• Ultrasonography
• /
• v.32 no.1
• /
• pp.59-65
• /
• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Geophysics and Geophysical Exploration
• /
• v.1 no.1
• /
• pp.25-30
• /
• 1998

Time-lapse crosswell seismic data, recorded before and after the cavity filling, showed that the filling increased the velocity at a known cavity zone in an old mine site in Inchon area. The seismic response depicted on the tomogram and in conjunction with the geologic data from drillings imply that the size of the cavity may be either small or filled by debris. In this study, I attempted to evaluate the filling effect by analyzing velocity measured from the time-lapse tomograms. The data acquired by a downhole airgun and 24-channel hydrophone system revealed that there exists measurable amounts of source statics. I presented a methodology to estimate the source statics. The procedure for this method is: 1) examine the source firing-time for each source, and remove the effect of irregular firing time, and 2) estimate the residual statics caused by inaccurate source positioning. This proposed multi-step inversion may reduce high frequency numerical noise and enhance the resolution at the zone of interest. The multi-step inversion with different starting models successfully shows the subtle velocity changes at the small cavity zone. The inversion procedure is: 1) conduct an inversion using regular sized cells, and generate an image of gross velocity structure by applying a 2-D median filter on the resulting tomogram, and 2) construct the starting velocity model by modifying the final velocity model from the first phase. The model was modified so that the zone of interest consists of small-sized grids. The final velocity model developed from the baseline survey was as a starting velocity model on the monitor inversion. Since we expected a velocity change only in the cavity zone, in the monitor inversion, we can significantly reduce the number of model parameters by fixing the model out-side the cavity zone equal to the baseline model.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.22 no.1
• /
• pp.98-102
• /
• 2018

Purpose When examining patients with digestive system Leakage, it is not easy to distinguish between bile leakage and bleeding only with Planar images. I would like to evaluate the utility of leakage of bile, confirmation of gastrointestinal bleeding and location discrimination using SPECT-CT. Materials and Methods SPECT-CT was performed according to the request of the reading room after acquiring Planar image for a total of 13 patients, including 8 patients suspected of bile leakage and 5 patients suspected of gastrointestinal bleeding, among patients visiting this specification went. We used Symbia T16 from SIEMENS and Discovery 670 from GE. Planar and SPECT-CT images were evaluated with a score of 1 to 10 by 4 experienced nuclear medicine doctors. Using the sensitivity and the specificity, the evaluation of the inspection by the ROC curve was carried out. The final diagnosis was confirmed by follow-up observation as a result of reoperative surgery. Results The sensitivity, specificity and accuracy of SPECT-CT were 91.7%, 100% and 94.2%, respectively. Planar images were 83.3%, 68.8% and 78.8%, respectively. Planar images showed lower diagnostic accuracy compared to SPECT-CT (78.8%, 94.2%, p<0.05). Moreover, the reliability of the diagnosis of SPECT-CT by ROC curve analysis showed a more useful result than the Planar image (p<0.05). Conclusion SPECT-CT had high sensitivity and specificity for diagnosis of biliary leakage and gastrointestinal bleeding and location discrimination. When SPECT-CT is additionally performed together with Planar images, it may be considered to improve bile leakage and diagnosis of gastrointestinal bleeding patients and position discrimination evaluation. There is usefulness depending on the patient's age and position, but consideration of additional CT exposure may be done sufficiently.

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
• /
• v.6 no.1
• /
• pp.81-97
• /
• 2000

