• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.135-144
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• 2010

Purpose: The purpose of this study is that through production of phantom for respiration gated radiotherapy, assessing appropriacy of exposure dose for the therapy using RPM (Real-time Position Management). Materials and Methods: We located measurement object on the phantom for respiration gated radiotherapy made of 2 linear actuator, acrylic panel, stanchion, iron plate ets. to drive (up, down, front, back). Using 4D CT scan, we analyzed patient's respiration and reproduced the movement by computer. On the phantom, we located a 2D-Array (PTW) and an White water phantom (4.5 cm) and used DMLC (interval 2 cm) in the field size $10{\times}10\;cm$, then exposed 21EX X-ray 100 MU, in the case of phantom was (1) static (2) moving (3) gated using RPM respectively gantry $0^{\circ}$ and $90^{\circ}$ We measured with a 0.125 CC ionization chamber (PTW) on the phantom (7.5 cm) in the same condition. Results: Ionization chamber: There were within 0.3% of error with gating respiration and approximately 2% of error without gating in the same condition. 2D-Array: Gantry $90^{\circ}$, field size $10{\times}10\;cm$, using DMLC. There were within 3% of error with gating respiration and approximately 16% of error without gating. Conclusion: The phantom for respiration gated radiotherapy makes plans considering patient's movement, quantitative analysis of exposure dose and proper assessment therapy for IMRT patients using RPM possible.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.377-384
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• 2016

This is a study on the optimized dispensing of the auto dispenser used for the purpose of reducing the exposure dose and accurate radiation dose of radioisotope with regard to the PET/CT practitioners. The research method was to find the optimized dispensing method through evaluating the results according to the syringe type, dispensing rate, and vial pressure and through the application of corrected values. As a result of this study, 9.38 mCi has been dispensed on average in the case of 5 ml syringe, and the reproducibility close to 10 mCi was shown at the dispense of 9.55 mCi in the case of 3 ml syringe. In the evaluation according to the dispensing rate, the quantity of radioisotope close to 10 mCi was dispensed at the rate of 5 mm/min when the measurement was carried out by increasing the rate by 5 mm/min units in the order of 5, 10, 15 and 20 mm/min. In the evaluation result according to the vial pressure before/after the use of Needle filter, it was measured to be 9.53 mCi before use and 9.84 mCi after use confirming that the dispensing after using Needle filter showed the optimal value. In addition, in the evaluation of radioactivity before/after the application of corrected values according to the increase in dispense frequency, it was measured 9.53 mCi before correction and 10.07 mCi after correction confirming that the value with correction applied was closer to the quantitative value. Thus, a good optimized method was confirmed to use a 3 ml syringe with dispensing rate of 5 mm/min, to use a Needle filter at dispensing, and to set the corrected value of [$y=0.097{\times}x$] according to the dispensing frequency of equipment.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.67-75
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• 2022

The aim of this study is to establish a new QC method that can simultaneously evaluate the resolution of the x/y plane and the z-axis by producing a phantom that can reflect exposure and reconstruction parameter of MDCT system. It was used with Aquilion ONE(Cannon Medical System, Otawara, Japan), and the examination was scanned using of 120 kV, 260 mA, and the D-FOV of 300 mm². It produced new SSP phantom modules in which two aluminum plates inclined at 45° to a vertical axis and a transverse axis to evaluate high contrast resolution of x/y plane and z axis. And it changed factors such as the algorithm, distance from gantry iso-center. All images were reconstructed in five steps from 0.6 mm to 10.0 mm slice thickness to measure resolution of x/y plane and z-axis. The image data measured FWHM and FWTM using Profile tool of Aquarius iNtusion Edition ver. 4.4.13 P6 software(Terarecon, California, USA), and analysed SPQI and signal intensity by ImageJ program(v1.53n, National Institutes of Health, USA). It decreased by 4.09~11.99%, 4.12~35.52%, and 4.70~37.64% in slice thickness of 2.5 mm, 5.0 mm, and 10.0 mm for evaluating the high contrast resolution of x/y plane according to distance from gantry iso-center. Therefore, the high contrast resolution of the x/y plane decreased when the distance from the iso-center increased or the slice thickness increased. Additionally, the slice thicknesses of 2.5 mm, 5.0 mm, and 10.0 mm with a high algorithm increased 74.83, 15.18 and 81.25%. The FWHM was almost constant on the measured SSP graph for evaluating the accuracy of slice thickness which represents the resolution of x/y plane and z-axis, but it was measured to be higher than the nominal slice thickness set by user. The FWHM and FWTM of z-axis with axial scan mode tended to increase significantly as the distance increased from gantry iso-center than the helical mode. Particularly, the thinner slice thickness that increased error range compare with the nominal slice thickness. The SPQI increased with thick slice thickness, and that was closer to 90% in the helical scan than the axial scan. In conclusion, by producing a phantom suitable for MDCT detectors and capable of quantitative resolution evaluation, it can be used as a specific method in the management of research quality and management of outdated equipment. Thus, it is expected to contribute greatly to the discrimination of lesions in the field of CT imaging.

