• Title/Summary/Keyword: Pet image

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Image-Based Assessment and Clinical Significance of Absorbed Radiation Dose to Tumor in Repeated High-Dose $^{131}I$ Anti-CD20 Monoclonal Antibody (Rituximab) Radioimmunotherapy for Non-Hodgkin's Lymphoma (반복적인 $^{131}I$ rituximab 방사면역치료를 시행 받은 비호지킨 림프종 환자 군에서 종양 부위의 영상기반 방사선 흡수선량 평가와 임상적 의의)

  • Byun, Byung-Hyun;Kim, Kyeong-Min;Woo, Sang-Keun;Choi, Tae-Hyun;Kang, Hye-Jin;Oh, Dong-Hyun;Kim, Byeong-Il;Cheon, Gi-Jeong;Choi, Chang-Woon;Lim, Sang-Moo
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.1
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    • pp.60-71
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    • 2009
  • Purpose: We assessed the absorbed dose to the tumor ($Dose_{tumor}$) by using pretreatment FDG-PET and whole-body (WB) planar images in repeated radioimmunotherapy (RIT) with $^{131}I$ rituximab for NHL. Materials and Methods: Patients with NHL (n=4) were administered a therapeutic dose of $^{131}I$ rituximab. Serial WB planar images alter RIT were acquired and overlaid to the coronal maximum intensity projection (MIP) PET image before RIT. On registered MIP PET and WB planar images, 2D-ROls were drawn on the region of tumor (n=7) and left medial thigh as background, and $Dose_{tumor}$ was calculated. The correlation between $Dose_{tumor}$ and the CT-based tumor volume change alter RIT was analyzed. The differences of $Dose_{tumor}$ and the tumor volume change according to the number of RIT were also assessed. Results: The values of absorbed dose were $397.7{\pm}646.2cGy$ ($53.0{\sim}2853.0cGy$). The values of CT-based tumor volume were $11.3{\pm}9.1\;cc$ ($2.9{\sim}34.2cc$), and the % changes of tumor volume before and alter RIT were $-29.8{\pm}44.3%$ ($-100.0%{\sim}+42.5%$), respectively. $Dose_{tumor}$ and the tumor volume change did not show the linear relationship (p>0.05). $Dose_{tumor}$ and the tumor volume change did not correlate with the number of repeated administration (p>0.05). Conclusion: We could determine the position and contour of viable tumor by MIP PET image. And, registration of PET and gamma camera images was possible to estimate the quantitative values of absorbed dose to tumor.

Evaluation of Standardized Uptake Value applying EQ PET across different PET/CT scanners and reconstruction (PET/CT 장비와 영상 재구성 차이에 따른 EQ PET을 이용한 표준섭취계수의 평가)

  • Yoon, Seok Hwan;Kim, Byung Jin;Moon, Il Sang;Lee, Hong Jae
    • The Korean Journal of Nuclear Medicine Technology
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    • v.22 no.1
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    • pp.35-42
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    • 2018
  • Purpose Standardized uptake value(SUV) has been widely used as a quantitative metric of uptake in PET/CT for diagnosis of malignant tumors and evaluation of tumor therapy response. However, the SUV depends on various factor including PET/CT scanner specifications and reconstruction parameter. The purpose of this study is to validate a EQ PET to evaluate SUV across different PET/CT systems. Materials and Methods First, NEMA IEC body phantom data were used to calculate the EQ filter for OSEM3D with PSF and TOF reconstruction from three different PET/CT systems in order to obtain EARL compliant recovery coefficients of each spheres. The Biograph true point 40 PET/CT images were reconstructed with a OSEM3D+PSF reconstruction, images of the Biograph mCT 40 and Biograph mCT 64 PET/CT scanners were reconstructed with a OSEM3D+PSF, OSEM3D+TOF, OSEM3D+PSF+TOF. Post reconstructions, the proprietary EQ filter was applied to the reconstruction data. Recovery coefficient can be estimated by ratio of measured to true activity concentration for spheres of different volume and coefficient variability(CV) value of RC for each sphere was compared. For clinical study, we compared SUVmax applying different reconstruction algorithms in FDG PET images of 61 patients with lung cancer using Biograph mCT 40 PET/CT scanner. Results For the phantom studied, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.05, 0.04, 0.04 and 0.03 respectively for RC. Application of the proprietary EQ filter, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.04, 0.03, 0.03 and 0.02 respectively for RC. Clinical study, there were no statistical significance of the difference applying EQ PET on SUVmax of 61 patients FDG PET image. (p=1.000) Conclusion This study indicates that CV values of RC in phantom were decreased after applying EQ PET for different PET/CT system and The EQ PET reduced reconstruction dependent variation in SUVs for 61 lung cancer patients, Therefore, EQ PET will be expected to provide accurate quantification when the patient is scanned on different PET/CT system.