Objectives: This experimental study was carried out to evaluate the effects of aqueous and methanol extracts of Hedyotis diffusa which has long been used for cancer treatment in oriental medicines on the induction of apoptotic cell death in human lymphoid leukemia cell line, HL-60. Methods: Cells were treated with various concentrations (200 to $0.4{\mu}g$) and periods (6 to 30 hr) of $H_2O$ and methanol extracts of Hedyotis diffusa. Then, cells were tested for viability by MTT assay. Cells wrere treated with $200{\mu}g/ml$ of methanol extract fork various periods. Genomic DNA was isolated, separated, on 1.5% agarose gels, stained with ethidium bromide and visualized under UV light. Cells were treated with $200{\mu}g/ml$ of each extract for 16 hr. Then, cells were treated with Hoechst dye 33342 and observed by fluorescence microscopy. Cells were treated with various doses of each for 12 hr and $100{\mu}g/ml$ of methanol extract for various periods. Lysate from the cells used to measure the activity of Caspase-1 and-3 proteases by using fluorogenic peptide substrates including acetyl-YVAD-AMC and acetyl-DEVD-AMC, respectively. Cells were treated with $200{\mu}g/ml$ of each extract for various periods. Cell lysates were immunoprecipated with anti-JNKl antibodies. The immune complex was reacted with $32^p-ATP$ and c-Jun as a substrate. The phosphotransferase activity of JNKI was measured by using PhosphoImage analyzer (Fuji Co., Japan). Nuclear extracts were isolated and incubated with oligonucleotide probe of $NF-{\kappa}B$. Transcriptional activation of ${\kappa}B$ was measured by using EMSA and visualized by PhosphoImage analyzer (Fuji Co, Japan). Cell lysates were prepared and analyzed by Western blotting with anti-Bc12 antibodies and anti-Bax antibodies. Cells were pretreated with various doses of methanol extract for 2 hr. Then, the extract was removed by centrifugation. Cells were resuspended with RPMI-1640 media containing 0.3% agarose, 10% FBS, overlayred onto bottom layer agarose and incubated at $CO_2$ incubator for 6 days. The number of colony was counted under light microscopy ($\time100$). Results: The death of HL-60 cells was markedly induced by the addition of methanol extract of Hedyotis diffusa in a dose and time-dependent manners. The apoptotic characteristic ladder pattern of DNA strand break was observed in death of HL-60 cells. In addition, it was shown nucleus chromatin condensation and fragmentation under Hoechst staining. Therefore, Hedyotis diffusa extract-induced death of HL-60 cells is mediated by apoptotic signaling processes. The activity of Caspase 3-like proteases remained in a basal level in HL-60 cells treated with aqueous extract of Hedyotis diffusa. However, it was markedly increased in HL-60 cells treated with methanol extract of Hedyotis diffusa. In addition, the phosphotransferase activity of JNKl was increased in HL-60 cells treated with methanol extract of Hedyotis diffusa. Furthermore, the activation of transcriptional activator, $NF-{\kappa}B$ was markedly induced by methanol extract of Hedyotis diffusa. Anti-apoptotic Bc12 was cleaved into 23Kda fragment by treatment of methanol extract of Hedyotis diffusa. However, expression of proapoptotic Bax protein was increased by treatment of methanol extract of Hedyotis diffusa in a time-dependent manner. Furthermore, methanol extract markedly inhibited the colony forming efficiency of HL-60 cells in semisolid agar culture. Conclusions: Above results suggest that methanol extract of Hedyotis diffusa induces the apoptotic death of human leukemic HL-60 cells via activations of Caspase-3 proteases, JNKI, transcriptional activator $NF-{\kappa}B$, In addition, our results also suggest that methanol extract of Hedyotis diffusa reduces the malignant potential of HL-60 cells via down regulation of colony forming effciency through cleavage of Bc12 as well as induction of Bax.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.4
• /
• pp.382-390
• /
• 1998

Purpose: The purpose of this study was to evaluate the accuracy of radioactivity quantitation in Tc-99m SPECT by using combined scatter and attenuation correction. Materials and Methods: A cylindrical phantom which simulates tumors (T) and normal tissue (B) was filled with varying activity ratios of Tc-99m. We acquired emission scans of the phantom using a three-headed SPECT system (Trionix, Inc.) with two energy windows (photopeak window: $126{\sim}154keV$ and scatter window: $101{\sim}123keV$). We performed the scatter correction with dual-energy window subtraction method (k=0.4) and Chang attenuation correction. Three sets of SPECT images were reconstructed using combined scatter and attenuation correction (SC+AC), attenuation correction (AC) and without any correction (NONE). We compared T/B ratio, image contrast [(T-B)/(T+B)] and absolute radioactivity with true values. Results: SC+AC images had the highest mean values of T/B ratios. Image contrast was 0.92 in SC+AC, which was close to the true value of 1, and higher than AC (0.77) or NONE (0.80). Errors of true activity by SPECT images ranged from 1 to 11% for SC+AC, $22{\sim}47%$ for AC, and $2{\sim}16%$ for NONE in a phantom which was located 2.4cm from the phantom surface. In a phantom located 10.0cm from the surface, SC+AC underestimated by 24%, NONE 40%. However, AC overestimated by 10%. Conclusion: We conclude that accurate SPECT activity quantitation of Tc-99m distribution can be achieved by dual window scatter correction combind with attenuation correction.

