RESUMO
background The lead isotope ratios (LIR) differ among different sourced samples. Previous domestic and oversea studies on source tracing by LIR in human blood or urine mainly focused on the comparison of blood or urine samples from the same or different individuals, while few comparisons between biological and environmental samples, and the reported relative standard deviations (RSDs) of the main LIR (207/206Pb and 208/206Pb) fluctuate widely from 0.3% to 1%. Objective To optimize inductively coupled plasma mass spectrometry (ICP-MS), obtain a better RSD, and determine LIRs of human blood, urine, and related environmental samples. Methods The ICP-MS was optimized for operating conditions and parameters according to the sensitivity and RSD of LIR. The study subjects were 40 lead-exposed workers in a lead-acid battery factory and 2 lead poisoned children in a hospital. The samples included 40 blood and 40 urine samples from the workers before shift, 4 dust samples and 2 water samples in the workplace on the same day before shift, 2 blood and 3 urine samples from the children before hospital admission due to lead-poisoning, and 4 urine samples after medical treatment. After heating and acid digestion, the LIR (207/206Pb and 208/206Pb) of biological and environmental samples were determined by the optimized ICP-MS method. t-test and two-dimensional traceability graphics were adopted to analyze the detection results. Results The calibrated RSDs of the LIR (207/206Pb and 208/206Pb) of lead isotope standard solution were 0.11% and 0.08% respectively, and the NIST-SRM-981 actual values were 0.91531±0.00097 and 2.1670±0.0017, respectively. When the total concentration of lead was greater than 5 μg·L−1, the RSD of each isotope ratio was stable gradually; when the total concentration of lead was between 10-80 μg·L−1, the RSD was below 0.20%. There were statistically significant differences in the blood and urine LIR (207/206Pb and 208/206Pb) of the lead-exposed workers (t=5.831, P<0.001; t=21.021, P<0.001), the LIR (207/206Pb and 208/206Pb) between workplace dust samples and workers’ urine samples (t=−6.879, P=0.038; t=12.521, P<0.001), and the 208/206Pb between workplace dust samples and workers’ blood samples (t=−10.46, P<0.001), except the 207/206Pb between workplace dust samples and workers’ blood samples (t=−0.12, P=0.912). In the patients afflicted with lead poisoning, the projection points of LIR of blood and urine samples from the same individual were not at the same level in the two-dimensional model, nor was the LIR of urine samples before and after medical treatment of the same individual. Conclusion The optimized ICP-MS can control the RSD of main LIR (207/206Pb and 208/206Pb) below 0.20%. There are differences in the LIR distributions of different samples.
RESUMO
Objective To study the MRI features of toxoplasmosis encephalopathy.Methods There were totally 20 cases in the group,all patients accepted the examinations of MRI and immunisation sylum(EIISA) with Gd-DTPA enhanced MRI in 17 cases and repeted MRI in 15 cases.5 cases undengone stero-orientation biopsy under CT guided.Results Most of the focus situated at the juncture of gray and white matter of cerebral hemisphere (8 cases) and around the lateral ventricle (6 cases).The lesion was multiple .The lesions had different degrees of contrast enhancement after enhanced scans (17 cases),among them,the patchy enhancement was most commonly seen (9 cases),secondarily was circular or semicircular enhancemeut (7 cases).The immunological serum examination in all the cases were positive IgM or IgG.The treatment for anti-toxoplasma was in effect for all the cases.Conclusion MRI is of significant value in definiting the involved location,extent,time course of toxoplasmosis encephalopathy,and also evaluating the effect of therapy.
RESUMO
Objective To study the application of fusion of CT and MRI images in X-knife treatment for intracranial lesions.Methods Total 25 patients included:3 gliomas,3 acoustic neuroma,2 pituitary adenoma,one craniopharygioma to be remained or recurred postoperatily,2 pituitary micro-adenoma,5 AVM,4 cavernous angioma,3 metastatic tumour,one neoplasm located pituitary stem and midbrain respectively.Before the fusion of CT and MRI images MRI scan and CT scan for location of X-knife were performed respectively,then MR and CT image were transferred to workstation for the fusion of images.Results All lesions were showed clearly on fusional images and more nodules were observed in 3 metastatic tumour.Skull,soft tissue constructures and the profile of lesions were completely overlaped on overlaped images of CT and MR with an error less 1.0 mm.Conclusion CT and MRI images of head can be accurately registered.The images can show the radiologic informations more clearly than conventional CT image.It provides a safe,effective and little harmful method for X-knife treatment of intracranial lesions.
