• Progress in Medical Physics
• /
• v.22 no.4
• /
• pp.163-171
• /
• 2011

The purpose of this study was to investigate the effect of various technical parameters for the dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE) including the scatter radiation from the object, the blur caused by the focal spot, geometric magnification and detector characteristics. For the tube voltages ranging from 40 to 90 kVp in 10 kVp increments at the FDD of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at the same effective dose. The results showed that the eDQE was largest at 60 kVp when compares the eDQE at different tube voltage. Especially, the eDQE was considerably higher without the use of an anti-scatter grid on equivalent effective dose. This indicates that the reducing the scatter radiation did not compensate for the loss of absorbed effective photons in the grid. When the grid is not used the eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF). However, most of major hospitals in Korea employed a short FDD of 100 cm with an anti-scatter grid for the chest radiological examination of a 15 month old infant. As a result, the entrance surface air kerma (ESAK) values for the hospitals of this survey exceeded the Korean DRL (diagnostic reference level) of $100{\mu}Gy$. Therefore, appropriate technical parameters should be established to perform pediatric chest examinations on children of different ages. The results of this study may serve as a baseline to establish detailed reference level of pediatric dose for different ages.

• Journal of radiological science and technology
• /
• v.37 no.1
• /
• pp.7-14
• /
• 2014

By using a Chest Phantom(DUKE Phantom) focusing on dose reduction of diagnostic radiation field with the most use of artificial radiation, and attempt to reduce radiation dose studies technical radiation. Publisher of the main user of the X-ray Radiological technologists, Examine the effect of reducing the radiation dose to apply additional filtering of the X-ray generator. In order to understand the organ dose and effective dose by using the PC-Based Monte Carlo Program(PCXMC) Program, the patient receives, was carried out this research. In this experiment, by applying a complex filter using a copper and Al(aluminum,13) and filtered single of using only aluminum with the condition set, and measures the number of the disk of copper indicated by DUKE Phantom. The combination of the composite filtration and filtration of a single number of the disk of the copper is the same, with the PCXMC 2.0. Program looking combination of additional filtration fewest absorbed dose was calculated effective dose and organ dose. Although depends on the use mAs, The 80 kVp AP projection conditions, it is possible to reduce the effective amount of about 84 % from about 30 % to a maximum at least. The 120 kVp PA projection conditions, it is possible to reduce the effective amount of about 71 % from about 41 % to a maximum of at least. The organ dose, dose reduction rate was different in each organ, but it showed a decrease of dose rate of 30 % to up 100 % at least. Additional filtration was used on the imaging conditions throughout the study. There was no change in terms of video quality at low doses. It was found that using the DUKE Phantom and PCXMC 2.0 Program were suitable to calculate the effect of reducing the effective dose and organ dose.

• Journal of the Korean Society of Radiology
• /
• v.15 no.7
• /
• pp.1041-1047
• /
• 2021

In this study, the effective dose for frequently general radiography among the diagnostic reference level (DRL) for examinations provided by the government in Korea was evaluated using the Monte Carlo N-Particle eXtended (MCNPX) simulation tool. We were selected to evaluate for a total of 5 examination sites which included head anterior-posterior, chest (posterior-anterior, lateral), abdomen anterior-posterior and pelvis anterior-posterior. Physical conditions such as tube voltage and tube current used in MCNPX simulation were used in domestic conditions of the Korea Disease Control and Prevention Agency (KDCA). To evaluate domestic medical radiation exposure, we used the HDRK-Man computerized human phantom manufactured based on the international standard ICRP 103 that was applied to the MCNPX simulation. The phantom could represent the standard body shape of Koreans. As a results, the effective dose corresponding to the DRL based on adult males of head anterior-posterior position was 0.086 mSv, chest posterior-anterior position was 0.05 mSv, chest lateral was 0.354 mSv, abdomen anterior-posterior position was 0.548 mSv, and pelvis anterior-posterior position was 0.451 mSv.

