Objective To investigate the influence of discontinuance of methimazole (MMI) and propylthiouracil (PTU) on 24 h radioactive iodine uptake(RAIU) in normal rats.Methods A total of 66 female SD rats were randomly divided into 3 groups by simple random sampling method.MMI group (30 rats) received MMI with a dose of 0.6 mg·ml-1·d-1 orally for 2 weeks, PTU group (30 rats) received PTU with a dose of 6 mg·ml-1·d-1 orally for 2 weeks.At 1, 3, 5, 7 and 9 d after MMI or PTU was discontinued, 6 rats were sacrificed to measure 24 h RAIU respectively.The control group (6 rats) received normal saline with a dose of 1 ml/d orally for 2 weeks, and then they were sacrificed to measure 24 h RAIU too.Data were analyzed with two-sample t test or t′ test.Results Thyroid 24 h RAIU in normal rats was (14.6±4.3)%.The 24 h RAIU on 1, 3, 5, 7 and 9 d was (4.6±0.7)%, (24.2±7.2)%, (13.1±2.9)%, (14.1±2.6)%, (16.1±3.7)% respectively after MMI withdrawal.The 24 h RAIU was significantly lower than that in control group at day 1 (t′=5.55, P<0.01), higher at day 3 (t=-2.83, P<0.05), and returned to the normal level at day 5, 7, 9 (t=0.68, 0.24,-0.67, all P>0.05).The 24 h RAIU on 1, 3, 5, 7 and 9 d was (1.9±0.8)%, (3.3±1.2)%, (7.7±2.4)%, (29.0±4.0)%, (17.1±4.8)% respectively after PTU withdrawal.It was lower than that in control group (t=7.01, 6.10, 3.40, all P<0.05) at day 1, 3, 5, and higher at day 7 (t=-5.97, P<0.01).The 24 h RAIU of 9 d showed no difference when compared with that in control group (t=-0.95, P>0.05).Conclusions MMI and PTU can inhibit the iodine uptake of thyroid, the 24 h RAIU returns to normal level at day 5 after withdrawal of MMI and at day 9 after withdrawal of PTU in euthyroid rats.

Objective To investigate the critical value of TSH-stimulated Tg(sTg) in the diagnosis of metastasis from DTC, and to evaluate the diagnostic value of the ratio of sTg to suppressed Tg (sTg/suppressed Tg).Methods A total of 330 post-operative DTC patients(87 males, 243 females, age range: 12-70 years)who underwent thyroid remnant ablation from August 2008 to December 2014 were retrospectively reviewed.Their serum TgAb levels were normal.The patients were divided into non-metastasis group(147 cases)and metastasis group(183 cases) according to results of ultrasonography, CT and WBS.The difference of sTg between the two groups were compared by Mann-Whitney rank sum test.ROC curve was used to analyze the relationship between sTg, sTg/suppressed Tg ratio and metastasis, the cutoff value was calculated.Results The sTg was significantly different between the non-metastasis group and metastasis group: 1.0 (0.1, 2.0) μg/L vs 36.5 (3.9, 126.7) μg/L;u=-6.642, P<0.05.The AUC for ROC curve in metastasis group was 0.85, and the cutoff value was 2.05 μg/L, with the sensitivity 85.2%, specificity 67.3%, and accuracy 82.3%.While sTg<2.05 μg/L, the AUC of sTg/suppressed Tg ratio was 0.941, and the cutoff value was 4.3, with the sensitivity 93.3%, specificity 88.2%, and accuracy 92.3%.Conclusions The sTg has a specific value for the diagnosis of metastasis from DTC after operation and the cutoff value is 2.05 μg/L in this set of patients.The ratio of sTg/suppressed Tg could be used to correct the sTg and to improve the diagnostic sensitivity.

