• Journal of the Korean Society of Radiology
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• v.18 no.6
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• pp.681-690
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• 2024

This study aimed to quantitatively analyze the effect of anode angle on the heel effect and image quality in digital radiography systems. For this purpose, two X-ray devices with anode angles of 12° and 16° (Accuray D6 and INNOVISION-SH) were used to compare the radiation dose distribution and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in thoracic spine images, using a chest phantom under identical imaging conditions. In the radiation dose distribution study, it was observed that the device with a 12° anode angle showed more pronounced dose distribution non-uniformity, with a sharp decrease in dose from the cathode side to the anode side. In contrast, the 16° anode angle device exhibited a more gradual dose decrease and a more uniform distribution than the 12° device. It was confirmed that a smaller anode angle intensified the heel effect, causing the radiation intensity to be distributed unevenly. In the thoracic spine image analysis, it was found that, with an anode angle of 16°, the SNR and CNR improved when the chest phantom was placed in the standard orientation (T12 on the cathode side and T1 on the anode side). This suggests that the anode angle and patient positioning influence the effect of the heel effect on image quality. Compared to the reverse orientation (T1 on the cathode side and T12 on the anode side), the standard orientation provided superior image quality. Based on these findings, it is recommended that, in clinical practice, awareness of the anode angle and accurate differentiation between standard and reverse positioning during thoracic spine imaging with digital radiography systems can enhance image quality and improve diagnostic reliability.

• Journal of the Korean Society of Radiology
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• v.18 no.6
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• pp.725-732
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• 2024

Although radiation equipment are developing rapidly, general research on fundamental physics approaches is relatively lacking. Therefore, this study aims to analyze the energy difference of Anode Heel Effect(AHE) based on the tube voltages range of 50 kVp to 125 kVp of X-ray tube, and ultimately suggest an appropriate tube alignment for general radiography that can be used clinically. The radiation simulation was performed using the MCNP(Monte Carlo N-Particle), and the X-ray tube was modeled as E7869X(Japan) used in stationary X-ray equipment(Samsung GC58A). The tube voltages used in this study were 50, 65, 80, 95, 110, and 125 kVp, and the photon spectrum was analyzed to compare trends using MCNP and TASMIP(Tungsten Anode Spectral Model Interpolating Polynomials), and the AHE analysis was calculated into 1,849 sections consisting of 1 cm². Comparisons between the anode and the cathode side photon values of 50 kVp(0.1%), 65 kVp(9.1%), 80 kVp(16.5%), 95 kVp(16.3%), 110 kVp(20.6%), and 125 kVp(28.1%). Therefore, based on these findings, it is determined that the tube range requiring consideration of the AHE is 80, 95, 110, and 125 kVp, while for 50 and 65 kVp, AHE consideration is deemed unnecessary.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.223-229
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• 2011

When negative electron in x-ray tube is accelerated in to a high speed and then the currency of the electron is blocked by the target, x-ray happens by the conversion of the energy. The real area where the fast accelerated electron collides to a target area is called actual focal spot. When the string focused size is observed at the central ray side, where the direction x-ray comes out, the size seems to be reduced. This focus is called effective focal spot. According to radiation angle of x-rays tube, the degree of the negative pole side presents higher value than inclination, the amount of exposed radiation that patient receives differs by the angle of positive pole, which means effective focal spot is the variable. This paper presents the correlation between size of effective focal spot and amount of exposed radiation to the patient by it, and effective research for homogenized dose dispersion by the size of effective focal spot. In conclusion, following the focal size, effective range which was -8cm ~ 0 cm on average, was found and average dose rate was 0.019 R/min. Through this range, for patients with small radiation exposure, image with good density and resolution in aspect of diagnosing will be able to be obtained.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.435-442
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• 2016

This study was an investigation of the anode heel effect caused by changing the angle of the x-ray tube. We established the following conditions for experimental measurements: 70 kV, 30 mAs, focus-detector distance of 100cm, and a collimator setting of $35{\times}43cm^2$. The measurement points were set up at the center of the collimator and extended to each side in intervals of 3.5cm, with points A1, A2, A3, A4, A5, A6 on the anode side and points C1, C2, C3, C4, C5, C6 on the cathode side. We measured the entrance surface dose from point A6 to point C6 with each point perpendicular to an x-ray tube. And we did the same when measuring different angles of the x-ray tube from 15 to 30 degrees for every point on the anode and cathode sides. Using perpendicular x-ray tube, we found that the entrance surface dose of the A5 point was three times higher than that of the C5 point. Thus, we conclude that if the anode side is placed near highly radiosensitive organs, then there will be less radiation exposure when using a perpendicular x-ray tube. When imaging using x-ray tube angles, an angle to the cathode side can reduce the gap of the entrance surface dose on both the anode and cathode sides. When imaging areas where there are differences in thickness between the upper and lower sides, the angle to the cathode side that is closer to the thicker area can reduce the gap of the entrance surface dose and capture a higher quality image.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.297-303
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• 2016

This study was conducted to evaluate the dose of the space to the controller located within the mammography room conducted a research on ways to the reduction exposure to the radiation workers. Results, the dose of 6.18 mGy/year was measured when there is no difference in the hilar area of the controller position, the dose of 2.35E-11 mGy/year was measured when installing the Shielding door. In addition, when the direction of the X-ray tube anode be heading this direction controller, low average level measured was 0.30 mGy/year. Based on this study, the mammography should be considered when installing the anode and cathod directions. And, by installing the shielding door, it must be able to completely separate shooting space and control room. This is the best way radiation protection method in radiation workers.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.733-738
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• 2013

Sediment contains a high fraction of organic matter, high buffering capacity, and a large portion of fine grained particles such as silt and clay, which are major barriers to remove heavy metals from sediments. In this study, a lab-scale electrokinetic (EK) technique was applied to remove heavy metals effectively from marine sediment at a constant voltage gradient of 2 V/cm. A concentration of 0.1 M of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), $HNO_3$, and HCl were circulated in the cathode, and tap water was circulated in the anode. CA extracted 92.4% of Ni, 96.1% of Cu, 97.1% of Zn, and 88.1% of Pb from marine sediment. A higher voltage gradient enhanced the transport of citrate and EDTA into the sediment and, therefore, increased metal extraction from the marine sediment through a complexation reaction between metals and the chelates. Based on these results, the electrokinetic process using a high voltage gradient with EDTA and CA might be useful to extract heavy metals from marine sediment.