Development of an online radioactive xenon gas monitoring system for nuclear facilities / 中国辐射卫生

Objective Nowadays, radioactive xenon isotopes, including 131mXe, 133mXe, 133Xe, and 135Xe, are primarily released into the atmosphere through various reactor operation and major accidents of reactors. To improve the online monitoring capability of xenon in nuclear facilities and their gaseous effluents, a highly sensitive online xenon monitoring system was developed to monitor, warn, and alarm the activity concentration of radioactive xenon. Methods The online monitoring system for radioactive xenon gas in nuclear facilities was established using xenon membrane separation and concentration, xenon high-efficiency selective adsorption, and low-background gamma-ray spectrometry analysis methods. Results Under the operation mode of one-hour sampling and one-hour measuring, the minimum detectable activity concentration of the radioactive xenon online monitoring system for 133Xe was approximately (1.43 ± 0.03) Bq/m3. Conclusion This system can be effectively used for online monitoring of xenon activity concentration in nuclear facilities such as nuclear power plants and isotope production reactors, as well as in gaseous effluents. It helps improve the safety level of personnel, the environment, and nuclear facilities.

Neuroprotection and potential mechanism of xenon on neonatal hypoxic-ischemic encephalopathy / 中华围产医学杂志

Neonatal hypoxic-ischemic encephalopathy often causes long-term adverse effect on neurological system or even death in near-term or full-term infants, but no effective treatment is available currently. Studies have shown that xenon can reduce brain injury caused by hypoxia-ischemia and is promising in clinical practice. The possible mechanisms include antagonism to glutamic acid receptors, anti-apoptosis, promotion of cell repair and xenon preconditioning. This article reviews the mechanism and research progress on neuroprotection effect of xenon in the treatment of neonatal hypoxic-ischemic encephalopathy.

Effect of xenon post-conditioning on spinal cord ischemia/reperfusion injury in rats: regulating Akt signaling pathway and autophagy / 中国康复理论与实践

ObjectiveTo investigate the effect of xenon post-conditioning on autophagy after spinal cord ischemia/reperfusion injury (SCIRI) in rats and its relationship with protein kinase B (Akt) signaling pathway. MethodsA total of 30 male rats were randomized into sham-operated group (sham group), spinal cord ischemia/reperfusion injury group (I/R group) and I/R + xenon post-conditioning group (Xe group), with ten rats in each group. In the latter two groups, SCIRI was induced by clamping the abdominal aorta for 85 minutes followed by reperfusion for four hours. Xe group inhaled xenon and oxygen (1∶1) for one hour at one hour after initiation of reperfusion, while the other groups inhaled nitrogen and oxygen (1∶1) for one hour. After the reperfusion, they were assessed with Basso-Beattie-Bresnahan (BBB) scale and slanting board test. And then, their spinal cords of L3-5 were obtained. Nissl staining was used to count the number of normal neurons. Western blotting was used to detect the protein expression of Akt, p-Akt, p62, Beclin 1, microtubule-associated protein 1 light chain 3 (LC3) Ⅰ, LC3 Ⅱ. The mRNA expression of Beclin 1, p62 and LC3 Ⅱ in the spinal cord was measured with reverse transcription real-time quantitative polymerase chain reaction. ResultsCompared with the sham group, the BBB score and the maximum inclination of the slanting board test decreased, the count of normal neurons decreased, the protein expression of p62 and the p-Akt/Akt ratio decreased (P < 0.01), the protein and mRNA expression of Beclin 1 and LC3 Ⅱ, and the LC3 Ⅱ/LC3 Ⅰ ratio increased, the p62 mRNA expression decreased (P < 0.01) in the I/R group. Compared with the I/R group, the BBB score and the maximum inclination of the slanting board test increased, the count of normal neurons increased, the protein expression of p-Akt and p62 increased, the p-Akt/Akt ratio increased, the protein and mRNA expression of Beclin 1, LC3 Ⅱ and LC3 Ⅱ/LC3 Ⅰ ratio decreased, and the mRNA expression of p62 increased (P < 0.01) in Xe group. ConclusionXenon post-conditioning may relieve SCIRI in rats, which is related to activating Akt signaling pathway to inhibit autophagy.

