• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.600-603
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• 2003

Energy spectrum modulation of X-ray source in digital mammography has been studied. In this study, we calculated various filtered spectra using the scattering data. Primary spectra were generated by Molybdenum (Mo) and Tungsten (W) targets. The materials of added filters are Molybdenum and Rhodium (Rh) for 40 kVp Mo. primary spectrum, the amounts of photons over whole energy ranges are attenuated to 0.43 with 0.03 mm Mo filter and 0.38 with 0.06 mm Mo filter while the photons of energy ranged from 17 keV to 20 keV. The photons of low energy ranged below 17 keV are considerably attenuated. This effect brings out reducing the scattered radiation and dose to the patient, and enhancing subject contrast in the image. The results show that filtered spectra are not seriously affected by X-ray tube loadability. Because the energy range from 17 keV to 20 keV is directly transmitted although low and high energies are mainly filtered.

• The Korean Journal of Pain
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• v.35 no.2
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• pp.129-139
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• 2022

C-arm fluoroscopy is a useful tool for interventional pain management. However, with the increasing use of C-arm fluoroscopy, the risk of accumulated radiation exposure is a significant concern for pain physicians. Therefore, efforts are needed to reduce radiation exposure. There are three types of radiation exposure sources: (1) the primary X-ray beam, (2) scattered radiation, and (3) leakage from the X-ray tube. The major radiation exposure risk for most medical staff members is scattered radiation, the amount of which is affected by many factors. Pain physicians can reduce their radiation exposure by use of several effective methods, which utilize the following main principles: reducing the exposure time, increasing the distance from the radiation source, and radiation shielding. Some methods reduce not only the pain physician's but also the patient's radiation exposure. Taking images with collimation and minimal use of magnification are ways to reduce the intensity of the primary X-ray beam and the amount of scattered radiation. It is also important to carefully select the C-arm fluoroscopy mode, such as pulsed mode or low-dose mode, for ensuring the physician's and patient's radiation safety. Pain physicians should practice these principles and also be aware of the annual permissible radiation dose as well as checking their radiation exposure. This article aimed to review the literature on radiation safety in relation to C-arm fluoroscopy and provide recommendations to pain physicians during C-arm fluoroscopy-guided interventional pain management.

• Annual Conference of KIPS
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• 2017.11a
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• pp.917-919
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• 2017

본 연구에서는 X-ray 산란선 보정을 위한 신경망에서 학습기법의 세부 방법론을 고찰한다. 학습데이터의 생성 과정과 데이터의 표현 과정에서 X-ray 영상의 특성을 반영하여 다양한 방법을 제시하고 실험적으로 고찰하였다. 학습을 위한 계산량의 문제와 유효하지 않은 학습데이터로 인한 성능 저하를 개선하기 위하여 샘플링과정을 수행하고 로컬영역을 고려하는 학습데이터 생성방법을 제시하였다. 실제 동일 피사체에 대하여 그리드 장비를 사용한 영상과 비교한 실험 결과를 통하여 제안된 방법의 유용성을 평가하였다.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.9 no.1
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• pp.25-31
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• 1979

The utilization of x-ray for diagnosis and examination is increasing by about 5-15% every year, therefore, it would be mandatory to protect the patients from exposures and so, studies in this field are performed even now. In dental field, the area of irradiation is limited any to the head and neck area, but the irradiated angle is varied following the objected tooth, so the adjacent structures lens and thyroid gland would be fragile to radiation. And the scattered radiation is one of the complicated problems in the protection because of specificity of dental x-ray and its object structures. The author, by using TLD (Thermo luminescent Dosimeter; Teledyne Isotopes-Model 7300, Element; TLD 200(CaF₂:Dy) and Capintec(Capintec Model 192, PM-30 Diagnostic chamber 28㎖ active volume), tried a measurement of air dose distribution of the scattered radiation and the irradiated dose of lens and thyroid gland under the condition of taking the film on the left maxillary molar. The results were as follows: 1. The half value layer of adapted dental x-ray machine was measured, and is 1.44㎜ Al. 2. The time of irradiation on the left maxillary molar in the Alderson Rando Phantom, the measured doses of left and right lens, and thyroid gland were 8,9mR, 1,2mR and 2,8mR. Under the same conditions, the scattered radiation at the distance of 1 meter from the phantom were 84 μR at the front side, 11μR at the back side, 18μR at the right side and 72μR at the left side. 3. Under the same conditions, the dose showed higher value by about 5% in the presence of object(phantom) than in the case of absence.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.207-212
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• 2015

