored after injection, and the anti-tumor effect and toxicity of probe were evaluated. Repeated measurement analysis of variance (Bonferroni method) was used to analyze the data. Results:The optimal labeling condition was 70-80 ℃ for 30 min in the system of sodium acetate buffer solution with pH=4 and precursor mass of 50 μg. Under these conditions, the labeling rate of 177Lu-NOTA-MZHER2 was (99.3±0.4)% and radiochemical purity was >99%. After 12 d in PBS and plasma, the radiochemical purities were (95.0±1.5)% and (95.0±2.1)%. Results of cell experiment showed that the internalization of 177Lu-NOTA-MZHER2 accounted for (29.02±3.50)% of the total uptake, and the survival rate of SKOV-3 cells was (48±6)% with the probe concerntration of 6×10 -3 Bq/L. SPECT imaging showed that 177Lu-NOTA-MZHER2 was still concentrated at the tumor site 96 h after injection with a dose of 18.5 MBq. Relative tumor volume (RTV) of tumor-bearing mice in 22.2 MBq group, high-dose group and low-dose group was significantly different from that in control group ( F=21.75, P<0.001). Twenty days after injection, RTV and relative body mass of the tumor-bearing mice in high-dose group were (140±7)% and (80±9)%, respectively. Compared with control group, high-dose group had obvious anti-tumor effect (both P<0.001). Conclusion:177Lu-NOTA-MZHER2 is successfully prepared, which is simple and efficient, and the probe has good anti-tumor effect.

Objective:To radiolabel hyperbranched polymer (HG)-modified liquid metal nanodroplet (LMND)@HG with 177Lu, and explore the radiotherapy sensitization effect on anti-breast cancer therapy. Methods:The ultrasonication method was used to prepare LMND@HG, and then 177LuCl 3 was mixed with LMND@HG to label 177Lu by alloying reactions. The labeling rate, plasma stability and cytotoxicity of 177Lu-LMND@HG were detected. Xenograft mouse model of breast cancer was constructed, and the tumor inhibition test was performed by an intratumoral injection. The tumor progression was monitored by in vivo imaging system. The mechanism of tumor inhibition was verified by immunohistochemistry and immunofluorescence assays. One-way analysis of variance, repeated measures analysis of variance, and the least significant difference t test were used to analyze the data. Results:177Lu was successfully labeled to LMND@HG with a high labeling efficiency >95%. The product did not require further purification and the plasma radiochemical purity was still higher than 95% after 5 d. The cytotoxicity test showed that a dose of 888 kBq (40 mg/L) 177Lu-LMND@HG had obvious toxicity to 4T1 cells, which was significantly lower than 177LuCl 3 (cell viabilities: (16.48±7.81)% vs (85.77±8.87)%; F=77.81, t=11.73, P<0.001) and LMND@HG ((46.53±5.75)%; t=6.20, P<0.001). The biological distribution results showed that 177Lu-LMND@HG was mainly distributed in tumor tissue 5 d after intratumoral injection. The results of the tumor inhibition experiment showed that 1.48 MBq 177Lu-LMND@HG could significantly inhibit the tumor growth compared with the 177LuCl 3 (tumor volume: (222.66±97.70) vs (789.13±245.04) mm 3;F=18.55, t=4.29, P=0.005). In vivo optical imaging of small animals showed that 1.48 MBq and 3.70 MBq 177Lu-LMND@HG both significantly inhibited the tumor growth. Immunofluorescence and immunohistochemical results showed that 177Lu-LMND@HG caused double-stranded DNA break, and suppressed the tumor growth by inhibiting cell proliferation and angiogenesis. Conclusions:A novel 177Lu-liquid metal-based reactive oxygen species (ROS) radiation sensitizer is successfully prepared in this study. The preparation method is efficient and convenient, and the product has high stability. 177Lu-LMND@HG shows an obvious radiotherapy sensitization effect on breast tumor-bearing mice.