Evaluation of the 256ch Flat Panel PS-PMT on Positioning Image Histogram for PET

  • Orita, Narimichi;Murayama, Hideo;Kawai, Hideyuki;Inadama, Naoko;Umehara, Takaya;Kasahara, Takehiro;Tsuda, Tomoaki
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.324-327
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    • 2002
  • For a next generation PET that realizes high sensitivity and high resolution, we proposed a design of a depth of interaction detector. A unit of the detector is constructed of four stages rectangular blocks of 2 by 2 Gd$_2$SiO$\sub$5/: Ce (GSO) crystal array optically coupled to position sensitive photomultiplier tube (PS-PMT). The 256ch flat panel PS-PMT is under development by Hamamatsu Photonics K.K., JAPAN. It has large cathode area, 51.7 by 51.7 mm$^2$, and the ratio of the effective area to external size is about 90%. The feature will contribute high packing fraction, accordingly high sensitivity. The 256 anodes are arranged in 16 by 16 at intervals of 3.0 mm. So as to evaluate the detector capability for identifying crystal of interaction, we got positioning image histograms with coupling a 16 by 5 array of GSO crystals, 2.9 by 2.9 by 7.5 mm$^3$, to the PS-PMT by irradiating a gamma ray uniformly from a point source. Flat panel PS-PMT is a new promising device for PET. We need to evaluate it if its performance is sufficiency. The performance was compared to the one with a 16ch PS-PMT.

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Feature extraction of medical image using GLCM (GLCM을 이용한 의료영상 특징정보 추출)

  • Park, Yong Sung;Jeong, Su Young;Kim, Wook;Lim, Ilhan;Kang, Joo Hyun;Lim, Sang Moo;Woo, Sang-Keun
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2017.01a
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    • pp.239-240
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    • 2017
  • 본 연구는 의료영상내 특징정보를 추출 및 평가함으로서 정밀의료 실현 가능성을 확인하고자 하였다. 영상화는 PET/CT 및 MRI 스캐너를 이용하여 암환자의 기능적 정보와 해부학적 정보를 획득하고 관심영역을 설정하였으며 각각의 영상내 특징정보를 추출하였다. 영상내 특징정보는 GLCM을 이용하여 에너지, 대비, 엔트로피, 균질성을 획득하였고, 획득된 영상 데이터에 따른 관심영역 설정 차이를 확인하였다. 영상내 특징 정보는 MRI 영상의 해부학적 정보를 이용한 분석결과에서 엔트로피 및 균질성이 PET 보다 증가 하였고 대비는 감소함을 확인하였다. 추후연구는 다양한 영상내 특징 정보를 획득하고 정밀의료를 위한 기계학습에 활용할 예정이다.

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Clinical Application of Cardiac Hybrid Imaging in Coronary Artery Disease (관상동맥질환에서 심장 하이브리드 영상의 임상적 이용)

  • Gho, Ihn-Ho;Kong, Eun-Jung
    • Journal of Yeungnam Medical Science
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    • v.26 no.1
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    • pp.15-23
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    • 2009
  • Constant technological developments in coronary artery disease have contributed to the assessment of both the presence of coronary stenosis and its hemodynamic consequences. Hence, noninvasive imaging helps guide therapeutic decisions by providing complementary information on coronary morphology and on myocardial perfusion and metabolism. This can he done using single photon emission computed tomography (SPECT) or positron emission tomography (PET) and multidetector CT (MDCT). Advances in image-processing software and the advent of SPECT/CT and PET/CT have paved the way for the combination of image datasets from different modalities, giving rise to hybrid imaging. Three dimensional cardiac hybrid imaging helped to confirm hemodynamic significance in many lesions, add new lesions such as left main coronay artery disease, exclude equivocal defects, correct the corresponding arteries to their allocated defects and identify culprit segment. Cardiac hybrid imaging avoids the mental integration of functional and morphologic images and facilitates a comprehensive interpretation of coronaty lesions and their pathophysiologic adequacy by three dimensional display of fused images, and allows the best evaluation of myocardial territories and the coronary-artery branches that serve each territory. This integration of functional and morphological information were feasible to intuitively convincing and might facilitate development of a comprehensive non-invasive assessment of coronary artery disease.

