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SU-D-105-05: Independent Evaluation of Respiratory-Gated Treatments Using In-House Quality Assurance Tool

Medical Physics 2013年第6PART3期40卷 101-101页

作者： J Park Y Park J Lee H Kim Ye Interdisciplinary Program in Radiation Applied Life Science Seoul National University College of Medicine Seoul Korea Biomedical Research Institute Seoul National University Hospital Seoul Korea Institute of Radiation Medicine Seoul National University Medical Research Center Seoul Korea Department of Radiation Oncology Massachusetts General Hospital Boston MA Program in Biomedical Radiation Sciences Department of Transdisciplinary Studies Graduate School of Convergence Science and Technology Seoul National University Department of Radiation Oncology Seoul National University Hospital Seoul Korea

Purpose: To quantitatively evaluate the reproducibility of patient breathing between the calculated phase from respiratory signal and RPM (real-time position management system, Varian Medical Systems, Palo Alto, CA) within treatment. We developed an independent retrospective verification system (RVS) for gated-radiotherapy using full signal and gating window in RPM system. Methods: RVS was programmed by LabVIEW 2009 with wavelet-based multi-resolution analysis, which is a useful and accurate technique for identifying peaks and valleys of noisy signals. The respiratory signal and real-time calculated phase information from RPM was exported to RVS as a text file. Using this text file, several respiratory parameters were calculated by RVS, and were compared with the generated parameters from RPM. The evaluated parameters included phase-shift, total displacement, residual motion, baseline shift, and so forth. The analysis was conducted for both in-gate and full respiratory signal separately. The analysis report was automatically generated in Excel file format. Eleven patients of abdominal cancer were retrospectively analyzed for the evaluation. Results: The mean phase error of gated signal and full signal between RPM and our software ranged from 1.50% to 3.08% and 1.52% to 3.08%, respectively. Average phase shift was not significant but in-gate phase difference between RVS and RPM was found to be higher than 4% in two cases. At times, real-time phase calculation from RPM caused the beam to be turned on at incorrect time of the breathing cycle when the patient breathing was not regular. The total displacement varied from 0.672 cm to 1.732 cm, which showed patient-specific baseline shift during treatment. Conclusion: The developed software demonstrated competency in analyzing RPM signal and evaluating patient-specific respiratory parameters of radiotherapy. Thus, it can be used as an independent quality assurance tool for RPM phase-based gating treatment.

关键词： Quality assurance Computer software Radiation therapy Cancer Acoustic noise measurement

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Application of CT simulation technique for virtual ultra-low-dose trial in CT colonography

Application of CT simulation technique for virtual ultra-low...

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4th International Workshop on Computational and Clinical Applications in Abdominal Imaging, Held in Conjunction with the 15th International Conference on Medical Image Computing and Computer-Assisted Intervention, MICCAI 2012

作者： Kim, Chang Won Kim, Jong Hyo Interdisciplinary Program of Bioengineering Seoul National University College of Engineering San 56-1 Sillim-dong Gwanak-gu Seoul 151-742 Korea Republic of Department of Radiology Seoul National University College of Medicine Seoul 110-744 Korea Republic of Interdisciplinary Program in Radiation Applied Life Science Seoul National University College of Medicine Seoul 110-744 Korea Republic of Institute of Radiation Medicine Seoul National University Medical Research Center 101 Daehangno Jongno-gu Seoul 110-744 Korea Republic of Department of Intelligent Convergence Systems Graduate School of Convergence Science and Technology Seoul National University 864-1 Iui-dong Yeongtong-gu Suwon-si Gyeonggi-do 443-270 Korea Republic of

ISBN: (纸本)9783642336119

A low-dose CT simulation technique is presented which might allow for a virtual ultra-low-dose trial in CT colonography without requiring raw sinogram data. A virtual sinogram is generated by performing the line integral of the CT number-based attenuation value with use of the CT scan parameters available in the DICOM header and in the literature. A separate noise sinogram is generated with use of a noise model, which incorporates the X-ray photon flux depending on the mAs, system electronic noise, and virtual sinogram. A synthetic noise CT image is generated by application of the filtered back projection of the noise sinogram with use of an appropriate filter that depends on the reconstruction kernel of the original CT. Finally, a simulated low-dose CT image is generated by addition of the CT data for the synthetic noise to the original CT data. Clinical CT colonography images with and without fecal tagging were used as simulation input and 50%, 25%, and 12.5% dose images were generated and evaluated. Our results suggest that the proposed CT simulation technique has potential for application in virtual ultra-low-dose trial in CT colonography in which an unlimited number of scan protocols could be performed without repetition of the real CT exposure to the patients. © 2012 Springer-Verlag.

