Journal of X-Ray Science and Technology - Volume 22, issue 4

Authors: Arhatari, Benedicta D. | Andrewartha, Kathy | White, Maurice

Article Type: Research Article

Abstract: BACKGROUND: Most tooth cavities start to develop inside pits and fissures where brushing, saliva, fluoride toothpaste or mouthwashes have no access. Therefore, 3D morphology of pits and fissures is an important subject to be studied in relation to maintaining proper oral hygiene. OBJECTIVE: This study aimed to present high resolution images of pits and fissures in human teeth using a laboratory-based micro X-ray Computed Tomography (mXCT) and also to present the basic structure evaluation that could …be obtained. METHODS: Three human wisdom teeth were examined. Two different set-ups were used in this study achieving resolution of 14.59 μm (Field of View of 14.9 mm) and resolution of 4.43 μm (FOV of 4.5 mm) respectively. Automated segmentation was performed for further evaluation to distinguish between empty space (pits and fissures) and the filled space (enamel). RESULTS: The 3D tomography results demonstrate detailed morphology with accurate dimensions and the locations of the pits and fissures, which is important to investigate the relationship with tooth decay that mostly starts deep inside pits and fissures. CONCLUSIONS: Segmentation from the mXCT imaging of pits and fissures provides obvious visual evidence to help in promotion of oral health and to improve personal tooth care in preventive treatment protocols. Show more

Keywords: X-ray imaging, tomography, micro X-ray CT, pits and fissures

DOI: 10.3233/XST-140435

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 407-414, 2014

Authors: Zhao, Shuangren | Yang, Kang | Yang, Kevin

Article Type: Research Article

Abstract: For parallel beam geometry the Fourier reconstruction works via the Fourier slice theorem (or central slice theorem, projection slice theorem). For fan beam situation, Fourier slice can be extended to a generalized Fourier slice theorem (GFST) for fan-beam image reconstruction. We have briefly introduced this method in a conference. This paper reintroduces the GFST method for fan beam geometry in details. The GFST method can be described as following: the Fourier plane is filled by adding …up the contributions from all fanbeam projections individually; thereby the values in the Fourier plane are directly calculated for Cartesian coordinates such avoiding the interpolation from polar to Cartesian coordinates in the Fourier domain; inverse fast Fourier transform is applied to the image in Fourier plane and leads to a reconstructed image in spacial domain. The reconstructed image is compared between the result of the GFST method and the result from the filtered backprojection (FBP) method. The major differences of the GFST and the FBP methods are: (1) The interpolation process are at different data sets. The interpolation of the GFST method is at projection data. The interpolation of the FBP method is at filtered projection data. (2) The filtering process are done in different places. The filtering process of the GFST is at Fourier domain. The filtering process of the FBP method is the ramp filter which is done at projections. The resolution of ramp filter is variable with different location but the filter in the Fourier domain lead to resolution invariable with location. One advantage of the GFST method over the FBP method is in short scan situation, an exact solution can be obtained with the GFST method, but it can not be obtained with the FBP method. The calculation of both the GFST and the FBP methods are at O(N^3 ), where N is the number of pixel in one dimension. Show more

Keywords: Image reconstruction, fanbeam, conebeam CT, PET, SPECT, projection slice theorem, central slice theorem, Fourier slice theorem, generalized

DOI: 10.3233/XST-140436

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 415-436, 2014

Authors: Liu, Yan | Ma, Jianhua | Zhang, Hao | Wang, Jing | Liang, Zhengrong

Article Type: Research Article

Abstract: BACKGROUND: The negative effects of X-ray exposure, such as inducing genetic and cancerous diseases, has arisen more attentions. OBJECTIVE: This paper aims to investigate a penalized re-weighted least-square (PRWLS) strategy for low-mAs X-ray computed tomography image reconstruction by incorporating an adaptive weighted total variation (AwTV) penalty term and a noise variance model of projection data. METHODS: An AwTV penalty is introduced in the objective function by considering both piecewise constant property and local nearby intensity …similarity of the desired image. Furthermore, the weight of data fidelity term in the objective function is determined by our recent study on modeling variance estimation of projection data in the presence of electronic background noise. RESULTS: The presented AwTV-PRWLS algorithm can achieve the highest full-width-at-half-maximum (FWHM) measurement, for data conditions of (1) full-view 10 mA acquisition and (2) sparse-view 80 mA acquisition. In comparison between the AwTV/TV-PRWLS strategies and the previous reported AwTV/TV-projection onto convex sets (AwTV/TV-POCS) approaches, the former can gain in terms of FWHM for data condition (1), but cannot gain for the data condition (2). CONCLUSIONS: In the case of full-view 10 mA projection data, the presented AwTV-PRWLS shows potential improvement. However, in the case of sparse-view 80 mA projection data, the AwTV/TV-POCS shows advantage over the PRWLS strategies. Show more

