[Experimental Methods and Result Analysis of a Variety of Spectral Reflectance Properties of the Thin Oil Film].

In order to analysis the oil spill situation based on the obtained data in airborne aerial work, it's needed to get the spectral reflectance characteristics of the oil film of different oils and thickness as support and to select the appropriate operating band. An experiment is set up to measure the reflectance spectroscopy from ultraviolet to near-infrared for the film of five target samples, which means petrol, diesel, lubricating oil, kerosene and fossil, using spectral measurement device. The result is compared with the reflectance spectra of water in the same experimental environment, which shows that the spectral reflection characteristics of the oil film are related to the thickness and the type of the oil film. In case of the same thickness, the spectral reflectance curve of different types of film is far different, and for the same type of film, the spectral reflectance curve changes accordingly with the change of film thickness, therefore in terms of the single film, different film thickness can be distinguished by reflectance curves. It also shows that in terms of the same film thickness, the reflectance of diesel, kerosene, lubricants reaches peak around 380 nm wavelength, obviously different from the reflectance of water, and that the reflectance of crude oil is far less than that of water in more than 340 nm wavelength, and the obtained reflection spectrum can be used to distinguish between different types of oil film to some extent. The experiment covers main types of spilled oil, with data comprehensively covering commonly used detect spectral bands, and quantitative description of the spectral reflectance properties of film. It provides comprehensive theoretical and data support for the selection of airborne oil spill detection working band and the detection and analysis of water-surface oil spill.

[Study on in-orbit Vis/SWIR relative calibration monitoring system with high stability].

The present paper studied the in-orbit relative calibration monitoring system with high stability for onboard remote sensing calibration. The realizing principle and the critical technologies are described in detail. The calibration detector assembly with high stability was developed based on both visual (Vis) and shortwave infrared (SWIR) trap structure. Vis and SWIR photodetectors with high sensitivity were chosen to realize the photoelectric conversion. On the one hand, the detectors worked in the zero-bias photovoltaic mode with better linearity and lower dark current. On the other hand, the critical parameters of the analog operational amplifier circuit and data acquisition circuit were designed so that the trap-structure detector assembly could work properly. Thus the relative calibration monitoring system with high stability for measurement of spaceborne calibration radiance source was realized. The experiments were carried out using the laboratory integrating spheres and the standard lamps provided by the national measurement institution. The results showed that the relative standard deviation of the digital numbers that the system acquired reached to 0.030%-0.046% (Vis) and 0.040%-0.059% (SWIR). It was proved that the accuracy and the stability of the monitoring system could meet the in-orbit calibration system requirement and it could serve as a good solution for in-orbit relative calibration of remote sensor in the future.

Neovascularization in the carotid atherosclerotic plaque is not associated with inflammatory cell aggregation.

BACKGROUND: Monocytes and macrophages in atherosclerotic plaque lead to plaque instability. The aim of the study was to determine if plaque neovascularization led to inflammation. METHODS: Patients were consecutively enrolled if their carotid intimal media thickness was > 2 mm, as revealed by duplex ultrasound. The patients then underwent dynamic contrast enhanced magnetic resonance imaging (DCE MRI) and fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography combined with computed tomography (PET CT). A target to background ratio (TBR) of ≥ 1.25 or < 1.25 served as the cutoff point for the presence and absence of inflammation, respectively. RESULTS: Twenty-six patients underwent bilateral carotid DCE MRI and 24 patients also underwent PET CT. One hundred and fifty-five plaques were evaluated by both DCE MRI and PET CT. There was no significant difference in plaque morphology between the TBR ≥ 1.25 (n = 61) and TBR < 1.25 (n = 94) groups. No significant differences were found in plasma volume and transfer constant between the TBR ≥ 1.25 and TBR < 1.25 groups. CONCLUSION: Our study did not find a significant correlation between plaque neovascularization and the aggregation of inflammatory cells.

