• Journal of radiological science and technology
• /
• v.44 no.3
• /
• pp.205-210
• /
• 2021

The purpose of this study was to analyze the spatial dose according to the distance by location of medical workers when using a mobile X-ray fluoroscopy device in the operating room through a simulation experiment. The MCNPX program was used for the simulation, and the location of medical workers was set around the operating table, and the spatial dose distribution according to the distance and changes in imaging conditions was evaluated. As a result, The highest score was 2.74×10^-4 mGy, 2.72×10^-4 mGy, and 1.18×10^-4 mGy based on the 10 cm distance from the operating table. Spatial dose depending on the distance 100cm, A point 5.15×10^-5 mGy is decreased 19% of 10cm, D point 5.12×10^-5 mGy, 19 % of 10cm, and G pint, 1.73×10^-5 mGy is reduced by 15% of 10cm. Based on this study, medical-related workers directly or indirectly participating in surgery carry potential risks of radiation exposure during surgery, but there are difficulties in radiation protection due to the nature of their work. Therefore, efforts to reduce exposure suitable for the operating room environment will be required.

• Archives of Plastic Surgery
• /
• v.50 no.4
• /
• pp.340-347
• /
• 2023

Background Though in facial plastic surgery, the ideal nasal characteristics are defined by average European-American facial features known as neoclassical cannons, many ethnicities do not perceive these characteristics as suitable. Methods To investigate the preferences for nasofrontal angle, nasolabial angle, dorsal height, alar width, and nasal tip projection, manipulated pictures of one male and one female model were shown to 203 volunteer patients from a tertiary university hospital's facial plastic clinic. Results The most aesthetically preferred nasofrontal angles were 137.64 ± 4.20 degrees for males and 133.55 ± 4.53 degrees for females. Acute nasofrontal angles were more desirable in participants aged 25 to 44. The most preferred nasolabial angles were 107.56 ± 5.20 degrees and 98.92 ± 4.88 degrees, respectively. Volunteers aged 19 to 24 preferred more acute male nasolabial angles. A straight dorsum was the most desirable in both genders (0.03 ± 0.78 and 0.26 ± 0.75 mm, respectively). The ideal male and female alar widths were -0.51 ± 2.26 and -1.09 ± 2.18 mm, respectively. More 45- to 64-year-old volunteers preferred alar widths equal to intercanthal distance. The ideal female and male tip projections were 0.57 ± 0.01 and 0.56 ± 0.01, respectively. Conclusion Results indicate that the general Iranian patients prefer thinner female noses with wider nasofrontal angles for both genders. However, the ideal nasolabial angles, dorsal heights, and tip projections were consistent with the neoclassical cannons. Besides ethnic differences, the trend of nasal beauty is also affected by gender, age, and prior history of aesthetic surgery.

• Restorative Dentistry and Endodontics
• /
• v.47 no.4
• /
• pp.39.1-39.12
• /
• 2022

Objectives: This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans. Materials and Methods: CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ² test. Intra-observer agreement was analyzed with the kappa test (α = 0.05). Results: In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent. Conclusions: The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry.

• Journal of Cardiovascular Imaging
• /
• v.30 no.1
• /
• pp.25-34
• /
• 2022

BACKGROUND: The purpose of this study was to assess the utility of a handheld device (HH) used during common daily practice and its agreement with the results of a standard echocardiography study (STD) performed by experienced sonographers and echocardiographer. METHODS: A prospective follow-up was conducted in an adult outpatient echocardiography clinic. Experienced sonographers performed the STD and an experienced echocardiographer performed the HH. STD included 2-dimensional images, Doppler and hemodynamics analysis. Hemodynamic assessment was not performed with the HH device because the HH does not include such technology. The images were interpreted by blinded echocardiographers, and the agreement between the reports was analyzed. RESULTS: A total of 108 patients were included; and the concordance for left ventricle (LV) ejection fraction (EF), wall motion score index, LV and right ventricle (RV) function, RV size, and mitral and aortic stenosis was excellent with κ values greater than 0.80. Wall motion abnormalities had good concordance (κ value 0.78). The agreement for LV hypertrophy, mitral and aortic regurgitation was moderate, and tricuspid and pulmonary regurgitation agreements were low (κ values of 0.26 and 0.25, respectively). CONCLUSIONS: In a daily practice scenario with experienced hands, HH demonstrated good correlation for most echocardiography indications, such as ventricular size and function assessment and stenosis valve lesion analyses.

