• Title/Summary/Keyword: Fixed CT

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Association between the XRCC3 Thr241Met Polymorphism and Gastrointestinal Cancer Risk: A Meta-Analysis

  • Sahami-Fard, Mohammad Hossein;Mayali, Ali Reza Mousa;Tajehmiri, Ahmad
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.10
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    • pp.4599-4608
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    • 2016
  • Background: The x-ray repair cross-complementing group 3 (XRCC3) encodes a protein involved in the homologous recombination repair (HRR) pathway for double-strand DNA repair. Associations of the XRCC3 Thr241Met polymorphism with various cancers have been widely reported. However, published data on links between XRCC3 Thr241Met and gastrointestinal (GI) cancer risk are inconsistent. Objective and Methods: A meta-analysis was conducted to characterize the relationship between XRCC3 Thr241Met polymorphisms and GI cancer risk. Pooled odds ratios (ORs) and 95.0% confidence intervals were assessed using random- or fixed- effect models for 28.0 relevant articles with 30.0 studies containing 7,649.0 cases and 11,123.0 controls. Results: The results of the overall meta-analysis suggested a borderline association between the XRCC3 Thr241Met polymorphism and GI cancer susceptibility (T vs. C: OR=1.18, 9 % CI=1.0-1.4, POR=0.04; TT vs. CT+CC: OR=1.3, 95 % CI=1.0-1.6, POR=0.04). After removing studies not conforming to Hardy-Weinberg equilibrium (HWE), however, this association disappeared (T vs. C: OR=1.00, 95 % CI=0.9-1.1, POR=0.96; TT vs. CT+CC: OR=0.9, 95 % CI=0.8-1.1, POR=0.72). When stratified by ethnicity, source of controls or cancer type, although some associations between XRCC3 Thr241Met polymorphism and GI cancer susceptibility were detected, these associations no longer existed after removing studies not conforming to HWE. Conclusion: Our meta-analysis suggests that the XRCC3 Thr241Met polymorphism is not associated with risk of GI cancer based on current evidence.

Conversion coefficients for the estimation of effective dose in cone-beam CT

  • Kim, Dong-Soo;Rashsuren, Oyuntugs;Kim, Eun-Kyung
    • Imaging Science in Dentistry
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    • v.44 no.1
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    • pp.21-29
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    • 2014
  • Purpose: To determine the conversion coefficients (CCs) from the dose-area product (DAP) value to effective dose in cone-beam CT. Materials and Methods: A CBCT scanner with four fields of view (FOV) was used. Using two exposure settings of the adult standard and low dose exposure, DAP values were measured with a DAP meter in C mode ($200mm{\times}179mm$), P mode ($154mm{\times}154mm$), I mode ($102mm{\times}102mm$), and D mode ($51mm{\times}51mm$). The effective doses were also investigated at each mode using an adult male head and neck phantom and thermoluminescent chips. Linear regressive analysis of the DAP and effective dose values was used to calculate the CCs for each CBCT examination. Results: For the C mode, the P mode at the maxilla, and the P mode at the mandible, the CCs were 0.049 ${\mu}Sv/mGycm^2$, 0.067 ${\mu}Sv/mGycm^2$, and 0.064 ${\mu}Sv/mGycm^2$, respectively. For the I mode, the CCs at the maxilla and mandible were 0.076 ${\mu}Sv/mGycm^2$ and 0.095 ${\mu}Sv/mGycm^2$, respectively. For the D mode at the maxillary incisors, molars, and mandibular molars, the CCs were 0.038 ${\mu}Sv/mGycm^2$, 0.041 ${\mu}Sv/mGycm^2$, and 0.146 ${\mu}Sv/mGycm^2$, respectively. Conclusion: The CCs in one CBCT device with fixed 80 kV ranged from 0.038 ${\mu}Sv/mGycm^2$ to 0.146 ${\mu}Sv/mGycm^2$ according to the imaging modes and irradiated region and were highest for the D mode at the mandibular molar.

