• The Korean Journal of Nuclear Medicine Technology
• /
• v.22 no.1
• /
• pp.46-50
• /
• 2018

Purpose Generally, a collimator that installed in front of detector set a direction of gamma ray and remove a scatter ray. By the way, a lateral or oblique scatter ray is detected into crystal through collimator. At this study, we will evaluate a mount of count and spectrums of lateral scatter ray. Materials and Methods We used the SKY LITE (philips, netherlands) as a gamma camera, and $^{99m}Tc$, 1.11 GBq point source as a phantom. we put this point source at backside 50 cm of detector. After acquiring this for 1 min, we turned a detector next 10 degrees. Likely this, we acquired images at every 10 degrees from $0^{\circ}$ to $360^{\circ}$, analyzed images and spectrums. In case of patient study, we choose a 3 phase bone scan patient who had a hand disease, because scatter rays from body would detect on crystal. After acquiring blood flow and blood pool images, we analyzed images and spectrums. Additional, we put a lead gown on patient's hand, body. And then we compared and evaluated 3 type blood pool images (non lead gown, lead gown on a hand and on body). Results In case of phantom study, scatter ray counts at backside ($270^{\circ}-90^{\circ}$) are same with a background count. By the way, counts of scatter ray of oblique side ($0^{\circ}-50^{\circ}$, $220^{\circ}-270^{\circ}$) are 100-600 cps, furthermore, counts at frontside are over 4 Mcps. In case of patient study, a counts of hand blood pool scan are 1510 cps. But counts of hand with lead gown on hands and on body are each 1554 cps, 1299 cps. Conclusion Therefore, even though there is a collimator in front of detector, lateral scatter rays detect on crystal and affect to images and spectrums. Especially, if there is a high activity source at outside of detector when we examine low activity organs like hands or foot, we have to shield and remove the source at outside for a good image.

• Journal of radiological science and technology
• /
• v.36 no.4
• /
• pp.291-297
• /
• 2013

This study is aimed to evaluate the effect of $T_{1/2}$ upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with $^{99m}TcO_4^-$ of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in $x^2$ test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of $T_{1/2}$ error from change of gradient with -0.25% to +0.25%, if $T_{1/2}$ is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see $T_{1/2}$ error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a tendency that count rate changes over time at this study, and we proved that it can effect $T_{1/2}$. And also, there is need of appropriate phantoms and the method of quality management like this study, because there are not any advice or limitation degrees for domestic medical purpose scintillation camera.

• Nuclear Medicine and Molecular Imaging
• /
• v.40 no.5
• /
• pp.257-262
• /
• 2006

Purpose: The standard protocol using large volume of oral contrast media may cause gastrointestinal discomfort and contrast-related artifacts in PET/CT. The aim of this study was to evaluate the usefulness of low dose oral contrast in $^{18}F-FDG$ PET/CT. Materials and Methods: We retrospectively reviewed the whole-body PET/CT images in a total of 435 patients. About 200 ml of oval contrast agent (barium sulfate) was administered immediately before injection of $^{18}F-FDG$. The FDG uptake of intestines was analyzed by visual and semi- quantitative method on transaxial, coronal and saggital planes. Results: Seventy (16%, 113 sites) of 435 images showed high FDG uptake (peak SUV > 4); 50 (74%, 84 sites) with diffuse and 20 (15%, 29 sites) with focal uptake. The most commonly delivered site of oral contrast media was small bowel (n=27, 39%). On PET/CT images, FDG uptake coexisted with oral contrast media in 26 patients (54%, 38 sites) with diffuse pattern and 9 (45%, 9 sites) with focal pattern, and by sites, those were 38 (45%) and 9 (31%), respectively. In small bowel regions, the proportion of coexistence reached as high as 61% (29/47 sites). A visual analysis of available non-attenuation corrected PET images of 27 matched regions revealed no contrast-related artifact. Conclusion: We concluded that the application of low dose contrast media could be helpful in the evaluation of abdominal uptake in the FDG PET/CT image.

• Radiation Oncology Journal
• /
• v.28 no.3
• /
• pp.166-176
• /
• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.3
• /
• pp.225-237
• /
• 1998