• Journal of the Mineralogical Society of Korea
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• v.16 no.2
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• pp.135-149
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• 2003

Domestic zeolite ores are mostly composed of Ca-type clinoptilolite, accompanying a little amounts of mordenite. However, other types of zeolite ores rich in ferrierite, heulandite, or mordenite are less commonly found. Based on the quantitative XRD analysis, zeolite contents are determined to be nearly 50∼90 wt%. Impurities (mostly ＞ 10 wt%) in the zeolite ores chiefly consist of quartz, feldspar, smectite, and opal-CT. The determined CEC values ($CEC_{AA}$ ) of powdery samples (grain size: < 125 $\mu\textrm{m}$) of zeolite ores by the Ammonium Acetate method are mostly higher than 100 meq/100 g. Some zeolites from the Guryongpo area, corresponding to the clinoptilolite ore, are measured to be dominantly high in CEC values ranging 170∼190 meq/100 g. Cation exchange property of the zeolite ores varies greatly depending on the types or zeolite species present in the ores. Despite of the lower grade in zeolite content, the $CEC_{AA}$ of ferrierite ore is comparatively high. Compared to this, the $CEC_{AA }$ of heulandite ore is very low, though the zeolite ore exhibits the highest grade ranging up to about 90 wt%. In addition, the CEC values calculated theoretically from the framework composition of clinoptilolite-heulandite series are not consistent with those determined by the cation exchage experiment. The measured $CEC_{AA}$ of clinoptilolite ores are generally higher than those of heulandite ores. This may be due to the higher Ca abundance in exchangeable cation composition and the presence of probable stacking faults in heulandite. The variation of $CEC_{CEC}$ is roughly proportional, though not strictly compatible, to the zeolite contents in clinoptilolite ores. It seems to be caused by the fact that the $CEC_{AA}$ of clinoptilolite locally varies depending on crystal-chemical diversity, i. e., the variation in framework composition (Si/Al) and exchangeable cation composition (especially, the contents of Ca and K). In addition, the determined CEC values ($CEC_{MB}$ ) of zeolite ores by the Methylene Blue method are much higher than those calculated from smectite contents. It suggests a probable reaction of Methylene Blue ion ($C_{16}$ $H_{18}$ $N_3$S+) with larger-pore zeolites than clinoptlolite-heulandite series, i.e., ferrierite and mordenite as well as with smectite. This can be supported by the fact that the ferrierite ore accompanying little amount of smectite has the highest value in CE $C_{MB}$ .