• The Journal of Korean Society for Radiation Therapy
• /
• v.29 no.1
• /
• pp.49-56
• /
• 2017

Purpose: To evaluate the accuracy of the Iterative Metal Artifact Reduction (IMAR) algorithm in correcting CT (computed tomography) images distorted due to a metal artifact and to evaluate the usefulness when proton therapy plan was plan using the images on which IMAR algorithm was applied. Materials and Methods: We used a CT simulator to capture the images when metal was not inserted in the CIRS model 062 Phantom and when metal was inserted in it and Artifact occurred. We compared the differences in the CT numbers from the images without metal, with a metal artifact, and with IMAR algorithm by setting ROI 1 and ROI 2 at the same position in the phantom. In addition, CT numbers of the tissue equivalents located near the metal were compared. For the evaluation of Rando Phantom, CT was taken by inserting a titanium rod into the spinal region of the Rando phantom modelling a patient who underwent spinal implant surgery. In addition, the same proton therapy plan was established for each image, and the differences in Range at three sites were compared. Results: In the evaluation of CIRS Phantom, the CT numbers were -6.5 HU at ROI 1 and -10.5 HU at ROI 2 in the absence of metal. In the presence of metal, Fe, Ti, and W were -148.1, -45.1 and -151.7 HU at ROI 1, respectively, and when the IMAR algorithm was applied, it increased to -0.9, -2.0, -1.9 HU. In the presence of metal, they were 171.8, 63.9 and 177.0 HU at ROI 2 and after the application of IMAR algorithm they decreased to 10.0 6,7 and 8.1 HU. The CT numbers of the tissue equivalents were corrected close to the original CT numbers except those in the lung located farthest. In the evaluation of the Rando Phantom, the mean CT numbers were 9.9, -202.8, and 35.1 HU at ROI 1, and 9.0, 107.1, and 29 HU at ROI 2 in the absence, presence of metal, and in the application of IMAR algorithm. The difference between the absence of metal and the range of proton beam in the therapy was reduced on the average by 0.26 cm at point 1, 0.20 cm at point 2, and 0.12 cm at point 3 when the IMAR algorithm was applied. Conclusion: By applying the IMAR algorithm, the CT numbers were corrected close to the original ones obtained in the absence of metal. In the beam profile of the proton therapy, the difference in Range after applying the IMAR algorithm was reduced by 0.01 to 3.6 mm. There were slight differences as compared to the images absence of metal but it was thought that the application of the IMAR algorithm could result in less error compared with the conventional therapy.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.1
• /
• pp.185-194
• /
• 2014

This study investigates the methodology to evaluate the quantified performance of pavement markings and traffic guide signs using digital images. This methodology is significant to attempt to quantify their performance without large brightness photometer at the nighttime and bad weather. The retroreflective performance of pavement markings are evaluated through the contrast of gray levels of pavements and markings in collected digital images under the case of rain, dampness, and dryness. In addition, the appraisal of retroreflective performance of traffic guide signs are implemented through the comparison between interior illuminated and the existing retroreflective traffic guide signs using the contrast of luminance extracted from the value of RGB of backgrounds and legends in collected digital images according to geometric design, driving lanes, and the distance between the car and the sign. As a result, the retroreflective performance of pavement markings deteriorates about 3.5 times and 2 times under the case of rain and dampness respectively than dryness. Also, the performance of the existing traffic guide signs is significantly influenced by geometric design, driving lanes, and the distance, otherwise interior illuminated traffic guide signs. This methodology can be utilized to construct objective information of performance of traffic safety facilities to select appropriate position of expensive high reflective pavement markings and interior illuminated traffic guide signs considering diverse weather and geometric design.

