Objective To verify the reliability of dose parameters of radiotherapy under reference and non-reference conditions by using TLD.Methods Dose parameters were verified by using TLDs under reference and non-reference conditions,including the maximum dose in axel of 5 electron beams with energy of 9 MeV and the variations of dose by depth,source-skin distance,exposure field and 45° wedge for 10 photon beams with energy of 6 MV in 5 hospitals.Results The average relative deviation of 6 MV photon beam measured between TLDs and finger ionization chambers were 4.45％,within ± 7％ as required by IAEA.The average relative deviation of 9 MeV electron beam measured between TLDs and plane parallel chambers were 2.45％,within ± 5％ was required by IAEA.Conclusions Measuring dosimetric parameters by using TLDs under reference and non-reference conditions was reliable and feasible.

Objective To investigate the association of duration of untreated psychosis(DUP) and the gray matter volumes in patients with first-episode schizophrenia.Methods 39 patients with first-episode schizophrenia were divided into two groups according to DUP:long-DUP group and short-DUP group.All the subjects underwent T1 weighted magnetic resonance imaging.After transformed with MRIcro software,all the images underwent standardization,segmentation,modulation and smoothing with Statistical Parametric Mapping 5 (SPM5) software.The gray matter volumes of the two groups underwent two-sample t-test with a Voxel-based morphometry (VBM)using SPM5 software.Results Long-DUP schizophrenic patients presented significantly reduced GM volume in the left thalamus(MNI:-6,-16,2;cluster=141 voxels)and the left temporal lobe(MNI:-46,-58,-6;cluster=69 Voxels),compared with short-DUP schizophrenic patients.Conclusion Delayed DUP may increase the loss of gray matter in schizophrenia.

Objective To observe the quantitative corpus callosum (CC) segmentation MRI topology and brain white matter tractography variations in patients with multiple sclerosis (MS),and to assess the correlation between quantitative indicators and scores of expanded disability status scale (EDSS).Methods Conventional MRI and diffusion tensor imaging (DTI) were applied in 32 MS patients and 32 healthy volunteers,admitted to our hospital from June 2011 to June 2013.The areas,average diffusion coefficent (ADC) values,fractional anisotropy (FA) values and tracked lines of each CC segment (1-5) and total CC were measured.T tests were used to compare the above quantitative indices in MS patients with those in controls.Linear regression model was used to determine the relationship between quantitative indices and scores of EDSS in MS patients.Results Various degrees of damage of white matter tracts in CC of MS patients could be visually identified by tractography.The areas,FA values and tracked lines of each CC segment in MS patients were smaller than those in controls (P＜0.05),and the ADC values of segment 1-3 in MS patients were larger than those in controls (P＜0.05).Moreover,the areas ([549.13±64.07] mm2),FA values (0.55±0.05) and tracked lines (519.78±79.03) of total CC in MS patients were smaller than those in controls ([614.56±39.67] mm2,[0.67±0.02] and [612.34±39.51],P＜0.05),and the ADC values ([0.93±0.09]×10-3 mm2/s) of total CC in MS patients were larger than those in controls ([0.86±0.03]×10-3 mm2/s,P＜0.05).Both areas and tracked lines of each CC segment in MS patients had negative correlations with EDSS scores (P＜0.05).Moreover,both areas and tracked lines of total CC in MS patients were found having negative correlations with EDSS scores (r=-0.686,P=0.000;r=-0.676,P=0.000).Conclusion Both areas and tracked lines of each CC segment and total CC reflect the degrees of clinical disability in MS patients,which can be used for disease and efficacy evaluation of MS patients.

