• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.457-460
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• 2002

The image quality of three-dimensional (3D) images has been widely investigated by the qualitative analysis method. A need remains for an objective and quantitative method to assess the image quality of 3D volume-rendered images. The purpose of this study was to evaluate the quantitative accuracy of distance measurements on 3D volume-rendered images of a dry human skull by using multi-detector computed tomography (MDCT). A radiologist measured five times the twenty-one direct measurement line items composed among twelve reference points on the skull surface with a digital vernier caliper. The water filled skull specimen was scanned with a MDCT according to the section thicknesses of 1.25, 2.50, 3.75, and 5.00 mm for helical (high quality; pitch 3:1) scan mode. MDCT data were reconstructed with its acquisition section thickness and with 1.25 mm section thickness for all scans. An observer also measured seven times the corresponding items on 3D volume-rendered images with measuring tools provided by volumetric analysis software. The quantitative accuracy of distance measurements on the 3D volume-rendered images was statistically evaluated (p-value < 0.05) by comparatively analyzing these measurements with the direct distance measurements. The accuracy of distance measurements on the 3D volume-rendered MDCT images acquired with 1.25, 2.50, 3,75 and 5.00 mm section thickness and reconstructed with its section thickness were 48%, 33%, 23%, and 14%, respectively. Meanwhile, there were insignificant statistical differences in accuracy of distance measurements among 3D volume-rendered images reconstructed with 1.25 mm section thickness for the each acquisition section thickness. MDCT images acquired with thick section thickness and reconstructed with thin section thickness in helical scan mode should be effectively used in medical planning of 3D volume-rendered images. The quantitative analysis of distance measurement may be a useful tool for evaluating the quantitative accuracy and the defining optimal parameters of 3D volume-rendered CT images.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.206-207
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• 2002

The effective dose due to the X-Ray radiography in the patient positioning for the heavy ion radiotherapy was measured on three regions, chest, upper-abdomen and pelvis. All the radiographic systems and the conditions used in the measurements were same as the clinical trial being performed in National Institute of Radiological Sciences, Japan. The organ or tissue for measurements was selected by following ICRP60$^1$ and the effective dose was calculated from measured organ doses and the surface dose.

• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.329-329
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• 2002

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.506-508
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• 2002

As an advancement of medical imaging modalities and analyzing software with multi-function, active researches to acquire high contrast and high resolution image being done. In recently, development of medical imaging modalities like as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is aiming to display anatomical structure more accuracy and faster. Thus, one of the important areas in CT today is the use of CT scanner for the quantitative evaluation of 3-D reconstruction images from 2-D tomographic images. In CT system, the effective slice thickness and the quality of 3-D reconstructed image will be influenced by imaging acquisition parameters (e.g. pitch and scan mode). In diagnosis and surgical planning, the accurate distance measurements of 3-D anatomical structures play an important role and the accuracy of distance measurements will depend on the acquisition parameters such as slice thickness, pitch, and scan mode. The skull phantom was scanned with SDCT for various acquisition parameters and acquisition slice thicknesses were 3 and 5 mm, and reconstruction intervals were 1, 2, and 3 mm to each pitch. 3-D visualizations and distance measurements were performed with PC based 3-D rendering and analyzing software. Results showed that the image quality and the measurement accuracy of 3-D SDCT images are independent to the reconstruction intervals and pitches.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4122-4129
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• 2021

The counting efficiencies obtained using anthropomorphic physical phantoms are generally used in whole-body counting measurements to determine the level of internal contamination in the body. Geometrical discrepancies between phantoms and measured individuals affect the counting efficiency, and thus, considering individual physical characteristics is crucial to improve the accuracy of activity estimates. In the present study, the counting efficiencies of whole-body counting measurements were calculated considering individual physical characteristics by employing Monte Carlo simulation for calibration. The NaI(Tl)-based stand-up and HPGe-based bed type commercial whole-body counters were used for calculating the counting efficiencies. The counting efficiencies were obtained from 19 computational phantoms representing various shapes and sizes of the measured individuals. The discrepancies in the counting efficiencies obtained using the computational and physical phantoms range from 2% to 33%, and the results indicate that the counting efficiency depends on the size of the measured individual. Taking into account the body size, the equations for estimating the counting efficiencies were derived from the relationship between the counting efficiencies and the body-build index of the subject. These equations can aid in minimizing the size dependency of the counting efficiency and provide more accurate measurements of internal contamination in whole-body counting measurements.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.15 no.2
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• pp.19-31
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• 2020