Objective To quantitatively compare the diagnostic capability of 68Ga-NGR and 18F-FDG in well-differentiated hepatocellular carcinoma (HCC) bearing mice by microPET/CT imaging.Methods The in vitro cellular uptake, in vivo microPET/CT imaging and biodistribution studies of 68Ga-NGR and 18F-FDG were quantitatively compared in SMMC-7721-based well-differentiated HCC.The human fibrosarcoma (HT-1080) and human colorectal adenocarcinoma (HT-29) cells/xenografts were respectively used as positive and negative reference groups for CD13.The expression of CD13 was qualitatively verified by immunohistostaining.The levels of CD13 and glucose-6-phosphatase (G6Pase) were semi-quantitatively analyzed by Western blot test for all 3 types of tumors.Two-sample t test was used for data analysis.Results The in vitro cellular uptake showed that the 68Ga-NGR uptake in SMMC-7721 and HT-1080 cells was higher than that in HT-29 cells, and the 68Ga-NGR uptake was higher than 18F-FDG uptake in SMMC-7721 cells.The in vivo microPET/CT imaging results revealed that the uptake of 68Ga-NGR in SMMC-7721 tumor was (2.17±0.21) %ID/g, remarkably higher compared to (0.73±0.26) %ID/g of 18F-FDG uptake (t=8.826, P<0.01).The tumor/liver ratio of 68Ga-NGR was 2.05±0.16, which was 2.03-fold higher than that of 18F-FDG.In the HT-1080 tumors, the uptakes of 68Ga-NGR and 18F-FDG were both high, and the values were (2.46±0.23) %ID/g, (3.47±0.31) %ID/g.The uptake of 68Ga-NGR was significantly lower than that of 18F-FDG in HT-29 tumors: (0.67±0.20) %ID/g vs (3.17±0.29) %ID/g;t=4.221, P<0.01.Western blot and immunohistostaining results were as follows: HT-1080(CD13+, G6Pase-), SMMC-7721(CD13+, G6Pase+), HT-29(CD13-, G6Pase-).Conclusions The uptake of 68Ga-NGR is higher than 18F-FDG uptake in SMMC-7721 tumor bearing mice, therefore it is worthwhile to consider the feasibility of clinical translation for PET/CT in diagnosis of HCC.Furthermore, because of the difference in 68Ga-NGR and 18F-FDG avidities in tumors with different molecular phenotypes of CD13 and G6Pase, there is an underlying potential for molecular imaging in the determination of molecular phenotypes.

Objective To determine whether glucagon-like peptide-1 (GLP-1) receptor PET/CT with 68Ga-exendin-4 is accurate in localizing insulinomas, by comparing with conventional imaging techniques.Methods In this prospective cohort study, patients with biochemically proven endogenous hyperinsulinemic hypoglycemia from March 2014 to November 2016 were recruited consecutively.68Ga-exendin-4 PET/CT, CT, MRI, endoscopic ultrasound (EUS), and SSTR imaging were performed before elective surgery.Surgical pathology results were considered as the gold standard.Sensitivity based on patient-analysis and positive predictive value (PPV) based on lesion-analysis were calculated and compared using χ2 test and generalized score test.Results A total of 109 patients were recruited (47 males, 62 females;average age (45.1±14.8) years), and 96 of them with insulinomas proved pathologically were included in the main assessment.Thirteen patients with positive 68Ga-exendin-4 PET/CT findings did not undergo surgical intervention.Based on patient-analysis, the sensitivities of 68Ga-exendin-4 PET/CT, CT, MRI, EUS and SSTR imaging for detecting insulinomas were 98.96%(95/96), 81.25%(78/96), 79.41%(54/68), 81.40%(35/43) and 21.84%(19/87), respectively.Based on lesion-analysis, the PPV of the above 5 methods were 100%(102/102), 97.56%(80/82), 95.16%(59/62), 83.72%(36/43) and 90.48%(19/21), respectively.68Ga-exendin-4 PET/CT showed the highest diagnostic sensitivity than others (all P<0.01) and higher PPV than MRI, EUS and SSTR imaging (all P<0.05).Conclusion 68Ga-exendin-4 PET/CT is a highly sensitive imaging technique for detection of insulinoma.

As a type of neuroendocrine tumors, neuroblastoma (NB) is the most common extra-cranial solid tumor of childhood.123/131I-MIBG scintigraphy is a standard imaging modality in staging and evaluating therapeutic effect of pediatric NB with high accuracy.131I-MIBG treatment is effective for children with high-risk and relapsed/refractory NB.Combined with chemotherapy, stem cell transplantation, 131I-MIBG treatment shows efficacy in decreasing the relapse of pediatric NB.This review summarizes the application of MIBG scintigraphy and 131I-MIBG treatment for pediatric NB.