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.189-203
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• 2008

The physical and chemical properties of radioactive waste drums, which have been temporarily stored on site, should be characterized before their shipment to a disposal facility in order to prove that the properties meet the acceptance guideline. The investigation of NDT(Nondestructive Test) method was figured out that the contents in drum, the quantitative analysis of free standing water and void fraction can be examined with X-ray NDT techniques. This paper describes the characteristics of X-ray NDT such as its principles, the considerations for selection of X-ray system, etc. And then, the waste drum characteristics such as drum type and dimension, contents in drum, etc. were examined, which are necessary to estimate the optimal X-ray energy for NDT of a drum. The estimation results were that: $(R)\acute{A}$ the proper X-ray energy is under 3 MeV to test the drums of 320 ${\beta}\S$ and less; $(R)\ddot{E}$ both X-ray systems of 450 keV and/or 3 MeV might be needed considering the economical efficiency and the realization. The number of drums that can be tested with 450 keV and 3 MeV X-ray system was figured out as 42,327 and 18,105 drums (based on storage of 2006. 12), respectively. Four testing scenarios were derived considering equipment procurement method, outsourcing or not, etc. The economical and feasibility assessment for the scenarios was resulted in that an optimal scenario is dependent on the acceptance guide line, the waste generator's policy on the waste treatment and the delivery to a disposal facility, etc. For example, it might be desirable that a waste generator purchases two 450 keV mobile system to examine the drums containing low density waste, and that outsourcing examination for the high density drums, if all NDT items such as quantitative analysis for 'free standing water' and 'void fraction', and confirmation of contents in drum have to be characterized. However, one 450 keV mobile system seems to be required to test only the contents in 13,000 drums per year.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.91-97
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• 2007

Purpose: To evaluate the feasibility of a commercial ion chamber array for intensity modulated radiation therapy (IMRT) quality assurance (QA) was performed IMRT patient-specific QA Materials and Methods: A use of IMRT patient-specific QA was examined for nasopharyngeal patient by using 6MV photon beams. The MatriXX (Wellhofer Dosimetrie, Germany) was used for IMRT QA. The case of nasopharyngeal cancer was performed inverse treatment planning. A hybrid dose distribution made on the CT data of MatriXX and solid phantom all of the same gantry angle (0$^\circ$). The measurement was acquired with geometrical condition that equal to hybrid treatment planning. The $\gamma$-index (dose difference 3%, DTA 3 mm) histogram was used for quantitative analysis of dose discrepancies. An absolute dose was compared at the high dose low gradient region. Results: The dose distribution was shown a good agreement by gamma evaluation. A proportion of acceptance criteria was 95.8%, 97.52%, 96.28%, 98.20%, 97.78%, 96.64% and 92.70% for gantry angles were 0$^\circ$, 55$^\circ$, 110$^\circ$, 140$^\circ$, 220$^\circ$, 250$^\circ$ and 305$^\circ$, respectively. The absolute dose in high dose low gradient region was shown reasonable agreement with the RTP calculation within $\pm$3%. Conclusion: The MatriXX offers the dosimetric characteristics required for performing both relative and absolute measurements. If MatriXX use in the clinic, it could be simplified and reduced the IMRT patient-specific QA workload. Therefore, the MatriXX is evaluated as a reliable and convenient dosimeter for IMRT patient-specific QA.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.99-106
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• 2013

The purpose of this study is to investigate the effects of supplementation of mulberry powder, mulberry extract and silkworm powder during the 8 weeks of resistance exercise on Androgen receptor(AR) mRNA and Myogenic regulatory factors(MRFs) expression of rats muscle. Fifty males, Sprague-Dawley rat, were randomly divided into 5 groups: CON(control group, n = 10), REG(resistance exercise group, n = 10), MP REG(mulberry powder intake and resistance exercise group, n = 10), ME REG(mulberry extract intake and resistance exercise group, n = 10) and SP REG(silkworm powder intake and resistance exercise group, n = 10). After climbing the ladder without weights during the 1 week of adaptation period, the rats in the resistance exercise group were trained to climb a 0.98-m vertical(80 degree incline) ladder with weights in their tail during 7 weeks(10 times each day, 2 days per week). After exercise, the skeletal muscle was extracted from the flexor hallucis longus. After separating the total ribonucleic acid (RNA) of each group, quantitative polymerase chain reaction was used to analyze RNA quantitatively. AR mRNA and MRFs expression revealed that all of the treated groups had significantly difference. AR mRNA expression increased in ME REG $6.24{\pm}1.85$ and SP REG $9.68{\pm}0.28$ fold compared to CON. Myod mRNA expression increased in MP REG $6.04{\pm}0.47$, ME REG $4.31{\pm}1.58$ and SP REG $8.11{\pm}0.57$ fold compared to CON. And myogenin mRNA expression increased in MP REG $4.11{\pm}0.42$, ME REG $4.12{\pm}0.45$ and SP REG $6.50{\pm}0.61$ fold compared to CON. In conclusion, during the resistance exercise, providing mulberry and silkworm gives positive effect on AR mRNA and MRFs expression increase.