Objective:To prepare a novel 68Ga-labeled bicyclic peptide targeting poliovirus receptor related protein 4 (PVRL4, Nectin-4), and evaluate its feasibility for breast cancer imaging via in vitro and in vivo experiments. Methods:A Biotin-modified bicyclic peptide targeting Nectin-4, Biotin-BMIC, was synthesized, and its targeting properties were preliminarily evaluated by in vitro cell staining experiments. BMIC was modified by 1, 4, 7-triazonane-1, 4-diacetic acid (NODA) and the labeling precursor NODA-BMIC was prepared. A potential PET probe targeting Nectin-4, 68Ga-NODA-BMIC was prepared by one-step labeling strategy. The imaging properties of the probe were investigated by in vivo microPET imaging and in vitro experiments in mice bearing breast tumors. Data were analyzed by independent-sample t test and repeated measures analysis of variance. Results:Fluorescence staining of the cells showed that the fluorescently labeled bicyclic peptide, Biotin-BMIC, was highly aggregated in Nectin-4 positive BT474 breast cancer cells compared to those in Nectin-4 negative MDA-MB-231 cells. The uncorrected yield of 68Ga-NODA-BMIC was (71.5±2.2)% and the radiochemical purity was greater than 95%. The specific activity was greater than 3 GBq/μmol. After incubation 10, 30, 60 and 120 min, higher radioactivity uptakes were found in BT474 breast cancer cells compared to those in MDA-MB-231 breast cancer cells respectively ( F=1 302.00, P<0.001). MicroPET imaging showed that the BT474 xenograft tumors were clearly visible with favorable contrast. A significant statistical difference in uptakes between BT474 and MDA-MB-231 xenograft tumor uptake at 10, 30, 60, and 120 min after probe injection respectively was existed ( F=1 826.00, P<0.001). At 60 min postinjection, the uptake value of BT474 tumors was (5.03±0.14) percentage activity of injection dose per gram of tissue (%ID/g), which was significantly higher than that of MDA-MB-231 tumors ((0.19±0.04) %ID/g; t=79.40, P<0.001). Meanwhile, the tumor-to-muscle ratios in the former were also greater than those in the latter ( F=222.00, P<0.001). At 60 min postinjection, the tumor-to-muscle ratio in the former was significantly higher than that in the latter (24.75±3.10 vs 1.30±0.15; t=14.31, P=0.002). The results were consistent with the immunohistochemistry staining. Conclusions:A novel bicyclic peptide PET probe targeting Nectin-4, 68Ga-NODA-BMIC, is easy to be synthesized and owns satisfactory labeling yield and radiological purity. The imaging performance is good and the target tissues could be visualized. It may play a unique role in the diagnosis and treatment of breast cancer.

Objective:To label mesenchymal stem cells (MSCs) with 89Zr-oxine complex, and assess its characteristics of PET imaging in systemic lupus erythematosus (SLE) model (MRL/lpr mice). Methods:SLE mice were screened by 18F-FDG PET imaging. 89Zr-oxine was prepared and used for labeling MSCs (10 6 MSCs and 1 MBq 89Zr-oxine). 89Zr-oxine-labeled MSCs (0.2 MBq) were injected into MRL/lpr mice and BALB/c mice (each n=5) via tail vein at a dose of 1.2×10 6 cells per mouse, and followed with microPET imaging in vivo at 2 h, 6 h, 1 d, 3 d, 7 d, 10 d and 14 d after injection. The percentage activity of injection dose per gram of tissue (%ID/g) was calculated. Independent-sample t test was used to analyze the data. Results:MSCs was successfully labeled with 89Zr-oxine, with the labeling efficiency of 20% and cell viability >90%. MicroPET imaging showed that MSCs were mainly distributed in lungs and the liver sites at 2 h after injection. The number of MSCs homing to kidneys of MRL/lpr mice ( n=5) increased significantly 24 h after the injection, and the renal uptake of MSCs in MRL/lpr mice was much higher than that in BALB/c mice ((8.28±1.27) vs (4.33±0.94) %ID/g; t=3.54, P=0.024). The renal uptake increased firstly and then decreased and then leveled off, indicating MSCs homing to kidneys. Conclusions:A method for 89Zr-oxine labeling of MSCs is successfully established. 89Zr-labeled MSCs can home to kidneys of SLE mice. PET imaging of 89Zr-labeled MSCs can be effectively used to explore the in vivo distribution and migration behavior of transplanted MSCs during the treatment of diseases such as SLE.

