Traditional X-ray Research Articles

The recalcitrant invention of X-ray images

ABSTRACTThis article extends new materialist theorizing on the constructive role played by the physical stuff of the world. Specifically, it draws on Kenneth Burke’s writings on recalcitrance to theorize the materialities of rhetorical invention. It takes X-rays as a case study in recalcitrance-driven invention, focusing on two particular applications, traditional medical X-rays, a pervasive category of contemporary technical communication, and backscatter X-ray airport security scans, a controversial and short-lived one. Its analysis shows how recalcitrance (1) is harnessed as means of technical invention and (2) is key to invention’s bidirectionality, by which our material interventions, in turn, work upon us.

Percutaneous kyphoplasty treatment of osteoporotic vertebral compression fracture under the guidance of G-arm X-ray machine

Objective To explore the clinical application value of percutaneous kyphoplasty (PKP) under the guidance of G arm X ray machine in the treatment of osteoporotic vertebral compression fracture (OVCF). Methods The medical records of eighty-two patients (94 vertebral bodies) with OVCF treated with PKP were collected retrospectively.Thirty-nine cases (44 vertebral bodies) were guided by G-arm X-ray machine to implement PKP, which were recorded as G-arm group.Forty-three cases (50 vertebral bodies) were guided by C-arm X-ray machine to carry out PKP, which were recorded as C-arm group.The operation time, intraoperative fluoroscopy times, bone cement leakage cases, preoperative and postoperative anterior height of injured vertebrae, Cobb angle of injured vertebrae, visual analogue scale scores and Oswestry disability index of the two groups were recorded. Results There was significant difference in operation time and intraoperative fluoroscopy times between the G-arm group and C-arm group (the operation time: (31.6±5.2) vs.(45.8±6.7) min, the intraoperative fluoroscopy times: (9.5±2.3) times vs.(18.7±3.5) times, t=-10.64, -13.91, P 0.05). Compared postoperative and preoperative anterior height of injured vertebrae, Cobb angle of injured vertebrae, visual analogue scale scores and Oswestry disability index scores of G-arm group and C-arm group respectively, the differences were significant( t=-3.41 vs.-3.28, 6.67 vs.7.66, 26.63 vs.25.75 and 10.41 vs.11.90, P 0.05). Conclusion The treatment of OVCF with PKP guided by G-arm X-ray machine could significantly shorten operation time, reduce the intraoperative fluoroscopy times and the operative difficulty, and increase operation safety than PKP guided by traditional C-arm X-ray machine. Key words: Osteoporotic vertebral compression fracture; Percutaneous kyphoplasty; G-arm X-ray machine; C-arm X-ray machine

Laser-Generated Au Nanoparticles for Bio-Medical Applications

BackgroundThe present study it is part of the study of the applications of biocompatible nanoparticles in a biological environment. Nowadays, in fact, nanoparticles are making it possible to reach surprising results in the field of biomaterials, drug delivery and their transport in the blood flux, as the use of the contrast medium for medical imaging and to be injected in tumors before to apply radio and thermal therapy. Nanoparticles modify the chemical and physical properties of solids, liquids, and gases and in particular of physiological liquids, soft and hard biological tissues. MethodsThe present article focalizes on the role of Au nanoparticles for biological and medical applications in which their insertion in cells, tissues, and organs may improve the diagnostic imaging contrast with traditional X-ray imaging and the absorbed doses due to radio- and thermal-therapies. Their injection in the tissue, in fact, increases the effective atomic number of the tissue, thus the increment of the electron density of the medium causes higher radiation LET (linear energy transfer) with the increment of released dose and major effects of radiotherapy expositions. Main findingsThe present paper shows the possibility to generate spherical gold nanoparticles with an average diameter of about 5 nm, pure and not agglomerated, biocompatible, stable and without the addition of chemical agents, by laser ablation of gold material in water. The solution can be directly injected in the extracellular liquid of cell cultures or directly in the blood flux of mice to be transported inside the complex living system. Here it is accumulated in specific organs in which the up-take and decay can be measured using suitable images of fluorescence of the organs of the mouse. ConclusionsThe aim of this research is to transport the nanoparticles in places where tissue disease exists and reduce their concentration in healthy tissues. This permit a better observation of the diseased tissues and their preparation as targeting for radio- and thermal-therapy to be applied to damage tumor cells saving healthy tissues.