关键词： Computerized tomography

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SU-E-J-98: Evaluating Commercial Orthopedic Metal Artifact Reduction Tool (OMAR) for CT Simulation in Radiotherapy for Head-And-Neck Cases

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Medical Physics 2013年第6PART8期40卷 173-173页

作者： H Kwon J Kim K Kim Y Chun J Park S Ye Interdisciplinary program in Radiation Applied Life Science Seoul National University College of Medicine Seoul Korea Biomedical Research Institute Seoul National University Hospital Seoul Korea Institute of Radiation Medicine Seoul National University Medical Research Center Seoul Korea Department of Radiation Oncology Seoul National University Hospital Seoul Korea Department of Radiation Oncology Seoul National University College of Medicine Seoul Korea Philips Healthcare Korea Seoul Korea Program in Biomedical Radiation Sciences Department of Transdisciplinary Studies Graduate School of Convergence Science and Technology Seoul National University Seoul Korea

Purpose: Many head-and-neck (H&N) patients have dental implants which can induce severe metal artifacts in CT images. This study assessed the performance and the effectiveness of the commercial orthopedic metal artifact reduction function (O-MAR) for radiotherapy of H&N patients. Methods: 20 H&N images scanned by Philips Brilliance Big Bore CT were used for the assessment. After O-MAR correction, the CT Hounsfield number and noise were measured and compared between the original and OMAR corrected images. Structures were contoured by a radiation oncologist on each of the two image sets. These contoured structure volumes on the original CT image were compared with those on O-MAR corrected CT image by radiation therapy planning system. After volumetric-modulated arc therapy (VMAT) planning was performed on the original CT image, this plan was translated and calculated on O-MAR corrected images. Each DVH was compared and the gamma passing rate was calculated for comparing dose distributions. Results: CT Hounsfield numbers became closer to the reference values after O-MAR correction. The standard deviations of the selected ROIs were reduced from 323.9 HU to 195.6 HU in air and from 43.5 HU to 24.7 HU in tissue. The volumes of contoured structure showed minute change. The difference between two DVH was less than 0.5%. The gamma pass rates of dose distributions calculated on the original and OMAR corrected images were higher than 99.9% in the case of closed-mouth-images but were about 80% in the case of opened-mouth-images when using 1mm and 1% distance-to-agreement criterion. Conclusion: The O-MAR algorithm is suitable for the entire radiation treatment planning process by increasing the accuracy of CT Hounsfield numbers and reducing noises. Although there was no significant difference in dose distribution for most cases, the O-MAR correction was shown to have an impact on opened-mouth-images.

关键词： Medical imaging Computed tomography Dosimetry Radiation therapy Medical image noise Tissues Medical image artifacts Radiation treatment Cancer

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0SU-E-T-326: Assessment of 2D / 3D Intra-Fractional Tumor Motion for Respiratory-Gated Radiotherapy

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Medical Physics 2013年第6PART15期40卷 279-279页

作者： J Lee Y Park K Choi S Ye Program in Biomedical Radiation Sciences Department of Transdisciplinary Studies Graduate School of Convergence Science and Technology Seoul National University Suwon Korea Biomedical Research Institute Seoul National University Hospital Seoul Korea Institute of Radiation Medicine Seoul National University Medical Research Center Seoul Korea Department of Radiation Oncology Massachusetts General Hospital Boston MA Department of Radiation Oncology Seoul National University Hospital Seoul Korea