Keywords: X-ray computed tomography, low-mAs protocol, penalized re-weighted least-squares, adaptive weighted total variation, projection onto convex sets

DOI: 10.3233/XST-140437

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 437-457, 2014

Authors: Eskandarlou, Amir | Jafari, Amir Abbas | Mohammadi, Mohammad | Zehtabian, Mehdi | Faghihi, Reza | Shokri, Abbas | Pourolajal, Jalal

Article Type: Research Article

Abstract: The effectiveness of added filters including conventional and rare earth materials for dental radiography tasks was investigated using a simulation approach. Current study focuses on the combination of a range of various filters to investigate the reduction of radiation absorbed dose and improving the quality of a radiography image. To simulate the X-ray beam spectrum, a MCNP5 code was applied. Relative intensity, beam quality, and mean energy were investigated for a typical dental radiography …machine. The impact of different rare-earth materials with different thicknesses and tube voltages on the X-ray spectrum was investigated. For Aluminum as a conventional filter, the modeled X-ray spectra and HVL values were in a good agreement with those reported by IPEM. The results showed that for a 70 kVp voltage, with an increase of the thickness and atomic number of a given added filters, an increase of HVL values were observed. However, with the increase of the attenuator thickness, X-ray beam intensity decreases. For mean energy, different results were observed. It was also found that rare earth made filters reduce high energy X-ray radiation due to k-edge absorption. This leads to an ideal beam for intra-oral radiography tasks. However, as a disadvantage of rare earth added filters, the reduction of the tube output levels should also be considered. Show more

Keywords: Dental radiography, diagnostic X ray, rare earth elements

DOI: 10.3233/XST-140438

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 459-470, 2014

Authors: Chikawa, Jun-ichi | Mouri, Yoshitaka | Shima, Hiroki | Yamada, Kousaku | Yamamoto, Hitoshi | Yamamoto, Shingo

Article Type: Research Article

Abstract: Elemental concentrations in hair and dried serum have been evaluated by X-ray fluorescence analysis using relative concentration independent of specimen thickness. Dried serum samples from 5 male and 5 female subjects given two-week Ca supplementation showed the same concentration for Ca, and for each of the other elements Cl, K, S and P under renal control by parathyroid hormone (PTH). Hair concentrations of these elements have been evaluated for 50 randomly-selected females aged between 30 and …80. It was found that each element has two distinct levels in hair. The content of an element in growing hair must be equal to the inflow of that element into the hair-making cells from serum. Using this principle, the two levels can be attributed to the gating and closing of the ion channels in cell membranes and given as functions of the dried serum standard concentrations. Especially, the difference between [Ca] and [Sr] in hair shows whether Ca channels are gating or closing. The lower level of hair [Ca]_H is normal and is equal to 1/2 of the dried serum [Ca]; only the Ca on serum protein is to be incorporated into the hair in steady-state growth. Store-operated Ca channel gating occurs so as to maintain the normal [Ca]_H . The higher level is seen in cases of calcium deficiency, and implicated in other disease states. Prolonged Ca deficiency causes a higher hair [Ca]_H with Ca channel closing. PTH-operated Ca channel gating induces the Ca^{2+} inflow into the cells to form the hair [Ca]_H upper level and to deteriorate cell functions such as excretion of excess metals by hepatocytes. Hair analysis provides a new diagnostic tool based on cell ion channels. Show more

Keywords: Hair and serum elements, Ca deficiency, ion channels, parathyroid hormone PTH

DOI: 10.3233/XST-140439

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 471-491, 2014

Authors: Wang, Wenying | Wang, Li | Xu, Jianfeng | Shi, Shufang | Tian, Ye | Zhang, Yuanyuan