A comparison of respirable crystalline silica concentration measurements using a direct-on-filter Fourier transform infrared (FT-IR) transmission method vs. a traditional laboratory X-ray diffraction method

Evaluation and control of respirable crystalline silica (RCS) exposures are critical components of an effective mine industrial hygiene program. To provide more timely exposure data in the field, an end-of-shift Fourier transform infrared (FT-IR) spectrometry method has been developed for evaluation of direct-on-filter RCS. The present study aimed to apply this FT-IR method using field samples collected in three Northwestern U.S. metal/nonmetal mines and compare the results to traditional laboratory X-ray diffraction analysis (XRD). Seventy-five dust samples were analyzed using both methods. Samples for each mine were split in half by random assignment, with half used to create a calibration factor for the FT-IR analysis and half used to apply the calibration. Nonparametric correlational and two-sample comparative tests were used to assess the strength of association and the level of agreement between the two methods. Strong, positive correlations were observed between FT-IR and XRD RCS concentrations, with Spearman rank correlation coefficients ranging between 0.84 and 0.97. The mean RCS concentrations determined through FT-IR analysis were lower than through XRD analysis, with mean differences ranging from −4 to −133 ug/m3 and mean percent errors ranging from 12% to 28%. There was a statistically significant improvement in the level of agreement between log FT-IR and log XRD RCS concentrations following calibration at two of the three mines, with mean differences of −0.03 (p = 0.002) and −0.02 (p = 0.044) in the log scale. The reduction in mean difference following calibration at the other mine was not statistically significant (mean log scale difference = −0.05, p = 0.215), but the differences between FT-IR and XRD were not significantly different without calibration (mean log scale difference = −0.07, p = 0.534). The results indicate that mine-specific calibration factors can improve the level of agreement between RCS concentrations determined via a field-based, end-of-shift FT-IR method in metal/non-metal mines as compared to traditional XRD analysis.

Bremsstrahlung x-ray generation for high optical depth radiography applications on the National Ignition Facility.

We have tested a set of x-ray sources for use as probes of highly attenuating, laser-driven experiments on the National Ignition Facility (NIF). Unlike traditional x-ray sources that optimize for a characteristic atomic transition (often the n = 2 → n = 1 transition in ionized, He-like atoms), the design presented here maximizes the total photon flux by optimizing for intense, broadband Bremsstrahlung radiation. Three experiments were performed with identical targets, including a uranium x-ray source foil and a tungsten substrate with a narrow (25 μm wide) collimating slit to produce a quasi-1D x-ray source. Two experiments were performed using 12 beams from the NIF laser, each delivering approximately 46 kJ of laser energy but with different laser spatial profiles. This pair yielded similar temporal x-ray emission profiles, spatial resolution, and inferred hot electron temperature. A third experiment with only 6 beams delivering approximately 25 kJ produced a lower hot electron temperature and significantly lower x-ray flux, as well as poorer spatial resolution. The data suggest that laser pointing jitter may have affected the location and intensity of the emitting plasma, producing an emission volume that was not well centered behind the collimating slit and lower intensity than designed. However, the 12-beam design permits x-ray radiography through highly attenuating samples, where lower energy line-emission x-ray sources would be nearly completely attenuated.

Diacylglycerol kinases: Relationship to other lipid kinases.

