• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.453-458
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• 2017

Computed Tomography (CT) provides information on the Diagnostic Reference Level Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP) for accurate diagnosis of patients. However, it does not provide a dose change according to the table height for the diagnostic reference level provided by the CT equipment. The purpose of this study was to evaluate the image and dose according to the table height change using phantom (PMMA: Polymethyl Methacrylate) in order to find the optimal image and the minimum dose during computed tomography examination. When examining using a 32 cm PMMA phantom with the same thickness as the abdomen of an adult, there was little change in dose with table height. However, the noise evaluation of the image caused a high fluctuation of noise depending on the table height. and in the case of the 16 cm PMMA phantom, the change of the noise was small, but the dose change was about 30%. In conclusion, the location of the patient and the center of the detector are important during computed tomography (CT) examinations. In addition, table height setting is considered to be important for examinations with optimized image and minimum dose.

• Nuclear industry
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• v.4 no.6 s.22
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• pp.72-79
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• 1984

방사선관리의 엄격화에 따른 관리의 복잡화와 노력의 증가에 의해서 관리의 합리화, 성력화가 요구되고 있다. 이에 대응하여 마이컴을 이용한 장치, 컴퓨터와 접속시켜서 관리할 수 있는 시스템, 신기술인 광전송을 받아들인 시스템 등이 출현하고 있다. 또한 종래에는 저레벨측정을 주로 하여 기술개발이 진행되어 왔으나 TMI사고를 계기로 고레벨측정도 재검토되고 있다. 다음은 주로 일본에서 사고시의 계측을 위해 개발된 모니터, 합리화와 성력화를 목적으로한 모니터, 신기술을 이용한 모니터의 개요이다.

• Progress in Medical Physics
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• v.19 no.4
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• pp.276-284
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• 2008

A computed tomography (CT) is a powerful system for the effectively fast and accurate diagnosis. The CT system, therefore, has used substantially and developed for improving the performance over the past decade, resulting in growing concerns over the radiation dose from the CT. Advanced CT techniques, such as a multidetector row CT scanner and dual energy or dual source CT, have led to new clinical applications that could result in further increases of radiation does for both patients and workers. The objective of this study was to review the international guidelines of the shielding requirements for a CT facility required for a new installation or when modifying an existing one. We used Google Search Engine to search the following keywords: computed tomography, CT regulation or shield or protection, dual energy or dual source CT, multidetector CT, CT radiation protection, and regulatory or legislation or regulation CT. In addition, we searched some special websites, that were provided for sources of radiation protection, shielding, and regulation, RSNA, AAPM, FDA, NIH, RCR, ICRP, IRPA, ICRP, IAEA, WHO (See in Table 1 for full explanations of the abbreviations). We finally summarized results of the investigated materials for each country. The shielding requirement of the CT room design was very well documented in the countries of Canada, United States of America, and United Kingdom. The wall thickness of the CT room could be obtained by the iso-exposure contour or the point source method. Most of documents provided by international organizations were explained in importance of radiation reduction in patients and workers. However, there were no directly-related documents of shielding and patient exposure dose for the dual energy CT system. Based international guidelines, the guideline of the CT room shielding and radiation reduction in patients and workers should be specified for all kinds of CT systems, included in the dual energy CT. We proposed some possible strategies in this paper.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.207-214
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• 2016

In this study, it was an investigation of the degree of awareness and consciousness of the radiology technicians about radiation protection working in the computed tomography room in Busan when the pediatric underwent brain CT scan. It was sorted by university hospital, general hospital and hospital and compared the scores of awareness and consciousness. As a result of awareness, university hospital had the highest point of 42.29 followed by general hospital and hospital of 38.43 and 34.06 respectively. On the other hand, the average score of consciousness was the highest in hospital of 29.19 followed by general hospital and university hospital of 24.68 and 21.37 respectively. It is considered to need assistance to cultivate an awareness of the radiation through refresher training and conferences, etc in order to increase the awareness of the general hospitals and hospitals for CT workers. In addition, it is also expected to pay for efforts to increase the consciousness of CT workers in university hospitals seeking the optimization of radiation protection and dose reduction of radiation exposure for the pediatric.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.407-414
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• 2014

The aim of the present study was to carry out quantitative analysis of spatial resolution for the influence of the focus size and digital image post-processing on the Computed Radiography (CR). The modulation transfer functions of an edge measuring method (MTF) was used for the evaluation of the spatial resolution. The focus size of X-ray tube was used the small focus (0.6 mm) and the large focus (1.2 mm). We evaluated the 50% and 10% of MTF for the enhancement of edge and contrast by using multi-scale image contrast amplification (MUSICA) in digital image post-processing. As a results, the edge enhancement than the contrast enhancement were significantly higher the spatial resolution of MTF 50% in all focus. Also the spatial resolution of the obtained images in a large focus were improved by digital image processing. In conclusion, the results of this study should serve as a basic data for obtain the high resolution clinical images, such as skeletal and chest images on the CR.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.314-320
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• 2000

