Comparison with 1.5Tesla and 3.0Tesla of Acoustic Noise Spectrum of DWI MR Pulse Sequence

Dae Cheol Kweon(권대철),Jiwon Choi(최지원) 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.4

1.5Tesla와 3.0Tesla의 MRI 검사의 DWI (diffusion-weighted imaging) 펄스시퀀스에서 노이즈 스펙트럼을 분석하여 MRI검사의 기초자료를 제공하여 임상에서 적용하는데 목적이 있다. MRI 검사에서 ACR (Americ an College of Radiology) 팬텀과 노이즈 스펙트럼은 Wavepad sound editor version 8.13 (NCH software, Green wood Village, CO, USA)로 FFT (fast Fourier transform), TFFT (time based fast Fourier transform)를 분석하였 다. MR 1.5Tesla와 3.0Tesla의 DWI 펄스 시퀀스에서 검사실에 따른 노이즈 스펙트럼 및 FFT와 TFFT를 분석하였다. 1.5Tesla에 비해 3.0Tesla에서 FFT 및 TFFT에서 주파수 진폭의 노이즈 임계값은 1.5Tesla에서 –6 dB 사이였고, 3.0Tesla에서는 0 dB 사이로 분석되어 환자의 소음감소를 위한 DWI 펄스시퀀스를 환자에게 적절하게 임상에서 적용할 필요가 있다. The purpose of this study is to analyze the noise spectra in DWI (diffusion-weighted imaging) pulse sequences of 1.5 Tesla and 3.0 Tesla MRI, The ACR (American College of Radiology) phantom and noise spectrum were analyzed by FFT (fast Fourier transform) and TFFT (temporal frequency analysis) using WavePad sound editor version 8.13 (NCH software, Greenwood Village, CO, USA). Noise spectra, FFT and TFFT were analyzed for laboratory 1.5Tesla and 3.0Tesla DWI MR pulse sequences. The noise threshold of the frequency amplitude in the FFT and TFFT at 3.0Tesla compared to 1.5Tesla was between 1.5Tesla and –6 dB, and between 3.0Tesla and 0 dB, the DWI pulse sequence for the patient s noise reduction was appropriately MR examination needs to be applied.

A study on the Cochlear View Radiography in Multichannel Cochlear Implantees

Kweon Dae Cheol,Kim Seong Lyong,Chung Kyung Mo,Kim Hae Seong,Lee Yong Woo Korean Radiological Technologists Associaton 1999 대한방사선사협회지 Vol.25 No.1

Purpose : Cochlear implant poses a contraindication to the magnetic resonance imaging (MRI) process, because MRI generates artifacts, inducing an electrical current and causing device magnetization. CT is relatively expensive and the metal electrodes scat

AN IV CATHETER FRAGMENTS DURING MDCT SCANNING OF HUMAN ERROR: EXPERIMENTAL AND REPRODUCIBLE MICROSCOPIC MAGNIFICATION ANALYSIS

Kweon, Dae-Cheol,Lee, Jong-Woong,Choi, Ji-Won,Yang, Sung-Hwan,Dong, Kyung-Rae,Chung, Woon-Kwan The Korean Association for Radiation Protection 2011 방사선방어학회지 Vol.36 No.4

The use of intravenous catheters are occasionally complicated by intravascular fragments and swelling of the catheter fragments. We present a patient in whom an intravenous catheter fragments was retrieved from the dorsal metacarpal vein following its incidental CT examination detection. The case of demonstrates the utility of microscopy and multi-detector CT in localizing small of subtle intravenous catheter fragments as a human error. A case of IV catheter fragments in the metacarpal vein, in which reproducible and microscopy data allowed complete localization of a missing fragments and guided surgery with respect to the optimal incision site for fragments removal. These reproducible studies may help to determine the best course of action and treatment for the patient who presents with such a case.

AN IV CATHETER FRAGMENTS DURING MDCT SCANNING OF HUMAN ERROR: EXPERIMENTAL AND REPRODUCIBLE MICROSCOPIC MAGNIFICATION ANALYSIS

DAE CHEOL KWEON,JONG‐WOONG LEE,JIWON CHOI,SUNG HWAN YANG,KYUNG‐RAE DONG,WOON‐KWAN CHUNG 대한방사선방어학회 2011 방사선방어학회지 Vol.36 No.4

Protection of superficial organs using bismuth and iodine shielding during computed tomography in phantoms

Kweon Dae Cheol,Lee Jong-Woong,Choi Jiwon 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.1