• Journal of the Korean Society of Radiology
• /
• v.9 no.4
• /
• pp.235-238
• /
• 2015

The aims of this study were to evaluate the difference of renal uptake rate in $^{99m}Tc-DMSA$ scan on pediatrics by including the bladder. Phantom and Clinical studies were performed. In the phantom study, we put $^{99m}TcO_4{^-}$ (300uCi, 11 MBq) in 3cups filled with distilled water at the rate 1:1:0, 1:1:0.5, 1:1:1, 1:1:2 and were placed Lt kidney, Rt kidney and bladder position on the table. To acquire the image, we used Symbia-E gamma camera from Siemens with preset count method(400,000 counts). In quantitative analysis, the counts of drawing ROIs on the phantom were analyzed. In clinical studies, we analyzed the 20 pediatrics who were examined by $^{99m}Tc-DMSA$ scan. At first, the images were acquired with both kidney and bladder. Secondly we acquired images after shielding the bladder. And the data were compared using a pared t-test by SPSS(ver.22.0). As a result of renal phantom's experiment, we compared with average of uptake rate(%), 1:1:0 was Lt 43.32%, Rt 45.97%, 1:1:0.5 was Lt 35.79%, Rt 36.89%, 1:1:1 was Lt 29.68%, Rt 31.45% and 1:1:2 was Lt 22.89%, Rt 24.32%. There was no correlation between the zoom and uptake rate. The results of patient were that excluded bladder was $29.83{\pm}8.81%$(Lt), $24.29{\pm}6.66%$(Rt) and included bladder was $26.65{\pm}8.03%$(Lt, $21.78{\pm}6.24%$(Rt). This is deemed statistically significant (p<0.05). Renal uptake rate was undervalued because the counts of bladder were included in the total counts.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.3
• /
• pp.222-228
• /
• 2011

Purpose: The purposes of this study were to evaluate the stress distributions and the displacements of obturator for edentulous maxillectomy patients and to compare them with those of complete denture using three-dimensional finite element analysis. Materials and methods: Based on the CT image of edentulous patient, three-dimensional finite element model of edentulous maxillae was constructed. Three-dimensional finite element model of edentulous maxillae with palatal defect was also fabricated. On each model, complete denture and obturator prosthesis were created. Vertical static force of 200 N was applied on the left maxillary premolar and molar region. The von Mises stress values and the displacements of models were analyzed using three-dimensional finite element analysis. Results: Maximum von Mises stress values were recorded in the cortical bones of both models. The von Mises stress value in the complete denture model was 2.73 MPa and 2.69 MPa in the obturator model. High von Mises stress values were also observed on the tissue surface of prosthesis. The maximum value of the displacement in the obturator was higher than that of complete denture. Conclusion: The obturator showed a worse result in terms of stress distribution and displacement than complete denture. In the prosthodontic rehabilitation of edentulous maxillectomy patient accurate impression procedure based on patients'anatomy and application of prosthodontic principle should be considered.

• Research in Community and Public Health Nursing
• /
• v.13 no.1
• /
• pp.161-170
• /
• 2002

Purpose: To evaluate community health nursing practice by nursing students for basic data to improve nursing practice education, and to determine the clinical practice experiences of nursing students at public health centers. Method: According to methodological triangulation, all data was collected from March 2001 to June 2001 through prepared questionnaires with 62 Participants, and in depth interviews with 2 Participants, and content analysis with 8 Participants. Results: 1. Clinical practice content was needed to make up professionally. 2. Clinical practice instructor was satisfied with teaching by community health nursing professor, but not by public health center nurse. 3. Clinical environment was perceived as good. 4. Clinical practice time was perceived suitable, but practice evaluation was given a low grade. 5. Experience of nursing students was grouped into 9 categories and 20 themes. 9 Categories are as follows: change of public health center image, difficulty in the personal relationship, positive personal relationships, doubt about the attitude, doubt about the task, tension, worth, ambivalance of the conference, feeling about the end stage of the clinical practice. Twenty themes are stereotypic of the public health care center: recognition, difficulty between tasks and interrelationships with the clients, decrease of self esteem due to deficiency of trust with the students, exchange of feelings in the relationships, the situation of clients was not considered, feelings were disregarded, not systematic, regarding students as supplementory manpower, independent work but not enough contents, anxiety & fear, self-trust, be skilled in the practice, pragmatic knowledge formation, understanding of the old person, self-study of oneself. live up to the expectation, consider as the job, dissolve the stress and impose burden, feeling the lack regarding active approach in the practice. Conclusion: The students have perceived the need of community health nursing through the clinical practice. Clinical practice of community health nursing requires content supplement, correction of instruction by public center nurses, environmental alteration, evaluation criteria set up. Experience of clinical practice in the public health center was as follows: Getting rid of the stereotype about public health center, nursing students comprehended variety and were worth while to do clinical practice in spite of tension& anxiety and fear. And they thought to be a community nurse someday.