• 대한방사선기술학회지:방사선기술과학
• /
• 제41권6호
• /
• pp.595-602
• /
• 2018

Quality control (QC) of Computed Tomography (CT) devices is based on image quality measurement on AAPM CT phantom which is a standard phantom. Although it is possible to control the accuracy of the CT apparatus, it is expensive and has a disadvantage of low penetration rate. Therefore, in this study, we make image quality measurement phantom at low cost using FFF (Fused Filament Fabrication) type three-dimensional printer and try to analyze the usefulness, compare it with existing standard phantom. To print a phantom, We used three-dimensional printer of the FFF system and PLA (Poly Lactic Acid, density: $1.24g/cm^3$) filament, and the CT device of 64 MDCT (Aquilion CX, Toshiba, Japan). In addition, we printed a phantom using three-dimensional printer after design using various tool based on existing standard phantom. For image quality evaluation, AAPM CT phantom and self-generated phantom were measured 10 times for each block. The measured data were analyzed for significance using the Mannwhiteney U-test of SPSS (Version 22.0, SPSS, Chicago, IL, USA). As a result of the analysis, phantom fabricated with three-dimensional printer and standard phantom showed no significant difference (p>0.05). Furthermore, we confirmed that image quality measurement performance of a phantom using three-dimensional printer is similar to the existing standard phantom. In conclusion, we confirmed the possibility of low cost phantom fabrication using three dimensional printer.

• 한국의학물리학회지:의학물리
• /
• 제31권4호
• /
• pp.189-193
• /
• 2020

An MR-based attenuation correction (MRAC) map plays an important role in quantitative positron emission tomography (PET) image evaluation in PET/magnetic resonance imaging (MRI) systems. However, the MRAC map is affected by the magnetic field inhomogeneity of MRIs. This study aims to evaluate the characteristics of MRAC maps of physical phantoms on PET/MRI images. Phantom measurements were performed using the Siemens Biograph mMR. The modular type physical phantoms that provide assembly versatility for phantom construction were scanned in a four-channel Body Matrix coil. The MRAC map was generated using the two-point Dixon-based segmentation method for whole-body imaging. The modular phantoms were scanned in compact and non-compact assembly configurations. In addition, the phantoms were scanned repeatedly to generate MRAC maps. The acquired MRAC maps show differently assigned values for void areas. An incorrect assignment of a void area was shown on a locally compact space between phantoms. The assigned MRAC values were distorted using a wide field-of-view (FOV). The MRAC values also differed after repeated scans. However, the erroneous MRAC values appeared outside of phantom, except for a large FOV. The MRAC map of the phantom was affected by phantom configuration and the number of scans. A quantitative study using a phantom in a PET/MRI system should be performed after evaluation of the MRAC map characteristics.

• 대한방사선기술학회지:방사선기술과학
• /
• 제42권1호
• /
• pp.53-59
• /
• 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.

• 대한의용생체공학회:의공학회지
• /
• 제36권1호
• /
• pp.7-15
• /
• 2015

The egg white phantom is a thermal lesion visualization phantom able to illustrate a thermal lesion. It is often used to evaluate the performance of HIFU and is less expensive than the BSA phantom. This study determined the optimal phantom composition for evaluated therapeutic ultrasound machines by varying the egg white concentration in the egg white phantom and demonstrated its utility as a therapeutic ultrasound phantom. The egg white phantom at varying egg white concentrations (10-40% in 10% intervals) was fabricated, and its thermal properties and acoustic properties were assessed. In addition, the size and shape of the formed lesion were compared between the egg white phantom and bovine liver tissue according to the electrical power. The results showed that 30% egg white phantom was optimal for the performance evaluation due to its thermal and acoustic properties. The generated thermal lesions formed sequentially as a cigar, ellipse, tadpole, and cone shapes according to the electrical power; a similar tendency was observed in the liver tissue. Hence, we conclude that the egg white phantom will prove useful in quantitatively evaluating the thermal effects of therapeutic ultrasound.