Use of 3D Printing Model for the Management of Fibrous Dysplasia: Preliminary Case Study

  • Choi, Jong-Woo;Jeong, Woo Shik
    • Journal of International Society for Simulation Surgery
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    • v.3 no.1
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    • pp.36-38
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    • 2016
  • Fibrous dysplasia is a relatively rare disease but the management would be quite challenging. Because this is not a malignant tumor, the preservation of the facial contour and the various functions seems to be important in treatment planning. Until now the facial bone reconstruction with autogenous bone would be the standard. Although the autogenous bone would be the ideal one for facial bone reconstruction, donor site morbidity would be the inevitable problem in many cases. Meanwhile, various types of allogenic and alloplastic materials have been also used. However, facial bone reconstruction with many alloplastic material have produced no less complications including infection, exposure, and delayed wound healing. Because the 3D printing technique evolved so fast that 3D printed titanium implant were possible recently. The aim of this trial is to try to restore the original maxillary anatomy as possible using the 3D printing model, based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. And we molded Titanium mesh to reconstruct three-dimensional maxillary structure during the operation. This prefabricated Titanium-mesh implant was then inserted onto the defected maxilla and fixed. Three dimensional printing technique of titanium material based on the computer simulation turned out to be successful in this patient. Individualized approach for each patient could be an ideal way to restore the facial bone.

3D Printed Titanium Implant for the Skull Reconstruction: A Preliminary Case Study

  • Choi, Jong-Woo;Ahn, Jae-Sung
    • Journal of International Society for Simulation Surgery
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    • v.1 no.2
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    • pp.99-102
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    • 2014
  • The skull defect can be made after the trauma, oncologic problems or neurosurgery. The skull reconstruction has been the challenging issue in craniofacial fields for a long time. So far the skull reconstruction with autogenous bone would be the standard. Although the autogenous bone would be the ideal one for skull reconstruction, donor site morbidity would be the inevitable problem in many cases. Meanwhile various types of allogenic and alloplastic materials have been also used. However, skull reconstruction with many alloplastic material have produced no less complications including infection, exposure, and delayed wound healing. Because the 3D printing technique evolved so fast that 3D printed titanium implant were possible recently. The aim of this trial is to try to restore the original skull anatomy as possible using the 3D printed titanium implant, based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. And we fabricated Titanium implant to reconstruct three-dimensional orbital structure in advance, using the 3D printer. This prefabricated Titanium-implant was then inserted onto the defected skull and fixed. Three dimensional printing technique of titanium material based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the traumatic patients in near future.

Effectiveness of anchorage with temporary anchorage devices during anterior maxillary tooth retraction: A randomized clinical trial

  • Barthelemi, Stephane;Desoutter, Alban;Souare, Fatoumata;Cuisinier, Frederic
    • The korean journal of orthodontics
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    • v.49 no.5
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    • pp.279-285
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    • 2019
  • Objective: This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance. Methods: Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome. Results: Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater. Conclusions: In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

The Optimization of Reconstruction Method Reducing Partial Volume Effect in PET/CT 3D Image Acquisition (PET/CT 3차원 영상 획득에서 부분용적효과 감소를 위한 재구성법의 최적화)

  • Hong, Gun-Chul;Park, Sun-Myung;Kwak, In-Suk;Lee, Hyuk;Choi, Choon-Ki;Seok, Jae-Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.13-17
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    • 2010
  • Purpose: Partial volume effect (PVE) is the phenomenon to lower the accuracy of image due to low estimate, which is to occur from PET/CT 3D image acquisition. The more resolution is declined and the lesion is small, the more it causes a big error. So that it can influence the test result. Studied the optimum image reconstruction method by using variation of parameter, which can influence the PVE. Materials and Methods: It acquires the image in each size spheres which is injected $^{18}F$-FDG to hot site and background in the ratio 4:1 for 10 minutes by using NEMA 2001 IEC phantom in GE Discovey STE 16. The iterative reconstruction is used and gives variety to iteration 2-50 times, subset number 1-56. The analysis's fixed region of interest in detail part of image and compute % difference and signal to noise ratio (SNR) using $SUV_{max}$. Results: It's measured that $SUV_{max}$ of 10 mm spheres, which is changed subset number to 2, 5, 8, 20, 56 in fixed iteration to times, SNR is indicated 0.19, 0.30, 0.40, 0.48, 0.45. As well as each sphere's of total SNR is measured 2.73, 3.38, 3.64, 3.63, 3.38. Conclusion: In iteration 6th to 20th, it indicates similar value in % difference and SNR ($3.47{\pm}0.09$). Over 20th, it increases the phenomenon, which is placed low value on $SUV_{max}$ through the influence of noise. In addition, the identical iteration, it indicates that SNR is high value in 8th to 20th in variation of subset number. Therefore, to reduce partial volume effect of small lesion, it can be declined the partial volume effect in iteration 6 times, subset number 8~20 times, considering reconstruction time.