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A Case Study on Digital Interactive Training Content <Tamagotchi> and <Peridot>

  • DongHee Choi;Jeanhun Chung
    • International journal of advanced smart convergence
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    • v.12 no.4
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    • pp.306-313
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    • 2023
  • Having pet is one of the activities people living in modern society do to relieve stress and find peace of mind. Currently, the object of companion animals has moved beyond being a real 'living entity' and has developed to a stage where the animal's upbringing process can be enjoyed in a virtual space by being programmed in digital content. This paper studies detailed elements such as character design, interaction, and realism of 'Tamagotchi (1996)', which can be said to be the beginning of digital training content, and 'Peridot (2023)', a recently introduced augmented reality-based training content. The point was that it was training content using portable electronic devices. However, while the environment in the electronic device in which Tamagotchi's character exists was a simple black and white screen, the environment in which Peridot's character operates has been changed to the real world projected on the screen based on augmented reality. Mutual communication with characters in Tamagotchi remained a response to pressing buttons, but in Peridot, it has advanced to the point where you can pet the characters by touching the smartphone screen. In addition, through object and step recognition, it was confirmed that the sense of reality had become more realistic, with toys thrown by users on the screen bouncing off real objects. We hope that this research material will serve as a useful reference for the development of digital training content to be developed in the near future.

The Evaluation of the Difference of the SUV Caused by DFOV Change in PET/CT (PET/CT 검사에서 확대된 표시시야가 표준섭취계수에 미치는 영향 평가)

  • Kwak, In-Suk;Lee, Hyuk;Choi, Sung-Wook;Seok, Jae-Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.15 no.2
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    • pp.13-20
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    • 2011
  • Purpose: The limited FOV(Field of View) of CT (Computed Tomography) can cause truncation artifact at external DFOV (Display Field of View) in PET/CT image. In our study, we measured the difference of SUV and compared the influence affecting to the image reconstructed with the extended DFOV. Materials and Methods: NEMA 1994 PET Phantom was filled with $^{18}F$(FDG) of 5.3 kBq/mL and placed at the center of FOV. Phantom images were acquired through emission scan. Shift the phantom's location to the external edge of DFOV and images were acquired with same method. All of acquired data through each experiment were reconstructed with same method, DFOV was applied 50 cm and 70 cm respectively. Then ROI was set up on the emission image, performed the comparative analysis SUV. In the clinical test, patient group shown truncation artifact was selected. ROI was set up at the liver of patient's image and performed the comparative analysis SUV according to the change of DFOV. Results: The pixel size was increase from 3.91 mm to 5.47 mm according to the DFOV increment in the centered location phantom study. When extended DFOV was applied, $_{max}SUV$ of ROI was decreased from 1.49 to 1.35. In case of shifted the center of phantom location study, $_{max}SUV$ was decreased from 1.30 to 1.20. The $_{max}SUV$ was 1.51 at the truncated region in the extended DFOV. The difference of the $_{max}SUV$ was 25.9% higher at the outside of the truncated region than inside. When the extended DFOV was applied, $_{max}SUV$ was decreased from 3.38 to 3.13. Conclusion: When the extended DFOV was applied, $_{max}SUV$ decreasing phenomenon can cause pixel to pixel noise by increasing of pixel size. In this reason, $_{max}SUV$ was underestimated. Therefore, We should consider the underestimation of quantitative result in the whole image plane in case of patient study applied extended DFOV protocol. Consequently, the result of the quantitative analysis may show more higher than inside at the truncated region.

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Evaluation of MR Based Respiratory Motion Correction Technique in Liver PET/MRI Study (Liver PET/MRI 검사 시 MR 기반 호흡 움직임 보정 방법의 유용성 평가)