Conventional transcatheter aortic valve replacement is normally recommended with transthoracic echocardiography, and contrast agent mediated fluoroscopy under anesthesia to guide a better implantation of the transcatheter valve. However, iodine-containing contrast agent possibly damages the patient’s kidney, and even induces the acute kidney injury. We reported a 75-year-old patient diagnosed with severe aortic valve stenosis, moderate regurgitation, and chronic renal failure. We performed the aortic valve replacement under the guidance of fluoroscopy and transesophageal ultrasound without contrast agent. Seven days after surgery, the patient recovered well and discharged with alleviated aortic stenosis and fixed transcatheter aortic valve.

Objective:To synthesize N- 18F-fluoroethyl-tofacitinib, and explore its feasibility in the diagnosis of rheumatoid arthritis (RA). Methods:The " two-step method" was used to modify tofacitinib with 18F-fluoroethyl, and the labeling rate and radiochemical purity of the probe were measured by high performance liquid chromatography (HPLC), and the stabilities of the probe in vivo and in vitro were investigated. BALB/c mice (normal group; n=3) and collagen-induced arthritis (CIA) model mice (CIA group; n=3) were injected with N- 18F-fluoroethyl-tofacitinib and CIA model mice injected with tofacitirrib and N- 18F-fluoroethyl-tofacitinib were as blocking group ( n=3). All mice underwent microPET imaging and the percentage injection dose per gram of tissue (%ID/g) and the uptake ratio of inflamed joints to muscle (T/M) were calculated. One-way analysis of variance and the least significant difference (LSD) t test were used to analyze the data. Results:The synthesis time of N- 18F-fluoroethyl-tofacitinib was about 120 min, with the yield approximately 1%, the specific activity >13.6 GBq/μmol, and the radiochemical purity >99%. After the probe incubated with PBS, plasma or in vivo for 2 h, the radiochemical purity was still more than 95%. MicroPET imaging showed that 30 min after injection, the uptake of N- 18F-fluoroethyl-tofacitinib in the inflamed joints of CIA group was higher than that of normal group and blocking group ((10.22±1.64), (2.71±0.26) and (2.81±0.33) %ID/g; F=58.26, t values: 7.83, 7.67, P values: 0.001, 0.002). The T/M of CIA group was also higher than that of normal group and blocking group (24.73±5.77, 2.75±1.36 and 2.89±0.54; F=40.64, t values: 6.42, 6.53, P values: 0.003, 0.003). Conclusions:N- 18F-fluoroethyl-tofacitinib is successfully prepared and it is stable in vitro with good imaging performance in vivo. It may be used in clinic for the diagnosis of RA.

Objective    To evaluate the changes of ascending aortic (AA) diameter after transcatheter aortic valve replacement (TAVR), and evaluate the safety and efficacy of TAVR in patients with AA dilation. Methods    We retrospectively included 87 patients who underwent TAVR at our center from 2016 to 2019. These patients were divided into 2 groups based on the preoperative AA diameter. There were 17 patients in the AA diameter≥45 mm group (including 10 males, aged 74.4±5.6 years), and 70 patients in the AA diameter<45 mm group (including 39 males, aged 75.9±7.0 years). Results     The baseline variables were similar between two groups (P>0.05). The overall device success rate was 97.7% (85/87). The median computed tomography (CT) follow-up time was 24.2±11.8 months in patients with AA diameter≥45 mm and 23.0±10.7 months in patients with AA diameter<45 mm, and the median annual dilation rate of AA were 0.36 mm/year and 0.00 mm/year, respectively. No statistical significance was observed between two groups (P>0.05). No adverse aortic events occurred during the follow-up period. Conclusion    TAVR is safe and effective in patients with preoperative AA diameter≥45 mm, and the AA diameter remains stable after the procedure. Patients with preoperative AA diameter≥45 mm and AA diameter<45 mm have similar annual dilation rates.

