• Journal of radiological science and technology
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• v.38 no.3
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• pp.213-220
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• 2015

This research was study the accuracy of three-dimensional stereotactic breast biopsy, using a core Needle Biopsy and to assess the accuracy of Stereotactic biopsy and Sono guided biopsy. Using Stereotactic QC phantom to measure the accuracy of the 3D sterotactic machine. CT Scan and equipment obtained in the measured X, Y, Z and compares the accuracy of the length. Using Agar power phantom compare the accuracy of the 3D sterotactic machine and 2D ultrasound machine. Z axis measured by the equipment to compare the accuracy and reliability. Check the accuracy by using visual inspection and Specimen Medical application phantom. The accuracy of the 3D sterotactic machine measured by Stereotactic QC phantom was 100%. Accuracy as compared to CT, all of X, Y, Z axis is p > 0.05. The accuracy of the two devices was 100% as measured by Agar powder phantom. There was no difference between t he t wo d evices as C T and p > 0.05. 3D sterotactic machine of the ICC was 0.954, 2D ultrasound machine was 0.785. 2D ultrasound machine was different according to the inspector. Medical application phantom experiments in 3D sterotactic machine could not find the Sliced boneless ham. 2D ultrasound machine has not been able to find a small chalk powder group. The reproducibility of the three-dimensional stereotactic breast biopsy was better than effect of Sono guided biopsy.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.607-614
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• 2016

The study investigates the necessity of 3 dimensional dose distribution evaluation instead of point dose and 2 dimensional dose distribution evaluation. Treatment plans were generated on the RANDO phantom to measure the precise dose distribution of the treatment site 0.5, 1, 1.5, 2, 2.5, 3 cm with the prescribed dose; 1,200 cGy, 5 fractions. Gamma analysis (3%/3 mm, 2%/2 mm) of dose distribution was evaluated with gafchromic EBT2 film and ArcCHECK phantom. The average error of absolute dose was measured at $0.76{\pm}0.59%$ and $1.37{\pm}0.76%$ in cheese phantom and ArcCHECK phantom respectively. The average passing ratio for 3%/3 mm were $97.72{\pm}0.02%$ and $99.26{\pm}0.01%$ in gafchromic EBT2 film and ArcCHECK phantom respectively. The average passing ratio for 2%/2 mm were $94.21{\pm}0.02%$ and $93.02{\pm}0.01%$ in gafchromic EBT2 film and ArcCHECK phantom respectively. There was a more accurate dose distribution of 3D volume phantom than cheese phantom in patients DQA using tomotherapy. Therefor it should be evaluated simultaneously 3 dimensional dose evaluation on target and peripheral area in rotational radiotherapy such as tomotherapy.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.433-439
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• 2013

In this study, human head-mimicking phantom was developed for brain disease treatment study using focused ultrasound. Acoustic parameters of skin, skull and brain were investigated through literature investigation and adequate substitutes according to each tissue were suggested. In the case of skin phantom, construction ratio of glycerol-based TMM phantom was controlled to mimic real skin. The suitability of skull substitutes was evaluated through measurement of acoustic parameters. In the case of brain phantom, transparent egg white phantom was used to observe thermal properties of focused ultrasound. Combined human-head-mimicking phantom using each substitutes was fabricated for development of brain disease treatment protocol. Denaturation of brain phantom according to ultrasonic condition was observed for validation.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.106-106
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• 2002

Purpose： The purposes of our study are (1) to develop a brain phantom which can be used for multimodal image registration, (2) to evaluate the accuracy of image registration with the home-made phantom. Method： A brain phantom which could be used for image registration technique of CT-MR and CT-SPECT images using chamfer matching was developed. The brain phantom was specially designed to obtain imaging dataset of CT, MR, and SPECT. The phantom had an external frame with 4 N-shaped pipes filled with acryl rods for CT, MR imaging and Pb rods for SPECT imaging. 8 acrylic pipes were inserted into the empty space of the brain phantom to be imaged for geometric evaluation of the matching. Accuracy of image fusion was assessed by the comparison between the center points of the section of N-shaped bars in the external frame and the inserted pipes of the phantom. Technique with partially transparent, mixed images using color on gray was used for visual assessment of the image registration process.

• Korean Journal of Digital Imaging in Medicine
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• v.16 no.2
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• pp.15-24
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• 2014

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 99mTc-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 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. 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.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.322-323
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• 2002

Partial volume averaging effect of PET data influences on the accuracy of quantitative measurements of regional brain metabolism because spatial resolution of PET is limited. The purpose of this study was to evaluate the accuracy of partial volume correction carried out on $^{18}$ F-PET images using Hoffman brain phantom. $^{18}$ F-PET Hoffman phantom images were co-registered to MR slices of the same phantom. All the MR slices of the phantom were then segmented to be binary images. Each of these binary images was convolved in 2 dimensions with the spatial resolution of the PET. The original PET images were then divided by the smoothed binary images in slice-by-slice, voxel-by-voxel basis resulting in larger PET image volume in size. This enlarged partial volume corrected PET image volume was multiplied by original binary image volume to exclude extracortical region. The evaluation of partial volume corrected PET image volume was performed by region of interests (ROI) analysis applying ROIs, which were drawn on cortical regions of the original MR image slices, to corrected and original PET image volume. From the ROI analysis, range of regional mean values increases of partial volume corrected PET images was 4 to 14%, and average increase for all the ROIs was about 10% in this phantom study. Hoffman brain phantom study was useful for the objective evaluation of the partial volume correction method. This MR-based correction method would be applicable to patients in the. quantitative analysis of FDG-PET studies.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.985-991
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• 2023