When performing Chest x-ray examination to pregnant woman, normally we shield back side of abdomen. In this situation, scattered rays made by equipment and surrounding structure can enter front side of abdomen. Therefore, in this study, we evaluate suitability of abdomen shield especially to pregnant woman. In case of One shielding material placed back of abdomen, the measured value is $0.676{\pm}0.19uSv/hr$. Two shielding material is $0.764{\pm}0.04uSv/hr$. Three is $0.685{\pm}0.16uSv/hr$. The exposure dose inferred in this study does not excess annual effective dose limit. But It is not mean absolute safety. So we have to minimize occurrence of stochastic effect of radiosensitivity by shielding front side of abdomen of pregnant woman in clinic.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.895-908
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• 2018

As modern science is developed and advanced, examination and number of times using radiation are increasing daily. General diagnostic X-ray generator is installed on stationary form, But X-ray generator was developed because patient who is in the intensive care unit, operation room, emergency room can not move to general x-ray room. What we examine patient by x-ray generator is certainly necessary, So patient exposure is inevitable. but reducing radiation exposure is highly important matter about radiation technology, guardian, patient in the same hospital room, nurse etc. For this reason, rule regarding safety control of diagnostic x-ray generator revised for radiation worker, patient and protector proclaim that mobile diagnostic x-ray shield must placed in case of examine different location excluding operation room, emergency room, intensive care unit. But, radiogical technologist is having a lot of difficulties to examine with mobile x-ray generator, diagnostic x-ray shield partition, image plate and lead apron. So, when we use x-ray generator, we manufacture shield tools can be attached to the mobile x-ray generator On behalf of x-ray shield partition and conduct analysis and in comparison to part of body and distribution of dose rate and find way to reduce radiation exposure through distribution of dose rate of patient within the radiogical technologist, medical team. Mobile x-ray generator aimed at SHIMADZU inc. R-20, We manufactured equipment for shielding x-ray scattered x-ray by installing shielding wall from side to side based on support beam on the mobile x-ray generator. Shielding wall when moving can be folded and designed to expand when examine. Experiment measured five times in each by an angle for dose rate of eyes, thyroid, breast, abdomen and gonad on exposure condition of upper and lower extremity, chest, abdomen which is examined many times by mobile x-ray generator. We used dosimeter RSM-100 made by IJRAD and measured a horizontal dose rate by body part. The result of an experiment, shielding decreasing rate of the front and the rear showed 77 ~ 98.7%. Therefore using self-production shielding wall reduce scattered x-ray occurrence rate and confirm can decrease exposure dose consequently. Therefore, through this study, reduction result which is used shielding wall of self-production will be a role of shielding optimization and it could be answer about reduction of medical exposure recommended by ICRP 103.

• Journal of radiological science and technology
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• v.42 no.5
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• pp.365-371
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• 2019

We have developed and applied a diagnostic Multi-Leaf Collimator (MLC) to optimized the X-ray field in medical imaging and the usefulness evaluated through the fusion of infrared image and X-ray image acquired by infrared camera. The hand and skull radiography with multi-leaf collimator(MLC) showed significant area dose reductions of 22.9% and 31.3% compared to ARC and leakage dose was compliant with KS A 4732. Also scattering doses of 50 cm and 100 cm showed a significant decrease to confirm the usefulness of MLC. It was confirmed that the fusion of infrared images with an adjustable degree of transparency was possible in the X-ray images. Therefore, fusion of anatomical information with physiological convergence is expected to contribute and improvement of diagnostic ability. In addition, the feasibility of convergence X-ray imaging and DITI devices and the possibility of driving MLC with infrared images were confirmed.

