[en] A procedure was developed for detecting deep vein thrombosis (DVT) in lower extremities. 30 min after i.v. of in vivo labelled ^99mTc-RBC to the arm, equilibrium venography (EV) was performed. Radionuclide plethysmography (RPG was continued and divided into two types: cuff above knees and above ankles. The following information were provided by this technique: 91) equilibrium images of both legs, (2) segment of thrombosed vein (iliac, femoral, popliteal or tibial), (3) RPG curves, amount and speed of venous flow, (4) degree of venous occlusion (complete and incomplete obstruction). Among 350 patients with suspected DVT, (1) 78 cases were normal in venous flow, (2) 133 cases had unilateral and 108 had bilateral obstruction, (3) 31 cases suffered from venous insufficiency. Equilibrium method was compared with radionuclide venography (RNV) in 50 patients and compared with contrast venography (CV) in 10 patients. The coincidence rates were both 90%. Instead of RNV, equilibrium method (EV + RPG) is recommended for routine examination of patients suspected DVT

[en] Objective: The most common encountered intracranial malignant tumors included glioblastomas, metastatic tumors and intracranial primary malignant lymphomas (IPML). The aim of the study was to comparatively analyze the ¹⁸F-FDG PET manifestations of the three tumors, in particular the image features of IPML. Methods: Ten IPML, 20 glioblastomas and 15 cerebral metastases underwent ¹⁸F-FDG PET. The images were analyzed on the basis of lesion location, uptake value and distribution pattern of FDG. Ratios of tumor to contralateral corresponding region (T/CCR) and of cortex surrounding tumor to the contralateral cortex (TSC/CCRC) were measured using ROI method. Results: In 10 IPML, there were 6 cases with solitary focus located on the cerebra surface and 4 multiple lesions neighboring to the midline of brain, basal ganglia and thalamus. All lesions presented as intensely hypermetabolic. There was also mild to moderate hypometabolism in the cortex around the lesions, ¹⁸F-FDG uptake in IPML was higher than glioblastomas and cerebral metastases, but the decrease accumulation of ¹⁸F-FDG in the cortex around IPML was less than that of the other two kinds of tumors. Conclusion: IPML presented on PET images as solitary or multiple foci with higher hypermetabolic change and less disturbance on ¹⁸F-FDG uptake in nearby cortex than those of glioblastoma and cerebral metastases, which might serve the purpose of differential diagnosis for intracranial tumors. (authors)

[en] Objective: To analyse ¹⁸F-fluorodeoxyglucose (FDG) PET images of patients with sarcoidosis, make an abstract of image characteristics. Methods: Twenty-four cases with sarcoidosis underwent both PET and CT. Among them, 5 were with pathologic evidence and had clinical symptoms, 19 were with positive Kveim test but asymptomatic. All 24 cases kept a fast of 6 h and the blood glucose was controlled below 6.7 mmol/L before injection of FDG. 40 min after administration, PET scan was performed with Siemens ECAT 47. After getting images through reconstruction by computer, the location and contour of the lesions were reviewed; the sizes and standardized uptake value (SUV) were measured. Results: For all 24 cases, strings of nodules were observed along the hili of lungs and the mediastinum, one of them had a nodule with high uptake of ¹⁸F-FDG in the left axilla in addition to the nodules along the hili of lungs and mediastinum. Sizes of nodules of 5 cases with symptoms and of 19 without symptoms were (2.16±0.67) and (1.55±0.21) cm, respectively; SUV were 2.68 ± 0.58 and 1.46±0.24, respectively. There was significant difference in the sizes and SUV of nodules between 5 with symptoms and 19 without symptoms (P < 0.01). Only one out of the 24 cases with sarcoidosis was diagnosed by CT alone. Conclusions: It was ¹⁸F-FDG PET image characteristics of sarcoidosis i. e. strings of nodules distributing along the lung hili and mediastinum. Sizes of nodules were bigger and uptakes of ¹⁸F-FDG were higher for cases with symptoms than those for the asymptomatic cases

[en] Technetium-99m labeled human Immunoglobulin G was prepared by a direct labelling method which is simple and efficient. The biodistribution in animal and imaging were studied. The experiment results showed that the preparation can be used as a blood pool imaging agent