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Implant Supported Fixed Restoration for Maxillary Edentulism using CAD/CAM Guided Implant Surgery (NobelGuide$^{TM}$) and Immediate Loading (상악 완전 무치악 환자의 CAD/CAM 을 이용한 임플란트 식립(NobelGuide$^{TM}$) 및 즉시하중 후 고정성 보철수복 증례)

  • Huh, Yoon-Hyuk;Yi, Yang-Jin;Kim, Dae-Gon;Cho, Lee-Ra;Park, Chan-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.28 no.4
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    • pp.423-439
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    • 2012
  • This case report described a technique utilizing a computer-aided design (CAD)/computer-aided machining (CAM) - guided surgical implant placement and prefabricated temporary fixed prosthesis for an immediately loaded restoration. The advantages of CAD/CAM guided implant procedures are flapless, minimally invasive surgery and shorter surgery time. With this technique, less postoperative morbidity and delivery of prosthesis for immediate function would be possible. A patient with an edentulous maxilla received 8 implants in maxilla using CAD/CAM surgical templates. Prefabricated provisional maxillary implant supported fixed prosthesis were connected immediately after implant installation. Provisional prosthesis was evaluated for aesthetics, function during 6 months. Definitive implant supported fixed porcelain fused metal bridges were fabricated.

Phase II Clinical Study on the GEMOX Regimen as Second-line Therapy for Advanced Ovarian Cancer

  • Yuan, Shao-Fei;Zhang, Lian-Ping;Zhu, Lin-Jia;Chen, Wen-Jun;Zheng, Wei-E;Xiong, Jian-Ping
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.6
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    • pp.3949-3953
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    • 2013
  • Aim: To investigate the effectiveness and adverse effects of gemcitabine by fixed-dose rate infusion plus oxaliplatin (GEMOX regimen) as second-line therapy for advanced ovarian cancer. Methods: 64 patients with advanced ovarian cancer were divided into an experimental group (44 cases) and a control group (20 cases). The experimental group was treated with continuous intravenous infusion of gemcitabine at 1000 $mg/m^2$ with a fixed-dose rate of 10 $mg/m^2/min$, on days 1 and 8 and oxaliplatin at 100 $mg/m^2$ on day 1, IVGTT, repeated every 3 weeks. The control group was treated with intravenous infusion of gemcitabine at 1000 $mg/m^2$ within 30 min on days 1 and and oxaliplatin at 100 $mg/m^2$ on day 1, IVGTT, again repeated every 3 weeks. CT scans or MRI were used for review every 1-2 cycles. Results: The effective rate in the experimental group was significantly high than control group (43.2% vs 35.0%; P < 0.05), with no obvious difference of hematologic or non-hematologic toxicity between the two groups (P > 0.05). Conclusion: GEMOX regimen is very effective to treat advanced ovarian cancer, with low toxicity, good tolerance and improved life quality in patients.

Does matching relation exist between the length and the tilting angle of terminal implants in the all-on-four protocol? stress distributions by 3D finite element analysis

  • Li, Xiaomei;Cao, Zhizhong;Qiu, Xiaoqian;Tang, Zhen;Gong, Lulu;Wang, Dalin
    • The Journal of Advanced Prosthodontics
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    • v.7 no.3
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    • pp.240-248
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    • 2015
  • PURPOSE. To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS. Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle ($0^{\circ}$, $30^{\circ}$ and $45^{\circ}$) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS. 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION. Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.

Application of Targis-Vectris Provisional Restorations for an Oro-Maxillofacial Cancer Patient: A Case report (악성암종 수술 환자에서 임시수복물로서 Targis-Vectris의 응용)

  • Kim, Jin-Man;Han, Jung-Suk;Lee, Sun-Hyung;Yang, Jae-Ho;Lee, Jae-Bong
    • Journal of Dental Rehabilitation and Applied Science
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    • v.18 no.2
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    • pp.113-118
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    • 2002
  • Conventional radiograph, computed tomograph (CT), magnetic resonance image (MRI) are commonly used methods for diagnosis of oro-maxillofacial cancer. MRI is an effective tool to verify soft tissue lesion however, metal produces black artifacts in the image. Therefore, metal structure should be removed before taking MRI to diagnose head and neck cancer patients. A 52-year-old female patient with adenocarcinoma in the posterior right soft palate was referred to take a MRI before surgery. She has 7-unit porcelain fused to metal bridge in the maxilla. Eight-unit Tagis-Vectris fixed partial denture was fabricated to replace her existing PFM bridge to take a MRI without any artifact before and after surgery. The patient satisfied with her restorations in terms of esthetics, function after 11 months. Even though minor staining was detected, Tagis-Vectris restoration fixed partial denture was intact during observation period.