Article Type: Research Article

Abstract: The appendiceal diseases, particularly appendicitis, are the most common disorders in the digestive system localized at the right lower quadrant area. However, appendiceal carcinoma with vesico-appendiceal fistula is a rare clinical phenomenon. Lacking specific symptoms, appendiceal carcinomas with fistula formations are often misdiagnosed as acute appendicitis cases. The purpose of this study is to increase awareness of appendiceal neoplasms and appendicovesical fistulas. We reported our experiences in three complex cases related to …digestive and urological systems, and reviewed the literature on diagnosis with various X-ray imaging techniques for this lesion. In this report, the first case failed to be diagnosed. The other two patients with appendicovesical fistulas secondary to appendiceal adenocarcinomas were successfully detected with computed tomography (CT) and cystoscopy. The patients recovered after right hemicolectomies and en bloc partial cystectomies and survived without tumor metastasis up to 7-year follow-up. In conclusion, a combined use of CT imaging and endoscopy techniques provides an accurate diagnostic alternative for appendicovesical fistula secondary to appendiceal adenocarcinoma. Show more

Keywords: Appendix adenocarcinoma, bladder, fistula

DOI: 10.3233/XST-140440

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 493-501, 2014

Authors: Effendy, Nadia Mohd | Khamis, Mohd Fadhli | Soelaiman, Ima Nirwana | Shuid, Ahmad Nazrun

Article Type: Research Article

Abstract: BACKGROUND: Postmenopausal osteoporosis is best treated and prevented by estrogen replacement therapy (ERT). Although effective, ERT may cause breast cancer, uterine cancer and cardiovascular problems. Labisia pumila var. alata (LP), a herb with phytoestrogenic, antioxidative and anti-inflammatory effects has potential as an ERT alternative. OBJECTIVE: This study aimed to evaluate micro-CT analysis on the effects of LP supplementation on the trabecular microarchitecture of postmenopausal osteoporosis rat model. Micro-CT is an …effective tool in detecting changes in trabecular bone structure and providing a three dimensional information which may replace other conventional bone analysis methods. METHODS: Ninety-six female Sprague-Dawley rats (4 to 5 months old) were randomly divided into six groups of baseline group (BL) Sham-operated (Sham), ovariectomised control (OVXC), ovariectomised with 64.5 μg/kg of Premarin (ERT), ovariectomised with 20 mg/kg of LP (LP20) and ovariectomised with 100 mg/kg of LP at (LP100). The vehicle (deionized water), Premarin and LP were given via daily oral gavages for three, six and nine weeks of treatment periods. Rats in BL group were euthanized before the start of the study, while other rats were euthanized after completion of their treatments. Femora were dissected out and trabecular bone microarchitecture analysed with micro-CT. RESULTS: Micro-CT analysis of OVXC rats revealed significant osteoporotic changes in connectivity density, trabecular bone volume, trabecular thickness, trabecular separation and trabecular number. Both ERT and LP were able to reverse all the OVX-induced bone changes with the best results seen with 100 mg/kg of LP for nine weeks duration of treatment. CONCLUSION: Micro-CT provides accurate and reliable information on trabecular bone parameters which aid in the diagnosis and treatment of osteoporosis. LP supplementation at 100 mg/kg was more effective than ERT in reversing ovariectomy-induced bone changes. Further studies are required to explore the potential of LP as ERT alternative in the treatment and prevention of postmenopausal osteoporosis. Show more

Keywords: Micro-CT, osteoporosis, postmenopausal, bone microarchitecture, bone quality, Labisia pumila

DOI: 10.3233/XST-140441

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 503-518, 2014

Authors: Chen, Ping | Han, Yan | Pan, Jinxiao

Article Type: Research Article

Abstract: Energy auto-modulation is an important tool in X-ray imaging, as it can improve the quality and longevity of an x-ray imaging system. Because of the complex nature of imaged objects, X-ray energy auto-modulation may be difficult. If there is a physical model about imaging mechanism, one can forecast the best imaging parameters using a pre-scan that can be fed into this model. This paper offers a physical model, which is called the Voltage-Thickness-Gray (VTG) model. Based …on equivalent single-energy, this paper uses the empirical formula of X-ray attenuation and X-ray photon intensity to build this VTG model. Then use linear regression to estimate the model's parameters, by multi-voltage imaging about the steel wedge block. At last, by the experiment of the steel step block, verify this model and forecast the imaging tube voltage. The result shows this model can better reflect X-ray attenuation imaging properties, and can be used to forecast the imaging voltage. Also the forecast precision can achieve 90% or so. Show more

Keywords: X-ray imaging, energy auto-modulation, VTG (Voltage-Thickness-Gray) model, parameter estimation

DOI: 10.3233/XST-140442

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 519-527, 2014

Authors: El-Gebaly, Reem H. | Maamoun, Islam K. | Madian, Noha G.

