• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.1-8
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• 2017

Purpose: The purpose of this study is to compare the accuracy of the CT guided implant template that was produced by using an intraoral scanner according to the edentulous distance. Materials and methods: Five maxillary casts were fabricated using radiopaque acrylic resin with the second premolars, first molars, and second molars missing. Then a virtual cast was acquired by scanning each resin cast. Implant treatment was planned on the missing sites by superimposing the presurgical CT DICOM file and the virtual cast. Then the implants were placed using a surgical template followed by postsurgical CT scan. The distance and angle of the platform and apex between the presurgical implant and postsurgical implant were measured using the X, Y, and Z axis of the superimposed presurgical CT and postsurgical CT via software followed by statistical analysis using Kruskall-Wallis test and Mann-Whitney test. Results: The implant placement angle error increased towards the second molars but there was no statistically significant difference. The implant placement distance error at the platform and apex also increased towards the second molars and there was a statistically significant error at the second molars. Conclusion: Although the placement angle had no statistically significant difference between the presurgical implant and postsurgical implant, the placement distance at the platform and apex showed a larger error and a statistically significant difference at the second molar implant.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.183-191
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• 2017

The purpose of this study was to evaluate a clinical preventative care program, based on a dental hygiene process (accessment, diagnosis, planning, implementation, evaluation; ADPIE) in a dental clinic, by analyzing patient recognition, knowledge, practice, and satisfaction with respect to oral health. The collected data (in percentages) were analyzed Fisher's exact test and paired t-test using IBM SPSS ver. 21.0 (IBM Co., USA). This study demonstrated a significant difference in oral health knowledge, recognition, and practice before and after the clinical preventive care program (p<0.05). The results were significant in the individual preventive plan within the planning stage, and in the professional teeth cleaning implementation stage (p<0.05). This result can be attributed to the sympathy of the dental hygienist (p<0.05). There was a positive correlation between recommending dental checkups and regular checking of the (r=0.552, p<0.05), undergoing radiography (r=0.434, p<0.01), following an individual preventive plan (r=0.568, p<0.01), undergoing proximal machine teeth cleaning (r=0.437, p<0.05), following tooth brushing instructions (r=0.552, p<0.05), and the evaluation results (r=1.000, p<0.05). Our results demonstrate, that the clinical preventive care program, based on dental hygiene, is an effective program. Given the positive effect of dental revisits and patient recommendations promoting dental hygienists, it is hoped that this preventative program will be widely used.

• Radiation Oncology Journal
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• v.28 no.2
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• pp.99-105
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• 2010

Purpose: To compare radiation dose of the brain and lens among various conventional whole brain radiotherapy (WBRT) techniques. Materials and Methods: Treatment plans for WBRT were generated with planning computed tomography scans of 11 patients. A traditional plan with an isocenter located at the field center and a parallel anterior margin at the lateral bony canthus was generated (P1). Blocks were automatically generated with a 1 cm margin on the brain (5 mm for the lens). Subsequently, the isocenter was moved to the lateral bony canthus (P2), and the blocks were replaced into the multileaf collimator (MLC) with a 5 mm leaf width in the craniocaudal direction (P3). For each patient plan, 30 Gy was prescribed at the isocenter of P1. Dose volume histogram (DVH) parameters of the brain and lens were compared by way of a paired t-test. Results: Mean values of $D_{max}$ and $V_{105}$ of the brain in P1 were 111.9% and 23.6%, respectively. In P2 and P3, $D_{max}$ and $V_{105}$ of the brain were significantly reduced to 107.2% and 4.5~4.6%, respectively (p<0.001). The mean value of $D_{mean}$ of the lens was 3.1 Gy in P1 and 2.4~2.9 Gy in P2 and P3 (p<0.001). Conclusion: WBRT treatment plans with an isocenter located at the lateral bony canthus have dosimetric advantages for both the brain and lens without any complex method changes.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.66-74
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• 2019