Purpose: This study aims to develop and evaluate the effectiveness of full 3-dimensional motion platform in respiratory-gated radiotherapy (RGRT) quality assurance (QA). For this study, a motion platform had been developed to simulate the patient specific QA in RGRT. Commercial motion platforms have the limited freedom of movement : lateral-longitudinal or vertical movement for tumor motion, and vertical movement for the external marker motion. Addition to these, the developed platform has the freedom of full 3-dimensional movement: simultaneous lateral, longitudinal as well as vertical motion for tumor motion. Methods: 3-dimensional tumor motions of ten abdomen cancer patients treated RGRT with no-motion, 2-dimensional 0motion, and 3-dimensional motion were extracted in phase sorted 4D-CT images. After deformable registration based on contoured image in 50% respiratory phase, the center of voxel was defined as the tumor position to trace its motion. Varian RPM log files were used to trace external markers. 3-dimensional tumor motions were simulated using the developed motion platform. On its polycarbonate panel, a radio-chromic film attached on 10 cm solid water slabs was placed for the dose verification. 2-dimensional and 3-dimensional tumor motions were performed with gated beam delivery to compare their dosimetric differences. The gating window was 35-65%. Gamma-index method was adopted to compare dose distributions of the measurement using radio-chromic film with those of treatment planning system. Results: The average gamma pass rates (2%/2 mm) were 96.11%, 89.69%, and 88.86% for static-continuous, 2D-gated, and 3D-gated, respectively. Excepting one case, static-continuous showed results over 94%. Some of 3D-gated resulted in pass rates larger than those of 2D-gated. Conclusion: 3-dimensional tumor motions showed lower gamma pass rates than those of 2-dimensional tumor motions during treatment. These imply the requirement of tools that provide the 3-dimensiona

关键词： Cancer Dosimetry Radiation therapy Medical imaging Therapeutics Medical treatment planning Quality assurance

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Application of CT simulation technique for virtual fecal tagging in CTC

Application of CT simulation technique for virtual fecal tag...

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作者： Yang, Zepa Jin, Hyeong-Min Kim, Jong Hyo Department of Biomedical Sciences Seoul National University College of Medicine Seoul 110-744 Korea Republic of Department of Radiology Seoul National University College of Medicine Seoul 110-744 Korea Republic of Interdisciplinary Program in Radiation Applied Life Science Seoul National University College of Medicine Seoul 110-744 Korea Republic of Institute of Radiation Medicine Seoul National University Medical Research Center 101 Daehangno Jongno-gu Seoul 110-744 Korea Republic of Department of Intelligent Convergence Systems Graduate School of Convergence Science and Technology Seoul National University 864-1 Iui-dong Yeongtong-gu Suwon-si Gyeonggi-do 443-270 Korea Republic of

ISBN: (纸本)9783642336119

An integrative CT simulation technique is presented that creates realistic CT images of virtual fecal-tagged material that was added to given clinical DICOM CT images. The energy spectrum of the CT X-ray source, the energy-dependent attenuation, and the scattering properties of the soft tissue and tagging material were incorporated in the generation technique for the DICOM image-based virtual sinograms, followed by CT reconstruction reflecting the vendor-specific filtering kernels. Dark band artifacts were generated by appropriate combining of beam-hardening and -scattering effects into the generation procedure for the virtual sinograms. We used a set of simple numerical phantoms to assess the basic behavior of artifact production. A reference set of CTC images with and without tagging material and artifacts was used for evaluation of the realism of the simulated results. The level of realism was evaluated in terms of the artifact strength and patterns around the added tagging material, compared to real tagging images. The results showed that our CT simulation technique provides sufficient realism for virtual fecal-tagged images that reflect a chain of physical and numerical processes, including beam hardening, scattering, and vendor-specific kernel filtered backprojection. The technique presented has the potential to be used as a tool for investigating the effect of tagging materials on image quality and to gauge how well the electronic cleansing technique performs. © 2012 Springer-Verlag.

关键词： Hardening

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Design of surface-plasmon-enhanced Ge-Si light-emitting diode

Design of surface-plasmon-enhanced Ge-Si light-emitting diod...

