Cerenkov luminescence imaging (CLI) is a new method of optical molecular imaging,which has been successfully applied in early clinical trials.However,weak signal intensity and limited ability in tissue penetration have impeded its clinical application.Cerenkov radiation energy transfer imaging and radiation excitation fluorescence imaging were adopted to solve these problems by enabling transformation of some of the blue-weighted Cerenkov luminescence (CL) spectra to red-shifted emissions,or by exciting rare earth particles to emit visible and near infrared light.This article reviews the development of Cerenkov signal enhancement by fluorescence excitation effect.

Objective To assess the effects of 7,8-dihydroxyflavone (7,8-DHF) on the striatum (ST) in normal cynomolgus monkeys using 99Tcm-TRODAT-1 imaging.Methods A total of six healthy female cynomolgus monkeys were included in this study.Three of them were fed with normal food (control group),and the other three were given oral administration of 7,8-DHF in addition to normal food (experimental group).The SPECT/CT imaging was performed at different time after 99Tcm-TRODAT-1 injection.The ROI of ST was drawn on images of 3 consecutive transverse slices that could be visualized best.The cerebellum (CB) was taken as the background reference area.The radioactivity uptake ratios of ST/CB at 1,3,4 and 5 h were calculated respectively.Paired-t test was used to analyze the data.Results ST radioactive uptake ratios showed continuing increase on the delay images.ST/CB uptake ratios of the control group at 1,3,4 and 5 h were 1.43±0.04,1.82±0.06,2.04±0.12,2.42±0.23,respectively,and those of the experimental group were 1.35±0.08,2.40±0.09,2.74±0.13 and 3.25±0.15 respectively.There was no significant difference between the two groups at 1 h (t =2.57,P＞0.05),while ST/CB uptake ratios of the experimental group at 3,4 and 5 h were significantly higher (t values:2.77,2.87 and 2.92,all P＜0.05).Conclusion 99Tcm-TRODAT-1 SPECT/CT imaging can be used to assess the DAT activation effect by 7,8-DHF on ST of cynomolgus monkeys.

Objective To investigate the effect of postoperative TSH suppression on bone mineral density (BMD) in postmenopausal women with DTC.Methods Postmenopausal women with postoperative DTC underwent thyroid residual ablation or 131I treatment for metastases at Xin Hua Hospital between September 2009 and December 2014 were enrolled and followed for 2 years.They were divided into suppressive TSH group (median TSH＜0.30 mU/L;group 1) and non-suppressive group (median TSH≥0.30 mU/L;group 2).Lumber 1-4 BMD levels (T scores) were measured by a dual energy X-ray absorptiometry bone densitometer at baseline,1 year and 2 years after treatment.All patients had calcium and vitamin D supplementation after TSH suppression.The T scores were compared with Mann-Whitney u test and Kruskal-Wallis test.Results A total of 126 patients were enrolled and followed up for 2 years,including 65 with average age (57.65±6.65) years in group 1 and 61 with average age (56.19±7.17) years in group 2.The T scores in group 1 and group 2 at baseline were-1.70(-2.30,-0.55) and-1.30(-2.10,-0.30) (z=-1.660,P＞ 0.05).The difference of T scores was significant in group 1 at baseline,1-year follow-up and 2-year follow-up (-2.25(-2.48,-0.83),-1.95(-2.70,-0.60);H=6.244,P＜0.05),but not significantly different in group 2 (H=1.102,P＞0.05).The T values were different between the 2 groups both in 1-year follow-up and 2-year follow-up (z values:-2.170,-2.160,both P＜0.05).Conclusions TSH suppression significantly increases the risk of postoperative osteoporosis.The BMD should be followed up annually in postmenopausal DTC patients.

Objective To retrospectively study the biodistribution of 68Ga-DOTA-TATE as a SSTR imaging agent in human subjects.Methods A total of 106 patients with suspected disease were enrolled in this study.All patients were histologically proven for having either a single tumor ＜2 cm or without evidence of tumor during follow-up.Patients underwent PET/CT whole-body scan 17-100 min after intravenous injection of 55.2-220.0 MBq 68Ga-DOTA-TATE.ROI was drawn for measuring SUV of tracer-avid pathologies.One-way analysis of variance and two-sample t test were used for statistical analysis.Results High 68Ga-DOTA-TATE avidity was found in pituitary,with SUVmax of 4.00± 1.21.Tracer was excreted mainly through urinary system resulting in highest uptake in the urinary tracts.The SUVmax of kidney cortex was 19.01 ± 5.45.Mediastinal blood pool and liver SUVmax were 0.93±0.33 and 7.69±2.26,respectively.Mild uptake of 68Ga-DOTA-TATE was found in the brain,cerebellum,lung and muscle,all lower than that of mediastinal blood pool.Moderate accumulation of 68 Ga-DOTA-TATE (close to or slightly higher than liver) was found in adrenal gland and spleen,with SUVmax 7.61 ± 3.42 and 8.63± 2.31,respectively.Other organs (pituitary,salivary gland,thyroid,pancreas,small intestine,colon,uterus,prostate and bone) showed tracer uptake in the range between those of mediastinal blood pool and liver.68Ga-DOTA-TATE distribution in pancreas was not uniform.Nine patients had focal accumulation in the uncinate process of pancreas with highest SUVm~ up to 8.48.However,the SUVmax and SUV in the rest of pancreas (head,neck,body and tail) showed insignificant difference (F values:0.703,0.563,both P＞0.05).68Ga-DOTA-TATE uptake in each organ reached equilibrium quickly after injection but with slight increase over time.The changes in SUV,however,showed insignificant difference among organs,including different parts of pancreas (t values:from -0.09 to 1.75,from-1.70 to-0.42,respectively,all P＞0.05).Conclusions The biodistribution of 68Ga-DOTA-TATE reaches equilibrium shortly after intravenous administration and is stably maintained.The biodistribution activities are organ-specific,and characteristic to that of SSTR concentration.