Objective To retrospectively analyze the cardiac systolic synchrony and cardiac function in patients with chronic heart failure (CHF） by gated SPECT myocardial perfusion imaging (GSMPI). Methods (1) From January 2010 to February 2015, 123 cases including 82 CHF patients (57 males, 25 females, age (59.5±11.0) years) and 41 healthy people (control group; 27 males, 14 females, age (33.8±5.2) years) were enrolled in this retrospective study. According to the New York Heart Association (NYHA) classification, the CHF patients were classified into grade Ⅰ-Ⅳ groups. The systolic synchrony and cardiac functional parameters including PHB, PSD, LVEF, EDV, summed rest scores (SRS) were acquired by Emory Cardiac Toolbox software. Differences of PHB, PSD and LVEF were compared between the CHF group and the control group using two-sample t test. The difference among the four CHF groups was compared by one-way analysis of variance. The difference of some clinical factors was compared between the two groups with and without damage of systolic synchrony. The relationship between the cardiac synchrony and myocardial perfusion was analyzed by Pearson correlation analysis. Results There was no obvious difference of PHB and PSD between the grade Ⅰ CHF patients and the control group (t=-1.502 and -0.448, both P>0.05), while LVEF was significant different (t=10.419, P<0.05). Significant difference of PHB, PSD and LVEF existed between the grade Ⅱ-Ⅳ CHF patients and the control group (t values: from -27.250 to 32.723, all P<0.05). There were significant differences of PHB, PSD and LVEF among the 4 CHF groups (F=118.05, 4.13 and 154.37; all P<0.05). The differences of LVEF, EDV and SRS were significant between the patients with and without damage of systolic synchrony (t=9.57, 10.85, 18.87, all P<0.05). The ratios of damage in systolic synchrony in grade Ⅰ-Ⅳ CHF patients were 8.7% (2/23), 60.0%（12/20）, 15/18 and100% (21/21), respectively. PHB and PSD were both positively correlated with SRS (r=0.808 and 0.773, both P<0.05). Conclusions The damage of systolic synchrony are getting severer from patients with NYHA grade Ⅱ to patients with NYHA grade Ⅳ. The damage could be accompanied by the heart failure progression. Diabetes mellitus, LVEF, EDV, ESV, and SRS are related to the damage. The myocardial perfusion damage is positively correlated with the damage of cardiac systolic synchrony. GSMPI is useful to early diagnosis and treatment of heart failure.

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.

Objective To evaluate the impact of low-dose 131I therapy and high-dose 131I therapy on the clinical outcome in PTC patients coexisting with Hashimoto's thyroiditis (HT).Methods A total of 140 non-distant metastatic PTC patients (16 males,124 females,age range:16-66 years) from July 2010 to December 2014 were enrolled in this retrospective study.Patients concurrent with HT (n=84,group A) were divided into low-dose group (1 110 MBq,n=56,group A1) and high-dose group (5 550 MBq,n=28,group A2) according to 131I ablation dose.Patients without HT (n =56) were enrolled as control group (group B),and received 1 110 MBq of 131I.The thyroid remnant ablation outcome was evaluated according to 131I diagnostic whole-body scan (Dx-WBS),neck ultrasonography (US),serum Tg and TgAb level 6-8 months after 131I ablation therapy.The successful ablation rates were compared by x2 test.Kruskal-Wallis rank sum test was also used.Results There were no significant differences among the 3 groups in terms of both clinicopathological features and postoperative remnant thyroid (H:0.203-2.944,x2:0.271-0.970,all P＞0.05).When negative Dx-WBS and US were deemed as successful ablation criterion,complete ablation rate was found significantly more in group B (94.6％,53/56) than that in group A1 (82.1％,46/56;x2=4.264,P＜0.05),but no significant difference was found between group A2 (85.7％,24/28) and group A1 (x2 =0.318,P＞0.05).When combining negative sTg (sTg＜1 μg/L,TgAb＜46 kU/L) with the above 2 criterions to assess remnant ablation outcome,group B also had a higher successful rate to achieve complete ablation (85.7％,48/56) compared with group A1 (75.6％,34/45),but without statistical significance (x2=2.978,P＞0.05),and no difference was observed between group A2 (12/15) and group A1 (x2=1.320,P＞ 0.05).Conclusion Non-distant metastatic PTC patients coexisting with HT has undesirable 131I ablation outcome compared with those without HT,increasing 131I dose is unhelpful to enhance efficiency of remnant ablation for PTC patients with HT.

