• Title/Summary/Keyword: deviation of position

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Change of Heart Rate Variability in Depressive Disorder after Physical or Psychological Stress (우울장애 환자에서 육체적 및 정신적 스트레스 시 심박변이도의 변화)

  • Lee, Jong-Hwa;Yu, Jaehak;Ryu, Seung-Ho;Ha, Ji-Hyeon;Jeon, Hong-Jun;Park, Doo-Heum
    • Sleep Medicine and Psychophysiology
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    • v.25 no.1
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    • pp.15-20
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    • 2018
  • Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress states in depressive disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 62 depressive disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity, respectively. Differences between HRV indices and VAS score were evaluated using paired t-tests. Gender difference analysis was conducted with ANCOVA. Results: SDNN (standard deviation of normal to normal intervals), LF/HF (low frequency/high frequency), and VLF (very low frequency) were significantly increased, while NN50 and pNN50 were significantly decreased in the upright position compared to resting state. SDNN, RMSSD (root mean square of the differences of successive normal to normal intervals), and VLF were significantly increased, while pNN50 was significantly decreased in the psychological stress state compared to resting state. SDNN, NN50, and pNN50 were significantly lower in an upright position compared to a state of psychological stress, and LF, HF, and LF/HF showed no significant differences Conclusion: The LF/HF ratio was significantly increased after physical stress in depressive disorder. However, the LF/HF ratio was not significantly increased after psychological stress, and the change in LF/HF ratio after physical stress and psychological stress did not significantly differ from each other. Significant increase in SDNN, NN50, and pNN50 in an upright posture compared to psychological stress suggests that depressive patients react more sensitively to physical stress than psychological stress.

The Evaluation of Attenuation Difference and SUV According to Arm Position in Whole Body PET/CT (전신 PET/CT 검사에서 팔의 위치에 따른 감약 정도와 SUV 변화 평가)

  • Kwak, In-Suk;Lee, Hyuk;Choi, Sung-Wook;Suk, Jae-Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.2
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    • pp.21-25
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    • 2010
  • Purpose: For better PET imaging with accuracy the transmission scanning is inevitably required for attenuation correction. The attenuation is affected by condition of acquisition and patient position, consequently quantitative accuracy may be decreased in emission scan imaging. In this paper, the present study aims at providing the measurement for attenuation varying with the positions of the patient's arm in whole body PET/CT, further performing the comparative analysis over its SUV changes. Materials and Methods: NEMA 1994 PET phantom was filled with $^{18}F$-FDG and the concentration ratio of insert cylinder and background water fit to 4:1. Phantom images were acquired through emission scanning for 4min after conducting transmission scanning by using CT. In an attempt to acquire image at the state that the arm of the patient was positioned at the lower of ahead, image was acquired in away that two pieces of Teflon inserts were used additionally by fixing phantoms at both sides of phantom. The acquired imaged at a were reconstructed by applying the iterative reconstruction method (iteration: 2, subset: 28) as well as attenuation correction using the CT, and then VOI was drawn on each image plane so as to measure CT number and SUV and comparatively analyze axial uniformity (A.U=Standard deviation/Average SUV) of PET images. Results: It was found from the above phantom test that, when comparing two cases of whether Teflon insert was fixed or removed, the CT number of cylinder increased from -5.76 HU to 0 HU, while SUV decreased from 24.64 to 24.29 and A.U from 0.064 to 0.052. And the CT number of background water was identified to increase from -6.14 HU to -0.43 HU, whereas SUV decreased from 6.3 to 5.6 and A.U also decreased from 0.12 to 0.10. In addition, as for the patient image, CT number was verified to increase from 53.09 HU to 58.31 HU and SUV decreased from 24.96 to 21.81 when the patient's arm was positioned over the head rather than when it was lowered. Conclusion: When arms up protocol was applied, the SUV of phantom and patient image was decreased by 1.4% and 9.2% respectively. With the present study it was concluded that in case of PET/CT scanning against the whole body of a patient the position of patient's arm was not so much significant. Especially, the scanning under the condition that the arm is raised over to the head gives rise to more probability that the patient is likely to move due to long scanning time that causes the increase of uptake of $^{18}F$-FDG of brown fat at the shoulder part together with increased pain imposing to the shoulder and discomfort to a patient. As regarding consideration all of such factors, it could be rationally drawn that PET/CT scanning could be made with the arm of the subject lowered.