• Progress in Medical Physics
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• v.26 no.4
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• pp.258-266
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• 2015

The modern radiotherapy technique which delivers a large amount of dose to patients asks to confirm the positions of patients or tumors more accurately by using X-ray projection images of high-definition. However, a rapid increase in patient's exposure and image information for CT image acquisition may be additional burden on the patient. In this study, by introducing structural similarity (SSIM) index that can effectively extract the structural information of the image, we analyze the differences between daily acquired x-ray images of a patient to verify the accuracy of patient positioning. First, for simulating a moving target, the spherical computational phantoms changing the sizes and positions were created to acquire projected images. Differences between the images were automatically detected and analyzed by extracting their SSIM values. In addition, as a clinical test, differences between daily acquired x-ray images of a patient for 12 days were detected in the same way. As a result, we confirmed that the SSIM index was changed in the range of 0.85~1 (0.006~1 when a region of interest (ROI) was applied) as the sizes or positions of the phantom changed. The SSIM was more sensitive to the change of the phantom when the ROI was limited to the phantom itself. In the clinical test, the daily change of patient positions was 0.799~0.853 in SSIM values, those well described differences among images. Therefore, we expect that SSIM index can provide an objective and quantitative technique to verify the patient position using simple x-ray images, instead of time and cost intensive three-dimensional x-ray images.

• Journal of radiological science and technology
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• v.34 no.1
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• pp.51-58
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• 2011

The aim of the study is to analyze the dose delivery error depending on the depth variation according to target positions and arc trajectories by comparing the simulated treatment planning with the actual dose delivery in conformal arc therapy. We simulated the conformal arc treatment planning with the three target positions (center, 2.5 cm, and 5 cm in the phantom). For the experiments, IMRT body phantom (I’mRT Phantom, Wellhofer Dosimetry, Germany) was used for treatment planning with CT (Computed Tomography, Light speed 16, GE, USA). The simulated treatment plans were established by three different target positions using treatment planning system (Eclipse, ver. 6.5, VMS, Palo Alto, USA). The radiochromic film (Gafchromic EBT2, ISP, Wayne, USA) and dose analysis software (OmniPro-IMRT, ver. 1.4, Wellhofer Dosimetry, Germany) were used for the measurement of the planned arc delivery using 6 MV photon beam from linear accelerator (CL21EX, VMS, Palo Alto, USA). Gamma index (DD: 3%, DTA: 2 mm) histogram and dose profile were evaluated for a quantitative analysis. The dose distributions surrounded by targets were also compared with each plans and measurements by conformity index (CI), and homogeneity index (HI). The area covered by 100% isodose line was compared to the whole target area. The results for the 5 cm-shifted target plan show that 23.8%, 35.6%, and 37% for multiple conformal arc therapy (MCAT), single conformal arc therapy (SCAT), and multiple static beam therapy, respectively. In the 2.5 cm-shifted target plan, it was shown that 61%, 21.5%, and 14.2%, while in case of center-located target, 70.5%, 14.1%, and 36.3% for MCAT, SCAT, and multiple static beam therapy, respectively. The values were resulted by most superior in the MCAT, except the case of the 5 cm-shifted target. In the analysis of gamma index histogram, it was resulted of 37.1, 27.3, 29.2 in the SCAT, while 9.2, 8.4, 10.3 in the MCAT, for the target positions of center, shifted 2.5 cm and 5 cm, respectively. The fail proportions of the SCAT were 2.8 to 4 times as compared to those of the MCAT. In conclusion, dose delivery error could be occurred depending on the target positions and arc trajectories. Hence, if the target were located in the biased position, the accurate dose delivery could be performed through the optimization of depth according to arc trajectory.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.