• Journal of the Korean Society of Radiology
• /
• v.12 no.2
• /
• pp.149-157
• /
• 2018

One of the purposes of radiation protection is to minimize stochastic effects. PCXMC 2.0 is a Monte Carlo Simulation based program and makes it possible to predict effective dose and the probability of cancer development through entrance surface dose. Therefore, it is especially important to measure entrance surface dose through dosimeter. The purpose of this study is to measure entrance surface dose through semiconductor dosimeter, general dosimeter, glass dosimeter, and to compare and analyze the effective dose and probability of disease of critical organs. As an experimental method, the entrance surface dose of skull, chest, abdomen was measured per dosimeter and the effective dose and the probability of cancer development of critical organs per area was evaluated by PCXMC 2.0. As a result, the entrance surface dose per area was different in the order of a general dosimeter, a semiconductor dosimeter, and a glass dosimeter even under the same condition. Base on this analysis, the effective dose and probability of developing cancer of critical organs were also different in the order of a general dosimeter, a semiconductor dosimeter, and a glass dosimeter. In conclusion, it was found that the effective dose and the risk of diseases differ according to the dosimeter used, even under the same conditions, and through this study it was found that it is important to present an accurate entrance surface dose model according to each dosimeter.

• Journal of radiological science and technology
• /
• v.37 no.3
• /
• pp.177-185
• /
• 2014

This study focused on effects of patient exposure dose reduction with AEC (Auto Exposure Control) marker that is designed for showing location of AEC in X-ray Chest radiography. It included 880 adults who have to use Chest X-ray Digital Radiography system (DRS, LISTEM, Korea). AEC (Ion chambers are posited in top of both sides) are used to every adult and set X-ray system as Field size $17{\times}17inch$, 120kVp, FFD 180cm. 440 people of control group are posited on detector to include both sides of lung field and the other 440 people of experimental group are set to contact their lung directly to Ion chamber (making marker to shows location). Then, measured every DAP and, estimated patient effective dose by using PCXMC 2.0. The average age of control group (M:F=245:195) is 53.9 and the average BMI is 23.4. BMI ranges from under weight: 35, normal range: 279, over weight: 106 to obese: 20 and average DAP is 223.56mGycm2, Mean effective dose is 0.045mSv. The average age of experimental group (M:F=197:243) is 53.7 and the average BMI is 22.7. BMI ranges from under weight: 34, normal range: 315, over weight: 85 to obese: 6 and average DAP is 207.36mGycm2, Mean effective dose is 0.041mSv. Experimental group shows less Mean effective dose as 0.004mSv (9.7%) than control group. Also, patient numbers who got over exposure more than 0.056mSv (limit point to know efficiency of AEC marker) is 65 in control group (14.7%), 19 in experimental group (4.3%) and take statistics with t-Test. The statistical difference between two groups is 0.006. In order to use proper amount of X-ray in auto exposure controlled chest X-ray system, matching location between ion chamber and body part is needed, and using AEC marker (designed for showing location of ion chamber) is a way to reduce unnecessary patient exposure dose.

• Journal of Radiation Protection and Research
• /
• v.28 no.1
• /
• pp.35-42
• /
• 2003

Methodology for calculating the organ equivalent doses and the effective doses of pediatric and adult patients undergoing medical X-ray examinations were established. The MIRD-type mathematical phantoms of 4 age groups were constructed with addition of the esophagus to the same phantoms. Two typical examination procedures, chest PA and abdomen AP, were simulated for the pediatric patients as well as the adult as illustrative examples. The results confirmed that patients pick up approximate 0.03 mSv of effective dose from a single chest PA examination, and 0.4 to 1.7 mSv from an abdomen AP examination depending on the ages. For dose calculations where irradiation is made with a limited field, the details of the position, size and shape of the organs and the organ depth from the entrance surface considerably affect the resulting doses. Therefore, it is important to optimize radiation protection by control of X-ray properties and beam examination field. The calculation result, provided in this study, can be used to implement optimization for medical radiation protection.

• Journal of the Korean Society of Radiology
• /
• v.11 no.1
• /
• pp.55-61
• /
• 2017

There are no recommended test conditions for digital photography in Chest PA examinations. However, each company recommends shooting examinations of the high voltage applied to the previous analog examination. The condition that satisfies the value of 200 ~ 800 which is the recommended Exposure Index value recommended by Philips was selected, and the dose was evaluated by Monte Carlo simulation, and the SNR and CNR were compared. As a result, it was possible to reduce the effective dose up to 77% by controlling the tube voltage, tube current, and additional filter, not the conventional high voltage imaging method. Although there were some differences according to the test conditions, the image evaluation results were similar to the images. We will compare the exposure dose according to changes in tube voltage, tube current, and additional filter at the digital chest radiograph and evaluate the image quality of the image to propose optimal conditions.

