• Journal of radiological science and technology
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• v.41 no.5
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• pp.391-396
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• 2018

The purpose of this study was to compare and analyze the patient dose according to the distance between the X-ray tube focus and the image receptor, and to propose a new method for quantitatively evaluating the image quality. Using this quantitative evaluation method, the optimal distance for increasing x-ray image quality with low radiation dose was estimated between source and image receptor in Rib series radiography. Phantom images were obtained by changing the distance between focus and image receptor (100 cm and 180 cm). The patient radiation dose was estimated using entrance surface dose and dose area product. In order to evaluate image quality objectively, a non - reference image evaluation method was employed with paper and salt noise and Gaussian filter. As a result of this study, when the SID was changed from 100 cm to 180 cm, the entrance surface dose decreased by 4 ~ 5 times and the dose area product decreased by 3 times. In addition, there is no significant difference in image quality between of SID 180 cm and SID 100 cm. In conclusion, it was demonstrated that performing the rib series radiography at SID 180 cm is an optimal method to reduce the exposure dose and improve the image quality.

• Journal of radiological science and technology
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• v.42 no.6
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• pp.483-489
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• 2019

This paper obtained and compared these dose values by setting and comparing the X-ray imaging conditions (tube voltage 60 kVp, 70 kVp, 80 kVp, tube current 10 mAs, 16 mAs and X-ray field size are 10 × 10 cm, 15 × 15 cm). Each dose value was measure 10 times and represented as an average value. The purpose of this experiment is to serve as a reference for the X-ray exposure of diagnostic areas according to the type of dosimeter and to help with another dose measurement. The results of the experiment showed very little difference between the glass dosimeter(GD) and semiconductor dosimeter values due to changes in tube voltage of 60, 70, 80 kVp, regardless of field sized, but for dose area product(DAP), the difference in dose value was significant according to field size.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.645-650
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• 2018

This research aims at measuring images density of according to DAP(dose area product), and suggesting the need to quality control of exposure dose. When tube voltage was fixed as 80 kVp and tube current was set as 1, 25, 50, 80, and 100 mAs, with the increase of DAP from 25 mAs to 50 mAs, the dose also rose 1.88 times as much as before, and with the increase from 50 mAs to 100 mAs, it got 2.05 time higher than before. However, the images density obtained as film grew as much as 48% with the increase from 25 mAs to 50 mAs, and 29% with the increase from 50 mAs to 100 mAs. In addition, it has been found out that the higher the DR images density got from 25 mAs to 50 mAs, the bigger it became by 12%, and that it got bigger by 30% with the increase from 50 mAs to 100 mAs. In other words, the differences in the image density by the increase of the dose with the digital imaging equipment in a proper condition was proved to be less than in the film images. Based on the results of this research, medical institutions using a digital imaging equipment are expected to be able to reduce exposure dose of each region of interest than now through the quality control of radiation dose.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.115-122
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• 2018

We aims to perform comparative analysis on the dose area and image qualities varying on the slice thickness when using Automatic Exposure Controller (AEC) and manual exposure; thus, it wants to suggest a measure to reduce exposure dose by setting the optimal examination condition for each slice thickness. The method was to set the thickness as Thin, Normal, and Heavy adult and evaluate the dose area, spatial resolution, low contrast resolution, Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) according to each slice thickness by using the AEC and the manual exposure controller. The dose area according to each slice thickness all increased both when using the AEC and the manual exposure. However, the manual exposure showed lower dose area product than the AEC. Spatial resolutions and low contrast resolutions were all observed to be higher than the evaluation standard. Also, the SNR and CNR of each thickness all increased when using the AEC. When using the manual exposure, SNR and CNR increased in all cases other than the Heavy Adult. Consequently, the Thin and Normal Adult showed dose reduction about 2 times when using the manual exposure controller, while ensuring the image quality. Heavy adult was able to maintain good image quality by using AEC.

• Journal of IKEEE
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• v.23 no.2
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• pp.739-742
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• 2019

In this paper, we propose enhanced DAP(Dose Area Product). The development of enhanced DAP proposed in this paper has optimized the area dose meter that was developed previously. The development of enhanced DAP performed Optimized design of charge integrator and ADC circuit, optimization of line transceiver for RS-485 communication, optimization of display circuit, and optimization of PC-based control program for interlocking and aging. As a result of evaluating the performance of the proposed system in an accredited testing laboratory, Radiation dose dependence and Radiation quality dependence were measured to be 4.2%, which is below ${\pm}15%$ of international standard. Energy range/Tube voltage was confirmed in the range of 30~150kV. The sensitivity difference between sensor field and sensor field area dose sensitivity was measured to be 4.3%, and it was confirmed that it operates normally under ${\pm}15%$ of international standard. In order to measure the reproducibility of the area dosimeter, it was confirmed that it was 0% and it was operated normally at less than 2% of IEC60580 recommendation. Digital resolution was confirmed to be a minimum unit of $0.01{\mu}Gy{\cdot}m^2$ within the error range for the reference dose per hour.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.139-145
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• 2021