Effects of Xenon on expression of CLIC4 mRNA in neonatal rats brain with white matter damage / 中华实用儿科临床杂志

Objective To investigate the mechanism of white matter damage (WMD) and the neuroprotective effect of Xenon on neonates with WMD.Methods Three-day-old SD rat pups (n =96) were randomly divided into the blank control group (n =24),the WMD control group (n =24),the Xenon intervention group A (n =24) and the Xenon intervention group B (n =24) by random number method according to their birth time.WMD rat models were successfully established by giving intraperitoneal injection of lipopolysaccharide(LPS) 0.05 mg/kg combined with carotid artery ligation and hypoxia for 1 hour in the WMD control group and the Xenon intervention groups.In the control group,only 9 g/L saline (0.05 mg/kg) was injected intraperitoneally,while carotid artery ligation and hypoxia were not administered.Rats in Xenon intervention group A and group B were given inhalation of 500 mL/L Xenon for 3 hours at 0 and 2 hours respectively after establishment of the models.Six rats in each group were randomly selected and decapitated at 0,24,48 and 72 hours after the intervention.The brain white matter on the right was analyzed by using HE staining and myelin basic protein(MBP) immunofluorescence staining,and real-time quantitative polymerase chain reaction was used to detect the expressions level of CLIC4 mRNA.Results (1) Brain tissue pathology:compared with the blank control group,the brain white matter on the right of the WMD control group and the Xenon intervention group A and group B had loose and disordered structure,nuclear pyknosis and cytoplasm loosening.However,the lesions in both Xenon intervention group A and group B were significantly less than those in the WMD control group,and there was no significant difference between the Xenon intervention group A and group B.(2) MBP measurement:the number of MBP-positive cells in the brain white matter on the right of WMD control group was significantly lower than that in the blank control group,while compared with WMD control group,they were significantly higher in Xenon intervention group A and group B.(3) CLIC4 mRNA expression level:compared with blank control group,the expressions levels of CLIC4 mRNA at most time point were higher both in the WMD control group and the Xenon intervention group A and group B (all P ＜ 0.05),except the time point 24 h in the Xenon intervention group A.The expressions of CLIC4 mRNA in group A and group B were significantly decreased compared with those in the WMD control group (all P ＜ 0.05).However,there were no significant differences between Xenon intervention group A and group B (P ＞ 0.05).Conclusions The expressions of CLIC4 mRNA in brain tissues on neonatal rats with WMD significantly increased,indicating that the mitochondrial pathway could be one of the pathological processes of WMD.Early Xenon intervention may reduce neonatal WMD by reducing the expression of CLIC4 mRNA,which plays a neuroprotective role.

Use of Inert Gases for the Preservation of Nuclear Blood Cells

Abstract The subject of the study was the stability of human white blood cell membranes subject to noble gases (xenon ad krypton, 0.6 mPa) clathrate cryoanabiosis (‒80°C). A unique portable stainless steel low pressure container with a compartment for flexible plastic container was designed to ensure that the cells are saturated with gases. The samples were warmed after 1 and 30 days in a water bath (+38°C) for 35-50 sec, while the container was being tilted (2-3 times per second), until the temperature of the biological object reached +3±1°C. It was demonstrated that after 30 days of clathrate anabiosis (-80°C) over 95% (of the original number) of leukocytes remain viable, and cell membranes of 54.5±3.4% of them is resistant to trypan blue; granulocyte survival rate is 73.5±2.7%, original lipid peroxidation rate and antioxidant activity are retained. Biological object cryopreservation in noble gases environment is a promising trend in biology and medicine.

Effects of xenon on the expression of EphB4 and EphrinB2 mRNA in neonatal rats with white matter damage / 中国新生儿科杂志