Lipid kinases regulate a wide variety of cellular functions and have emerged as one the most promising targets for drug design. Diacylglycerol kinases (DGKs) are a family of enzymes that catalyze the ATP-dependent phosphorylation of diacylglycerol (DAG) to phosphatidic acid (PtdOH). Despite the critical role in lipid biosynthesis, both DAG and PtdOH have been shown as bioactive lipids mediating a number of signaling pathways. Although there is increasing recognition of their role in signaling systems, our understanding of the key enzyme which regulate the balance of these two lipid messages remain limited. Solved structures provide a wealth of information for understanding the function and regulation of these enzymes. Solving the structures of mammalian DGKs by traditional NMR and X-ray crystallography approaches have been challenging and so far, there are still no three-dimensional structures of these DGKs. Despite this, some insights may be gained by examining the similarities and differences between prokaryotic DGKs and other mammalian lipid kinases. This review focuses on summarizing and comparing the structure of prokaryotic and mammalian DGKs as well as two other lipid kinases: sphingosine kinase and phosphatidylinositol-3-kinase. How these known lipid kinases structures relate to mammalian DGKs will also be discussed.

X-Ray Scattering and Imaging Studies of Electrode Structure and Dynamics.

We will review structures and dynamics of electrode interfaces studied in situ using x-ray scattering and imaging techniques. The examples cover single-crystal and nanocrystal structures relevant to electrocatalytic activities, anodic oxidation and corrosion, aqueous dissolution reactions, surface reconstructions, and surface modifications by under potential deposition. The x-ray techniques include the widely used traditional surface x-ray scattering, such as crystal truncation rods and x-ray reflectivity, as well as recently developed resonance surface scattering, coherent surface x-ray photon correlation spectroscopy, coherent x-ray Bragg diffraction imaging, and surface ptychography. Results relevant to various electrochemical phenomena will be highlighted.

Site specific, high-resolution characterisation of porosity in graphite using FIB-SEM tomography

Graphite is used as a moderator of fast neutrons in some types of nuclear reactors and for other industrial applications. The influence of smaller pores on the mechanical and physical properties of graphite remains to be fully understood. In this work, focused ion beam-scanning electron microscopy (FIB-SEM) tomography was applied to characterise the porosity of AGX graphite – an electrode material. FIB-SEM tomography consists in alternating the ion milling and SEM imaging at an area of interest with the objective of creating a 3D reconstruction. Regions containing a filler and a mixture of filler and binder were selected as the areas of interest. Resolutions of a few nanometers were achieved in volumes up to 1400 μm3 for both regions. Typical porous structures were detected in the filler and binder regions such as thermal cracks, gas evolution porosity and lenticular pores. The resolution achieved with these experiments made possible detection of pores smaller than 150 nm in diameter, that is of the length scale of voids generated by neutron irradiation, and an improvement in spatial resolution of traditional x-ray tomography studies. The resolution achieved by FIB-SEM tomography may be essential for the study of the microstructure of graphite, providing complimentary data to x-ray tomography experiments.

Treatment of left accessory cardiac pathway conduction disorders using radiofrequency catheter ablation under the guidance of the Ensite NavX 3D mapping system: a retrospective study.

To investigate the effectiveness and safety of using the Ensite NavX three-dimensional (3D) mapping system during Radiofrequency catheter ablation (RFCA) of left accessory pathway (AP) disorders. A total of 227 patients having their left AP treated by RFCA, were classified into study group (n = 112) and the control group (n = 115). X-ray irradiation time and exposure doses during the course of the operations were recorded. Time taken to place the mapping catheter along with total duration of operations and procedural complications were compared. The X-ray irradiation time and exposure doses in the course of manipulating the ablation catheters were significantly lower in the study group compared to control (5.1 ± 2.3min vs. 13.1 ± 3.1min; P < 0.05 and 5.7 ± 2.6mGy vs. 17.8 ± 4.3mGy; P < 0.05, respectively). The total duration of operation was also significantly shorter in the study group compared to control (53.1 ± 18.8min vs. 62.3 ± 20.6min; P < 0.05). No procedural complications were reported in both groups. The irradiation time and exposure dose along with total operation duration was significantly reduced when the Ensite NavX mapping system was used during RFCA in comparison with traditional X-ray fluoroscopy method.

Note: A Laue crystal imager for high energy quasi-monochromatic x-ray.