  • Do, Yong Ho;Lee, Hong Jae;Kim, Jin Eui;Noh, Gyeong Woon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.22 no.1
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    • pp.15-22
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    • 2018
  • Purpose Respiratory motion during PET/MRI acquisition may result in image blurring and error in measurement for volume and quantification of lesion. The aim of this study was to evaluate changes of quantitative accuracy, tumor size and image quality by applying MR based respiratory motion correction technique (MBRMCT) using integrated PET/MR scanner. Materials and Methods Data of 30 patients (aged $62.5{\pm}10.2y$) underwent $^{18}F-FDG$ liver PET/MR (Biograph mMR 3.0T, Siemens) study were collected. PET listmode data for 7 minutes was simultaneously acquired with maximum average gate (MAG), minimum time gate (MTG) and non gate (NG) T1 weighted MR images. Gated PET reconstruction was performed using mu-maps generated from MAG and MTG by setting 35% of efficiency window. Maximum SUV ($SUV_{max}$), peak SUV ($SUV_{peak}$), tumor size and full width at half maximum (FWHM) in the z-axis direction of MAG, MTG and NG PET images were evaluated. Results Compared to NG, mean $SUV_{max}$ and $SUV_{peak}$ were increased in MAG 13.15%(p<0.0001), 8.66%(p<0.0001), MTG 13.27%(p<0.0001), 8.80%(p<0.0001) and mean tumor size and FWHM were decreased in MAG 14.47%(p<0.0001), 15.49%(p=0.0004), MTG 14.89%(p<0.0001), 15.79%(p=0.0003) respectively. Mean $SUV_{max}$ and $SUV_{peak}$ of MTG were increased by 0.07%(p=0.8802), 0.13%(p=0.7766). Mean tumor size and FWHM of MTG were decreased by 0.49%(p=0.2786), 0.36%(p=0.2488) compared to MAG. There was no statistically significant difference between MAG and MTG which increase total scan time for about 7 and 2 minutes. Conclusion SUV, accuracy of tumor size and spatial resolution were improved in both of MAG and MTG by applying MBRMCT without installing additional hardware in liver PET/MR study. More accurate information can be provided with the increase of 2 minutes scan time if applying MTG of MBRMCT to various abdominal PET/MR studies affected by respiratory motion.

Development of an Automatic 3D Coregistration Technique of Brain PET and MR Images (뇌 PET과 MR 영상의 자동화된 3차원적 합성기법 개발)

  • Lee, Jae-Sung;Kwark, Cheol-Eun;Lee, Dong-Soo;Chung, June-Key;Lee, Myung-Chul;Park, Kwang-Suk
    • The Korean Journal of Nuclear Medicine
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    • v.32 no.5
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    • pp.414-424
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    • 1998
  • Purpose: Cross-modality coregistration of positron emission tomography (PET) and magnetic resonance imaging (MR) could enhance the clinical information. In this study we propose a refined technique to improve the robustness of registration, and to implement more realistic visualization of the coregistered images. Materials and Methods: Using the sinogram of PET emission scan, we extracted the robust head boundary and used boundary-enhanced PET to coregister PET with MR. The pixels having 10% of maximum pixel value were considered as the boundary of sinogram. Boundary pixel values were exchanged with maximum value of sinogram. One hundred eighty boundary points were extracted at intervals of about 2 degree using simple threshold method from each slice of MR images. Best affined transformation between the two point sets was performed using least square fitting which should minimize the sum of Euclidean distance between the point sets. We reduced calculation time using pre-defined distance map. Finally we developed an automatic coregistration program using this boundary detection and surface matching technique. We designed a new weighted normalization technique to display the coregistered PET and MR images simultaneously. Results: Using our newly developed method, robust extraction of head boundary was possible and spatial registration was successfully performed. Mean displacement error was less than 2.0 mm. In visualization of coregistered images using weighted normalization method, structures shown in MR image could be realistically represented. Conclusion: Our refined technique could practically enhance the performance of automated three dimensional coregistration.

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IMAGING IN RADIATION THERAPY

  • Kim Si-Yong;Suh Tae-Suk
    • Nuclear Engineering and Technology
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    • v.38 no.4
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    • pp.327-342
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    • 2006
  • Radiation therapy is an important part of cancer treatment in which cancer patients are treated using high-energy radiation such as x-rays, gamma rays, electrons, protons, and neutrons. Currently, about half of all cancer patients receive radiation treatment during their whole cancer care process. The goal of radiation therapy is to deliver the necessary radiation dose to cancer cells while minimizing dose to surrounding normal tissues. Success of radiation therapy highly relies on how accurately 1) identifies the target and 2) aim radiation beam to the target. Both tasks are strongly dependent of imaging technology and many imaging modalities have been applied for radiation therapy such as CT (Computed Tomography), MRI (Magnetic Resonant Image), and PET (Positron Emission Tomogaphy). Recently, many researchers have given significant amount of effort to develop and improve imaging techniques for radiation therapy to enhance the overall quality of patient care. For example, advances in medical imaging technology have initiated the development of the state of the art radiation therapy techniques such as intensity modulated radiation therapy (IMRT), gated radiation therapy, tomotherapy, and image guided radiation therapy (IGRT). Capability of determining the local tumor volume and location of the tumor has been significantly improved by applying single or multi-modality imaging fur static or dynamic target. The use of multi-modality imaging provides a more reliable tumor volume, eventually leading to a better definitive local control. Image registration technique is essential to fuse two different image modalities and has been In significant improvement. Imaging equipments and their common applications that are in active use and/or under development in radiation therapy are reviewed.