Comparison of diffusion-weighted MRI with 18F-fluorodeoxyglucose-positron emission tomography/CT and electroencephalography in sporadic Creutzfeldt-Jakob disease.

18F-fluorodeoxyglucose-positron emission tomography/CT (18F-FDG PET/CT) scanning may be a useful tool for early diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), as it may reveal lowered cellular glucose transport and metabolism in the cortex, cerebellum and basal ganglia. The aim of the present study was to compare the findings from PET/CT, MRI and electroencephalography (EEG) for patients with sCJD, to explore whether typical sites or reliable patterns of regional metabolic change could be found and to evaluate the results of diagnostic imaging in the light of clinical symptomatology. Five patients with biopsy-confirmed sCJD and nine with probable sCJD (aged 36-68 years) were evaluated using PET/CT, diffusion-weighted (DW)-MRI and EEG. In 13 of the 14 patients (92.86%), PET/CT imaging detected extra regions with abnormalities in addition to the hyperintense areas shown with DW-MRI. Two patients with no abnormal DW-MRI findings in the basal ganglia had bilateral extrapyramidal signs accompanied by basal ganglia hypometabolism on PET. Eight patients (57.14%) had decreased FDG uptake in the thalamic nuclei on PET scans; however, DW-MRI did not identify corresponding hyperintense changes in the thalamic nuclei. In 11 patients (78.57%), DW-MRI revealed more regions with abnormalities than EEG, and 10 patients (71.43%) had DW-MRI abnormalities in the thalamic nuclei and basal ganglia that EEG was unable to detect. There was a high level of correspondence among the PET/CT, DW-MRI and EEG results, with PET revealing more abnormal regions than the other imaging modalities. In the absence of neuropathological findings, FDG-PET could improve the accuracy of sCJD diagnosis when combined with DW-MRI and EEG, particularly for differentiating sCJD from paraneoplastic syndromes. Our results suggest that PET/CT is able to detect sCJD at an earlier stage and with greater sensitivity than DW-MRI.

[Research on the ultraviolet reflectivity characteristic of simulative targets of oil spill on the ocean].

The authors set up an experiment instrument to measure the ultraviolet (UV) characteristic of oil spill simulation targets for the marine oil spill. After selecting appropriate conditions for experiments, the authors tested UV reflective spectrum of four simulation targets for oil spill (gasoline, kerosene, diesel fuel, lubricating oil). The authors calculated the UV absolute spectrum reflectivity of all testing targets from the standard white board as reference, whose UV reflectivity was given. With processing and analyzing the data from experiments, the authors got the reflective characteristics of them in contrast to the reflectivity of water, which was measured in the same conditions. All targets were tested from 320 to 400 nm, and UV reflectivity wave-band between 360 and 380 nm was representative. Testing data were shown as follows: (1) The reflectivity of water was from 5.3% to 5.5%. (2) When the thickness of oil film was 400 microm, the reflectivity of gasoline was from 8.5% to 8.8%, 5.4%-5.8% for kerosene, 8.3%-8.4% for diesel fuel, and 9.4%-9.7% for lubricating oil in the same wave-band between 360 and 380 nm. Correspondingly, the indeterminacy of reflectivity was 0.32%, 0.45%, 0.25%, and 0.33% respectively. (3) Hence the thickness of oil film changed, the rule of the UV reflectivity varied depending on the sort of oil spill. The results show that there were some obvious reflectivity differences among oil films and water, which were mainly determined by the sort and thickness of oil film. This experiment method is also fit for the actual oil spill target, and it will fulfill some theory and experimental foundation for inspecting the marine oil spill by UV remote sensing in the future.

[Fluorine-18 fluorodeoxyglucose uptake in patients with benign pulmonary nodules].