• Journal of the Korean Society of Radiology
• /
• v.12 no.1
• /
• pp.23-30
• /
• 2018

To evaluate the effect of patient size on effective dose and image quality for Digital Chest Tomosynthesis(DTS) using additional 0.3 mm copper filtration. Eighty artificial nodules were placed in the thorax phantom("Lungman," Kyoto Kagaku, Japan), and Digital Chest Tomosynthesis(DTS) images of the phantom were acquired both with and without added 0.3 mm Cu filtration. To simulate patients of three sizes: small, average size and oversize, one or two 20-mm-thick layer of PMMA(polymethyl methacrylatek) blocks were placed on the phantom. The Effective dose was calculated using Monte Carlo simulations. Two evaluations of image quality methods have been employed. Three readers counted the number of nodules detected in the lung, and the measured contrast-to-noise ratios(CNRs) were used. Data were analyzed statistically. The ED reduced $26{\mu}Sv$ in a phantom, $33{\mu}Sv$ in one 20-mm-thick layer of PMMA block placed on the phantom, and $48{\mu}Sv$ in two 20-mm-thick layer of PMMA blocks placed on the phantom. The Effective dose(ED) differences between DTS with and without filtration were significant(p<0.05). In particular, when we used two 20-mm-thick layer of PMMA blocks placed on the phantom, the ED was significantly reduced by 36% compared with those without additional filtration. Nodule detection sensitivities were not different between with and without added filtration. Differences of CNRs were statistically insignificant(p>0.05). Use of additional filtration allows a considerable dose reduction during Digital Chest Tomosynthesis(DTS) without loss of image quality. In particular, additional filtration showed outstanding result for effective dose reduction on two 20-mm-thick layer of PMMA blocks placed on the phantom. It applies to overweight patients.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.11
• /
• pp.4411-4417
• /
• 2010

This study was retrospectively to compare the exposure dose and the imaging quality in coronary CT angiography by using the 64 channel multidetector computed tomography and the 128 channel DSCT. Effective dose was calculated dose length product (DLP) by multiplied the convention factor of chest (0.017). Imaging quality was assessed by radiologists using the 5-point Likert scale. The DLP was ranged from 851 to $1277mGy{\cdot}cm$ (mean: 17.23 mSv) in the 64 channel MDCT and from 82 to $110mGy{\cdot}cm$ (mean: 1.58 mSv) in the of 128 channel DSCT, respectively. The score of imaging quality was respectively $3.31{\pm}0.62$ in 64 channel MDCT and $4.05{\pm}0.46$ in the 128 channel DSCT. The exposure dose of 128 channel DSCT has decreased 1ess 1/10. The score of imaging quality was significant difference between two modalities and the frequency (>4 good) in the 128 channel DSCT is about three times than that of the 64 channel MDCT. Therefore, the 128 channel DSCT in coronary CT angiography is clinically more effective modality for both investigators and patients.

• Journal of radiological science and technology
• /
• v.42 no.3
• /
• pp.209-215
• /
• 2019

Comparison of the effective dose of the chest and the equivalent dose of the lens site in the radiation workers working at four medical institutions with the PET / CT room located in one metropolitan city and province from April 1 to June 30, 2018 Respectively. Radioactive medicine were measured at the time of dispensing and at the time of injection. In this experiment, the average dispensing time per patient was 5.7 minutes and the average injection time was 3.1 minutes. The equivalent dose at the lens site was $0.78{\mu}Sv/h$ for 1 mCi, and the effective dose for chest was $0.18{\mu}Sv/h$ per 1 mCi. The equivalent dose at the lens site during injection was $0.88{\mu}Sv/h$ per mCi and the effective dose of chest was $0.20{\mu}Sv/h$ per mCi. The daily effective dose of the chest was $0.9{\pm}0.6{\mu}Sv$ and the equivalent dose of the lens site was $3.6{\pm}1.4{\mu}Sv$ during daily dosing for 20 days. The effective dose of the chest during the day was $0.6{\pm}0.5{\mu}Sv$ and the equivalent dose of the lens was $2.2{\pm}1.0{\mu}Sv$. At the time of dispensing, the equivalent dose of the lens was $0.187{\pm}0.035mSv$, the effective dose of the chest was $0.137{\pm}0.055mSv$, the equivalent dose of the lens was $0.247{\pm}0.057mSv$, and the effective dose of the monthly chest was $0.187{\pm}0.021mSv$. As a result of the corresponding sample test, the equivalent dose and the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, The equivalent dose of the lens and the effective dose of the chest were statistically significant (p<0.05) with a significance of 0.000. However, there was no statistically significant difference (p>0.05) between the equivalent dose and the effective dose of the chest, the equivalent dose of the lens at the time of injection, and the effective dose of the chest at 0.138 and 0.230, respectively.