Journal of X-Ray Science and Technology - Volume 19, issue 4

Authors: Parveen, N. Ravia Shabnam | Sathik, M. Mohamed

Article Type: Research Article

Abstract: Pneumonia is the common type of infection found in the world. The infection spreads in the lungs area of a human body. The chest x-ray is performed to diagnose this infection. Physicians use this X-ray image to diagnose or monitor treatment for conditions of pneumonia. This type of chest X-ray is also used in the diagnosis of diseases like emphysema, lung cancer, line and tube placement and tuberculosis. Feature extraction methods like DWT, WFT, and WPT …can also be used. In this paper, detection of pneumonia infection by unsupervised fuzzy c-means classification learning algorithm is used. This approach gives better result than the rest of the methods. In fuzzy c-means, each resultant pixel gives accurate value since it has a weight associated with it. Show more

Keywords: Feature extraction, pneumonia, fuzzy c-means classification, unsupervised learning

DOI: 10.3233/XST-2011-0304

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 423-428, 2011

Authors: Bi, Bi | Zeng, Li | Jiang, Haina

Article Type: Research Article

Abstract: To reduce time cost and improve the performance of edge extraction in CT volume data which is often in large size, we propose a novel method of 3D crack edge extraction using two fusion steps, one is fusion on Finite Line Integral Transform (FLIT) values in spatial directions called SD-FLIT and another is fusion on Local Binary Pattern (LBP) values on spatial planes called SP-LBP. By analyzing the S function of LBP operator, we find that value "0" …of this function can describe the change between two equivalence planes. However, this property is sensitive to point difference, thus SD-FLIT is introduced to smooth noises and artifacts before the application of SP-LBP to extract 3D edge on binary volume data. Besides, fusions on directions and planes are aimed at extracting enough spatial information. Experimental results show that, owing to the sufficiency of information extraction and the simplicity of computation, our method can get continuous, thin and occlusive 3D edge, including the crack tip. Furthermore, it can be used to complicate volume data. Compared with 3D wavelet and Facet model, our method cost less time, saving at least 89% of that. Show more

Keywords: CT volume data, 3D crack edge, data fusion, LBP, FLIT

DOI: 10.3233/XST-2011-0305

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 429-442, 2011

Authors: Gossman, Michael S. | Paralikar, Kunal J. | Hebb, Adam O. | Wilkinson, Jeffrey D. | Graves-Calhoun, Alison R. | Lawson, Raymond C. | Lopez, Jeffrey P. | Powell, James S.

Article Type: Research Article

Abstract: Object: Where no society-based or manufacturer guidance on radiation limits to neuromodulation devices is available, this research provides the groundwork for neurosurgeons and radiation oncologists who rely on the computerized treatment plan clinically for cancer patients. The focus of the article is to characterize radiation parameters of attenuation and scatter when an incident therapeutic x-ray beam is directed upon them. At the time of this writing, manufacturers of Neuromodulation products do not recommend direct …exposure of the device in the beam nor provide guidance for the maximum dose for these devices. Methods: Ten neuromodulation models were chosen to represent the finite class of devices marketed by Medtronic before 2011. CT simulations permitted computer treatment modeling for dose distribution analysis as used routinely in radiation oncology for patients. Phantom case results were directly compared to actual clinical patient cases. Radiation detection measurements were then correlated to computational results. Where the x-ray beam passes through the device and is attenuated, dose reduction was identified with Varian Eclipse computer modeling for these posterior locations. Results: Although the computer algorithm did not identify physical processes of side-scatter and back-scatter, these phenomena were proven by radiation measurement to occur. In general, the computer results underestimated the level of change seen by measurement. Conclusions: For these implantable neurostimulators, the spread in dose changes were found to be −6.2% to −12.5% by attenuation, +1.7% to +3.8% by side-scatter, and +1.1% to +3.1% by back-scatter at 6 MV. At 18 MV, these findings were observed to be −1.4% to −7.0% by attenuation, +1.8% to 5.7% by side-scatter, and 0.8% to 2.7% by back-scatter. No pattern for the behavior of these phenomena was deduced to be a direct consequence of device size. Show more

Keywords: Accelerator, Medtronic, neuromodulation, neurostimulator, oncology, radiation

DOI: 10.3233/XST-2011-0306

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 443-456, 2011

Authors: Choi, Jiyoung | Kim, Kyung Sang | Kim, Min Woo | Seong, Won | Ye, Jong Chul

Article Type: Research Article

Abstract: Metal artifact removal (MAR) is one of the most important issues in x-ray CT reconstruction. Various methods have been suggested for metal artifact removal, among which projection modification and iterative methods are most popular. While those methods mainly focus on removing background artifacts, for some applications such as dental CT the correct reconstruction of metallic inserts is also important. For this application, we formulate the MAR problem as a sparse recovery problem since metallic inserts usually …occupy very little volume within a field of view. One of the main advantages of this approach is to overcome the inconsistency of sinograms from metal artifacts by imposing a geometric constraint, "sparsity". As a side product of this formulation, a significant reduction of the sample views is feasible for metal part reconstruction without sacrificing quality, thanks to the compressed sensing theory, which minimizes the additional computational overhead. Numerical results confirm that metallic inserts can be accurately reconstructed with a significant reduction of computation time. Show more

