Journal of X-Ray Science and Technology - Volume 16, issue 1

Authors: Dirican, Bahar | Oysul, Kaan | Pahsa, Alper | Beyzadeoǧu, Murat

Article Type: Research Article

Abstract: In this work, a new contour detection method is studied for detecting brain tumor regions based on their gradient magnitude information. Gradient magnitude data, an edge detection method, is generated from the brain slice image intensity or perceived brightness information. Contour map of the brain tumor is generated by using the gradient magnitude differences of the template masks (cropped from brain slice tumor image) and the sample masks (traverses the image) raw pixel and perceived brightness …(luminance) date. Then these differences are averaged and normalized to produce edge profiles of the brain tumor region contours. This data is used by the remote surgical devices for removing the tumor area. Show more

Keywords: Perceived brightness (luminance), gradient magnitude, contour profiling, edge detection

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 1-8, 2008

Authors: Baek, Jaeho | Park, Mignon

Article Type: Research Article

Abstract: The Digital X-ray Scanner System (DX-Scanner) using the Multichannel Ionization Chamber (MIC) has many advantages. On the other hand, the scanned medical image has distorted pixels because of unsuitable integration time at the nonlinear acceleration period and vibration of the AC servo motor during scanning a patient in the system. This paper proposes a correction algorithm based on fuzzy modeling. The proposed correction algorithm can correct the distorted medical image during scanning. Fuzzy modeling …uses a clustering method for the nonlinear motor velocity in the algorithm. The algorithm reconstructs the normal medical image lines by calculating the moving distance every integration time during acceleration period of AC servo motor. The algorithm analyzes by comparing the distance of the acceleration period with the distance of the uniform velocity period in every integration time. The velocity for the acceleration period is able to be compensated via this algorithm. In addition, several image processing procedures are also included in the algorithm. When the proposed correction algorithm is applied to the test pattern for checking the image resolution, its effectiveness is verified at scanning of 3.5 cm/sec, 7 cm/sec, and 14 cm/sec. The corrected image is a better image. Show more

Keywords: Digital X-ray radiography, distorted image, fuzzy modeling, correction algorithm, X-ray scanner, Multichannel Ionization Chamber

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 9-22, 2008

Authors: Bai, Henri | Zeng, Kai | Bai, Erwei | Wang, Ge

Article Type: Research Article

Abstract: In order to reduce contrast dose and radiation exposure involved in CT angiography, an automatic adaptive control scheme was proposed for bolus chasing, which offers substantial improvements over the conventional constant speed control scheme. In this paper, a manual control scheme is proposed to utilize the expert's knowledge optimally based on real-time imaging feedback. The technical objective is to synchronize the bolus dynamics and the imaging aperture. To test the proposed technique, a realistic simulator is …designed, developed and evaluated. It is shown statistically that the manual control outperforms the traditional constant speed control. Show more

Keywords: CT angiography, simulator, manual control

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 23-31, 2008

Authors: Rajab, Maher I.

Article Type: Research Article

Abstract: Since the introduction of epiluminescence microscopy (ELM), image analysis tools have been extended to the field of dermatology, as an attempt to algorithmically reproduce clinical evaluation. Accurate image segmentation of skin lesions is one of the key steps for useful, early, and non-invasive diagnosis of coetaneous melanomas. This paper proposes an image segmentation algorithm to extract the true border that reveals the global structure irregularity (indentations and protrusions), which may suggest excessive cell …growth or regression of a melanoma. The algorithm is applied to the blue channel of the RGB colour vectors to distinguish lesions from the skin and. Analysis of image background is applied by recursive measure of the median and standard deviation of background. This will facilitate automatic and recurring noise reduction and enhancement by image pre-processing. The algorithm also does not depend on the use of rigid threshold values, because an optimal thresholding algorithm "isodata algorithm" that is used determines an optimal threshold iteratively. Experiments are performed on diversity of synthetic skin images that model real hair and lesions of different border irregularities. The aim is to verify the capability of the segmentation algorithm in extracting and characterizing the true features of the processed skin lesions. The next phase of test applies the algorithm to real skin lesions representing high resolution ELM images. We demonstrate that we can enhance and delineate pigmented networks in skin lesions visually, and make them accessible for further analysis and classification. Show more

Keywords: Epiluminescence microscopy, skin lesion, optimal thresholding, image segmentation, SIAscope images

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 33-42, 2008

Authors: Li, Liang | Kang, Kejun | Chen, Zhiqiang | Zhang, Li | Xing, Yuxiang | Yu, Hengyong | Wang, Ge

Article Type: Research Article

Abstract: In this paper, we present an alternative derivation and description of Smith's data sufficiency condition for exact cone-beam reconstruction. Different from Smith's condition, our condition with new description can be considered as a bridge between the approximate and exact cone-beam reconstruction. When the data sufficiency condition is satisfied, a set of parallel-beam projections can be obtained for exact 3-D reconstruction. When it is not satisfied, some directional parallel-beam projections will be missed, …and only approximate reconstruction is achieved. Although our data sufficiency condition is theoretically proved to be equivalent to Smith's condition, its derivation is totally different. Show more

Keywords: CT, reconstruction, data sufficiency condition, projection transform

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 43-49, 2008

Authors: Deans, Abby | Hess, Linda | Koss, Michael | Liu, Hong | Chen, Wei R.

Article Type: Research Article

Abstract: Laser Doppler perfusion monitors have been used to study blood flow in tissue. They are useful tools to understand and monitor vascular changes during the treatment of lesions. In addition, lasers have been used in the treatment of cancers through photothermal and photochemical interactions, and the effects of laser treatment in many cases depend on the vasculature of the tumors and their surrounding tissue. In this study, an 805-nm laser was used to non-invasively irradiate subcutaneous …mammary and prostatic tumors in rats. The perfusions on the tumor surface, the overlying skin, and underlying muscle tissues were measured using laser Doppler flowmetry during the near-infrared laser treatment. The perfusion probe was fitted into a 16-gauge needle so that the probe could be inserted into the target tissue for the perfusion measurement. The perfusion on the surface of the tumor decreased at the beginning of the laser irradiation, followed by a significant increase. Then, the perfusion was decreased again to a pre-treatment level. The perfusion of the skin tissue and muscle tissue, however, remained relatively unchanged during laser irradiation. Our experimental results indicate that laser photothermal effects could be monitored by the laser Doppler flowmetry and that tumor vascular information could be used to improve the effectiveness of the laser treatment of cancer. Show more

Keywords: Perfusion, laser Doppler flowmetry, laser photothermal interaction, laser treatment of tumors

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 51-57, 2008

Authors: Fu, Ling | Zeng, Shaoqun | Luo, Qingming

Article Type: Research Article

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 59-63, 2008

Article Type: Other

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 1, pp. 65-65, 2008