A newly designed transmission type x-ray Laue imager for tens of keV hard x-rays is reported. Compared with the traditional reflection type x-ray crystal imager, the transmission geometry produces a much better image quality for high energy hard x-rays. This system was assessed via a calibration experiment performed at the SPring8 synchrotron radiation facility. With a Ta x-ray fluorescer, the mono-energetic x-ray at 70 keV from the synchrotron radiation was converted to an isotropically emitted Ta K-shell source at 57.5 keV and 65 keV. A tungsten pinhole array was employed as the test object, and clear images of the pinholes with a magnification of ∼5 were acquired. These images exhibited superior quality in the dispersion plane. As an extension of this work, a slit-free full-spectral Laue imager is proposed for high resolution hard x-ray imaging.

Application of differential resonant high-energy X-ray diffraction to three-dimensional structure studies of nanosized materials: A case study of Pt–Pd nanoalloy catalysts

Atoms in many of the increasingly complex nanosized materials of interest to science and technology do not necessarily occupy the vertices of Bravais lattices. The atomic scale structure of such materials is difficult to determine by traditional X-ray diffraction and so their functional properties remain difficult to optimize by rational design. Here, the three-dimensional structure of PtxPd100-x nanoalloy particles is determined, where x = 0, 14, 36, 47, 64 and 100, by a non-traditional technique involving differential resonant high-energy X-ray diffraction experiments conducted at the K edge of Pt and Pd. The technique is coupled with three-dimensional modeling guided by the experimental total and element-specific atomic pair distribution functions. Furthermore, using DFT (density functional theory) calculation based on the positions of atoms in the obtained three-dimensional structure models, the catalytic performance of Pt-Pd particles is explained. Thus, differential resonant high-energy X-ray diffraction is shown to be an excellent tool for three-dimensional structure studies of nanosized materials. The experimental and modeling procedures are described in good detail, to facilitate their wider usage.

RADIATION DIAGNOSIS OF RARE FORMS OF RESPIRATORY ORGAN SARCOIDOSIS

Objective: to evaluate the clinical and radiological features of rare forms of sarcoidosis of the respiratory organs (SRO).Material and methods. In 2006 to 2016, the Research Institute of Interstitial and Orphan Lung Diseases followed up 599 patients with sarcoidosis. 36 patients (6.0%) of them had atypical clinical and radiation manifestations that did not correspond to the traditional radiation pattern and the existing X-ray classification of SRO. Stages 2, 3, and 4 pulmonary sarcoidosis was diagnosed in 26, 7, and 3 patients, respectively. The patients’ mean age was 38.2±7.4 years (the female/male ratio was 26:10). All the patients underwent traditional X-ray studies (radiography in two projections), high-resolution computed tomography (CT), complex external respiratory function examination, and echocardiography.Results. Analysis of the results of radiation examinations revealed the following rare forms of SRO: interstitial edematous, fibrous, and cavitary ones that had recognizable CT patterns. Each of these forms had clinical and functional features. In single cases, the CT pattern combined the features incompatible with the generally accepted classification (Stages 1 and 4 SRO); this was an offstage form. The features of the radiation pattern and clinical course required the differential diagnosis of these patients with more severe diseases (idiopathic pulmonary fibrosis, lymphogenic carcinomatosis, pulmonary edema, diffuse connective tissue diseases, pneumoconiosis, mycobacteriosis, and exogenous allergic alveolitis) and morphological verification.Conclusion. The accumulation of experience with clinical and radiological examination of patients with SRO revealed its rare forms that are difficult to diagnose and necessitate the development of new approaches to therapy policy.

Efficacy and safety of three-dimensional electroanatomical mapping system for catheter ablation of paroxysmal supraventricular tachycardia in children