Keywords: Metal artifact removal, compressed sensing, dental X-ray CT, sparsity

DOI: 10.3233/XST-2011-0307

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 457-475, 2011

Authors: Aviles, Jorge E. Alpuche | Pistorius, Stephen | Elbakri, Idris A. | Gordon, Richard | Ahmad, Bashir

Article Type: Research Article

Abstract: Breast CT is an emerging modality that reconstructs 3D linear attenuation coefficient (μ) images of the breast. Its tomographic nature reduces the overlap of structures and may improve tissue visualization. Current prototype systems produce large levels of scatter that could be used to reconstruct electron density (ρ _{e} ) images. This could potentially enhance diagnosis. We are developing a first generation bench top CT system to investigate the benefits of simultaneous …imaging μ and ρ _{e} of the intact breast. The system uses an algorithm capable of reconstructing ρ _{e} images from single Klein-Nishina scatter. It has been suggested that this algorithm may be impractical since measurements include coherent, bound incoherent and multiple scatter. To investigate this, the EGSnrc Monte Carlo (MC) code was used to simulate scans using a first generation system. These simulations were used to quantify the dose per scan, to provide raw data for the ρ _{e} reconstructions and to investigate corrections for multiple and coherent scatter since these can not be directly related to ρ _{e} . MC simulations show that the dose coefficients are similar to those of cone beam breast CT. Coherent scatter is only ∼9% concentrated in scattering angles < 8°. Electron binding reduces the number of incoherently scattered photons but this reduction can be included in the quantification of scatter measured by the system. Multiple scatter was found to be the major source of errors and, if not corrected for, can result in an overestimation of ρ _{e} by more than a factor of two. Empirical corrections, based on breast thickness or radiological path, can be used to reconstruct images where the variance in ρ _{e} error is half of that found in images derived from primary photons only. Although some practical challenges remain in creating a laboratory system, this work has shown that it is possible to reconstruct scatter images of the breast with a 4 mGy dose and further experimental evaluation of this technique is warranted. Show more

Keywords: Computed tomography, scatter CT, scatter imaging, X-rays, breast CT

DOI: 10.3233/XST-2011-0308

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 477-499, 2011

Authors: Han, I. | Aygun, M. | Demir, L. | Narmanlı, E.

Article Type: Research Article

Abstract: The mean free path (mfp) and half value layer (x_{1 / 2} ) values of binary and ternary alloys consist of 3d transition metals have been have been calculated at photon energies 22.1, 25.0, 59.5 and 88.0 keV. The experimental linear attenuation coefficients (μ) for present photon energies have been used to obtain the values of mfp and x_{1 / 2} . The experimental mfp and x_{1 / 2} results have compared with the theoretically …calculated results based on attenuation coefficients obtained from WinXCom program. A good correspondence has been observed among the present results and the theoretical results. Show more

Keywords: Mean free path, half value layer, alloy, attenuation coefficient

DOI: 10.3233/XST-2011-0309

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 501-508, 2011

Authors: Wong, Molly Donovan | Wu, Xizeng | Liu, Hong

Article Type: Research Article

Abstract: The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The ability to decrease the risk of harmful radiation to the patient without compromising the detection capability would more effectively balance the tradeoff between image quality and radiation dose, and therefore benefit the fields of diagnostic x-ray imaging, especially mammography. The DQE and the average …glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results demonstrate a reduction of 15% to 24% for the range of beam hardening levels. The comparison of all quantities comprising the DQE exhibit very close correlation between the results obtained without added beam hardening to the results corresponding to the range of beam hardening levels. For the specific experimental conditions utilized in this preliminary study, the results are an indication that the use of beam hardening holds the potential to reduce the radiation dose without decreasing the performance of the system. Future studies will seek to apply this method in a clinical environment and perform a comprehensive image quality evaluation, in an effort to further evaluate the potential of beam hardening to balance the tradeoff between dose and image quality. Show more

Keywords: Diagnostic x-ray imaging, beam hardening, radiation dose, detective quantum efficiency (DQE), noise equivalent quanta (NEQ), modulation transfer function (MTF), noise power spectrum (NPS)

DOI: 10.3233/XST-2011-0310

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 509-519, 2011

Authors: Abliz, Erkinay | Collins, Joshua E. | Bell, Howard | Tata, Darrell B.