[en] Objective: To preliminarily evaluate the diagnostic value of co-registration and fusion of positron emission tomography and MR images in Alzheimer disease (AD). Methods: Twelve patients with AD (53-83 years) and six normal volunteer (45-71 years) were scanned by positron emission tomography (PET) and MR imaging. The interval between two examination was 1-32 days (average:18.2 +- 11.6 days). The disc and magnetic tape were used to transfer the imaging data to image work station (SGI O₂), then the special software for co-registration and fusion: Statistical Parametric Map was used to do automatic co-registration between PET and MR images of brain in 3D. Results: The findings of PET was completely accorded with the changes of AD in 9 patients (9/12), and accorded with AD, but should be differentiate from other diseases in 3 cases (3/12). According to the measurement of special cerebral structures, MR images could make the diagnosis of AD in 11 patients (11/12), and had no abnormal finding in 1 case. The medial temporal atrophy could be seen on the MR images co-registered with PET in AD patients, on the other hand, PET demonstrated the pink color region of metabolic rate of glucose decreased in temporoparietal lobes of cerebral hemisphere. The similar findings depicted on fusion images as red color region of metabolic rate of glucose decreased in temporoparietal lobes. Conclusion: The co-registered images can accurately observe the abnormal findings of PET and MR images, and fix the location of foci depicted by PET, in addition, fusion images increase the contrast of the foci. Analyzing the images of co-registration and fusion of PET and MRI can lead to the diagnosis of AD in all the patients

[en] Objective Along with more clinical application of ¹⁸F-fourodeoxyglucose (FDG) PET, statistical parametric mapping (SPM) had attracted a lot of attention in past few years. The purpose of this study was to investigate the regional cerebral glucose metabolism changes in Alzheimer's disease (AD) patients with different stages by PET and SPM, according to the k value of the SPM result. Methods: Twenty-seven patients with AD according to diagnostic and statistical manual of mental disorders, 4th edition, revised (DSM-IV-R) and 9 healthy persons as the contrast were examined with three-dimensional (3D) ¹⁸F- FDG PET brain imaging about 40 min post-injection of 3.7 MBq/kg ¹⁸F-FDG and mini-mental state examination (MMSE) evaluation. The 27 AD patients were divided into 3 groups based on their MMSE scores: mild group with the score more than or equal to 20 but less than 25, moderate group with the score between 10 and 20 ( not including 10 and 20), and severe group with the score less than or equal to 10. All the contrast subjects' MMSE scores were more than or equal to 25. On the base of Matlab 6.5, all of the PET images with SPM were normalized and smoothed. A statistical model was established, and the whole AD patients were compared with the contrast group. And then the 3 AD groups were compared with the contrast group respectively. The localization and the k value of the activated region was gotten at last. Results: Compared with the healthy group, the most significant metabolic decrease area was in bilateral frontal lobe, parietal lobe, temporal lobe, post cingulate area and precuneus in AD group. The k value of the mild, moderate and severe group was 929, 6743 and 24 678 in order, while the k value of the frontal lobe was 174, 2712 and 4981 in order. Conclusions: SPM can be used in evaluating the extension of the regional cerebral glucose metabolism decrease according to the k value. The reduction degree becomes severely along with the progress stages of dementia. (authors)

[en] Objective: To investigate the imaging characteristics and diagnostic criteria of ¹⁸F-FDG brain PET in diagnosis of Alzheimer's disease (AD). Methods: The sutdy included 12 normal subjects, 12 patients with AD and 11 patients with non-AD dementia. 40 min after intravenous administration of ¹⁸F-FDG, brain scan was performed using Siemens ECAT47 scanner. The transaxial, coronal and sagittal images were then reconstructed by computer. At the same time, semiquantitative analysis was also applied to help evaluation using the ratio of mean radioactivity of cerebral lobe to cerebellum (R_cl/cb). Results: In normal subjects PET scan showed clear images of cerebral cortex, basal ganglia, thalamus and cerebellum with symmetrical distribution of radioactivity. PET images from Alzheimer's disease patients were classified into 3 patterns: bilateral parietal hypometabolism in 5 cases, bilateral temporo-parietal hypometabolism in 4 cases and unilateral temporo-parietal hypometabolism in 3 cases. The R_cl/cb of AD patients in parietal and temporal lobe was significantly decreased than normal subjects (P<0.05). PET images from non-AD dementia were also classified into 3 patterns; multiple and asymmetrical patch foci with decreased radioactivity in 8 cases, bilateral temporo-parietal with diffuse cortical hypometabolism in 2 cases, and normal imaging in 1 case. The hypometabolic involvement was found in accord with severity of dementia. The R_cl/cb was also reflecting thedementia degree. Compared with MRI imaging , 12 patients with AD had cerebral hypometabolism but only 10 had hippocampus atrophy. 10 patients with non-AD dementia had local structural foci seen in MRI, including old hemorrhage, infarction and encephalomalacia, but these lesions were not found in AD. Conclusions: Based on excluding cerebral structural lesions which are better detected by MRI, bilateral or unilateral parietal or temporo-parietal hypometabolism found in FDG PET can be considered indicative of Alzheimer's disease. Semiquantitative analysis of the images yielded can help to evaluate the dementia degree