• Journal of Radiation Protection and Research
• /
• 제41권3호
• /
• pp.274-281
• /
• 2016

Background: Whole-body counters are widely used to evaluate internal contamination of the internal presence of gamma-emitting radionuclides. In internal dosimetry, it is a basic requirement that quality control procedures be applied to verify the reliability of the measured results. The implementation of intercomparison programs plays an important role in quality control, and the accuracy of the calibration and the reliability of the results should be verified through intercomparison. In this study, we evaluated the reliability of 2 whole-body counting systems using 2 calibration methods. Materials and Methods: In this study, 2 whole-body counters were calibrated using a reference male bottle manikin absorption (BOMAB) phantom and a Radiation Management Corporation (RMC-II) phantom. The reliability of the whole-body counting systems was evaluated by performing an intercomparison with International Atomic Energy Agencyto assess counting efficiency according to the type of the phantom. Results and Discussion: In the analysis of counting efficiency using the BOMAB phantom, the performance criteria of the counters were satisfied. The relative bias of activity for all radionuclides was -0.16 to 0.01 in the Fastscan and -0.01 to 0.03 in the Accuscan. However, when counting efficiency was analyzed using the RMC- II phantom, the relative bias of $^{241}Am$ activity was -0.49 in the Fastscan and 0.55 in the Accuscan, indicating that its performance criteria was not satisfactory. Conclusion: The intercomparison process demonstrated the reliability of whole-body counting systems calibrated with a BOMAB phantom. However, when the RMC-II phantom was used, the accuracy of measurements decreased for low-energy nuclides. Therefore, it appears that the RMC-II phantom should only be used for efficiency calibration for high-energy nuclides. Moreover, a novel phantom capable of matching the efficiency of the BOMAB phantom in low-energy nuclides should be developed.

• 대한방사선기술학회지:방사선기술과학
• /
• 제39권2호
• /
• pp.157-161
• /
• 2016

본 연구에서는 자체 제작한 3종의 초음파 TM 팬텀의 음향학적 특성 및 온도 민감도를 측정하였으며, 초음파 영상학적 특성을 관찰, 평가하였다. TM 팬텀은 폴리우레탄을 주재료로 국제전기표준회의(International Electronical Committee, IEC) 기준안에 따라 제작하였으며 외부 온도 변화 따른 초음파 영상학적 특성은 $22^{\circ}C$ 이하에서 온도감소에 따라 휘도 및 영상투과심도가 비례하여 감소하는 것이 확인되었다. 본 연구를 통하여 산란재 특성이 상이한 TM 팬텀을 제작하는 기초자료를 제공하였으며, TM 팬텀의 사용 온도는 $22^{\circ}C$ 이상에서 사용하는 것이 적합한 것으로 판단되었다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제44권4호
• /
• pp.343-350
• /
• 2021

3D printing technology is an additive manufacturing technology produced through 3D scanning or modeling method. This technology can be produced in a short time without mold, which has recently been applied in earnest in various fields. In the medical field, 3D printing technology is used in various fields of radiology and radiation therapy, but related research is insufficient in the field of nuclear medicine. In this study, we compare the characteristics of traditional nuclear medicine phantom with 3D printing technology and evaluate its applicability in clinical trials. We manufactured the same size phantom of poly methyl meta acrylate(PMMA) and acrylonitrile butadiene styrene(ABS) based on the aluminum step wedge. We used BrightView XCT(Philips Health Care, Cleveland, USA) SPECT/CT. We acquired 60 min list mode for Aluminum, PMMA and ABS phantoms using Rectangular Flood Phantom (Biodex, New York, USA) ^99mTcO₄ 3 mCi(111 MBq), 6 mCi (222MBq) and ⁵⁷Co Flood phantom(adq, New Hampshire, USA). For the analysis of acquired images, the region of interest(ROI) were drawn and evaluated step by step for each phantom. Depending on the type of radioisotope and radiation dose, the counts of the ABS phantom was similar to that of the PMMA phantom. And as the step thickness increased, the counts decreased linearly. When comparing the linear attenuation coefficient of Aluminum, PMMA and ABS phantom, the linear attenuation coefficient of the aluminium phantom was higher than that of the others, and the PMMA and ABS phantom had similar the linear attenuation coefficient. Based on ABS phantom manufactured by 3D printing technology, as the thickness of the PMMA phantom increased, the counts and linear attenuation coefficient decreased linearly. It has been confirmed that ABS phantom is applicable in the clinical field of nuclear medicine. If the calibration factor is applied through further research, it is believed that practical application will be possible.