Article Type: Research Article

Abstract: Introduction: In this communication we report on a novel non-invasive methodology in utilizing "soft" energy diagnostic X-rays to indirectly activate a photo-agent utilized in photodynamic therapy (PDT): Photofrin II (Photo II) through X-ray induced luminescence from Gadolinium Oxysulfide (20 micron dimension) particles doped with Terbium: Gd_{2} O_{2} S:Tb. Photodynamic agents such as Photo II utilized in PDT possess a remarkable property to become preferentially retained within the tumor's micro-environment. …Upon the photo-agent's activation through (visible light) photon absorption, the agents exert their cellular cytotoxicity through type I and type II pathways through extensive generation of reactive oxygen species (ROS); namely, singlet oxygen ^{1} O_{2} , superoxide anion O_{2}^{-} , and hydrogen peroxide H_{2} O_{2} , within the intra-tumoral environment. Unfortunately, due to shallow visible light penetration depth (∼ 2 mm to 5 mm) in tissues, the current PDT strategy has largely been restricted to the treatment of surface tumors, such as the melanomas. Additional invasive strategies through optical fibers are currently utilized in getting the visible light into the intended deep seated targets within the body for PDT. Methods: X-ray induced visible luminescence from Gd_{2} O_{2} S:Tb particles were spectroscopically characterized, and the potential in-vitro cellular cytotoxicity of Gd_{2} O_{2} S:Tb particles on human glioblastoma cells (due to 48 Hrs Gd_{2} O_{2} S:Tb particle exposure) was screened through the MTS cellular metabolic assay. In-vitro human glioblastoma cellular exposures in presence of Photo II with Gd_{2} O_{2} S:Tb particles were performed in the dark in sterile 96 well tissue culture plates, and the corresponding changes in the metabolic activities of the glioblastoma due to 15 minutes of (diagnostic energy) X-ray exposure was determined 48 Hrs after treatment through the MTS assay. Results: Severe suppression (> 90% relative to controls) in the cellular metabolic activity of human glioblastoma was measured due to the treatment of clinically relevant concentrations of 20 μg/ml Photo II, with Gd_{2} O_{2} S:Tb particles, and (120 kVp) diagnostic X-rays. Taken together, the in-vitro findings herein provide the basis for future studies in determining the safety and efficacy of this non-invasive X-ray induced luminescence strategy in activating photo-agent in deep seated tumors. Show more

Keywords: X-ray induced luminescence, photodynamic therapy, reactive oxygen species detection, singlet oxygen, Photofrin II, Gadolinium Oxysulfide particles

DOI: 10.3233/XST-2011-0311

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 521-530, 2011

Authors: Zhang, Jiang | Wang, James Z. | Yuan, Zhen | Sobel, Eric S. | Jiang, Huabei

Article Type: Research Article

Abstract: This study presents a computer-aided classification method to distinguish osteoarthritis finger joints from healthy ones based on the functional images captured by x-ray guided diffuse optical tomography. Three imaging features, joint space width, optical absorption, and scattering coefficients, are employed to train a Least Squares Support Vector Machine (LS-SVM) classifier for osteoarthritis classification. The 10-fold validation results show that all osteoarthritis joints are clearly identified and all healthy joints are ruled out …by the LS-SVM classifier. The best sensitivity, specificity, and overall accuracy of the classification by experienced technicians based on manual calculation of optical properties and visual examination of optical images are only 85%, 93%, and 90%, respectively. Therefore, our LS-SVM based computer-aided classification is a considerably improved method for osteoarthritis diagnosis. Show more

Keywords: Osteoarthritis, finger joints, x-rays, diffuse optical tomography, least squares support vector machine, statistical analysis

DOI: 10.3233/XST-2011-0312

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 531-544, 2011

Authors: Xiao, Feng-Lian | Gao, Wei-Jie | Liu, Cheng-Yi | Wang, Xiao-Ping | Chen, Tong-Sheng

Article Type: Research Article

Abstract: Artemisinin (ARTE), an antimalarial phytochemical component from the sweet wormwood plant, has been shown a potential anticancer activity by inducing cell apoptosis. The aim of this report is to explore the mechanism of ARTE-induced human lung adenocarcinoma (ASTC-a-1) cell apoptosis. Cell counting kit (CCK-8) assay showed that ARTE induced cytotoxcity in a dose- and time-dependent manner. Confocal microscopy fluorescence imaging of cells stained with Hoechst 33258 and flow cytometry (FCM) analysis of cells stained …with Annexin V-FITC/propidium iodide (PI) showed that ARTE induced reactive oxygen species (ROS)-dependent apoptosis. Confocal fluorescence resonance energy transfer (FRET) imaging of single living cells expressing SCAT3, SCAT9 or CFP-Bid-YFP and fluorometic substrate assay showed that ARTE induced the activation of caspase-3, -8 and -9. Moreover, inhibition of caspase-8 or -9 completely blocked ARTE-induced apoptosis which was only partially attenuated by caspase-3 inhibitor. Interestingly, silencing Bax and Bak by RNA interference (RNAi) did not attenuate ARTE-induced apoptosis. Collectively, ARTE induces caspase-dependent but Bax/Bak-independent apoptosis in ASTC-a-1 cells. Show more

Keywords: Artemisinin (ARTE), apoptosis, caspase, fluorescence resonance energy transfer (FRET), Bax/Bak

DOI: 10.3233/XST-2011-0313

Citation: Journal of X-Ray Science and Technology, vol. 19, no. 4, pp. 545-555, 2011