[en] Objective: To investigate the damaged characteristics of cerebral glucose metabolism (CGM) and cerebral blood flow (CBF) in ischemic cerebrovascular disease (ICVD) patients with severe cerebral artery stenosis or occlusion. Methods: Thirty-three cases of ICVD patients were examined by ¹⁸F-FDG PET and ¹³N-Ammonia PET, obtaining the same stages of cerebral blood perfusion and glucose metabolism image. According to the semi-quantitative analysis, the rate of reductions in CGM and CBF, and the ratio of CGM/CBF were figured out. Results: (1) There were 121 foci in total, positive rate of ¹⁸F-FDG imaging was 91.7%, and ¹³N-Ammonia imaging was 78.5%. (2) ICVD foci were mostly characterized with multifocal and asymmetric distribution. (3) Based on visual analysis to the relationship of FDG images and Ammonia images, 121 foci were divided into two types: matched damage in 66 foci (54.5%, type I) and mismatched damage in 55 foci (45.5%, type II-type V). (4) Based on semi-quantitative study to matched and mismatched group, the ratio of CGM/CBF with 1.1-1.3 may be considered as the parameter in evalu-ation. (5) Based on the rate of reductions in CGM and CBF, 66 matched foci were divided into mild (27 fo-ci, 40.9%), moderate (15 foci,22.7%) and severe (24 foci, 36.4%) damage group. (6) 4 cases with unilat-eral foci appeared crossed cerebellar diaschisis. Conclusions: The matched relationship of CGM and CBF was markedly damaged in IVCD patients with sever cerebral artery stenosis but different degrees of injury on metabolism and blood flow were also found.The application of combined imaging with ¹⁸F-FDG and ¹³N-Ammonia brain PET is able to greatly improve ICVD diagnosis and management. (authors)

[en] Methyl-2-(4-(2-fluoroethoxy) benzamido)-3-phenylpropanoate (MFBPA) and its hydrolysis product 2-(4-(2-fluoroethoxy)benzamido)-3-phenylpropanoic acid (FBPA) were synthesized and labeled by "1"8F. To evaluate applicability of "1"8F-MFBPA and "1"8F-FBPA in detecting malignant fibrosarcoma, some studies were carried on biodistribution, stabilities in vitro or in vivo and auto radiophotography. After 60 min of intravenous injection the accumulations of "1"8F-MFBPA and "1"8F-FBPA in tumor, muscle, blood and brain were 0.78 ± 0102, 0.72 ± 0.04, 0.66 ± 0.07, 0.38 ± 0.03%ID/g and 0.95 ± 0.05, 0.64 ± 0.06, 0.65 ± 104, 0.34 ± 0.01%ID/g, respectively. Their ratios of tumor to muscle, tumor to blood, and tumor to brain were 1.18, 1.08, 2.05 and 1.46 1.48, 2.79, respectively. The results indicated that "1"8F-FBPA might have more potential to be PET imaging agent. (authors)

[en] ¹⁸FMISO is synthesized automatically on CPCU by adjusting the parameters. The synthesis time is 55 min; The radiochemical yield and purity are 46.2% (EOS) and >99%, respectively. It's of much importance to carry out automatic synthesis of common nucleophilic fluoro-substituted radiopharmaceuticals on original ¹⁸FDG-synthesis special module, and thus will promote the domestic study on ¹⁸F-labelled radiopharmaceuticals. (authors)