Objective To investigate the pathogenesis of white matter damage (WMD) and the effects of xenon intervention on the expression of EphB4 and EphrinB2 mRNA in the brain tissue of neonatal rats.Method Three-day-old SD rat pups (n =96) were randomly assigned into sham group (n =24),model group (n =24),xenon intervention group 1 (n =24) and xenon intervention group 2 (n =24).The WMD model was established by injected of lipopolysaccharide (LPS) 0.05 mg/kg combined with ligation of the right carotid artery for 1 h in the last three groups.Rats in xenon intervention group 1 inhaled 50％ xenon immediately for 3 h after modeling,while rats in xenon intervention group 2 inhaled 50％ xenon for 3 h at 2 h after modeling.After the completion of xenon intervention,6 rat pups in each groups were sacrificed at 0 h,24 h,48 h and 72 h.The pathologic examination of periventricular tissue was conducted with hematoxylin-eosin staining (HE) and the expression of EphB4 and EphrinB2 mRNA was assayed by real-time quantitative polymerase chain reaction (RT-PCR).Statistical analysis was then performed.Result (1)The structure of white matter in model group became loose,band net-like,with significant nucleus pyknosis.The pathological damages in xenon intervention group 1 and 2 were lighter at 24 h,48 h and 72 h than model group,with less karyopycnosis.(2) Compared with the sham group,the expressions of EphB4 and EphrinB2 mRNA at 0 h,24 h,48 h and 72 h were significantly higher in the model group and xenon intervention group 1 and 2 (P ＜ 0.05),except for the EphB4 mRNA in xenon intervention group 1 at 72 h (P ＞ 0.05).The expressions of EphB4 and EphrinB2 mRNA at each time point in xenon intervention group 1 and 2 were decreased significantly than the model group (P ＜ 0.05),except for the EphB4 mRNA in xenon intervention group 2 at 72 h (P ＞ 0.05).However,there was no statistically significant difference on EphB4 and EphrinB2 mRNA between two xenon intervention groups at each time point (P ＞ 0.05).Conclusion The expression of EphB4 and EphrinB2 mRNA are appreciably increased in brain tissue of neonatal rats with WMD,which indicates the reactive angiogenesis.The intervention with xenon may play a neuroprotective role through reducing the expressions of EphB4/EphrinB2 mRNA and angiogenesis,and early intervention may be better.

Treatment of symptomatic cerebral artery stenosis and occlusion with Xenon CT guided cerebral revascularization / 中国脑血管病杂志

Objective To investigate the roles of Xenon-CT cerebral blood flow perfusion imaging in cerebral revascularization before surgery and efficacy evaluation.Methods The clinical data of 15 patients with symptomatic cerebral artery stenosis/occlusion of anterior circulation were analyzed retrospectively.Eight patients were treated with endovascular stenting,1 was treated with internal carotid endarterectomy,and 6 were treated with superficial temporal artery-middle cerebral artery bypass grafting.The regional cerebral blood flow (rCBF) detected by Xenon CT within 2 weeks before and after procedure and the modified Ranking scale (mRS) scores at 6 months after procedure were compared.Results (1) The mean rCBF value of 12 patients with abnormal blood perfusion of target vessels before procedure was 30±10 ml/(100 g·min) and that was 32±14 ml/(100 g·min) after procedure.Compared with before procedure,the difference was statistically significant (P0.05).(2) The postoperative mRS score was decreased in 8 cases and stable in 7 cases.Compared with before procedure,there were significant differences in mRS scores after procedure in 15 cases (P<0.05).During the follow-up period,none of the patients had new neurological impairment.Conclusion Revascularization can improve the presence of hemodynamic disorders in patients with symptomatic anterior circulation cerebral artery stenosis or occlusion of the target blood vessels in the distal local cerebral perfusion and neurological deficit symptoms.The patients with abnormal perfusion of preoperative Xenon-CT cerebral blood flow perfusion imaging may be more beneficial than those with normal perfusion.

Design and development of matrix solar radiation simulation system / 军事医学

Objective To design a set of matrix solar radiation simulation ,that can be used to study the thermal comfort of armored vehicles.Methods With xenon lamps as the light source , the lifting matrix lamp array controlled by the computer was used to test the whole vehicles .Results The system could irradiate the top , the left and right sides of the armored vehicle, and the intensity of irradiation ranged from 200 to 1200 W/m2 in order to adapt to vehicles of different sizes and heights.Conclusion The system can meet the needs of solar simulation experiments of different armored vehicles.

Design and development of matrix solar radiation simulation system / 军事医学

Objective To design a set of matrix solar radiation simulation ,that can be used to study the thermal comfort of armored vehicles.Methods With xenon lamps as the light source , the lifting matrix lamp array controlled by the computer was used to test the whole vehicles .Results The system could irradiate the top , the left and right sides of the armored vehicle, and the intensity of irradiation ranged from 200 to 1200 W/m2 in order to adapt to vehicles of different sizes and heights.Conclusion The system can meet the needs of solar simulation experiments of different armored vehicles.

Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators

BACKGROUND: Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar–chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. METHODS: The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. RESULTS: It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. CONCLUSION: The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

Determination of Atmospheric Krypton and Xenon by Gas Chromatography-Mass Spectrometry in Direct Injection Mode / 分析化学

Volume concentration determination for atmospheric krypton and xenon is very important for krypton-85 and radioactive xenon isotopes monitoring. An injection setup integrated adjustable quantity sample injection and quantitative dilution function was designed. The effects of EI source parameters on the sensitivity of MS detector were studied. The optimized values were as following: ionization energy of 70 eV, emission current of 40 mA, cathode voltage of 27 mV, focus voltage of 85 mV and lens compensation of 20 V, respectively. A GC-MS method for the determination of krypton and xenon in atmosphere without of sample pretreatment was developed. The minimal detected concentrations for krypton and xenon were 3. 3×10-8(V/V) and 2. 6×10-9(V/V). Moreover, the krypton and xenon concentrations in the ground level air around our laboratory were measured with the results of 1 . 1 × 10-6 ( V/V ) and 9 . 3 × 10-8 ( V/V ) . The related combined standard uncertainties for krypton and xenon results were 2. 38% and 3. 15%, respectively.

A Development of Byzantine Christian Charities during the 4th-7th Centuries and the Birth of the Hospital / 의사학

This study aims to examine the beginning and the development of Christian Charities during the 4th-6th centuries which would eventually result in the birth of the hospital in modern sense in the first half of the 7th century. For this purpose, I looked carefully into various primary sources concerning the early Christian institutions for the poor and the sick. Above all, it's proper to note that the first xenodocheion where hospitality was combined with a systematic caring, is concerned with the Trinitarian debate of the 4th century. In 356, Eustathios, one of the leaders of homoiousios group, established xenodocheion to care for the sick and the lepers in Sebaste of Armenia, whereas his opponent Aetios, doctor and leader of the heteroousios party, was reckoned to have combined the medical treatment with his clerical activities. Then, Basil of Caesarea, disciple of Eustathios of Sebaste, also founded in 372 a magnificent benevolent complex named 'Basileias' after its founder. I scrupulously analysed several contemporary materials mentioning the charitable institution of Caesarea which was called alternatively katagogia, ptochotropheion, xenodocheion. John Chrysostome also founded several nosokomeia in Constantinople at the end of the 4th century and the beginning of the 5th century. Apparently, the contemporary sources mention that doctors existed for these Charities, but there is no sufficient proof that these 'Christian Hospitals,' Basileias or nosokomeia of Constantinople were hospitals in modern sense. Imperial constitutions began to mention ptochotropheion, xenodocheion and orphanotropheion since the second half of the 5th century and then some Justinian laws evoked nosokomium, brephotrophia, gerontocomia. These laws reveal that 'Christian Hospitals' were well clarified and deeply rooted in Byzantine society already in these periods. And then, new benevolent institutions emerged in the 6th century: nosokomeia for a specific class and lochokomeia for maternity. In addition, one of the important functions of Sampson Xenon was, according to Novel 59, to hold a funeral service for the people of Constantinople. Nevertheless, there is no sufficient literary material that could demonstrate the existence of a hospital in modern sense. The first hospital where outpatient service, hospitalization and surgery were confirmed was Sampson Xenon in the first half of the 7th century, figured in the tale of Stephanos of the The Miracles of St. Artemios. Why was the early Byzantine literary so reticent as to write the medical activities in the Christian Charities? It's because Christian innovation didn't rest on the medical treatment but caring for the poor and the sick, depending on the word of Mt. 25.35-36. In this meaning, I'd like to say that the Early Byzantine history of Christian Charities or 'Christian Hospitals' consists of only a footnote of the verse.