We sought to minimize streak artifacts caused by beam hardening on chest CT scan, obtain high-quality CT images and compare image quality and dose between with and without iodine and bismuth shielding material to protect superficial organs. During CT, the radiation dose was measured and the images evaluated before using the shielding material, iodine and bismuth. A body phantom of polymethyl methacrylate (PMMA) measuring 32 cm was used for image quality and radiation dose measurement according to the shielding material of the CT scan. During CT, phantom noise was measured to be 11.49 HU without shielding, 12.95 HU with bismuth, and 14.67 HU with iodine (p > 0.05). Based on the dose, in the absence of the shielding material, the shielding with iodine showed a dose reduction effect of 40.64% at 11 o'clock and 35.74% at 1 o'clock. In the case of bismuth shielding, the dose at 11 o'clock was decreased to 34.06% and the dose at 1 o'clock was decreased to 34.32%. Dose reduction was observed prior to the use of the shielding material and the application of the iodine and bismuth shielding materials (p < 0.05). In phantom chest CT, the dose reduction of the superficial organs using iodine and bismuth, a radiation shielding material, was confirmed.

Extravasation Injury of Contrast Media in the Neck and Thorax During MDCT Scanning with 3D Image Reformation Findings

Dae-Cheol Kweon(권대철),Keun-Jo Jang(장근조),Beong-Gyu Yoo(유병규),Jong-Seok Lee(이종석) 대한방사선과학회(구 대한방사선기술학회) 2007 방사선기술과학 Vol.30 No.3

  전산화단층촬영에서 조영제를 자동주입기로 주입하는 과정에서 발생하는 혈관외유출은 조직의 괴사 및 손상의 원인이 되고 있다. 대량의 혈관외유출은 구획증후군으로 발전하여 근막절개술을 시행하는 경우가 발생한다. 혈관외유출이 발생한 환자를 대상으로 혈관외유출 범위 및 부위 정도를 평가하기 위해 CT 검사에서 경정맥에 조영제을 주입하는 과정에서 혈관외유출이 발생한 환자를 대상으로 하였다. 조영제에 의한 혈관외유출 범위 및 손상을 확인하기 조영제 주입부위의 목 및 가슴의 부위를 MDCT를 이용하여 스캔하였다. 경정맥 주사부위의 혈관외유출부위를 MPR, MIP와 볼륨 렌더링의 3차원영상을 3D 프로그램을 이용하여 묘출하였다. 3차원 재구성 영상은 높은 해상력과 정확도를 제공하여 혈관외유출 범위 및 부위를 확인 하여, 환자의 예방의 필요성 및 사후 조치 및 적절한 치료와 수술 계획에 유용하게 이용될 것으로 기대된다.   Contrast media may cause tissue injury by extravasation during intravenous automated injection during CT examination. Here, we present a study in which contrast media extravasation was detected and localized in the neck and thorax by three-dimensional(3D) CT data reformation. The CT studies of the extavasation site were performed using a 3D software program with four different display techniques axial, multi planar reformation(MPR), maximum intensity projection(MIP), and volume rendering displays are currently available for reconstructing MDCT data. 3D image reconstructions provide accurate views of high-resolution imaging. This paper introduces extravasation with the MDCT and 3D reformation findings of contrast media extravasation in neck ant thorax. The followed injection of the external jugular vein into an existing intravenous catheter and a large volume of extravasation was demonstrated on by 3D MDCT.

MDCT Angiography of the Subclavian Artery Thrombosis of the 3D Findings

Dae Cheol Kweon 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.7

MDCT의 3D 유용성을 입증하기 위해 쇄골하 혈전증을 수반한 73세 남자 환자를 대상으로 MIP, 볼륨렌더링, MPR의 3D 영상을 획득하여 쇄골하동맥의 혈전증을 명확하게 탐지하고 위치를 확인하여 임상에서 기초자료를 제공하여 환자의 진단 및 치료에 적용하고자한다. 스캔 데이터를 3차원 CT영상인 MIP, 볼륨렌더링, curve multiplanar reformation (MPR), virtual endoscopy 영상을 획득하였다. CT검사 환자의 데이터를 3D 프로그램으로 전송한 영상에서 3D 프로그램에서 측정한 상행대동맥은 364.28 HU, 좌총경동맥 413.77HU, 좌쇄골하동맥 15.72 HU로 낮게 산출되었다. MIP coronal 영상으로 좌측의 쇄골하동맥의 혈전으로 폐쇄를 정확하게 보여주고 있다. 볼륨렌더링 3차원 영상으로 투과도 100%, 87-1265 HU를 적용하여 쇄골하동맥과 뼈를 동시에 묘출하고 있으며, 좌측 쇄골하동맥의 폐쇄 영상을 선명하게 보여주었으며 coronal curved MPR 및 sagittal curved MPR 영상으로 혈전의 의한 쇄골하동맥의 폐쇄를 3D 영상 처리 기능을 이용하여 정확하게 묘출하고 있다. 혈전에 의한 쇄골하동맥 폐쇄 증상 환자를 MDCT로 스캔하여 3D 영상 기법을 응용하여 쇄골하동맥의 폐쇄를 확인할 수 있어 임상에서 3D 기법을 응용하여 적절하게 진단에 적용할 수 있다. To demonstrate the 3D usefulness of MDCT, a 73-year-old male patient with subclavian thrombosis was obtained 3D images of maximum intensity projection (MIP), volume rendering, and multiplanar reformation (MPR) to clearly detect and locate the subclavian artery. The data will be provided to the patient for diagnosis and treatment. The scan data were acquired as 3D CT images MIP, volume rendering, curved MPR, and virtual endoscopy images. In the 3D program, the ascending aorta was measured as 364.28 HU, the left carotid artery was 413.77 HU, and the left subclavian artery was 15.72 HU. MIP coronal image shows the closure of the subclavian artery in the left side. Three-dimensional volume images were obtained with 100% permeability and 87-1265 HU. The coronal curved MPR and sagittal curved MPR images show the closure of the subclavian artery due to thrombus using 3D image processing. In the case of subclavian arterial occlusion due to thrombosis, the patient is scanned with MDCT and 3D image processing can be used to confirm occlusion of subclavian artery.

