• Journal of radiological science and technology
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• v.36 no.1
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• pp.49-55
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• 2013

Currently, commercially available phantom can reproduce and evaluate only a static situation, the study is incomplete research on phantom and system which is can confirmed functional situation in the kidney by time through dynamic phantom and blood flow velocity, various difference according to the amount of radioactive. Therefore, through this study, it has produced the dynamic kidney phantom to reproduce images through the dynamic flow of the kidney, it desires to evaluate the usefulness of nuclear medicine imaging. The production of the kidney phantom was fabricated based on the normal adult kidney, in order to reproduce the dynamic situation based on the fabricated kidney phantom, in this study, it was applied the volume pump that can adjust the speed of blood flow, so it can be integrated continuously radioactive isotopes in the kidney by using $^{99m}Tc$-pertechnate. Used the radioactive isotope was supplied through the two pump. It was confirmed the changes according to the infusion rate, radioactive isotopes and the different injection speeds on the left and right, analysis of the acquired images was done by drawn five times ROI in order to check the reproducibility of each on the front and rear of the kidney and bladder. Depending on the speed of injection, radioisotope was a lot of integrated and emissions up when adjusting the pressure of the pump as 30 stroke, it was the least integrated and emissions up when adjusting as 40 stroke. The integration of the left & right kidney was not reached in the amount of the highest when adjusting as 10 stroke. In the changes according to the amount of the radioactive isotope, 0.6 mCi(22.2 MBq), 0.8 mCi (29.6 MBq)was showed up similar tendency but, in the result of the different injection 0.8 mCi, it was showed up counts close to double of 0.6 mCi. In the result of the differently injection speed of the left & right kidney, as a result of different conditions that injection speed was 20 stroke through left kidney phantom, the injection speed was 30 stroke through right kidney phantom, it was enough difference in the resulting image can be easily distinguished with the naked eye. Through this study, the results showed that the dynamic kidney phantom system is able to similarly reproduce renogram in the actual clinical practice. Especially, the depicted over time for the flow to be excreted through the kidney into the bladder was adequately reproduce, it is expected to be utilized as basic data to check the quality of the dynamic images. In addition, it is considered to help in the field of functional imaging and quality control.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.3-9
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• 2013

Purpose: Currently commercially available phantom can reproduce and evaluate only a static situation, the study is incomplete research on phantom and system which is can confirmed functional situation in the kidney by time through dynamic phantom and blood flow velocity, various difference according to the amount of radioactive. Therefore, through this study, it has produced the dynamic kidney phantom to reproduce images through the dynamic flow of the kidney, it desire to evaluate the usefulness of nuclear medicine imaging. Materials and Methods: The production of the kidney phantom was fabricated based on the normal adult kidney, in order to reproduce the dynamic situation based on the fabricated kidney phantom, in this study it was applied the volume pump that can adjust the speed of blood flow, so it can be integrated continuously radioactive isotopes in the kidney by using $^{99m}Tc-pertechnate$. Used the radioactive isotope was supplied through the two pump. It was confirmed the changes according to the infusion rate, radioactive isotopes and the different injection speeds on the left and right, analysis of the acquired images was done by drawn ten times ROI in order to check the reproducibility of each on the front and rear of the kidney and bladder. Results: Under the same conditions infusion rate 40 mL/min fixed to adjust the pressure of the pump when the radiopharmaceuticals between 2-3 minutes in the most integrated in the kidney phantom was excreted inthe bladder. Glomerular filtration rate (GFR), respectively, by each device SYMBIA 1,091 mL/min, FORTE 1,232 mL/min, ARGUS 1,264 mL/min, INFINIA 1,302 mL/min in that there isno statistically significant difference was found, Tmax values and T1/2 values stars from all equipment with no statistically significant difference was found. CV values of the coefficient of variation less than 5% was found to be repeatable, and to 2.67% of the lowest SYMBIA appeared, INFINIA was the highest in the 4.86%. Conclusion: Through this study, the results showed that the dynamic kidney phantom system is able to similarly reproduce renogram in the actual clinical. Especially, the depicted over time for the flow to be excreted through the kidney into the bladder was adequately reproduce, it is expected to be utilized as basic data to check the quality of the dynamic images. In addition, it is considered to help in the field of functional imaging and quality control.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.157-164
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• 2012