Objective:To prepare a 68Ga labeled human epidermal growth factor receptor 2 (HER2) affibody 68Ga-1, 4, 7-triazacylononane-1, 4, 7-triacetic acid (NOTA)-maleimide (MAL)-Cysteine (Cys)-Glycine-Glycine-Glycine-Arginine-Aspartic acid-asparagine-HER 2: 342 affibody (GGGRDN-ZHER 2: 342)( 68Ga-MZHER), and evaluate its biodistribution and microPET characteristics. Methods:NOTA-MAL-Cys-GGGRDN-ZHER 2: 342 conjugate was labeled with 68Ga in one step. Radiochemical purity, radiolabeling yield and stability in vitro were analyzed. Normal mice ( n=24) were scarified at 15, 30, 60 and 120 min postinjection (1.85 MBq 68Ga-MZHER) to measure radioactive counts (percentage activity of injection dose per gram of tissue (%ID/g)) in main organs. Biodistribution and kinetics were evaluated by dynamic microPET in mice. Ovarian cancer (SKOV-3) models were established and microPET was performed at 30, 60 and 120 min postinjection of radiotracer. After administration of unlabeled Cys-ZHER 2: 342 peptide (10 mg/kg body weight) for 30 min, 68Ga-MZHER was injected into mice and PET images were acquired at 60 min postinjection. Region of interest (ROI) was drawn to access time-activity curve (TAC) in main organs and tumor. Six normal mice were used for the safety study. Results:68Ga-MZHER was synthesized in about 15 min with the yields more than 90%, and radiochemical purity more than 95%. The radiochemical purity was also determined to be more than 95% after being stored for 120 min at room temperature. Predominant uptake of 68Ga-MZHER was in the kidneys, and was cleared rapidly in normal tissues except the kidney. At 15 min postinjection, the renal uptake value was (106.36±15.74) %ID/g, then gradually increased with time, up to (145.15±28.04) %ID/g (60 min), and decreased to (86.12±22.75) %ID/g after 120 min postinjection. The blood pharmacokinetic of the probe in mice was fit with the two-compartment model. MicroPET imaging in mice bearing HER2 positive SKOV-3 tumors showed that the xenografts were clearly visualized with good contrast to normal tissue. The uptakes in tumors was determined to be (11.26±0.50), (12.27±1.13) and (12.65±0.89) %ID/g at 30, 60 and 120 min postinjection. Block experiment showed that the corresponding values decreased to (1.25±0.28) %ID/g at 60 min postinjection. Safety studies showed that after injection of 68Ga-MZHER for 30 d, the mice survived and no obvious abnormalities were observed in the main organs as shown in pathological results. Conclusions:68Ga-MZHER can be successfully labeled by one-step method. The 68Ga-MZHER probe owns the advantages of favorable imaging properties, convenient preparation, excellent stability, safety, rapid clearance in the blood, which support its application for further research.

Objective:To prepare 18F-Alfatide Ⅱ automatically based on the improved CFN-100 fluorine multifunctional module and assess its PET/CT imaging in prostate cancer patients. Methods:A certain volume (200-500 μl) of fluoride ion was separated into the reaction tube by a fluoride ion separator and reacted with the labeled precursor l, 4, 7-triazacylononane-1, 4, 7-triacetic acid-E[(polyethylene glycol) 4-cyclo(Arg-Gly-Asp- D-Phe-Tyr)] 2(NOTA-E[PEG 4-c(RGDfk)] 2) (lyophilized kit). In the aqueous phase, 18F was chelated with aluminum. After being separated and purified by C18 column, 18F-Alfatide Ⅱ was prepared automatically. The radiochemical yield and its quality were analyzed. Quality control was carried out and 18F-Alfatide Ⅱ PET/CT imaging was performed in 2 patients (72 and 66 years old)with prostate cancer. Results:18F-Alfatide Ⅱ was prepared automatically by the improved CFN-100 fluorine multifunctional module combined with a double channel-fluorine ion separation device. 18F-Alfatide Ⅱ was synthetized in about 30 min, with radiochemical yield of (28±3)% (non-decay corrected, n=6). The radiochemical purity of the product was more than 98%, the specific activity was 2.8×10 7 MBq/mmol and the nuclear purity was >99%. PET/CT imaging of 2 patients showed that 18F-Alfatide Ⅱ were highly concentrated in prostate cancer lesions with the maximum standardized uptake value (SUV max) of 35.6 and 5.0, respectively. Conclusion:18F-Alfatide Ⅱ can be prepared successfully by improved CFN-100 fluorine multifunctional module with stable synthesis method, short synthesis time and high radiochemical yield, which can be highly concentrated in prostate cancer.