Collateral Ventilation Quantification Using Xenon-Enhanced Dynamic Dual-Energy CT: Differences between Canine and Swine Models of Bronchial Occlusion

OBJECTIVE: The aim of this study was to evaluate whether the difference in the degree of collateral ventilation between canine and swine models of bronchial obstruction could be detected by using xenon-enhanced dynamic dual-energy CT. MATERIALS AND METHODS: Eight mongrel dogs and six pigs underwent dynamic dual-energy scanning of 64-slice dual-source CT at 12-second interval for 2-minute wash-in period (60% xenon) and at 24-second interval for 3-minute wash-out period with segmental bronchus occluded. Ventilation parameters of magnitude (A value), maximal slope, velocity (K value), and time-to-peak (TTP) enhancement were calculated from dynamic xenon maps using exponential function of Kety model. RESULTS: A larger difference in A value between parenchyma was observed in pigs than in dogs (absolute difference, -33.0 +/- 5.0 Hounsfield units [HU] vs. -2.8 +/- 7.1 HU, p = 0.001; normalized percentage difference, -79.8 +/- 1.8% vs. -5.4 +/- 16.4%, p = 0.0007). Mean maximal slopes in both periods in the occluded parenchyma only decreased in pigs (all p < 0.05). K values of both periods were not different (p = 0.892) in dogs. However, a significant (p = 0.027) difference was found in pigs in the wash-in period. TTP was delayed in the occluded parenchyma in pigs (p = 0.013) but not in dogs (p = 0.892). CONCLUSION: Xenon-ventilation CT allows the quantification of collateral ventilation and detection of differences between canine and swine models of bronchial obstruction.

Computer-Aided Classification of Visual Ventilation Patterns in Patients with Chronic Obstructive Pulmonary Disease at Two-Phase Xenon-Enhanced CT

OBJECTIVE: To evaluate the technical feasibility, performance, and interobserver agreement of a computer-aided classification (CAC) system for regional ventilation at two-phase xenon-enhanced CT in patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: Thirty-eight patients with COPD underwent two-phase xenon ventilation CT with resulting wash-in (WI) and wash-out (WO) xenon images. The regional ventilation in structural abnormalities was visually categorized into four patterns by consensus of two experienced radiologists who compared the xenon attenuation of structural abnormalities with that of adjacent normal parenchyma in the WI and WO images, and it served as the reference. Two series of image datasets of structural abnormalities were randomly extracted for optimization and validation. The proportion of agreement on a per-lesion basis and receiver operating characteristics on a per-pixel basis between CAC and reference were analyzed for optimization. Thereafter, six readers independently categorized the regional ventilation in structural abnormalities in the validation set without and with a CAC map. Interobserver agreement was also compared between assessments without and with CAC maps using multirater kappa statistics. RESULTS: Computer-aided classification maps were successfully generated in 31 patients (81.5%). The proportion of agreement and the average area under the curve of optimized CAC maps were 94% (75/80) and 0.994, respectively. Multirater kappa value was improved from moderate (kappa = 0.59; 95% confidence interval [CI], 0.56-0.62) at the initial assessment to excellent (kappa = 0.82; 95% CI, 0.79-0.85) with the CAC map. CONCLUSION: Our proposed CAC system demonstrated the potential for regional ventilation pattern analysis and enhanced interobserver agreement on visual classification of regional ventilation.

Measuring and imaging small airways dysfunction in asthma

Asthma is a chronic inflammatory disorder of the airways causing typical symptoms, and the diagnosis is supported by evidence of airflow obstruction which is variable, reversible or inducible. However, standard assessment of lung function with spirometry does not measure dysfunction in small airways which are < 2 mm in diameter towards the periphery of the lung. These airways make only a small contribution to airway resistance under normal circumstances. Nevertheless, there is mounting evidence that pathology and dysfunction in these small airways are implicated in the pathogenesis and natural history of asthma. Using forced oscillation and the multibreath nitrogen washout techniques, uneven ventilation (ventilation heterogeneity) due to small airways dysfunction has been shown to be an important marker of asthma disease activity, even in the absence of abnormalities in standard spirometric measurements. Recent advances in imaging research, particularly with hyperpolarised gas magnetic resonance imaging, have also given insights into the significance and dynamic nature of ventilation heterogeneity in asthma. The challenge is to integrate these new physiological and imaging insights to further our understanding of asthma and facilitate potential new treatments.