This study is to confirm the range of tube voltage for Chest X-ray in DR system by comparing with dose area product (DAP) and effective dose in efficient detector exposure index (DEI) range. GE definium 8000 was used to for the phantom study. The range of tube voltage is 60~130 kVp and of mAs is 2.5~40 mAs. The acquired images were classified into efficient DEI groups, then calculated effective dose with DAP by using a PC-Based Monte Carlo Program 2.0. The signal to noise ratio (SNR) was measured at 4 regions, including the thoracic spine, the lung area with the ribs, the lung area without the ribs, and the liver by using Picture Archiving and Communication System. The significance of the group for each tube voltage was verified by performing the kruskal-wallis test and the mann-whitney test as a post-test. When set to 4 groups dependned on the tube voltage, DAP showed significant differences; 60 kVp and 80 kVp, and 60 kVp and 90 kVp (p= 0.034, 0.021). Effective dose exhibited no statistically significant differences from the all of the group (p>0.05). SNR exhibited statistically significant differences from the all of the group in the liver except compared to 80 kVp and 90 kVp (p<0.05). Therefore, high tube voltages of 100 kVp or more need to be reconsidered in terms of patient dose and imaging in order to represent an appropriate chest X-ray image in a digital system.

• Journal of the Korean Society of Radiology
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• v.18 no.5
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• pp.447-454
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• 2024

In this study, we compared the dose using the DAP (Dose Area Product) and Air kerma values across the five most frequently used views in percutaneous coronary intervention, We also evaluated the images based on Contrast to Noise Ratio (CNR) and Signal to Noise Ratio (SNR). Compared to the control group, which did not use magnification, reducing the Field of View (FOV) for magnification resulted in a statistically significant increase in the average DAP and average Air kerma values across all five views. However, no statistically significant difference was observed between the control group and the magnification method that used the Live zoom function. When comparing the CNR of the magnification method using the Live zoom function and the magnification method by reducing the FOV, it was confirmed that the average CNR and average SNR values were significantly improved in all but one of the 15 points. Therefore, it was confirmed that the magnification method using the Live zoom function improved the image quality without increasing the dose.

• Journal of radiological science and technology
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• v.34 no.3
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• pp.209-214
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• 2011

Goal of this study was to measure effective radiation dose of highly exposed patients who were treated by TACE, interventional radiology from June to September 2010. The effective radiation dose was approximately measured by weighted DAP (dose area product) with the ionization chamber which is inserted in angiography equiment (Philips Allura Xper FD 20). Radiation dose was measured by TLD which was attached to patients' thyroid and genital gland. The average of ED (effective dose) was 18.43${\pm}$6.63 mSv per person and the average of radiation dose of thyroid and genital gland was 0.37 mSv, 0.77 mSv, respectively. The mean radiation dose of operators who wear the protector was 0.07 mSv for thyroid, and 0.01 mSv for genital gland, respectively. All staffs involved in TACE treatment, have to keep them aware and use the appropriate protectors to reduce the radiation dose of patient.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.347-353
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• 2015

The purpose of this study is to suggest proper additional filtration by comparisons patient dose and image quality among additional filters in digital chest tomosynthesis (DTS). We measured the effective dose, dose area product (DAP) by changing thickness of Cu, Al and Ni filter to compare image quality by CD curve and SNR, CNR. Cu, Al and Ni exposure dose were similar thickness 0.3 mm, 3 mm and 0.3 mm respectively. The exposure dose using filter was decreased average about 33.1% than non filter. The DAP value of 0.3 mm Ni were decreased 72.9% compared to non filter and the lowest dose among 3 filter. The effective dose of 0.3 mm Ni were decreased 48% compared to 0.102 mSv effective dose of non filter. At the result of comparison of image quality through CD curve there were similar aspect graph among Cu, Al and Ni. SNR was decreased average 19.07%, CNR was average decreased 18.17% using 3 filters. In conclusion, Ni filtration was considered to be most suitable when considered comprehensive thickness, character, sort of filter, dose reduction and image quality evaluation in DTS.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.501-508
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• 2023

This study used a adult absorption dose phantom (CIRS model 701-G, USA) made of human equivalent material and the vascular imaging equipment Allura Xper FD 20 (Philips, Netherlands). Optically stimulated luminescent dosimeters (OSLD) were inserted into the anatomical positions corresponding to each organ, and the exposure dose was measured. Dose area product (DAP) and air kerma (AK) measured by the dose meter in the equipment were compared. Continuous imaging was performed at two angles for a total of 20 minutes, with a frame per seconds of 3.75 and 7.5 fps and an FOV of 42 cm, 37 cm, and 31 cm, respectively, under the conditions of fluoflavor I, II, and III, each selected for 5 repetitions. This study was found that selecting a lower fps was the most effective way to reduce patient exposure dose, and adjusting the fluoflavor was a good alternative method for reducing patient exposure dose at high fps. Therefore the method of condition change with the greatest dose reduction effect is to set the minimum FPS and can reduce patient exposure dose according to geometric conditions and fluoflavor characteristics.