Objective To validate the reproducibility of abnormal cerebral metabolic characteristics in PD patients from different medical centers using 18F-FDG PET imaging.Methods A total of 108 subjects who were referred for resting-state brain 18 F-FDG PET imaging were retrospectively reviewed.Thirtythree PD patients (15 males,18 females,age:38-79 years) and 33 age-matched healthy controls (15 males,18 females,age:40-77 years) underwent evaluation at Shanghai Huashan Hospital Affiliated to Fudan University.Seventeen PD patients (10 males,7 females,age:44-74 years) and 17 age-matched healthy controls (6 males,11 females,age:42-67 years) underwent evaluation at the First Affiliated Hospital of Sun Yat-sen University.SPM was used to investigate the cerebral metabolic characteristics of the patients with two-sample t test.Statistically significant voxels were obtained by using familywise error rate (FWE;P＜0.05).Two sets of PD patients with abnormal glucose metabolism of brain regions were obtained and the cerebral metabolic characteristics were compared.Results Regarding the PD patients from Shanghai Huashan Hospital,the features of cerebral glucose metabolism by SPM analysis were demonstrated as follows:increased metabolism was found in the region of pons,cerebellum,thalamus,putamen and pallidum,while decreased metabolism was displayed in the region of parietal lobe and occipital lobe.The increased regions referred to 8 110 voxels and decreased regions referred to 2 810 voxels (P＜0.05).The similar metabolic pattern was found in PD patients from the First Affiliated Hospital of Sun Yat-sen University.The increased metabolism was shown in the regions of pons,cerebellum,thalamus,putamen and pallidum,and referred to 15 573 voxels.The metabolism-decreased regions included parietal lobe,occipital lobe and frontal lobe,and referred to 3 945 voxels (P＜0.05).Conclusions 18F-FDG PET/CT imaging results demonstrate similar metabolic pattern in PD patients from different medical centers,in whom the metabolism-increased regions are found in the pons,cerebellum,thalamus and pallidum and decreased regions were demonstrated in the parietal lobe and occipital lobe.The reproducibility from 18F-FDG PET/CT imaging provides reliable evidence for the multi-center study in the differential diagnosis of PD.

Objective To compare the diagnostic values of 18F-FDG and 18F-FLT PET/CT in patients with suspicious recurrence of glioma after multimodal treatment.Methods A total of 20 patients (13 males,7 females;age range:12-73 years) with glioma who underwent 18F-FDG and 18F-FLT PET/CT due to abnormal enhancement on MRI from January 2012 to June 2015 were enrolled in this retrospective study.According to the pathological or follow-up results,patients were divided into therapy-related benign changes (TRBC) group and recurrent glioma group,the later was subdivided into initial low-grade glioma (LGG) group and initial high-grade glioma(HGG) group.T/NT ratios of 18F-FDG and 18F-FLT between HGG (LGG) group and TRBC group were compared using one-way analysis of variance and the least significant difference t test.ROC curve analysis was conducted to calculate the differential diagnostic efficiency of 18F-FDG and 18F-FLT between TRBC and recurrent glioma.Results A total of 14 patients were proved as recurrent glioma and 6 patients as TRBC.The mean 18F-FDG T/NT ratios of HGG group,LGG group and TRBC group were 2.31±0.86,1.32±0.86 and 1.32±0.64,respectively.The 18F-FDG T/NT ratio of the HGG group was significantly higher than that of the TRBC group(F=3.671,t=-2.471,P＜0.05).The mean 18F-FLT T/NT ratios of HGG group,LGG group and TRBC group were 8.94±3.14,7.18±3.29 and 1.92±1.20,respectively (F=13.301,t values:-5.150 and-2.360,both P＜0.05).The optimal T/NT cutoff values for 18 F-FDG and 18F-FLT PET/CT were 1.62 and 4.58,respectively.The sensitivity,specificity and accuracy of detecting recurrent glioma with optimal T/NT cutoff value were 11/14,5/6 and 16/20 for 18F-FDG PET/CT,and those for 18F-FLT PET/CT were 13/14,6/6 and 19/20,respectively.No significant difference was observed between the diagnostic efficiencies of the two imaging modalities (x2 values:1.167,1.091 and 2.057;all P＞0.05).Conclusion There were no statistical significances between 18F-FDG and 18F-FLT PET/CT on the differential diagnosis of glioma recurrence.

Vasodilator stress MPI plays an important role in the detection of abnormal myocardial perfusion.Currently as the only selective A2A adenosine receptor agonist approved by FDA,the new myocardial stress agent regadenoson has been increasingly used in vasodilator stress MPI on clinic.This review describes the pharmacologic properties and overviews the clinical data on regadenoson,especially its diagnostic efficacy,prognosis predicting value and adverse effect as a vasodilator stress agent.