Purpose: We investigated the statistical methods to compose the functional brain map of human working memory and the principal factors that have an effect on the methods for localization. Materials and Methods: Repeated PET scans with successive four tasks, which consist of one control and three different activation tasks, were performed on six right-handed normal volunteers for 2 minutes after bolus injections of 925 MBq $H_2^{15}O$ at the intervals of 30 minutes. Image data were analyzed using SPM96 (Statistical Parametric Mapping) implemented with Matlab (Mathworks Inc., U.S.A.). Images from the same subject were spatially registered and were normalized using linear and nonlinear transformation methods. Significant difference between control and each activation state was estimated at every voxel based on the general linear model. Differences of global counts were removed using analysis of covariance (ANCOVA) with global activity as covariate. Using the mean and variance for each condition which was adjusted using ANCOVA, t-statistics was performed on every voxel To interpret the results more easily, t-values were transformed to the standard Gaussian distribution (Z-score). Results: All the subjects carried out the activation and control tests successfully. Average rate of correct answers was 95%. The numbers of activated blobs were 4 for verbal memory I, 9 for verbal memory II, 9 for visual memory, and 6 for conjunctive activation of these three tasks. The verbal working memory activates predominantly left-sided structures, and the visual memory activates the right hemisphere. Conclusion: We conclude that rCBF PET imaging and statistical parametric mapping method were useful in the localization of the brain regions for verbal and visual working memory.

• Restorative Dentistry and Endodontics
• /
• v.30 no.4
• /
• pp.303-311
• /
• 2005

The purpose of this study was to evaluate which type of Ni-Ti files are able to maintain canal configuration better in the simulated canal with abrupt curvature near it's apex. Ninety six simulated root canals were made in epoxy resin and $\sharp$15 finger spreader was used as root canal templates. The simulated root canals were made with radius of curvature of 1.5mm, 3.0mm, 4.0mm, 6.0mm respectively and the angle of curvature of all simulated canals were adjusted to 90 degree. The simulated canals were instrumented by ProFile, ProTaper, Hero 642, and $K^3$ at a 300 rpm using crown-down pressureless technique. Pre-instrumented and post-instrumented images were taken by digital camera and were superimposed with Adobe Photos hop 6.0 program. Images were compared by image analysis program. The changes of canal width at the inner and outer side of the canal curvature. canal transportation were measured at 9 measuring point with 1 mm interval. Statistical analysis among the types of Ni-Ti files was performed using Kruskal-Wallis test and Mann-Whitney U-test. The result was that ProFile maintain original canal configuration better than other engine driven Ni-Ti files in the canals above 3.0mm radius of curvature, and in the 1.5mm radius of curvature, most of Ni-Ti flies were deformed or separated during instrumentation.

• Journal of the Korean earth science society
• /
• v.42 no.2
• /
• pp.201-220
• /
• 2021

The objective of this study is to increase awareness and interest regarding polar science and thereby aid in establishing the concept and future direction of polar literacy. To analyze the current status, textbooks based on the common school curriculum pertaining to polar topics were reviewed. Six countries that actively conduct polar science, namely Korea, France, Japan, Germany, the United States, and the United Kingdom, were chosen. Subsequently, 402 cases in 110 science and social studies (geography) textbooks of these countries were analyzed through both quantitative and qualitative methods. Based on the obtained results, the importance of polar research in geoscience education and the need for spreading awareness regarding polar research as an indicator of global environmental changes were examined. It was found that the primary polar topics described in the textbooks are polar glaciers, polar volcanism, solid geophysics, polar infrastructure, and preservation of geological resources and heritage. This demonstrates that the polar region is a field of research with important clues to Earth's past, present, and future environments and is also a good teaching subject for geological education. However, an educational approach is needed for systematically laying emphasis on polar research. The implications of this study are manifold, such as the establishment of a cooperative system between polar scientists and educators, extraction of core concepts for polar literacy and content reconstruction, discovery of new polar topics associated with the curriculum, diversification of forms of presentation in textbooks, and development of an affective image that is based on correct cognitive understanding. Furthermore, through the continuance of polar topics in textbooks, students can improve their awareness regarding polar literacy and polar science culture, which in turn will serve as the driving force for sustainable polar research in the future.

• Journal of the Korean Society of Radiology
• /
• v.84 no.2
• /
• pp.441-453
• /
• 2023

Purpose To evaluate the development, location, and volume of a VX2 carcinoma using four inoculation methods in a rabbit brain. Materials and Methods Inoculation of a VX2 cell suspension was performed 1) on the appointed day, 2) seven days after storing a VX2 carcinoma in a freezer or 3) seven days after storing a VX2 carcinoma in a deep freezer after sacrificing the donor rabbits. 4) Without sacrificing the rabbits, the VX2 cell suspension was obtained using a gun biopsy, inoculation was performed on the appointed day. MR imaging was performed 10 days after inoculation. Brain tissues were obtained the day after. The development, location, and volume of the tumor were evaluated. Results Seventeen of the 18 rabbits inoculated on the appointed day developed tumors (average tumor volume, 106.32 mm³). One of five inoculated seven days after storing the VX2 tumor in the freezer, and three of five inoculated seven days after storing the VX2 tumor in the deep freezer developed tumors. Inoculation with a VX2 cell suspension obtained with a gun biopsy from five rabbits revealed development of tumors in only two rabbits. The tumors mostly developed in the superficial cortex. Conclusion TVX2 rabbit brain tumor model is easy to develop and revealed variable reproducibility. This model can be applicable in radiologic imaging, treatment planning, interventional treatment and drug delivery research. VX2 cell can be successfully innoculated into the brain using variable methods under researcher's variable conditions.

