Journal of X-Ray Science and Technology - Volume 26, issue 5

Authors: Zhan, Liping | Gao, Runtao | Fan, Jiao | Ma, Huarui

Article Type: Research Article

Abstract: OBJECTIVE: This study aims to evaluate the effect of dentoalveolar distraction extraction (DDE) on site preservation, and to evaluate how the technique keeps the height and width of alveolar bones to a greater extent. METHODS: 12 beagle dogs, randomly divided into three groups (DDE group, NH group, BOG group), were used. In the dogs of three groups, the root of the left or right third mandibular premolars were respectively extracted by three methods namely, DDE, traditional extraction with natural healing, and traditional extraction with Bio-Oss bone dust implanted and guided bone regeneration (GBR). Cone-beam computed tomography (CBCT) scans …and X-rays were taken immediately and three months after the tooth extraction. The height and width of the alveolar ridges were compared among different groups. RESULTS: Three months after tooth extraction, at the 1 mm level below the alveolar ridge crest, the amount and degree of buccal alveolar ridge width resorption in DDE group were significantly lower than that of NH and BOG group (P < 0.05). At the 2 mm and 3 mm level below the alveolar ridge crest, the amount and degree of buccal alveolar ridge width resorption in DDE group and BOG had no significant difference, and both were significant lower than that of NH group (P < 0.05). The height resorption of alveolar ridge in DDE group was significantly lower than NH and BOG groups (P < 0.05), while NH and BOG group had no statistically significant. CONCLUSIONS: To a greater extent, the alveolar ridge preservation through DDE could preserve the height and width of alveolar ridge crest. Show more

Keywords: Alveolar bone resorption, alveolar ridge preservation, dentoalveolar distraction extraction, CBCT

DOI: 10.3233/XST-18384

Citation: Journal of X-Ray Science and Technology, vol. 26, no. 5, pp. 843-851, 2018

Authors: Zhou, Zhengdong | Xin, Runchao | Guan, Shaolin | Li, Jianbo | Tu, Jiali

Article Type: Research Article

Abstract: Development of spectral X-ray computer tomography (CT) equipped with photon counting detector has been recently attracting great research interest. This work aims to improve the quality of spectral X-ray CT image. Maximum a posteriori (MAP) expectation-maximization (EM) algorithm is applied for reconstructing image-based weighting spectral X-ray CT images. A spectral X-ray CT system based on the cadmium zinc telluride photon counting detector and a fat cylinder phantom were simulated. Comparing with the commonly used filtered back projection (FBP) method, the proposed method reduced noise in the final weighting images at 2, 4, 6 and 9 energy bins up to 85.2%, …87.5%, 86.7% and 85%, respectively. CNR improvement ranged from 6.53 to 7.77. Compared with the prior image constrained compressed sensing (PICCS) method, the proposed method could reduce noise in the final weighting images by 36.5%, 44.6%, 27.3% and 18% at 2, 4, 6 and 9 energy bins, respectively, and improve the contrast-to-noise ratio (CNR) by 1.17 to 1.81. The simulation study also showed that comparing with the FBP and PICCS algorithms, image-based weighting imaging using MAP-EM statistical algorithm yielded significant improvement of the CNR and reduced the noise of the final weighting image. Show more

Keywords: Photon counting detector, spectral X-ray CT, image-based weighting, maximum a posteriori expectation-maximization (MAP-EM) algorithm

DOI: 10.3233/XST-180396

Citation: Journal of X-Ray Science and Technology, vol. 26, no. 5, pp. 853-864, 2018

Authors: Chen, Wei | Fang, Xiang-Ming | Wang, Xuan | Sudarshan, Sanjeev Kumar Pitla | Hu, Xiao-Yun | Chen, Hong-Wei

Article Type: Research Article

Abstract: Purpose: To evaluate the clinical efficacy of percutaneous trans-hepatic integrated 125 I seed stents implantation for malignant lower biliary tract obstruction. Methods: Thirty-two patients with malignant lower biliary obstruction were randomly divided into two groups. One group underwent the therapy with integrated 125 I seed stents (Test group, n = 13), and another group received conventional metal stents implantation for treatment (Control group, n = 19). The pre- and post-operative changes in biochemical indices, white blood cell count, IgG level, stent patency, survival time, tumor size and complications were compared between the two groups. RECIST 1.1 …(Response Evaluation Criteria In Solid Tumors) was used to evaluate therapeutic effects. The average follow-up time was 12.3 months. Results: The differences between pre- and post-operative (30 days) intragroup biochemical indices had statistically significant difference (P < 0.05), but there were no significant differences (P > 0.05) in leukocyte counts and IgG levels. As to the median time of stent patency and patients’ survival, there were significant differences (P < 0.05) between Control and Test groups (3.9 months vs. 8.1 months, 139 days vs. 298 days, respectively). Three months after the operation, the average tumor size was reduced in the Test group, but was increased in the Control group (P < 0.05). There was no significant difference in the incidence of complications between the two groups. The evaluation results using RECIST 1.1 showed that there were statistically significant differences between the two groups in terms of the rates of remission, control, and progression (χ 2 = 17.5, P < 0.05). Conclusions: The study indicates that integrated 125 I seed stents are effective in reducing jaundice symptoms, inhibiting tumor growth, improving stent patency and prolonging patient survival, which may serve as a safer and more feasible method in treating malignant lower biliary obstruction with minimal invasiveness. Show more

Keywords: Brachytherapy, stents, biliary obstruction, cancer

DOI: 10.3233/XST-180403

Citation: Journal of X-Ray Science and Technology, vol. 26, no. 5, pp. 865-875, 2018