Objectives This study was conducted to survey the trends of Korean medicine clinical research using radiological measurements of the musculoskeletal system. Methods We searched four domestic research databases (OASIS, NDSL, RISS, KISS) and three academic journals (Journal of Korean Medicine Rehabilitation, The Journal of Korea CHUNA Manual Medicine for Spine & Nerves, and Journal of Acupuncture Research). Selected studies were classified by publishing year, journal, the purpose of studies, and body region mainly researched in studies. Additionally, we analyzed the radiological measurements used in each body region. Results A total of 80 studies were selected. Most of the studies were published since2000. Most studies were published in the Journal of Korean Medicine Rehabilitation. The mainly researched body region was the lumbar spine. The main purpose of the studies was to analyze the characteristics of the disease. Conclusions Further research is needed about other different fields of Korean Medicine using X-ray on various body region and studies with purpose of analyzing radiological measurements need to be researched more.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.1-5
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• 2010

This study concerning the surface dose of eye and thyroid from panoramagraphy used thermoluminescent dosimeter (TLD) and photoluminescent dosimeter (PLD) to take measurements at ten hospitals in the Gwangju metropolitan area. The recommendations from ICRP 60 and ICRP 73 on the allowance standard for eye are 15 mSv and for thyroid is 1 mSv. The left eye TLD and PLD values are 0.19 mSv and 0.24 mSv respectively. The right eye TLD and PLD values are 0.23 mSv and 0.25 mSv respectively. Thyroid TLD and PLD values are 0.08 mSv and 0.25 mSv respectively and did not exceed the allowance standards(p<0.001). Also comparisons are made between TLD and PLD for each organ and PLD has higher dose measurements than TLD. There are statistically significant differences in left eye measurements and thyroid measurements (p<0.01). There is no significant difference in measurements for the right eye (p>0.05). The TLD and PLD measured dose from panoramagraphy instruments on eyes and thyroid from each hospital did not exceed the recommended dose from ICRP 60 for surface dose measurements. However, due to the probability of influence, consideration should be made for all levels of dose.

• International Journal of Contents
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• v.5 no.4
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• pp.7-12
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• 2009

In this paper, the authors showed that the removal of impulse noise in CR images was implemented using variety of median filters and SNR/PSNR measurements. They used three kinds of medical images-hand, skull, and knee- for experimental results. But the noise in CR image was only the impulse noise. In real medical image, the noise of an image would be very different type. Therefore. the lack of experimental results using different noise in CR images is one flaw.

• Journal of radiological science and technology
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• v.43 no.1
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• pp.15-21
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• 2020

This study was purpose to evaluation of Modulation Transfer Function in Measurements by using the International electrotechnical commission standard(IEC 62220-1) which were edge device each angle by using edge method. In this study was Aero(Konica, Japan) image receptor which is a indirect Flat panel detector(FPD) was used. The size of matrix 1994 × 2430 (14"× 17" inch) which performed 12 bit processing and pixel pitch is 175 ㎛. The results of shown as MTF measurements at IEC standard. The amount of data seemed reasonable and at an MTF value of 0.1 the spatial frequencies were 2.56 cycles/mm at an angle of 2.4°. MTF value of 0.5 the spatial frequencies were 1.32 cycles/mm at an angle of 2.4°. This study were to evaluate MTF by setting each angle 2.0°~2.8° degrees the most effective optimal edge angle and to suggest the quantitative methods of measuring by using IEC.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.507-513
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• 2022

When X-ray energy above 8 MV is used, photoneutrons are generated by the photonuclear reaction, which activates the components of linear accelerator (linac). Safely managing the radioactive material, when disposing linac or replacing components, is difficult, as the standards for the radioactive material management are not clear in Korea. We surveyed the management status of radioactive components occurred from medical linacs in Korea. And we also measured the activation of each part of the discarded Elekta linac using a survey meter and portable High Purity Germanium (HPGe) detector. We found that most medical institutions did not perform radiation measurements when disposing of radioactive components. The radioactive material was either stored within the institution or collected by the manufacturer. The surface dose rate measurements showed that the parts with high surface dose rates were target, primary collimator, and multileaf collimator (MLC). ⁶⁰Co nuclide was detected in most parts, whereas for the target, ⁶⁰Co and ¹⁸⁴Re nuclides were detected. Results suggest that most institutions in Korea did not have the regulations for disposing radioactive waste from linac or the management procedures and standards were unclear. Further studies are underway to evaluate short-lived radionuclides and to lay the foundation for radioactive waste management from medical linacs.