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91.
本文简要叙述了常用DR数字探测器的原理、性能以及常规维护的方法,旨在提高数字化X线摄影技术的水平。 相似文献
92.
骨肉瘤侵袭范围的MRI测量与确定合理切除平面的相关研究 总被引:1,自引:0,他引:1
目的 探讨MRI判断肢体骨肉瘤局部侵袭范围的准确性及据此确定保肢术中的安全切除平面。方法 冷冻后的骨肉瘤截肢标本19例,按照MRI确定的相应层面,在断层切片机上切取厚度为0+5cm的水平断层切片,肉眼测量肿瘤的软组织侵袭范围,并以0.5cm的间隔做连续病理切片,确定显微镜下肿瘤软组织侵袭范围。然后按照MRI确定的相应层面,纵向剖开标本,测量肿瘤的髓内肉眼范围,并以0.5cm的间隔做连续病理切片,确定显微镜下肿瘤的髓内侵袭范围。分别将肿瘤X线、MRI的侵袭范围与肉眼范围和病理侵袭范围进行统计学比较。结果 (1)X线、MRI、肉眼和病理测量的骨肉瘤髓内侵袭范围分别为(11.18±8.64)cm、(15.37±9.73)cm、(14.77±9.38)cm、(14.58±9.51)cm,经统计学分析MRI所确定的髓内侵袭范围与病理侵袭范围之间无显著性差异(P〉0.05)。(2)MRI、肉眼和病理测量的骨肉瘤软组织侵袭范围分别为:横径(6.62±2.23)cm、(6.22±2.21)cm、(6.23±2.38)cm;纵径(7.15±2.37)cm,(6.57±1.80)cm、(6.58±1.94)cm,经统计学分析MRI所确定的软组织侵袭范围与病理侵袭范围之间无显著性差异(P〉0.05)。MRI对骨肉瘤髓内和软组织的测量值均不超过病理范围10mm。结论 在确定骨肉瘤手术切除安全界面上,MRI较X线片有更高的准确性。以MRI为依据,在瘤体外2~3cm处截骨,软组织外1.0~1.5cm作为切除界面是安全可靠的。 相似文献
93.
Herrmann A Bonél H Stäbler A Kulinna C Glaser C Holzknecht N Geiger B Schätzl M Reiser F 《European radiology》2002,12(2):385-390
The purpose of this study was to evaluate the performance of standard-dose and low-dose cesium iodide (CsI)-doted amorphous silicon (a-Si) flat-panel detector technology (FDT) as compared with storage-phosphor technology (SPT) in the depiction of relevant anatomical structures in chest radiography. In 75 patients referred for thoracic CT, digital chest radiographs were randomly obtained with either SPT at a standard dose (speed class S400, n=25), standard-dose FDT (S400, n=25) or FDT at a low dose (S800, n=25). Five radiologists evaluated the visibility of eight pulmonary and mediastinal anatomical structures using a five-point rating scale. To determine statistically significant differences between the three groups, the Mann-Whitney U-test was employed. No statistically significant differences were found in the depiction of eight criteria between SPT and standard-dose or low-dose FDT chest radiographs. The performance of FDT S400 was equal to SPT for most criteria and better for retrocardiac structures and soft tissue. FDT S800 was inferior to both SPT and FDT S400. Standard-dose FDT is equivalent to SPT in the depiction of relevant anatomical structures of the chest. Our results also indicate that a dose reduction of 50% with FDT may result in small but not significant decrease of image quality. 相似文献
94.
95.
高效液相色谱荧光光谱法测定虎杖中的白藜芦醇及白藜芦醇苷含量 总被引:3,自引:0,他引:3
目的建立高效液相色谱(HPLC)法,分离和测定虎杖中的白藜芦醇的含量.方法采用NUCLEODUR 100-5 C18柱(250 mm×4.6 mm,5μm);流动相异丙醇和水二元梯度洗脱系统;流速0.6 mL·min-1;荧光检测器激发波长334 nm;发射波长404 nm.结果在选定色谱条件下其白藜芦醇苷和白藜芦醇的线性范围良好,样品加样回收率在96.5%~101.4%,相对标准偏差在0.75%~1.42%.结论本方法精密度好,结果可靠,适合虎杖中白藜芦苷和白藜芦醇的定量分析. 相似文献
96.
97.
98.