Excessive wear causes many complications when untreated, so that accurate diagnosis, analysis and predictive treatment plan should be made, and through evaluation of vertical dimension and stepwise treatment, a stable inter-arch relationship can be set. For the long-term success of implant treatment, ideal position and angle of implant is important, and its importance increases especially in multiple implant cases. Therefore, thorough diagnosis and planning, accurate surgery and prosthodontic procedures are significant. In this case, a 68-year-old male patient with a loss of vertical dimension due to multiple tooth loss and overall tooth wear was planned with systematic analyses from the pre-treatment stage to rehabilitate vertical dimension. Full-mouth fixed rehabilitation with computer tomography guided implant surgery was performed to the newly set vertical dimension and attained satisfactory outcomes both functionally and esthetically.

• Journal of the Korean Regional Science Association
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• v.39 no.3
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• pp.3-12
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• 2023

The issue to be discussed is set as the relationship between urban fragmentation and urban heat phenomena. The fragmentation is recognized as a negative form that commonly occurs in the process of urbanization. The purpose of this study is to examine the relationship between urbanization entropy and heat phenomenon by looking at the five major cities in Korea. The employed methods are InVEST Urban Cooling Model and MSPA (Morphological Spatial Pattern Analysis) by using the meteological data for the July 2018. The major results are as follows; First, a low rank correlation(rho=-0.3) is found in the relation between entropy and Cooling Capacity Index (CCi). Second, a very high level of rank correlation is observed between entropy and Average Temperature(℃)(rho=0.9). The implications are that 1) a city with a large degree of sprawling development can have a negative effect on urban heat phenomena; 2) the composition of land use including dispersion and concentration in non-urbanized areas, which has the characteristics of open space, can affect the urban thermal environment. Due to the limited number of case studies, it is appropriate to understand that a possibility, not generalization, is observed between entropy and heat phenomena in urbanized areas.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.33-39
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• 2023

Purpose: The purpose of this study is to find out the dose variation according to thickness of the air gap between the patient's body surface and immobilization device in the treatment plan. Materials and Methods : Four conditions were created by adjusting the air gap thickness using 5 mm bolus, ranging from 0 mm to 3 mm bolus. Immobilization was placed on top in each case. And computed tomography was used to acquire images. The treatment plan that 430 cGy (Relative Biological Effectiveness,RBE) is irradiated 6 times and the dose of 2580 cGy (RBE) is delivered to 95% of Clinical Target Volume (CTV). The dose on CTV was evaluated by Full Width Half Maximum (FWHM) of the lateral dose profile and skin dose was evaluated by Dose Volume Histogram (DVH). Result: Results showed that the FWHM values of the lateral dose profile of CTV were 4.89, 4.86, 5.10, and 5.10 cm. The differences in average values at the on the four conditions were 3.25±1.7 cGy (RBE) among D_95% and 1193.5±10.2 cGy (RBE) among D_95% respectively. The average skin volume at 1% of the prescription dose was 83.22±4.8%, with no significant differences in both CTV and skin. Conclusion: When creating a solid-type immobilization device for carbon particle therapy, a slight air gap is recommended to ensure that it does not extend beyond the dose application range of the CTV.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.49-63
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• 2018