Objective: To evaluate the efficacy and safety of three-dimensional electroanatomical mapping system for catheter ablation of paroxysmal supraventricular tachycardiain (PSVT) children. Methods: Clinical data from 187 children with paroxysmal supraventricular tachycardia undergoing radiofrequency catheter ablation in our department between January 2012 and April 2016 were analyzed. Among the patients, 91 cases were treated with traditional two-dimensional X-ray radiofrequency ablation, 96 cases were treated with radiofrequency ablation guided by three-dimensional electroanatomical mapping system. Postoperative electrocardiogram and echocardiography follow-up was performed at 1, 3, 6, 12, and 24 months. The success rate, recurrence rate, complication rate, operation time and amount of X-ray exposure were compared between the two groups. Kaplan-Meier survival curve was used to analyze the PSVT-free survival rate of the patients between the 2 groups. Results: The mean follow-up time was (739±92) days. The success rate (95.8%(92/96) vs. 94.5%(86/91), P=0.912), recurrence rate (5.4%(5/92) vs. 4.7%(4/86), P=0.807), complication rate (4.2%(4/96) vs. 5.5%(5/91), P=0.379), operation time ((73±31)min vs. (79±36)min, P=0.124) were similar between the two groups. However, X-ray exposure time ((8.1±2.9)min vs. (21.3±8.4)min, P=0.026), amount of X-ray ((23±11)mGy vs. (58±23)mGy, P=0.013) were significantly lower in the three-dimensional electroanatomical mapping system group than in the traditional two-dimensional X-ray radio frequency ablation group. PSVT-free survival rate was similar between the two groups (χ(2)=0.060, P=0.807) . Conclusion: Three-dimensional electroanatomical mapping system is safe and effective for radiofrequency ablation of paroxysmal supraventricular tachycardia in children, and can significantly reduce the amount of radiation as compared to the traditional two-dimensional X-ray radiofrequency ablation.

Identification of weak peaks in X-ray fluorescence spectrum analysis based on the hybrid algorithm combining genetic and Levenberg Marquardt algorithm

Accurate measurement of cadmium content in rice is of utmost importance to determine if the inspected rice product is safe to people. X-ray fluorescence analysis is frequently used for multi-element analysis because it has characteristics of fast, accurate and nondestructive. However, due to the low content of cadmium in rice, its corresponding characteristics energy peak is relatively weak and is sensitive to the background information in the X-ray energy spectrum. Thus, it is very tough to obtain the accurate values of cadmium content by utilizing traditional X-ray fluorescence analysis. In this paper, the identification of weak peaks of cadmium is much improved by proposing a hybrid algorithm combining genetic algorithm (GA) and Levenberg-Marquardt algorithm (LM). The hybrid algorithm not only takes full advantages of GA and LM respectively but also inhibits their unwanted properties: poor local search ability of GA and locally convergent of LM. The proposed hybrid algorithm is employed to identify weak peaks in X-ray spectra of six contaminated rice samples with different contents of cadmium. Two comparative experiments are conducted to compare the performance between GA, LM and the proposed hybrid algorithm. One of the comparative experiments has the relative error varying with the number of calculations, which aims to verify the accuracy and stability. The results show that the hybrid algorithm is a better option in terms of accuracy and stability. Another comparative experiment of which the average relative error varies with the number of iterations is conducted to verify the computing efficiency. The experiments show that the hybrid algorithm exhibits a faster convergence rate. Two numerical experiments demonstrate that the proposed algorithm can well resolve the identification issue of the cadmium in the X-ray spectra and significantly improve the content measurement accuracy of cadmium in the quality evaluation experiment of rice products.

Portal hypertension complicated by bleeding from esophageal and gastric varices: the present state of the problem of treatment and prevention