γ-Spectrometry permits the identification and quantification of different γ-isotopes in the same aliquot. To estimate the sensitivity and discriminative power of a comparably small and inexpensive 8% germanium detector, we determined the detection limits for simultaneously applied 210Pb, 73As, 109Cd, 203Hg and 59Fe. The concentration of Fe and of each of the four potential environmental contaminants was determined in aliquots from all organs and tissues 10 days after simultaneous i.v. administration (2 μmol/kg body weight) to adult and growing iron-deficient and iron-adequate rats. Relating these values to the total size of each organ permitted to derive a whole body distribution pattern for all five isotopes in each individual animal. Cumulative renal and faecal excretion values were determined during the 10 day distribution period to calculate the half-lives for both excretory pathways for all five isotopes simultaneously. Distribution and excretion values corresponded well to literature data. Extrapolation of the results showed that the detector would be sensitive enough to discriminate and quantify the five metals at human dietary exposure levels. The results recommend to use γ-spectrometry to investigate kinetic aspects of interactions between toxic and essential trace metals, because the method reduces the number of required animals drastically. 相似文献
99.
In this paper, we propose a method to determine the equilibrium factor using a bare LR 115 detector. The partial sensitivities ρi of the LR 115 detector to 222Rn and its alpha-emitting short-lived progeny, 218Po and 214Po, were investigated. We first determined the distributions of lengths of major and minor axes of the perforated alpha tracks in the LR 115 detector produced by 222Rn, 218Po and 214Po through Monte Carlo simulations. The track parameters were calculated using a track development model with a published V function, by assuming a removed active layer of 6.54 μm. The distributions determined for different alpha emitters were found to completely overlap with one another. This implied equality of partial sensitivities for radon and its progeny, which was also confirmed through analytical considerations. Equality of partial sensitivities makes possible convenient measurements of the proxy equilibrium factor Fp, which is defined in the present work as (F1+F3) and is equal to the ratio between the sum of concentrations of the two alpha emitting radon progeny (218Po+214Po) to the concentration of radon gas (222Rn). In particular, we have found Fp=(ρ/ρitC0)−1, where ρ (track/m2) is the total track density on the detector, ρi=0.288×10−2 m, t is the exposure time and C0 (Bq/m3) is the concentration of 222Rn. If C0 is known (e.g. from a separate measurement), we can obtain Fp. The proxy equilibrium factor Fp is also found to be well correlated with the equilibrium factor between radon gas and its progeny through the Jacobi room model. This leads to a novel method for long-term determination of the equilibrium factor. 相似文献
100.
I. Gál T. Nagy M. Péter I. Országh 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1982,357(1):11-18
Zusammenfassung Die Verfasser haben in 18 Jahren 289 transduodenale Sphincterotomien und 87 Sphincterplastiken durchgeführt (295 Patienten bei der ersten und 81 Patienten bei weiteren Gallenoperationen). Im unmittelbaren postoperativen Stadium verstarben 20 Patienten (5,3%), die Sektionsergebnisse zeigen jedoch, daß die Sphincteroperation lediglich für den Tod von 10 Patienten (2,6%) verantwortlich gemacht werden kann. Von den anderen 356 Patienten konnten wir nur 270 (75,8%) 1–11 Jahre postoperativ untersuchen. Das Spätergebnis ist in 89,6% ausgezeichnet bzw. gut. Zur Klärung der unbefriedigenden Ergebnisse wurden klinische, labormedizinische, radiologische und endoskopische Untersuchungen durchgeführt. Die unbefriedigenden Ergebnisse können in 6,6% auf bilio-pankreatische, in 0,7% auf extrabiliäre organische und in 1,5% auf nicht-organische Ursachen zurückgeführt werden. Die Bedeutung der endoskopischen Untersuchung zur Klärung der Gründe der unbefriedigenden Operationsergebnisse nach Sphincteroperationen wird hervorgehoben.
Late results of transduodenal sphincterotomy and sphincteroplasty based on 18 years of experience (with special respect to the analysis of unsatisfactory results)
Summary In the course of 18 years the authors performed transduodenal sphincterotomy on 289 and sphincteroplasty on 87 patients. The operations were connected, in 295 cases with prismary in 81 cases with repeated biliary surgery. Twenty of the patients (5.3%) died during the immediate postoperative period. However, on the grounds of autopsy data the death of only 10 patients (2.6%) can be attributed to the surgery of the sphincter. Out of the 356 surviving patients 270 were available for a follow-up study and were examined 1–11 years after the operation. Late results of the operation were found excellent or good in 89.6% of the patients. To clear up the unsatisfactory results clinical, laboratory, radiological, and endoscopic examinations were carried out. The unsatisfactory results can be explained by biliopancreatic (6.6%), organic extrabiliary (0.7%) and non-organic (1.5%) reasons. The authors emphasize the significance of endoscopic examinations following the surgery of the sphincter in the elucidation of the causes of unsatisfactory results.相似文献