Purpose : The purpose of this study is investigating the changes of treatment plan and comparing skin dose with or without the skin flash. To investigate optimal applications of the skin flash, the changes of skin dose of each plans by various thicknesses of skin flash were measured and analyzed also. Methods and Material : Anthropomorphic phantom was scanned by CT for this study. The 2 fields hybrid IMRT and the 6 fields static IMRT were generated from the Eclipse (ver. 13.7.16, Varian, USA) RTP system. Additional plans were generated from each IMRT plans by changing skin flash thickness to 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm and 2.5 cm. MU and maximum doses were measured also. The treatment equipment was 6MV of VitalBeam (Varian Medical System, USA). Measuring device was a metal oxide semiconductor field-effect transistor(MOSFET). Measuring points of skin doses are upper (1), middle (2) and lower (3) positions from center of the left breast of the phantom. Other points of skin doses, artificially moved to medial and lateral sides by 0.5 cm, were also measured. Results : The reference value of 2F-hIMRT was 206.7 cGy at 1, 186.7 cGy at 2, and 222 cGy at 3, and reference values of 6F-sIMRT were measured at 192 cGy at 1, 213 cGy at 2, and 215 cGy at 3. In comparison with these reference values, the first measurement point in 2F-hIMRT was 261.3 cGy with a skin flash 2.0 cm and 2.5 cm, and the highest dose difference was 26.1 %diff. and 5.6 %diff, respectively. The third measurement point was 245.3 cGy and 10.5 %diff at the skin flash 2.5 cm. In the 6F-sIMRT, the highest dose difference was observed at 216.3 cGy and 12.7 %diff. when applying the skin flash 2.0 cm for the first measurement point and the dose difference was the largest at the application point of 2.0 cm, not the skin flash 2.5 cm for each measurement point. In cases of medial 0.5 cm shift points of 2F-hIMRT and 6F-sIMRT without skin flash, the measured value was -75.2 %diff. and -70.1 %diff. at 2F, At -14.8, -12.5, and -21.0 %diff. at the 1st, 2nd and 3rd measurement points, respectively. Generally, both treatment plans showed an increase in total MU, maximum dose and %diff as skin flash thickness increased, except for some results. The difference of skin dose using 0.5 cm thickness of skin flash was lowest lesser than 20 % in every conditions. Conclusion : Minimizing the thickness of skin flash by 0.5 cm is considered most ideal because it makes it possible to keep down MUs and lowering maximum doses. In addition, It was found that MUs, maximum doses and differences of skin doses did not increase infinitely as skin flash thickness increase by. If the error margin caused by PTV or other factors is lesser than 1.0 cm, It is considered that there will be many advantages in with the skin flash technique comparing without it.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.145-153
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• 2021

Purpose: The purpose of this study is to evaluate the ovarian dose during radiation therapy for breast cancer in women of childbearing age through an experiment. The ovarian dose is evaluated by comparing and analyzing between the calculated dose in the treatment planning system according to the treatment technique and the measured dose using a thermoluminescence dosimeter (TLD). The clinical usefulness of lead (Pb) apron is investigated through dose analysis according to whether or not it is used. Materials and Methods: Rando humanoid phantom was used for measurement, and wedge filter radiation therapy, 3D conformal radiation therapy, and intensity modulated radiation therapy were used as treatment techniques. A treatment plan was established so that 95% of the prescribed dose could be delivered to the right breast of the Rando humanoid phantom 3D image obtained using the CT simulator. TLD was inserted into the surface and depth of the virtual ovary of the Rando hunmanoid phantom and irradiated with radiation. The measurement location was the center of treatment and the point moved 2 cm to the opposite breast from the center of the Rando hunmanoid phantom, 5cm, 10cm, 12.5cm, 15cm, 17.5cm, 20cm from the boundary of the right breast to the center of treatment and downward, and the surface and depth of the right ovary. Measurements were made at a total of 9 central points. In the dose comparison of treatment planning systems, two wedge filter treatment techniques, three-dimensional conformal radiotherapy, and intensity-modulated radiation therapy were established and compared. Treatments were compared, and dose measurements according to the use of lead apron were compared and analyzed in intensity-modulated radiation therapy. The measured value was calculated by averaging three TLD values for each point and converting using the TLD calibration value, which was calculated as the point dose mean value. In order to compare the treatment plan value with the actual measured value, the absolute dose value was measured and compared at each point (%Diff). Results: At Point A, the center of treatment, a maximum of 201.7cGy was obtained in the treatment planning system, and a maximum of 200.6cGy was obtained in the TLD. In all treatment planning systems, 0cGy was calculated from Point G, which is a point 17.5cm downward from the breast interface. As a result of TLD, a maximum of 2.6cGy was obtained at Point G, and a maximum of 0.9cGy was obtained at Point J, which is the ovarian dose, and the absolute dose was 0.3%~1.3%. The difference in dose according to the use of lead aprons was from a maximum of 2.1cGy to a minimum of 0.1cGy, and the %Diff value was 0.1%~1.1%. Conclusion: In the treatment planning system, the difference in dose according to the three treatment plans did not show a significant difference from 0.85% to 2.45%. In the ovary, the difference between the Rando humanoid phantom's treatment planning system and the actual measured dose was within 0.9%, and the actual measured dose was slightly higher. This did not accurately reflect the effect of scattered radiation in the treatment planning system, and it is thought that the dose of scattered radiation and the dose taken by CBCT with TLD inserted were reflected in the actual measurement. In dosimetry according to the with or without a lead apron, when a lead apron was used, the closer the distance from the treatment range, the more effective the shielding was. Although it is not clinically appropriate for pregnancy or artificial insemination during radiotherapy, the dose irradiated to the ovaries during treatment is not expected to significantly affect the reproductive function of women of childbearing age after radiotherapy. However, since women of childbearing age have constant anxiety, it is thought that psychological stability can be promoted by presenting the data from this study.