• (The) Research of the performance art and culture
• /
• no.18
• /
• pp.513-557
• /
• 2009

The procession depicted in Goguryeo's ancient tomb mural consists of guards, honor guards, music band, and performing artists. Since this coincides with the royal processions of Goryeo and Joseon Dynasties, the relationship of its impact can be examined. The performing arts appearing in such street procession were mostly sanakbaekhui. During the Goryeo Dynasty, the king visited Bongeunsa templ when the lotus lantern festival was celebrated. At such time, on the left and right sides of the road travelled by the king were installed mountains made of lanterns and trees made of lanterns. The procession was quite large in scale and was accompanied by colorful music and performances. In the narye ceremony of the Goryeo Dynasty, as in China, street procession and performing arts took place. The jisinbarbgi performed by a peasant band in early January is a custom of narye. A new character appears in the royal narye during the first half of the Joseon period. Therefore the features of narye transforming according to the changes of the times can be examined. In the Joseon Dynasty's procession of a king returning to the palace, the royal band in front and behind the carriage of the king played marching music, and led by a sanbung this street procession headed toward the palace. Various performances also took place during this time. The samilyuga and munhuiyeon were festivals of the yangban class(nobility). Those who passed the state examination hired musicians and performers and paraded around town in Seoul for three days to celebrate the auspicious outcome for their family and to show off their family's power. In the Joseon's dongje and eupchijeui ceremonies, street processions were carried out with a shrine deity image or symbolic flag at the head. The dongje in a Korean village, combined with jisinbarbgi, incorporated a procession with the flags ymbolizing the guardian deity of the village at the head, and this went from house to house. The procession of suyeongyaru had the publicity impact of a mask play performance, and by creating a sense of unity among the participants, heightened the celebratory atmosphere. At the core of the bukcheonggun toseongri gwanweonnori was as treet procession imitating the traveling of high government officials. The toseong gwanweonnori has the folk religion function of praying for safe human living and abundance of grains for the village, the entertainment function of having fun and joy through street processions and various performances, and the social function of creating unity and harmony among the residents. In all the aforementioned events, the street procession had a large role in creating a celebratory atmosphere, and the performance of traditional performing arts in the middle of the procession or after the procession enabled the participants to feel united. The participants of the street procession felt cultural pride and self-confidence through the various events and they were able to have the opportunity to show off and proudly display their abilities.

• Journal of the Korean Society of Radiology
• /
• v.8 no.6
• /
• pp.317-323
• /
• 2014

This study aims to suggest and test methods using an orally inserted guiding device in order to improve a motion artifact by involuntary oral motor such as removing one's dentures and swallowing saliva clinically structured cervical spine scan and to make the optimal image by minimizing motion artifact. A cervical spine test was conducted with 30 patients who wore dentures among those who had a cervical spinal disease from January 1, 2014 through June 30, 2014. As for testing methods, after removing denture, T1-TSE-Sagittal, T2-TSE-Sagittal, T1-TSE-Axial and T2-TSE-Axial were obtained in a normal position and a supine position; the orally inserted guiding device was inserted in patients' mouth; and then T1-TSE-Axial and T2-TSE-Axial were retested. As a result, in SNR, T1-TSE-Axial before inserting an orally inserted guiding device was $22.33{\pm}8.59$; T1-TSE-Axial after inserting the orally inserted guiding device was $25.21{\pm}7.93$; T2-TSE-Axial before inserting the orally inserted guiding device was $14.49{\pm}5.74$; and T2-TSE-Axial after inserting the orally inserted guiding device was $16.61{\pm}6.72$. In CNR, T1-TSE-Axial was measured at $0.23{\pm}0.01$ while T2-TSE-Axial at $0.21{\pm}0.01$. As a result of the qualitative analysis, T1-TSE-Axial before inserting the orally inserted guiding device was $3.49{\pm}0.11$; T1-TSE-Axial after inserting the orally inserted guiding device was $3.95{\pm}0.14$; T2-TSE-Axial before inserting the orally inserted guiding device was $3.25{\pm}0.18$; and T2-TSE-Axial after inserting the orally inserted guiding device was $3.68{\pm}0.09$. As a result of using an orally inserted guiding device, the resolution and contrast of the images improved as the patients' involuntary artifact decreased because of removing dentures and swallowing saliva, and it was found that the interpretation of the images and identification of the diseases improved.