The purpose of this study is to analyze the dose distribution when wedge filter is used in the various tissue electron density materials. The dose distribution was assessed that the enhanced dynamic wedge filter and physical wedge filter were used in the solid water phantom, cork phantom, and air cavity. The film dosimetry was suitable simple to measure 2D dose distribution. Therefore, the radiochromic films (Gafchromic EBT2, ISP, NJ, USA) were selected to measure and to analyze the dose distributions. A linear accelerator using 6 MV photon were irradiated to field size of $10{\times}10cm^2$ with 400 MUs. The dose distributions of EBT2 films were analyzed the in-field area and penumbra regions by using dose analysis program. In the dose distributions of wedge field, the dose from a physical wedge was higher than that from a dynamic wedge at the same electron density materials. A dose distributions of wedge type in the solid water phantom and the cork phantom were in agreements with 2%. However, the dose distribution in air cavity showed the large difference with those in the solid water phantom or cork phantom dose distributions. Dose distribution of wedge field in air cavity was not shown the wedge effect. The penumbra width, out of the field of thick and thin, was observed larger from 1 cm to 2 cm at the thick end. The penumbra of physical wedge filter was much larger average 6% than the dynamic wedge filter. If the physical wedge filter is used, the dose was increased to effect the scatter that interacted with photon and physical wedge. In the case of difference in electron like the soft tissue, lung, and air, the transmission, absorption, and scattering were changed in the medium at high energy photon. Therefore, the treatment at the difference electron density should be inhomogeneity correction in treatment planning system.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.295-305
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• 2014

This study is to provide accurate information as medical imaging equipment to check for the presence of body disease US equipment. We investigated the status of medical US equipment performance in Daegu and criteria US phantom (ATS-539) for US equipment performance measurements. The results in this study, 1. US phantom measurement results: The test passed rate were 88.6% and the failed rate were 11.4%. 2. The difference between the group of mean and the pass/failed groups were statistically significant. Focal zone and 4 mm functional resolution in the two items that are not present the passing standard. 3. The difference was statistically significant number of years and used equipment and pass the failed equipment (4.13 vs 7.25 years). We investigated the performance status of US equipment used in the clinical area in Daegu. The basis for the two items are not present this proposed passing standard. Equipment performance was associated with the number of years of using US equipment. It is necessary to maintain the best performance of the equipment phantom measurements for performance testing of US equipment.

• Journal of radiological science and technology
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• v.42 no.1
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• pp.53-59
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• 2019

In the field of nuclear medicine, the various static phantoms of international standards are used to assess the performance of the nuclear medicine equipment. However, we only reproduced a fixed situation in spite of the movement of the cardiac, and the demands for dynamic situations have been continuously raised. More research is necessary to address these challenges. This study used flexible materials to design the dynamic cardiac phantom, taking into account the various clinical situations. It also intended to reproduce the images through dynamic cardiac flow to confirm the usefulness of the proposed technique. The frame of dynamic cardiac phantom was produced based on the international standard phantom. A nuclear medicine dynamic cardiac phantom was produced rubber material and silicone implemented by 3D printing technique to reproduce endocardium and epicardium movement. Therefore we compared and evaluated the image of a cardiac phantom made of rubber material and a cardiac phantom made of silicone material by 3D printing technique. According to the results of this study, the analysis of the Summed Rest Score(SRS) showed abnormalities in the image of a cardiac phantom made of rubber material at 10, 20, and 30 stroke rates, but the image of a cardiac phantom made of silicone material by 3D printing technique showed normal levels. And the analysis of the Total Perfusion Deficit(TPD) showed that TPD in the image of a cardiac phantom made of rubber material was higher than that of the image of a cardiac phantom made of silicone material by 3D printing technique at 10, 20, and 30 stroke rates. The potential for clinical application of the proposed method was confirmed in the dynamic cardiac phantom implemented with 3D printing technique. It is believed that the objective information secures the reliability of inspection equipment and it contributes to improve the diagnostic value of nuclear medicine.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.123-130
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• 2016

Purpose : The aim of this study was to compare the differences between the volumes acquired with four-dimensional computed tomography (4DCT)images with a reconstruction image-filtering algorithm and cone-beam computed tomography (CBCT) images with dynamic phantom. Materials and Methods : The 4DCT images were obtained from the computerized imaging reference systems (CIRS) phantom using a computed tomography (CT) simulator. We analyzed the volumes for maximum intensity projection (MIP), minimum intensity projection (MinIP) and average intensity projection (AVG) of the images obtained with the 4DCT scanner against those acquired from CBCT images with CT ranger tools. Results : Difference in volume for node of 1, 2 and 3 cm between CBCT and 4DCT was 0.54~2.33, 5.16~8.06, 9.03~20.11 ml in MIP, respectively, 0.00~1.48, 0.00~8.47, 1.42~24.85 ml in MinIP, respectively and 0.00~1.17, 0.00~2.19, 0.04~3.35 ml in AVG, respectively. Conclusion : After a comparative analysis of the volumes for each nodal size, it was apparent that the CBCT images were similar to the AVG images acquired using 4DCT.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.113-122
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• 2010