Purpose :To investigate whether changes in plasma concentrations of transforming growth factor-$\beta$1(TGF-$\beta$1), tumor necrosis factor-alpha (TNF-$\alpha$) and interleukin-6 (IL-6) could be used to identify the development of radiation-induced pneumonitis in the lung cancer patients. Methods and Materials :Seventeen patients with lung cancer (11 NSCLC, 6 SCLC) were enrolled in a prospective study designed to evaluate clinical and molecular biologic correlation of radiation-induced pneumonitis. The study began in May 1998 and completed in July 1999. All patients were treated with radiotherapy with curative intent : 1.8 Gy per day, 5 fractions per week. Serial measurements of plasma TGF-$\beta$1, TNF-$\alpha$ and IL-6 were obtained in all patients before, weekly during radiotherapy and at each follow-up visits after completion of treatment. These measurements were quantified using enzyme linked immunosorbent assay (ELISA). All patients were evaluated for signs and symptoms of pneumonitis at each follow-up visit after completion of radiotherapy. High resolution CT (HRCT) scans were obtained when signs and symptoms of pneumonitis were developed after completion of radiotherapy. Results : Thirteen patients eventually developed signs and symptoms of clinical pneumonitis 씬file four patients did not. TGF-$\beta$ 1 levels were elevated in all 13 patients with pneumonitis, which showed characteristic pattern of elevation (38.45 ng/ml at pretreatment, 13.66 ng/ml during radiotherapy, then 60.63 ng/ml at 2-4 weeks after completion of radiotherapy). The levels of TNF- $\alpha$ and IL-6 were also elevated In the group of patients who developed pneumonitis but the pattern was not characteristic. Conclusions : Changes in plasma TGF$\beta$-1 levels before, during and after radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic pneumonitis. Other cytokines like TNF- $\alpha$ and IL-6 shows no meaningful changes in association with radiation pneumonitis.

• Progress in Medical Physics
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• v.9 no.1
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• pp.1-9
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• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.713-720
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• 2019

The purpose of this study was to propose a new measurement method for accurate measurement of vessel diameter in computed tomography angiography(CTA). CTA test was performed after non-ionic iodine contrast agent was flowed at a constant rate to self-maded perfusion phantom. After obtaining raw data, images were reconstructed with multi-planar reconstruction(MPR) and maximal intensity projection(MIP). Diameters of vascular models were measured for each technique. Relative and conventional measurements were then compared. The mean diameter of the vascular model was closer to the actual measurement when relative measurement was used compared to that when conventional measurement was used both in MPR and MIP. Relative measurements of MPR and MIP were closer to actual measurement than those of conventional measurement (34% VS, 24%, p<0.05). The relative measurement method proposed in this study was closer to the actual measurement than the conventional measurement method. However, both test methods were still larger than actual results. Therefore, further study of relative measurement method is needed using this study as basic data.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.589-594
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• 2017

The objective of this study was to evaluate the enhancement effects of the quantum denoising system (QDS) on brain CT images. This retrospective study was conducted with 45 adults who visited G Radiology located in Gyungbuk for having brain CT tests between Jul 2017 and Oct 2017 after receiving consents. Subjects were divided into a control group (A group; no QDS(-) application during the brain CT test) and a treatment group (B Group; QDS(+) application during the brain CT test). The following conclusions were obtained from the study. The noise values at the Pons part and the Vermis part were significantly (p<0.05) lower in B Group ($Pons=5.41{\pm}1.05HU$; $Vermis=5.28{\pm}0.73HU$) than A Group ($Pons=6.92{\pm}0.98HU$; Vermis=6.72). The SNR values at the Pons part and the Vermis part were significantly (p<0.05) higher in B Group ($Pons=7.28{\pm}2.56$; $Vermis=8.63{\pm}3.04$) than A Group ($Pons=5.21{\pm}1.28$; $Vermis=6.23{\pm}1.49$). In conclusion, the results of this study suggested that the application of QDS to the brain CT test would enhance the signal to noise ratio (SNR) and the contrast to noise ratio (CNR) to provide an image more appropriate for diagnosis.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.6 no.2
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• pp.81-93
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• 2013

This review was described to investigate the feasibility of using ultrasound as an image tool for interventions of lumbar spine. This article will first provide an overview of lumbosacral spine surface anatomy and sonoanatomy. A detailed understanding of anatomy is critical for interpretation of ultrasound and procedural performance at spine. Fluoroscopy is most commonly used in interventional spine procedures, but radiation exposure is the major concern when obtaining fluoroscopic images. Ultrasound is radiation-free, is easy to use, and can provide real-time images with high accuracy. Also this device can be used in virtually any clinical setting. Ultrasound guidance offers a reliable alternative to fluoroscopy or computed tomography for lumbar interventions and can be safely performed without radiation exposure.