Background. Objective: to evaluate the effectiveness of comprehensive treatment and prevention of bleeding from esophageal and gastric varices in portal hypertension, including with the use of minimally invasive methods. Material and me­thods. The results of treatment were analyzed in 972 patients with portal hypertension who were treated in the HI “City Clinical Hospital 4 of Grodno” in the period from 2012 to 2016. Results. Endoscopic sclerotherapy of bleeding esophageal and gastric varices was successfully used in 67 patients with portal hypertension. Endoscopic ligation was performed in 12 patients. Sengstaken-Blakemore tube was used in 198 patients, while 22.7 % of them observed a relapse of bleeding after 12 hours. Endoscopic sclerotherapy for bleeding prevention was applied in 90 patients. Ten operations of azygoportal disconnection in the modification of Paciora were performed due to the ineffectiveness of other methods of hemostasis, 7 patients died. Seventeen operations of azygoportal disconnection in the modification of Sugiura-Futagawa and Hassab were carried out in 2012–2017, 1 patient died on the 11th day due to the progression of hepatic insufficiency. Sixteen operations of laparoscopic azygoportal disconnection, 15 transjugular intrahepatic portosystemic shunts were also performed. Thirty-day in-hospital mortality was not observed in these groups. Over 5 years, out of 277 patients with bleeding from esophageal and gastric varices, 121 died, lethality was 43.7 %. Among 695 patients with portal hypertension hospitalized in the department of gastroenterology, 11 died, lethality was 1.6 %, total lethality — 13.6 %. Conclusions. Methods of endoscopic sclerotherapy and ligation in the treatment and prevention of acute bleeding from esophageal varices are preferred. Traditional laparoscopic and X-ray endovascular surgical technologies are effective reserve methods for the treatment and prevention of bleedings from esophageal and gastric varices.

Abstract 5831: Biopolymer β-brachytherapy delivered concomitantly with systemic paclitaxel outperforms traditional x-ray radiation to induce complete regression in multiple pancreatic tumor xenograft models

Abstract Pancreatic tumors remain one of the deadliest manifestations of cancer in clinical oncology. Even when tumors are diagnosed early, remain loco-regionalized, and receive cutting-edge cancer treatment, the 5-year survival rate remains less than 27%. This high mortality rate arises from the significant biologic barriers that inhibit drug delivery effectiveness in pancreatic tumors, as well as their underlying genetic mutations that confer resistance to traditional radiation and chemotherapeutic standards of care. In this work, we hypothesized that a new form of radiation brachytherapy might prove highly synergistic for overcoming the resistance native to pancreatic tumors. Utilizing the thermally stabilized biopolymer ELP, 131iodine radionuclides can be delivered intratumorally to provide continuous, focalized, high-dose β-radiation to treat pancreatic cancer from the inside out. Dose-escalation studies revealed that the two important variables for improving outcomes were the 131I-ELP radioactivity dose and the duration of concurrent paclitaxel therapy. 100% tumor regression was achieved across multiple genotypic models of pancreatic cancer models: MIA PaCa-2, AsPc-1, and BxPc3 (both subcutaneous and orthotopic). The potent synergistic results of 131I-ELP brachytherapy were replicated using both a novel micelle formulation of paclitaxel and the clinical standard Abraxane. Multigroup analysis revealed true molecular synergy as assessed by the Bliss Independence framework (p &amp;lt; 0.01). External beam irradiation, when similarly employed as comparison, merely induced growth inhibition when combined with paclitaxel utilizing a 5Gy hypofractionation regimen. Immunohistochemical analysis of treated tumors revealed differential modulation of biomolecular components that regulate the effectiveness of drug delivery and radiotoxicity. Levels of PECAM, VE-cadherin, claudin-4, HIF-1α, and stromal collagen were all specifically investigated, while macroscopic analysis revealed significantly enhanced accumulation and retention of fluorescently tagged paclitaxel when tumors were treated with biopolymer brachytherapy. Standard x-ray therapy indicated little to no improvement. No signs of any toxic side effects were observed in serologic enzyme analysis and multiorgan biodistribution studies. Citation Format: Jeffrey L. Schaal, Jayanta Bhattacharyya, Xinghai Li, Samagya Banskota, Jeremy Brownstein, David Kirsch, Michael Zalutsky, Ashutosh Chilkoti. Biopolymer β-brachytherapy delivered concomitantly with systemic paclitaxel outperforms traditional x-ray radiation to induce complete regression in multiple pancreatic tumor xenograft models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5831.