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8th IEEE International Conference on Group IV Photonics, GFP 2011

作者： Jeong, Intae Park, Young June Department of Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Suwon Korea Republic of School of Electrical Engineering and Computer Science College of Engineering Seoul National University Seoul Korea Republic of

ISBN: (纸本)9781424483389

We propose a FIN type Germanium-Silicon heterojunction light-emitting diode with metal gates on both sides. The metal gates provide the plasmon enhancement and the electrical modulation of the PN diode. Using the numerical analysis, we propose the optimal device structure to achieve the best light emitting efficiency. © 2011 IEEE.

关键词： Light emitting diodes

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Piezoelectric Materials: All‐Solution‐Processed Flexible Thin Film Piezoelectric nanogenerator (Adv. Mater. 45/2012)

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Advanced Materials 2012年第45期24卷

作者： Sung Yun Chung Sunyoung Kim Ju‐Hyuck Lee Kyongjun Kim Sang‐Woo Kim Chong‐Yun Kang Seok‐Jin Yoon Youn Sang Kim Program in Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Seoul 151‐744 Republic of Korea SKKU Advanced Institute of Nanotechnology School of Advanced Materials Science and Engineering Sungkyunkwan University (SKKU) Suwon 440‐746 Republic of Korea Electronic Materials Center Korea Institute of Science and Technology Seoul 136‐791 Republic of Korea Advanced Institutes of Convergence Technology 864‐1 Iui‐dong Yeongtong‐gu Suwon‐si Gyeonggi‐do 443‐270 Republic of Korea

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Nutzung des Krafft‐Effekts zur Herstellung von idealen nicht‐micellaren tensidstabilisierten nanopartikelsuspensionen†

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Angewandte Chemie 2012年第13期124卷

作者： Sarah Dölle Bob‐Dan Lechner Ji Hyun Park Stefan Schymura Jan P. F. Lagerwall Giusy Scalia Martin‐Luther‐Universität Halle‐Wittenberg Institut für Chemie von‐Danckelmann‐Platz 4 06120 Halle (Deutschland) Seoul National University Graduate School of Convergence Science and Technology and Advanced Institutes of Convergence Technologies Department of Nano Science and Technology Suwon‐si Gyeonggi‐do 443‐270 (Korea) http://***

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Design of surface-plasmon-enhanced Ge-Si light-emitting diode

Design of surface-plasmon-enhanced Ge-Si light-emitting diod...

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IEEE International Conference on Group IV Photonics

作者： Intae Jeong Young June Park Department of Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Suwon South Korea 2School of Electrical Engineering and Computer Science College of Engineering Seoul National University Seoul South Korea

关键词： Logic gates Photonic band gap

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Enhancement of Interface Properties between Passivation Layers and InSb by Using Remote PECVD

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AIP Conference Proceedings 2011年第1期1399卷 105-106页

作者： Jaeyel Lee Jong‐Seok Woo Sehun Park Jungsub Kim Changjae Yang Sujin Kim Chulkyun Seok Kang Il Lee Jinsub Park Min‐Koo Han Kwang‐Seok Seo Euijoon Yoon aDepartment of Materials Science and Engineering Seoul National University Seoul Korea dDepartment of Electrical Engineering Seoul National University Seoul Korea bHybrid Materials Program (WCU) Department of Materials Science and Engineering Seoul National University Seoul Korea cDepartment of Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Suwon Korea

We report the enhanced interface properties between passivation layers and InSb by using remote PECVD system. SiO2 and Si3N4 layers deposited by remote PECVD showed lower interface trap densities than layers deposited by normal PECVD. SiO2 layers deposited by remote PECVD showed 7.1×1011 cm−2 eV−1 of interface trap density at midgap which is slightly lower than SiO2 layers deposited by PECVD. Si3N4 layers deposited by remote PECVD showed 1.6∼1.7×1012 cm−2 eV−1 at midgap which is 3 times lower than Si3N4 layers deposited by PECVD. Interface properties of SiO2 are superior to that of Si3N4 in both case of PECVD and remote PECVD. To investigate the interface properties between SiO2 and InSb, X‐ray photoelectron spectroscopy was conducted. Indium and antimony oxide phases were found at the interface and these oxide phases could act as the origin of interface traps.

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