Objective To explore the predictive ability of magnetic resonance spectroscopy (MRS) in overall survival (OS) and progression-free survival (PFS) of patients with glioblastoma multiforme (GBM) before,during,and 2 months after radiotherapy with concomitant/adjuvant temozolomide (TMZ).Methods GBM patients,admitted to our hospital from January 2011 to January 2016 and confirmed by pathology,were chosen in our study;all patients underwent postoperative three-dimensional conformal radiotherapy with concomitant/adjuvant TMZ.And 3D-MRS was performed before,during,and 2 months after radiotherapy,the levels of N-acetyl-aspartic acid (NAA),choline (Cho) and creatine (Cr),and ratios of Cho/NAA,Cho/Cr and NAA/Cr in the GBM/edge of surgery side and the normal brain tissues were observed.The survival curve,median overall survival (mOS) and median progression free survival (mPFS) of patients with standardized Cho decreased＜30％ and patients with standardized Cho decreased＞30％ 2 months after radiotherapy were compared.Results Twenty-one patients finished the scheduled MRS for 3 times.Until the end of our study,16 patients died and 5 survived.Standardized Cho gradually decreased before,during,and 2 months after radiotherapy (2.08±0.22,1.45 ±0.21 and 1.16±0.18),with significant differences (P＜0.05).Standardized Cho after radiotherapy was significantly decreased as compared with that before radiotherapy (P＜0.05).Ratios of Cho/NAA and Cho/Cr in the GBM/edge of surgery side were significantly higher than those in the normal brain tissues (P＜0.05),and ratio of NAA/Cr in the GBM/edge of surgery side was significantly lower than that in the normal brain tissues (P＜0.05).Ratio of Cho/NAA gradually decreased before,during,and 2 months after radiotherapy,with significant differences (P＜0.05).As compared with patients with standardized Cho decreased＜30％ 2 months after radiotherapy,patients with standardized Cho decreased＞30％ 2 months after radiotherapy had significantly decreased rates of OS and PFS,and statistically shorter mPFS and mOS (4.5 vs.13.5,10.9 vs.25.3,P＜0.05).Conclusion The changes of standardized Cho 2 months after radiotherapy have high prognostic significance for PFS and OS.

Objective To evaluate the application of multi-parameter three-dimension arterial spin labeling (3D-ASL) in observing the brain perfusion of patients with transient ischemic attack (TIA). Methods A total of 42 TIA patients, admitted to our hospital from July 2014 to March 2017, were included in this study. All subjects underwent conventional MRI, diffusion-weighted imaging (DWI), magnetic resonance angiography (MRA) and 3D-ASL scanning. Abnormal signals, and cerebral arterial stenosis or occlusion were observed under MRI, DWI and MRA; cerebral blood flow (CBF) map was drew after analyzing the 3D-ASL imaging, and abnormal reperfusion of ASL-CBF was qualitatively and quantitatively analyzed. The detection rate of abnormal reperfusion in TIA patients by 3D-ASL (PLD=1.5 s, PLD=2.5 s) and MRA were compared. Results Forty-two TIA patients showed no positive findings on conventional MRI and DWI maps, of which 18 patients showed different degrees of cerebral artery stenosis on MRA maps. Twenty-seven patients (PLD=1.5 s, 64.29％) and 21 (PLD=2.5 s, 50％) on ASL-CBF maps showed different sizes and degrees of abnormal hypoperfusion, and significant difference was found in detection rate of hypoperfusion by 3D-ASL (PLD=1.5 s and PLD=2.5 s, χ2=23.333, P=0.000). The detection rates of hypoperfusion by 3D-ASL (PLD=1.5 s and PLD=2.5 s) were 中华神经医学杂志2017年12月第16卷 第12期 Chin J Neuromed, December 2017, Vol.16, No.12 significantly higher than that by MRA (χ2=17.500, P=0.000; χ2=31.500, P=0.000). Conclusions The 3D-ASL can quantitatively analyze the degrees of perfusion of patients with TIA. 3D-ASL can comprehensively reflect the perfusion status in patients with TIA, and short PLD 3D-ASL is more sensitive than long PLD ASL in finding TIA, while long PLD 3D-ASL can reflect the perfusion status more truly.