UV scintillating particles as radiosensitizer enhance cell killing after X-ray excitation

Background and purposeRadiation therapy is the gold standard treatment for inoperable malignant tumors. However, due to the heterogeneity of the tumor, some regions are more radio resistant and can lead to metastasis and tumor recurrence. In this study, we propose combining traditional X-ray treatment with UVC-emitting LuPO4:Pr3+ nanoparticles (NPs) to increase the tumor control as well as to reduce tumor recurrence and metastasis. These NPs convert ionizing radiation into UVC-photons (UVC range: 200–280 nm) locally at the tumor site. Unlike X-ray, UVC-photons damage DNA directly via an oxygen-independent mechanism, which could improve treatment of radioresistant tumors such as hypoxic tumors. Materials and methodsThe effect of X-ray generated UVC-photons was tested on human fibroblasts incubated with NPs prior to radiation treatment. The surviving fraction of the cells was assessed by means of colony formation assay. Experiments were performed on normal and UVC sensitive cell lines to demonstrate the presence of UVC photons during treatment. In addition, UV-specific DNA damages were investigated using an immunofluorescence assay to measure cyclopyrimidine dimers (CPDs). ResultsCombined treatment showed an increased cell death of over 50%, compared to radiation alone. This results in a dose equivalent of 4 Gy for the combined treatment with 2 Gy irradiation. The formation of CPDs and the increased effect on UV sensitive cells indicate the presence of UV photons. The generated amount of CPDs is comparable to an UVC exposure of about 15 J × m−2. ConclusionCombining NPs with ionizing radiation results in a localized dose surge, which could increase tumor control. It could also allow lowering the total applied dose to minimize unwanted side effects to the surrounding normal tissue while maintaining tumor control.

Direct information retrieval after 3D reconstruction in grating-based X-ray phase-contrast computed tomography.

Grating-based X-ray differential phase-contrast imaging has attracted a great amount of attention and has been considered as a potential imaging method in clinical medicine because of its compatibility with the traditional X-ray tube source and the possibility of a large field of view. Moreover, phase-contrast computed tomography provides three-dimensional phase-contrast visualization. Generally, two-dimensional information retrieval performed on every projection is required prior to three-dimensional reconstruction in phase-contrast computed tomography. In this paper, a three-dimensional information retrieval method to separate absorption and phase information directly from two reconstructed images is derived. Theoretical derivations together with numerical simulations have been performed to confirm the feasibility and veracity of the proposed method. The advantages and limitations compared with the reverse projection method are also discussed. Owing to the reduced data size and the absence of a logarithm operation, the computational time for information retrieval is shortened by the proposed method. In addition, the hybrid three-dimensional images of absorption and phase information were reconstructed using an absorption reconstruction algorithm, hence the existing data pre-processing methods and iterative reconstruction algorithms in absorption reconstruction may be utilized in phase reconstruction immediately.

Numerical model built for the simulation of the earth magnetopause by lobster-eye-type soft X-ray imager onboard SMILE satellite.

Solar wind magnetosphere ionosphere link explorer (SMILE) scientific satellite is dedicated to observe solar wind-magnetosphere coupling. The key payload, soft X-ray imager (SXI), is designed to map the location, shape, and motion of dayside magnetospheric boundaries by Angel-type lobster-eye optical system. Contrast to traditional Wolter-type X-ray telescope with very narrow field-of-view, the lobster-eye-type optics has a unique capability of providing wide field of view for panoramic imaging with moderate spatial resolution in soft X-ray band. Since the lobster-eye optics focus X-ray by reflecting of the inner walls of the micro-channel array shaped in spherical surface, traditional optical design tools can't well match to the requirements of simulation for SXI. In this paper, a 3D Angel-type lobster-eye model is designed for simulation of lobster-eye optics and its capability is demonstrated for the applying scenarios including the imaging of point light source, surface light source with uniform and non-uniform intensity distribution. The simulation results are well consistent with those of theoretical estimate.

Development of Positioning and Navigation System Using for C-arm X-ray Apparatus for Minimally Invasive Surgeries

On account of the problem that traditional C-arm X-ray apparatus cannot provide precise route guidance for minimally invasive surgeries, we designed and developed a laser positioning and navigation system based on C-arm X-ray apparatus, which can achieve precise positioning function and reduce the exposure of doctors and patients to radiation in minimally invasive surgeries under the linear guidance of a laser beam. Furthermore, this system can enhance the refinement level of surgical operation in minimally invasive surgeries.