Purpose: To evaluate the accuracy of a target position at static and dynamic state by using Dynamic phantom for the difference between tumor's actual movement during respiratory gated radiation therapy and skin movement measured by RPM (Real-time Position Management). Materials and Methods: It self-produced Dynamic phantom that moves two-dimensionally to measure a tumor moved by breath. After putting marker block on dynamic phantom, it analyzed the amplitude and status change depending on respiratory time setup in advance by using RPM. It places marker block on dynamic phantom based on this result, inserts Gafchromic EBT film into the target, and investigates 5 Gy respectively at static and dynamic state. And it scanned investigated Gafchromic EBT film and analyzed dose distribution by using automatic calculation. Results: As a result of an analysis of Gafchromic EBT film's radiation amount at static and dynamic state, it could be known that dose distribution involving 90% is distributed within margin of error of 3 mm. Conclusion: As a result of an analysis of dose distribution's change depending on patient's respiratory cycle during respiratory gated radiation therapy, it is expected that the treatment would be possible within recommended margin of error at ICRP 60.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.77-82
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• 2007

Purpose: This study investigates peripheral dose from physical wedge and dynamic wedge system on a multileaf collimator (MLC) equipment linear accelerator. Materials and Methods: Measurments were performed using a 2D array ion chamber and solid water phantom for a 10$\times$10 cm, source-surface distance (SSD) 90 cm, 6 and 15 MV photon beam at depths of 0.5 cm, 5 cm through dmax. Measurments of peripheral dose at 0.5 cm and 5 cm depths were performed from 1 cm to 5 cm outside of fields for the dynamic wedge and physical wedge 15$^\circ$, 45$^\circ$. Dose profiles normalized to dose at the maximum depth. Results: At 6 MV photon beam, the average peripheral dose of dynamic wedge were lower by 1.4% and 0.1%. At 15 MV photon beam, the peripheral dose of dynamic wedge were lower by maximum 1.6%. Conclusion: This study showed that dynamic wedge can reduce scattered dose of clinical organ close to the field edge and reduced treatment time. The wedge systems produce significantly different peripheral dose that should be considered in properly choosing a wedge system for clinical use.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.133-141
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• 2010

The evaluation of Varian enhanced dynamic wedges (EDW) were performed in terms of quality assurance in external radiotherapy. The seven (10, 15, 20, 25, 30, 45, 60 deg.) EDW angles were evaluated for 6 and 15 MV x-rays in Varian Linac. The STT (segmented treatment table) for a field were calculated and compared with actual movement of the jaw using Dynalog files in order to evaluate mechanical operation. Two dimensional array detector and an ionization chamber were used to measure dose distributions in phantom from Linac. The mechanical movement of jaw was agreed with its expectation and two dimensional dose distributions including beam profiles were in agreement with RTP data approximately. In comparison with RTP calculations the percentage difference of output dose values for 100 MU irradiation was less than 2.9% and measured wedge factor was less than 2.6%. These results are shown that there is no problem in clinical applications of EDW equipped on this linac.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.407-413
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• 2008

Measurements of the peripheral dose were performed using a 2D array ion chamber and solid water phantom for a $10{\times}10cm$, source-surface distance (SSD) 90cm, 6 and 15MV photon beam at depths of 0.5cm, 5cm through $d_{max}$. Measurements of peripheral dose at 0.5cm and 5cm depths were performed from 1cm to 5cm outside of fields for the dynamic wedge and physical wedge $15^{\circ}$, $45^{\circ}$. For 6MV photon beam, the average peripheral dose of dynamic wedge were lower by 1.4% and 0.1% than that of physical wedge For 15MV photon beam, the peripheral dose of dynamic wedge were lower by maximum 1.6% that of physical wedge. The results showed that dynamic wedge can reduce scattered dose of clinical organ close to the field edge. The wedge systems produce different peripheral dose that should be considered in properly choosing a wedge system for clinical use.