Objective To explore optimized method of estimating 131I effective half-life(EHL) in patients with Graves' disease(GD).Methods The EHL was obtained by measuring thyroid radioactive iodine uptake (RAIU) of 126 patients (32 males,94 females,average age (38.47± 11.49) years) with GD at 4,24,48,96,120,144,168,192 and 216 h.Two-sample t test,bivariate correlation analysis and curve estimation were used for statistical analysis.Results The EHL of 126 patients was 0.5-7.5 (4.70±1.46) d.The EHL was 3.0-7.5(5.25±1.01) d and 0.5-6.0(3.24±1.52) d in group A (94 patients,without advanced peak of RAIU) and group B (32 patients,with advanced peak of RAIU),respectively,and the difference between the 2 groups was significant (t =8.499,P＜0.01).The EHL had no significant correlation with RAIU4h/RAIU24h(r=-0.177,P＞0.05) in group A,while it had negative correlation with RAIU4h/RAIU24h in group B (r =-0.724,P＜0.01).In group A,the EHL of patients with RAIU24h/RAIU48h ＞100％ was 3.0-7.5 (5.11 ±0.98) d,the EHL of patients with RAIU24h/RAIU48h ≤ 100％ was 4.0-7.0(5.91±0.94) d (t=3.141,P＜0.01).In group B,when RAIU4h/RAIU24h+RAIU24h/RAIU48h was used as the independent variable in S curve model to estimate the EHL,the result was the best (R2=0.930,F=397.22,both P＜0.01,b0 =-3.038 0,b1 =9.659 4).Conclusions In order to optimally estimate EHL,patients should be grouped according to 131I turnover.In patients with advanced peak of RAIU,the EHL should be calculated by using formula of (RAIU4h/RAIU24h +RAIU24h/RAIU48h).If no advanced peak of RAIU exists,patients should be further divided according to RAIU24h/RAIU48h ＞ 100％ or RAIU24h/RAIU48h ≤100％,and the EHL mean value of each group is taken as the estimated EHL.

Objective To establish rat models of extrahepatic biliary atresia,and to observe the characteristics of 99Tcm-MIBI hepatobiliary scintigraphy and evaluate its association with the expression Pglycoprotein (P-gp) in intestinal tissues.Methods A total of 12 SD rats were randomly divided into the normal control group (3 rats) and the group of common bile duct ligation (CBDL;9 rats).CBDL was used to establish the rat model of extrahepatic biliary atresia.99Tcm-MIBI hepatobiliary scintigraphy was performed at 2,3 and 4 weeks after ligation in the CBDL group and normal control group with continuous dynamic acquisition (3 min/frame) for 30 min and then delaying imaging at 30 min,1,2 and 3 h.After that,all rats were sacrificed,and the blood samples were taken out for the determination of serum ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA,and the tissues of duodenum,jejunum,ileum,colon and cecum were taken out for analyzing the expression level of P-gp by immunohistochemistry.Two-sample t test and one-way analysis of variance were used.Results Compared with the normal control group,the serum levels of ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA were significantly increasing at 2,3,4 weeks after ligation in CBDL group (t:-3.04 to-44.54,all P＜0.05).99Tcm-MIBI hepatobiliary imaging showed that there was radioactive accumulation in colon or cecum area,excluding the duodenum,jejunum and ileum area,at 3 h after intravenous injection of 99Tcm-MIBI in CBDL group.The results of immunohistochemistry showed that with the obstruction time prolonged,the expression levels of P-gp in duodenum,jejunum and ileum segments were gradually decreased (F=5.17,9.07,23.52;all P＜0.05),while the expression levels in the colon and cecum segments were not changed obviously (F=2.00,3.17;both P＞0.05).Conclusion 99Tcm-MIBI can be excreted through intestinal mucosa,and this process may be associated with P-gp expression.