Quantitative Experimental Phantom Study Based on Abdominal MR Contrast Media Using Deep Learning

Dae Cheol Kweon 한국자기학회 2023 Journal of Magnetics Vol.28 No.2

This study provides data for the development of oral contrast media for abdominal magnetic resonance imaging (MRI) examinations for potential use in clinical practice. The signal intensities, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were quantified using various contrast media with longitudinal (T1) and transverse relaxation (T2) pulse sequences. Prediction accuracy error comparisons were conducted according to the mean-squared, mean-absolute, and root-mean-squared errors of the contrast media intensities using the Orange data mining software. The signal strength and SNR were higher in canola oil and pineapple juice (T1- weighted images), while the intensities of blueberry juice and apple juice were high in the T2-weighted images; SNR was high in blueberry and cranberry juice, and CNR was high in Solotop® and blueberry syrup. The accuracy of the deep-learning prediction errors of MR signal intensities was high. In conclusion, data from ex vivo MRI research can be used for the development of oral contrast media.

Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

Dae Cheol Kweon,Peom Park 대한방사선방어학회 2001 방사선방어학회지 Vol.26 No.4

방사선피폭관리시스템를 위한 D-Shuttle 선량계의 방사선 선량측정

권대철(Dae Cheol Kweon) 한국방사선학회 2017 한국방사선학회 논문지 Vol.11 No.5

D-Shuttle (Chiyoda Technol Corporation, Tokyo, Japan) 선량계를 이용하여 개인피폭관리 및 자연방사선량 의 모니터링을 위한 기초자료를 제공하는데 연구의 목적이 있다. D-Shuttle을 이용하여 선량을 산출하였다. 선량보고서에서 400 일 노출되었을 때에 1.346 mSv 이었고, 연간선량 (annual dose per year)은 1.228 mSv/ye ar, 평균시간선량 (average dose per hour)은 0.014 μSv/hr 이었다. 국내의 개인 외부피폭선량 (1.295 mSv/year =Korea average natural individual external dose), 국내의 연간부가선량 (additional dose per year)은 -0.0663 mSv /year 이다. D-Shuttle은 방사선모니터링을 위한 개인선량계로 방사선의 검출성능 우수한 기능, 실시간 방사선 피폭관리, 방사선 작업의 경보 기능, 효율적이고 사용이 편리한 개인 방사선선량의 피폭관리로 ALARA 에 매우 유용한 선량계로 사용할 수 있다. 방사선작업종사자와 지역주민의 방사선모니터링 측정기기로 병원, 산업, 의료현장, 원전사고 지역과 비파괴 분야의 위험한 지역에서 방사선모니터링으로 활용될 수 있다. The purpose of the study is to provide basic data for the management of individual exposure and the monitoring of natural radiation dose using D-Shuttle dosimeter (Chiyoda Technol Corporation, Tokyo, Japan). The dose was calculated using D-Shuttle dosimeter. The dose was 1.346 mSv when exposed for 400 days, the annual dose per year was 1.228 mSv/year and the average dose per hour was 0.014 μSv/hr. Domestic individual external dose (1.295 mSv/year = Korea average natural individual external dose) and domestic additional dose per year is –0.0663 mSv/year. D-Shuttle is a personal dosimeter for radiation monitoring. It can be used as a very useful dosimeter for ALARA because of its excellent detection capability of radiation, real-time radiation exposure management, alarm function of radiation work, and efficient and easy to use personal radiation dose management.. Radiation monitoring equipment for radiation workers and local residents can be used for radiation monitoring in hospitals, industry, medical sites, nuclear accident areas and hazardous areas in non-destructive areas.