Article Type: Research Article

Abstract: BACKGROUND: Myocardial perfusion imaging (MPI) can provide the valuable cardiac functions.Image quality in nuclear medicine tomography is critically dependent on the activity administered into patients. OBJECTIVE: This study was designed to evaluate the optimum injected dose of 99mTc-MIBI for quantitative assessment of image quality as compared with standard injected dose used for that purpose. METHODS: The image quality parameters (Contrast, relative noise and contrast to noise ratio) were determined in 32 patients (21 male, 11 female, …age 45–60 y) with weight 60 ± 15 kg. Patients were classified into four groups; each one consisted of 8 patients. The first group received 370 MBq, the second one received 555 MBq, the third group received 740 MBq and the last group received 925 MBq. RESULTS: Qualitative assessments of the images revealed equivalent scintigraphic patterns in all patients. There was a significant difference in the image contrast. The image contrast in the 370 MBq group was greater than other groups. The image noise between the four groups was significantly different. It increased with injected dose reduction. Contrast to noise ratio (CNR) was significantly different between 370 MBq and other groups. CONCLUSION: It is concluded that results from the first group which received 370 MBq are sufficiently similar to those of the fourth group (standard group) which received 925 MBq. Consequently,accurate estimations of differential cardiac functions are possible with the 370 MBq dose. Show more

Keywords: 99mTc-MIBI, image quality parameters, image quality, qualitative assessment, image contrast, image noise

DOI: 10.3233/XST-140443

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 529-537, 2014

Authors: Li, Xiaohu | Wang, Xu | Yu, Yonqqiang | Liu, Bin | Cai, Jing | Xia, Li | Luo, Li | Wang, Wanqin | Ding, Qianyun | Zhang, Chao | Wang, Jie

Article Type: Research Article

Abstract: OBJECTIVE: To assess the feasibility and diagnostic value of detecting uric acid depositing among patients with tophaceous gout using a dual energy CT based Gemstone spectral imaging (GSI) technology for qualitative analysis of uric acid. METHODS: Thirty one patients with clinically detectable tophaceous gout and 10 healthy volunteers underwent Discovery CT 750 HD scan with GSI mode. We selected four case groups of tophi, muscles, cortical bone, and cancellous bone. Each has a region of …interest (ROI) of 10 mm diameter. We then analyzed and compared the difference of CT imaging spectroscopy quantitative parameters including concentration of uric acid, calcium, and water levels. The univariate analysis of variance and independent samples t-test were applied in data analyses. RESULTS: In case group of tophi base substance, the concentration levels were 1268.8 ± 32.2 mg/cm^3 for uric acid (Ca), 19.4 ± 9.5 mg/cm^3 for calcium (uric acid), 10.8 ± 9.5 mg/cm^3 for calcium (water), and 1171.0 ± 26.8 mg/cm^3 for water (calcium), respectively. In cortical bone case group, the four base substance concentration levels changed to 1333.6 ± 83.8 mg/cm^3 , 271.1 ± 85.0 mg/cm^3 , 262.6 ± 85.4 mg/cm^3 , and 1230.8 ± 77.0 mg/cm^3 . In muscles case group, the four base substance concentration levels were 1143.5 ± 15.7 mg/cm^3 , 12.3 ± 5.0 mg/cm^3 , 4.4 ± 1.9 mg/cm^3 , and 1054.1 ± 14.6 mg/cm^3 . Finally, in cancellous bone case group, the corresponding base substance concentration became 1070.9 ± 26.4 mg/cm^3 , 85.1 ± 46.9 mg/cm^3 , 77.4 ± 46.7 mg/cm^3 , and 988.0 ± 23.4 mg/cm^3. Except tophi and muscle differences between Calcium (uric acid) concentration and differences in Calcium (water) concentration, which were not significantly different (p> 0.29), the remaining group pairwise comparisons of the parameters were significantly different (p < 0.05). CONCLUSION: Dual-energy spectral CT can detect gout tophi within the peripheral joints of the patients. The quantitative measurement of the tophi concentration provides a new imaging method for quantitatively monitoring clinical outcomes of tophi. Show more

Keywords: Hyperuricemia, tomography, X-ray computed, comparative study

DOI: 10.3233/XST-140444

Citation: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 541-549, 2014