• Journal of Radiation Protection and Research
• /
• 제34권3호
• /
• pp.137-143
• /
• 2009

본 연구는 호흡에 따라 움직임이 큰 흉부나 복부 장기의 방사선 수술에 적용되는 사이버나이프 $Synchrony^{TM}$ 호흡 추적장치의 정확성을 평가하였다. $Synchrony^{TM}$ 호흡 추적장치의 정확성 평가를 위해 금침이 삽입된 움직임 Phantom을 이용하였고, Phantom은 아크릴 볼이 들어 있는 정육면체에 Radiochromic 필름을 삽입하여 가상의 치료용적인 아크릴 볼에 21 Gy, 70% 등선량곡선으로 처방하였다. 고정된 Phantom의 금침추적방법과 움직임 Phantom의 $Synchrony^{TM}$ 호흡추적 방법으로 나누어 각각 5회 측정한 정확성 평가는 고정된 Phantom 추적 시 총 에러는 $0.0195{\sim}0.652mm$, 총 에러 평균은 0.3926 mm로 나타났으며, 움직임 Phantom을 이용한 $Synchrony^{TM}$ 호흡 추적 방법의 결과로 총 에러는 $0.4405{\sim}0.7665mm$, 총 에러 평균은 0.5673 mm로 나타나 두 방법에 유의한 차이가 없었다. 본 연구를 통해 사이버나이프 $Synchrony^{TM}$ 호흡 추적 장치의 정확성을 평가하였으며 체부의 방사선 수술 적용 시 그 유용성을 확인할수 있었다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제30권3호
• /
• pp.237-243
• /
• 2007

방사성의약품을 이용한 핵의학적 영상기록에 있어 장기가 함유하고 있는 정보량을 최대한 묘출시켜 양질의 진단정보를 제공해야 한다는 것은 매우 중요하다. 그것을 위한 기술적인 문제를 비롯하여 장비성능의 유지관리에 많은 노력을 기울이고 있으며, 다양한 종류로 상업화되어 이용되고 있는 우수한 phantom들이 사용되고 있다. 본 연구에서 인체의 연부조직과 매우 흡사한 물리적 조건을 가지고 있으며 구입하기 쉬운 Paraffin을 이용하여 기존에 사용되고 있는 acryl thyroid phantom과 동일하게 paraffin phantom을 제작하였으며, 판매되고 있는 acryl thyroid phantom에서 측정할 수 있는 것 보다 더 높은 분해능을 측정할 수 있도록 작은 3mm와 6mm 직경의 cold area를 삽입한 paraffin thyroid phantom을 수작업으로 제작하였다. 방사성의약품 $^{99m}TcO_4$를 이용하고 pinhole collimator를 이용하여 상업화되어 사용되고 있는 acryl thyroid phantom과 본 연구를 위하여 제작한 paraffin thyroid phantom의 특성을 비교 분석한 결과 paraffin을 이용한 phantom도 상업화되어 사용 중인 acryl thyroid phantom과 동일한 물리적 특성을 유지하고, 오히려 분해능이 높은 부분을 측정할 수 있고 연부조직의 특성을 연구할 수 있는 등가물질로서 구입하기 쉽고 제작이 수월한 장점을 비롯하여 경제성이 있음을 증명하는 계기가 되었다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제42권6호
• /
• pp.441-446
• /
• 2019

The purpose of this paper is to recognize the usefulness of the Phantom produced with 3D printing technology by reproducing the original phantom with 3D printing technology. Using CT, we obtained information from the original phantom. The acquired file was printed by the SLA method of ABS materials. For inspection, SPECT/CT was used to obtain images. We filled the both Phantom with a solution mixed with ^99mTcO4 1 mCi in 1 liter of water and acq uired images in accordance with the standard protocol. Using Image J, the SNR for each slice of the image was obtained. As a reference images, AC images were used. For the analysis of acquired images, ROI was set in the White mater and Gray mater sections of each image, and the average Intensity Value within the ROI were compared. According to the results of this study, 3D printed phantom's SNR is about 0.1 higher than the conventional phantom. And the ratio of Intensity Value was shown in the original 1 : 3.4, and the printed phantom was shown to be 1 : 3.2. Therefore, if Calibration Value is applied, It is assumed that it can be used as an alternative to the original.