A tissue-equivalent phantom is necessary for quality control of hyperthermia therapy. However, since there is no phantom for this purpose, phantoms made from agar are being used in various studies. The tissue-equivalent properties of the agar phantom were confirmed by comparison with the tissue-equivalent material bolus in this study. CT images of the agar phantom and bolus were acquired, and tissue equivalent characteristics were analyzed with image analysis and dose calculation using a computerized radiation therapy planning system. The average pixel value was 96.960±10.999 in bolus, 108.559±8.233 in 3% agar phantom, and 111.844±8.651 in 4% agar phantom. Using the SSD technique, 100 cGy was prescribed at a depth of 1.5 cm and 6 MV X -ray was set to irradiated to 10x10 cm2, and the absorbed dose according to depth was calculated from the central axis of the beam. The intraclass correlation coefficient of dose distribution of bolus, 3% agar phantom, and 4% agar phantom was 0.979 (p<.001, 95%CI .957-.991). The density (g/cm3) at the point where the absorbed dose was calculated was 0.990±0.020 at the bolus, 1.018±0.020 at the 3% agar phantom, and 1.035±0.024 at the 4% agar phantom. In this study, the internal density distribution and uniformity of the agar phantom were confirmed to be appropriate as a tissue equivalent material by analysis of CT images and a computerized radiation therapy planning system.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.43-45
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• 2018

Purpose In this study, we evaluated image by applying with and without point spread function algorithm(PSF) according to reconstruction type. Materials and Methods Biograph mMR (Siemens, Germany) was used as PET/MR scanner. For phantom study, we used NEMA IEC Body phantom maintaining radioactivity ratio (hotsphere:background = 8:1). To evaluate phantom image quality, percent contrast recovery and signal to noise ratio (SNR) were used by drawing ROI to 4 spheres. In clinical study, the 20 patients who underwent simultaneous PET/MR was selected and set the ROI at liver. we evaluated images as SNR. Results In the phantom results, The percent contrast recovery applying PSF algoritm was high 5 % compared to without PSF algoritm and SNR was also high 11 %. In the clinical study result, we confirmed that The SNR applying PSF algoritm was high 5 % compared to without PSF algoritm. Conclusion We need to simulate a lot of phantom study and clinical analysis to improve image quality for PET/MRI.

• Progress in Medical Physics
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• v.13 no.3
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• pp.139-148
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• 2002

The measured attenuation correction with transmission (Tx) scans produced quantitatively accurate images. However, it was not clear for optimal emission (Ex) and Tx scan time in PET imaging. This study was to evaluate acceptable Ex and Tx scan time by simulating clinical situations using various phantoms. Cylindrical and NEMA phantom were used for $^{18}$ F-PET scan using 2D protocol in GE Advance PETTM scanner. Cylindrical phantom was filled with 136 MBq 18F, and five regions of interests (ROI) were drawn on 23 slices. NEMA phantom had three inserts containing water, air and polytetrafluoro-ethylene (PTFE). Outside of these inserts were filled with 309 MBq of $^{18}$ F, and total 12 ROIs were drawn on 23 slices. Scans were carried out according to five Ex scan times: 2, 5, 10, 15, and 30 min, and nine Tx scan times: 2, 3, 4, 5, 7, 10, 15, 20, and 30 min. Images were reconstructed using measured attenuation correction, and ROI analyses were performed for all images, and mean, standard deviation (SD), coefficient of variation and percent errors were calculated. For cylindrical phantom study, ROI mean and SD were decreased as Ex and Tx time increased. Coefficients of variation were kept constant, when Tx was greater than 10 min. The amount of error decreased for the increment of Ex time from 10 min to 15 min was almost the same to that from 15 min to 30 min. In NEMA phantom Tx 15 min showed the lowest er개r level when the percent errors for three inserts were summed for all of the Ex times. This study suggested that Ex 15 min and Tx 15 min were acceptable as optimal scan time for the scanning protocol and the dose of radiopharmaceuticals used in these phantom study.

• Journal of Biomedical Engineering Research
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• v.41 no.4
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• pp.147-153
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• 2020

This study was to evaluate the usability of self-developed phantom for evaluating automatic exposure control (AEC) using three-dimensions (3D) printer. 3D printer of fused deposition modeling (FDM) type was utilized to make the self-developed AEC phantom and image acquisitions were conducted by two different type of scanners. The self-developed AEC phantom consisted of four different size of portions. As a result, two types of phantom (pyramid and pentagon shape) were created according to the combination of the layers. For evaluating the radiation dose with the two types of phantom, the values of tube current, computed tomography dose index volume (CTDIvol), and dose length product (DLP) were compared. As a result, it was confirmed that the values of tube current were properly reflected according to the thickness, and the CTDIvol and DLP were not significantly changed regardless of AEC functions of different scanners. In conclusion, the self-developed phantom by using 3D printer could assess whether the AEC function works well. So, we confirmed the possibility that a self-made phantom could replace the commercially expensive AEC performance evaluation phantom.