• Annual Conference of KIPS
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• 2021.11a
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• pp.708-710
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• 2021

본 논문에서는 X-ray 진단에서 산란선으로 인한 영상의 왜곡을 보정하는 방법으로서 수정된 구조의 AE(Auto-Encoder) 모델에 기반한 방법론을 제안한다. 기존 AE 모델의 계층에 따라 특징지도의 크기가 축소되고 팽창되는 과정에서 영상 복원에 필요한 정보가 소실될 가능성을 보완하기 위하여 동일 레벨 계층 간에 스킵 연결을 추가하였다. 또한 X-ray 영상에서 피사체 세부 부위의 두께와 밀도에 따라 산란선의 영향이 서로 다른 형태로 나타난다는 특성을 학습 과정에 효과적으로 반영하기 위하여 어텐션 모듈을 추가한 네트워크 구조를 도입하였다. 총 80 쌍의 흉부 X-ray 영상 데이터에 대하여 기존의 AE 모델을 사용한 방법 및 U-Net 과 FFA-Net 모델을 사용한 영상 복원 기법의 실험 결과를 상호 비교함으로써 제안된 방법의 타당성을 평가하였다.

• Journal of Radiation Protection and Research
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• v.42 no.4
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• pp.197-204
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• 2017

Background: X-ray imaging detectors for the nondestructive cargo container inspection using MeV-energy X-rays should accurately portray the internal structure of the irradiated container. Internal and external factors can cause noise, affecting image quality, and scattered radiation is the greatest source of noise. To obtain a high-performance transmission image, the influence of scattered radiation must be minimized, and this can be accomplished through several methods. The scatter rejection method using an anti-scatter grid is the preferred method to reduce the impact of scattered radiation. In this paper, we present an evaluation the characteristics of the signal and noise according to physical and material changes in the anti-scatter grid of the imaging detector used in cargo container scanners. Materials and Methods: We evaluated the characteristics of the signal and noise according to changes in the grid ratio and the material of the anti-scatter grid in an X-ray image detector using MCNP6. The grid was composed of iron, lead, or tungsten, and the grid ratio was set to 2.5, 12.5, 25, or 37.5. X-ray spectrum sources for simulation were generated by 6- and 9-MeV electron impacts on the tungsten target using MCNP6. The object in the simulation was designed using metallic material of various thicknesses inside the steel container. Using the results of the computational simulation, we calculated the change in the scatter-to-primary ratio and the signal-to-noise ratio improvement factor according to the grid ratio and the grid material, respectively. Results and Discussion: Changing the grid ratios of the anti-scatter grid and the grid material decreased the scatter linearly, affecting the signal-to-noise ratio. Conclusion: The grid ratio and material of the anti-scatter grid affected the response characteristics of a container scanner using high-energy X-rays, but to a minimal extent; thus, it may not be practically effective to incorporate anti-scatter grids into container scanners.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.4
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• pp.171-178
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• 2019

The use of anti-scatter grids in radiographic imaging has the advantage of preventing the image distortion caused by scattered radiation. However, it carries the side effect of leaving artifacts in the X-ray image. In this paper, we propose a grid line suppression technique using discrete cosine transform(DCT). In X-ray images, the grid lines have different characteristics depending on the shape of the object and the area of the image. To solve this problem, we adopt the DCT transform based on a dynamic segmentation, and propose a filter transfer function for each individual segment. An algorithm for detecting the band of grid lines in frequency domain and a band stop filter(BSF) with a filter transfer function of a combination of Kaiser window and Butterworth filter have been proposed. To solve the blocking effects, we present a method to determine the pixel values using multiple structured images. The validity of the proposed theory has been evaluated from the experimental results using 140 X-ray images.