• Journal of the Korean Physical Society
• /
• v.80
• /
• pp.247-256
• /
• 2022

Our objective was to investigate radiomics signatures and prediction models defined by four segmentation methods in using 2-[¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET) imaging of lung metastases of soft-tissue sarcomas (STSs). For this purpose, three fixed threshold methods using the standardized uptake value (SUV) and gradient-based edge detection (ED) were used for tumor delineation on the PET images of STSs. The Dice coefficients (DCs) of the segmentation methods were compared. The least absolute shrinkage and selection operator (LASSO) regression and Spearman's rank, and Friedman's ANOVA test were used for selection and validation of radiomics features. The developed radiomics models were assessed using ROC (receiver operating characteristics) curve and confusion matrices. According to the results, the DC values showed the biggest difference between SUV40% and other segmentation methods (DC: 0.55 and 0.59). Grey-level run-length matrix_run-length nonuniformity (GLRLM_RLNU) was a common radiomics signature extracted by all segmentation methods. The multivariable logistic regression of ED showed the highest area under the ROC (receiver operating characteristic) curve (AUC), sensitivity, specificity, and accuracy (AUC: 0.88, sensitivity: 0.85, specificity: 0.74, accuracy: 0.81). In our research, the ED method was able to derive a significant model of radiomics. GLRLM_RLNU which was selected from all segmented methods as a meaningful feature was considered the obvious radiomics feature associated with the heterogeneity and the aggressiveness. Our results have apparently showed that radiomics signatures have the potential to uncover tumor characteristics.

• The Journal of Korean Society for Radiation Therapy
• /
• v.15 no.1
• /
• pp.1-9
• /
• 2003

I. Purpose The multileaf collimator(MLC) has many advantages, but use of the MLC increased effective penumbra and isodose undulation in dose distribution compared with that of an alloy block. In this work, we introduced the HD-270 MLC, which can improve the above disadvantages of MLC, and reported its feasibility study. II. Method and Materials The HD-270 MLC is a technique which combines the use of the existing Siemens multileaf collimator(3D MLC) with patient translation perpendicular to the leaf plane. The technique produces a smoothed isodose distribution with the reduced isodose undulation and effective penumbra. To assess the efficacy of the HD-270 technique and determine the appropriate resolution, a polygonal shaped MLC field was made to produce field edge angles from 0 degree to 75 degree with a step of 15 degree. Each HD-270 group was generated according to the allowed resolution, i. e., 5, 3, and 2mm. The experiment was carried out on Primus, a Siemens linear accelerator configured with HD-270 MLC. The total 60 MU of 6 MV photon beam was delivered to X-Omat film(Kodak, USA) at a SAD of 100 cm and 1.5 cm depth in solid water phantom. Exposed films were scanned by Lumiscan75(LUMISYS) and analyzed using RIT113 software(Radiological Imaging Technology Inc., USA). To test the mechanical accuracy of table movement, the transverse, longitudinal, and vertical positions were controlled by a consol with ${\pm}5\;mm,\;{\pm}4\;mm,\;{\pm}3\;mm,\;and\;{\pm}2\;mm$ steps, and then measured using a dial gauge with an accuracy of 0.001 inch. During the experiments, the table loaded with about 50Kg human phantom to simulate the real treatment situation. III. Results The effective penumbra and isodose undulation became larger with increase the resolution and field edge angle. The accuracy of the table movement on each direction is good within the ${\pm}1\;mm$. IV. Conclusion Clinical use of the MLC can be increased by using of the HD-270 MLC which complements to the disadvantages of the MLC.

• Journal of radiological science and technology
• /
• v.32 no.2
• /
• pp.195-203
• /
• 2009

Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.

• Geophysics and Geophysical Exploration
• /
• v.1 no.1
• /
• pp.49-56
• /
• 1998

Seismic tomography has been widely used as high resolution subsurface imaging techniques in engineering applications. Although most of the techniques have been using travel time inversion, waveform method is being driven forward owing to the progress of computational environments. Although full-waveform inversion method has been known as the best method in terms of model resolving power without high-frequency restriction and weak scattering approximation, it has practical disadvantage that it is apt to get stuck in local minimum if the initial guess is far from the actual model and it consumes so much time to calculate. In this study, 2-D full-waveform inversion algorithm in acoustic medium is developed, which uses result of traveltime tomography as initial model. From the application on synthetic data, it is proved that this approach can efficiently reduce the problem of conventional approaches: our algorithm shows much faster convergence rate and improvement of model resolution. Result of application on physical modeling data also shows much improvement. It is expected that this algorithm can be applicable to real data.