• Progress in Medical Physics
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• v.22 no.3
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• pp.107-116
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• 2011

Respiratory gated radiation therapy and stereotactic body radiation therapy require identical tumor motions during each treatment with the motion detected in treatment planning CT. Therefore, this study developed a tumor motion monitoring and analysis system during the treatments employing RPM data, gated setup OBI images and a data analysis software. A respiratory training and guiding program which improves the regularity of breathing was used to patients. The breathing signal was obtained by RPM and the recorded data in the 4D console was read after treatment. The setup OBI images obtained gated at 0% and 50% of breathing phases were used to detect the tumor motion range in crenio-caudal direction. By matching the RPM data recorded at the OBI imaging time, a factor which converts the RPM motion to the tumor motion was computed. RPM data was entered to the institute developed data analysis software and the maximum, minimum, average of the breathing motion as well as the standard deviation of motion amplitude and period was computed. The computed result is exported in an excel file. The conversion factor was applied to the analyzed data to estimate the tumor motion. The accuracy of the developed method was tested by using a moving phantom, and the efficacy was evaluated for 10 stereotactic body radiation therapy patients. For the sine wave motion of the phantom with 4 sec of period and 2 cm of peak-to-peak amplitude, the measurement was slightly larger (4.052 sec) and the amplitude was smaller (1.952 cm). For patient treatment, one patient was evaluated not to qualified to SBRT due to the usability of the breathing, and in one patient case, the treatment was changed to respiratory gated treatment due the larger motion range of the tumor than treatment planed motion. The developed method and data analysis program was useful to estimate the tumor motion during treatment.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.263-270
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• 2008

Purpose: This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. Materials and Methods: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system ($Synchrony^{TM}$). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. Results: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and $13.9{\pm}5.5\;mm$, respectively from the superior to the inferior direction, 3.9 mm and $1.9{\pm}0.9mm$, respectively from left to right, and 8.3 mm and $4.9{\pm}1.9\;mm$, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be $3.3^{\circ}$ and $2.6{\pm}1.3^{\circ}$, respectively for X (Left-Right) axis rotation, $4.8^{\circ}$ and $2.3{\pm}1.0^{\circ}$, respectively for Y (Crania-Caudal) axis rotation, $3.9^{\circ}$ and $2.8{\pm}1.1^{\circ}$, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was $1.1{\pm}0.7\;mm$. Conclusion: In this study real-time movement of a liver tumor during the radiosurgery could be verified quantitatively and the accuracy of the radiosurgery with the Synchrony Respiratory motion tracking system of robot could be evaluated. On this basis, the decision of treatment volume in radiosurgery or conventional radiotherapy and useful information on the movement of liver tumor are supposed to be provided.