Objective To investigate the characteristics of 18F-Alfatide II PET/CT imaging in normal breasts and breast cancer lesions.Methods From March 2016 to August 2017,22 female patients(age:(52±10)years)with suspected breast malignant nodules or masses were prospectively enrolled.All patients underwent 18F-Alfatide II PET/CT imaging prior to biopsy or surgery.The imaging characteristics of normal breasts were assessed visually and the difference of maximum standardized uptake value(SUVmax)in normal breasts and uterus between patients with and without menopause was compared,SUVmax of cancer lesions and normal breasts was also compared.Breast cancer lesions were classified according to the distribution characteristics of radioactive uptake,and molecular subtypes ware determined by immunohistochemistry and fluorescence in situ hybridization.The SUVmax of different morphological and molecular subtypes were analyzed.Two-sample t test and Pearson or Spearman correlation analysis were used to analyze the data.Results There were 23 breast cancer lesions(one patient had bilateral breast cancer lesions and one had a history of one-side breast resection),20 normal breasts and 21 normal uteruses.Those normal breasts and uteruses didn't show any malignant change after being followed up for more than 1 year(one patient had uterine fibroids resection).There was a slight increase of radioactivity uptake in the cord-like connective tissue region at the margin of the gland in 11 mammary glands,and the SUVmax was higher than that of glandular tissue in the central region(1_81±0.67 vs 0.79±0.37;t = 6.771,P<0.00l).Of the 11 cases,except for one patient whose uterus was removed,the other 10 patients were accompanied by increased diffuse radioactivity of the uterus.SUVmax of 19 normal breast connective tissues(1.31±0.80)and uterus(3.80+1.79)were positively correlated(r = 0.785,P<0.05).For patients with/without menopause(n= 11 each group),the SUVmax of normal breast connective tissues(0.72±0.39 vs 1.81±0.67)and uterus(2.04±0.39 vs 5.11 + 1.06)were significantly different(t values:4.42 and 8.66,both P<0.01).Different levels of radioactive uptake were observed in all 23 breast cancer lesions,with SUVmax of 6.93±3.97,which was significantly higher than the nipple,connective tissue and glandular tissue of normal breasts(t values:6.784-7.559,all P<0.05).According to the characteristics of the radioactivity uptake distribution of the lesion,among the 23 breast cancer lesions,5 were mass type,3 were nodular type,4 were diffuse type,and 11 were multi-focal/multi-center type,and the SUVmax of multi-focal/multi-center type was the highest(F=3.55,P<0.05).The SUVmax of basal-like breast cancer lesions(2.49±1.67)was lower than the other three molecular subtypes.Lesions with high level human epidermal growth factor receptor 2(HER2)positive expression had higher SUVmax.Conclusions 18F-Alfatide II PET/CT imaging shows that normal breasts have a slight radioactive distribution,mainly concentrate in the nipple and connective tissues around the glandular,and the uptake have a positive correlation with the radioactive uptake of the uterus.The degree of radioactive uptake of breast cancer lesions is significantly higher than that of normal breasts.Breast cancer lesions with different moqjhological features all have obvious radioactive uptake,especially the multi-focal/multi-center type.Different molecular subtypes have different radioactive uptake levels.SUVmax is lower in basal-like breast cancer lesions,and higher in HER2 positive expression lesions.