Evaluation of hemodynamic effects of xenon in dogs undergoing hemorrhagic shock

OBJECTIVES: The anesthetic gas xenon is reported to preserve hemodynamic stability during general anesthesia. However, the effects of the gas during shock are unclear. The objective of this study was to evaluate the effect of Xe on hemodynamic stability and tissue perfusion in a canine model of hemorrhagic shock. METHOD: Twenty-six dogs, mechanically ventilated with a fraction of inspired oxygen of 21% and anesthetized with etomidate and vecuronium, were randomized into Xenon (Xe; n = 13) or Control (C; n = 13) groups. Following hemodynamic monitoring, a pressure-driven shock was induced to reach an arterial pressure of 40 mmHg. Hemodynamic data and blood samples were collected prior to bleeding, immediately after bleeding and 5, 20 and 40 minutes following shock. The Xe group was treated with 79% Xe diluted in ambient air, inhaled for 20 minutes after shock. RESULT: The mean bleeding volume was 44 mL.kg-1 in the C group and 40 mL.kg-1 in the Xe group. Hemorrhage promoted a decrease in both the cardiac index (p<0.001) and mean arterial pressure (p<0.001). These changes were associated with an increase in lactate levels and worsening of oxygen transport variables in both groups (p<0.05). Inhalation of xenon did not cause further worsening of hemodynamics or tissue perfusion markers. CONCLUSIONS: Xenon did not alter hemodynamic stability or tissue perfusion in an experimentally controlled hemorrhagic shock model. However, further studies are necessary to validate this drug in other contexts.

Redistributed Regional Ventilation after the Administration of a Bronchodilator Demonstrated on Xenon-Inhaled Dual-Energy CT in a Patient with Asthma

We report here on the redistributed regional ventilation abnormalities after the administration of a bronchodilator and as seen on xenon-inhaled dual-energy CT in a patient with asthma. The improved ventilation seen in the right lower lobe and the decreased ventilation seen in the right middle lobe after the administration of a bronchodilator on xenon-inhaled dual-energy CT could explain a positive bronchodilator response on a pulmonary function test. These changes may reflect the heterogeneity of the airway responsiveness to a bronchodilator in patients with asthma.

Collateral Ventilation to Congenital Hyperlucent Lung Lesions Assessed on Xenon-Enhanced Dynamic Dual-Energy CT: an Initial Experience

OBJECTIVE: We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT. MATERIALS AND METHODS: Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated. RESULTS: Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 +/- 0.6 mSv. CONCLUSION: Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.

Evaluation of cerebrovascular reserve by xenon computed tomography in patients with ischemic stroke / 中华内科杂志

Objective To evaluate the cerebrovascular reserve(CVR) in patients of ischemic stroke with cerebrovascular stenosis by Xenon-enhanced CT. Methods Twenty subjects of ischemic stroke with cerebrovascular stenosis were recruited. All subjects were examined by Xenon-enhanced CT before and after acetazolamide (ACZ) challenge test to quantitatively measure the regional cerebral blood flow (rCBF) and CVR. Results We compared the rCBF in the corresponding region supplied with stenosed artery (divided manually) with that in the region of normal side. There was no significant difference in resting rCBF but in CVR [ipsilateral side vs. normal side ( 5.9 ± 24. 3 ) % vs ( 25.9 ± 32. 6 ) % , P ＜ 0. 05]. Conclusion Impaired CVR is an important character of the patients with cerebrovascular stenosis suffered from ischemic stroke.

Clinical characteristics and cerebral blood flow in 15 patients of progressive stroke / 中华神经科杂志

Objective To observe the clinical characteristics of progressive stroke (PS) patients with vascular stenosis and the relationship between PS and cerebral blood flow (CBF). Methods Fifteen patients of PS with anterior circulation vascular stenosis were chosen, their clinical documents and CBF were analyzed with Xenon-CT when they were in progression. Results These patients mostly presented hemiparalysis and language dysfunction at the beginning ( 13/15 ) before the disease developed rapidly into a serious state. The infarction usually happens in the periventricular area (10/15). Upper limbs paralyzed more severely than low limbs(11/15). Cerebral hypoperfusion areas around the infarction in 11 patients ( 10 ml·100 g-1·min-1 < CBF < 20 ml·100 g-1·min-1 ) were found. Conclusions Patients of PS with vascular stenosis present typically clinical characteristics, Low CBF caused by cerebral artery stenosis may be one of the most important factors leading to PS.