OBJECTIVE: To assess the features of fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with benign pulmonary nodules. METHODS: From October 1998 to July 2004, 47 patients with benign pulmonary nodules were imaged with FDG-positron emission tomography (PET). Diagnoses were confirmed by surgery. FDG-PET data was analyzed by visual method and semi-quantitive method. When pulmonary nodules with abnormal FDG intake appeared in PET scans confirmed by visual method, their maximum and mean standard uptake value (SUVmax and SUVmean) and SUV of normal lung (SUVlung) were measured using semiquantitative method. RESULTS: Twenty-one cases showed nothing abnormal in PET scans, including 17 calcification and fibrosis, 2 hamartomas and 2 sclerosing hemangiomas. 26 pulmonary nodules were detected by FDG-PET (17 active tuberculous, 6 inflammatory pseudotumors, 3 cryptococcosis). FDG uptake of these 26 nodules was higher than that of normal lung (SUVmax, SUVmean and SUVlung were 3.04 +/- 1.65, 2.48 +/- 1.35 and 0.40 +/- 0.07, respectively, P < 0.001). Correlations were not found between FDG uptake and nodule size or SUV of normal lung or age or blood glucose level in these 26 patients (P > 0.05). SUV in 9 cases (9/26, 35%) were beyond 2.5. CONCLUSIONS: Some benign pulmonary nodules were FDG avid.

[Value of carbon-11 choline positron emission tomography in patients with pulmonary abnormalities].

OBJECTIVE: To assess the value of carbon-11 choline (CH) positron emission tomography (PET) in patients with pulmonary nodules. METHODS: From September 2002 to December 2004, 39 patients with pulmonary nodules were imaged with CH-PET. CH-PET data was analyzed by visual method and semiquantitative method. When pulmonary nodules with abnormal CH uptake appeared in PET scans confirmed by visual method, their maximum and mean standard uptake value (SUVmax and SUVmean) were measured using semiquantitative method. Diagnoses were confirmed by surgery or biopsy and follow-up survey. RESULTS: Twenty-four cancerous and 3 inflammatory nodules and 1 bronchogenic cyst were detected by CH-PET and were diagnosed malignant with visual method. Three bronchial alveolar carcinoma, 2 metastatic tumor from kidney and colon, 3 fibrous nodules, 1 cryptococcosis, 1 hamartoma and 1 sclerosing hemangioma showed nothing abnormal in PET scans. For identification of pulmonary nodules with CH-PET, the sensitivity was 89% (24/29), the specificity was 60% (6/10), and the accuracy was 77% (30/39). There were differences in SUV between 8 squamous cell carcinomas and 9 adenocarcinomas (Z = -2.937, -2.887, P < 0.01). In diagnosing 70 resected enlarged lymph nodes beyond 1 cm in 17 lung cancer patients, CH-PET had the sensitivity of 86% (25/29), the specificity of 90% (37/41), and the accuracy of 89% (62/70). CH-PET confirmed 7 distant metastases in 25 lung cancer patients. In 5 cases suspected brain metastases CH-PET identified 2 cases positive correctly. CONCLUSIONS: CH-PET can confirm malignant pulmonary nodules, but still there were false positive and false negative cases. CH-PET can evaluate N stage effectively in patients with lung cancer. CH-PET can depict brain metastases accurately.

[Value of fluorine-18 fluorode oxyglucose-positron emission tomography in patients with small cell lung cancer].

OBJECTIVE: To investigate the value of fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging in patients with small cell lung cancer. METHODS: From February 2000 to July 2003, 17 patients with small cell lung cancer were imaged with FDG-PET. FDG-PET scans were analyzed by visual method. The FDG-PET results were compared with the pathological results and results of follow-up survey. RESULTS: 15 primary tumors were all FDG avid. By visual method 63 areas metastatic lymph nodes in 15 cases were revealed and more distant metastases outside the hemithoraxes were confirmed by FDG-PET than by routine examinations. FDG-PET corrected the diagnosis 5 cases from local disease (LD) to extended disease (ED). CONCLUSION: FDG-PET has great value in staging and treatment of patients with small cell lung cancer.