• Nuclear Medicine and Molecular Imaging
• /
• v.40 no.5
• /
• pp.263-270
• /
• 2006

Purpose: Several radioisotope-labeled thymidine derivatives such as $[^{11}C]$thymidine was developed to demonstrate cell proliferation in tumor. But it is difficult to track metabolism with $[^{11}C]$thymidine due to rapid in vivo degradation and its short physical half-life. 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) was reported to have the longer half life of fluorine-18 and the lack of metabolic degradation in vivo. Here, we described the synthesis of the 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) and compared with $([^{18}F]FET)\;and\;([^{18}F]FDG)$ in cultured 9L cell and obtained the biodistribution and PET image in 9L tumor hearing rats. Material and Methods: For the synthesis of $[^{18}F]$FLT, 3-N-tert-butoxycarbonyl-(5'-O-(4,4'-dimet hoxytriphenylmethyl)-2'-deoxy-3'-O-(4-nitrobenzenesulfonyl)-${\beta}$-D-threopentofuranosyl)thymine was used as a FLT precursor, on which the tert-butyloxycarbonyl group was introduced to protect N3-position and nitrobenzenesulfonyl group. Radiolabeling of nosyl substitued precursor with $^{18}F$ was performed in acetonitrile at $120^{\circ}C$ and deproteced with 0.5 N HCI. The cell uptake was measured in cultured 9L glioma cell. The biodistribution was evaluated in 9L tumor bearing rats after intravenous injection at 10 min, 30 min, 60 min and 120 min and obtained PET image 60 minutes after injection. Results: The radiochemical yield was about 20-30% and radiochemical purity was more than 95% after HPLC purification. Cellular uptake of $[^{18}F]$FLT was increased as time elapsed. At 120 min post-injection, the ratios of tumor/blood, tumor/muscle and tumor/brain were $1.61{\pm}0.34,\;1.70{\pm}0.30\;and\;9.33{\pm}2.22$, respectively. The 9L tumor was well visualized at 60 min post injection in PET image. Conclusion: The uptake of $[^{18}F]$FLT in tumor was higher than in normal brain and PET image of $[^{18}F]$FLT was acceptable. These results suggest the possibility of $[^{18}F]$FLT at an imaging agent for brain tumor.

• Journal of Acupuncture Research
• /
• v.33 no.2
• /
• pp.11-20
• /
• 2016

Objectives : The purpose of this study is to investigate the clinical effectiveness of Korean medical combination treatment for cervical disc herniation. Methods : This is an observational study. 102 patients diagnosed with cervical disc herniation by MRI (Magnetic Resonance Imaging) were investigated from January, 2015 through to December, 2015 at Daejeon Jaseng Hospital of Korean Medicine. They were sorted according to the distribution of sex, age, causing factor, the period of disease, admission day and pain area. All patients were treated with acupuncture, Chuna treatment, and herbal therapy and physical therapy during the admission period. After treatment, NRS (Numeric Rating Scale), NDI (Neck Disability Index) and EQ-5D were assessed to evaluate the treatment efficacy. Results : There were more females than Males with a ratio of 1 : 1.37, the age of fifty was the most with 35.29 %, reason unknown was the most with 72.55 % and the subacute stage was the most with 38.24 %. According to disc herniation types, patients with protruded disc types were the most with 66.67 % and a lesion of C5/6 was the most with 41.18 %. For patients diagnosed with cervical disc herniation, neck and shoulder pain NRS decreased from $6.43{\pm}1.77$ to $3.96{\pm}1.96$(p<0.001) and radiating pain NRS decreased from $5.64{\pm}1.96$ to $3.57{\pm}1.88$ (p<0.001). NDI decreased from $41.72{\pm}14.04$ to $30.84{\pm}15.34$(p<0.001), and the EQ-5D index increased from $0.68{\pm}0.17$ to $0.79{\pm}0.14$(p<0.001) after treating cervical disc patients. Conclusion : Korean medical combination treatment might be effective in decreasing pain and raising the life quality of patients with cervical disc herniation.