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A Study on the Efficiency of Clinical Practice for Nursing Education in the Junior College of Nursing in Korea (전문대학 간호과의 임상 실험 효율화를 위한 연구)

  • Lee, Kun-Ja;Kim, Myung-Soon;Yang, Young Hee
    • Journal of Korean Public Health Nursing
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    • v.3 no.2
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    • pp.77-108
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    • 1989
  • The purpose of this study was to find out the present condition of clinical practice and to develop a scheme on the efficiency of clinical practice for nursing education in junior college of nursing in korea. This study was conducted by 2 sections. Ist section was to find out the present condition of clinical practice to 42 directors of nursing collegd and data were collected July 8 to September 30, 1988. 2nd section wat to develop a scheme on the efficiency of clinical practice for nursing education and subjects were nursing professors 258: and clinical nurses 223 in 42 junior nursing colleges their clinical settings in korea. So total subjects were 481. Data were collected july 8, 1988 to June 30, 1988 and were analysed to get the mean, standand deviation, frequency, percentage, t-test, x-test used by SPSS - pc. Major findings were as follows: 1. The present condition of clinical education in junior college of nursing in Korea. 1) 32 colleges (76.2%) were managed by a-yeas system. 2) 25 colleges (59.5%) were performed by individual practice for each subject. 3) 4 weeks interval between class education and clinical education was a major type among total colleges(36.6%, J5 colleges) 4) 30 colleges (71.4%) provided clinical education for all subjects that should be practiced. Nursing administration wes not practiced in 5 colleges (41.9%) among the remainder(12 colleges). The main cause that all practice subjects were not practiced was the lack or absence of suitable clinical settings(8 colleges. 66.7%) 5) 18 colleges (42.9%) responded that a clinical educator was, subject-charged professor. 6) 12 colleges (29.3%) responded that a clinical instructor was in charge of 6~10 students. 7) The evaluation ration ratio(professor to head nurse) by each evaluator was mostly 50% to 50 % and 60% to 40%, respectively 11 colleges(27.5%) The most common evaluation methods were evaluation by head nures, report, presence, conference (11 colleges, 27.5%) 8) The field carrier of professor was mostly 2 years (79 persons, 20.7%) and mean was 3.2 years. The education carrier of a professor was mostly over than 6 years (261 persons, 66.4%) and mean was 9.2 years. The charge hours per-week of a professor were mostly 16-18 hours (16 persons, 131.8%) 9) 34 colleges (82.9%) approved that clinical practice hour was class hour and 18 colleges (43.9 %) counted that 2 hours of clinical education equaled 1 hour of class education. 2. A study 'on the efficiency of clinical practice for nursing education. L) general characteristics of subjects were as follows: kung-sang province (145 persons, 30.5%), 30-34 years (190 persons, 39.8%), graduated degree (245 persons, 51.5%), 6-10 years of carrier (199 persons, 41.4%) were the majority. 2) suitable clinical setting was responded the systematic ward with responsible clinical educator by 210 persons(43.8%) The response by working field of subjects showed a significant difference (p< 0.01) 3) 259 subjects (54.0%) responded that the desirable qualfication of clinical instructor was 3-5 years of clinical experience with master degree or higher. 4) The mean score of desirable quality degree of clinical instructor was 3.43 professors, score (3.54) was significantly higher than clinical nurses' (3.28) (p<0.01) 412 subjects (86.0%) responded that the insufficient guality of instructor was improved by continuing to seek more new information in reference. 5) 196 subjects (41.4%) responded that desirable qualification of head nurse was more than 2 years of head position among 5 years of clinical experience. The response by working' field of subjects showed a significant difference (p<0.05) 6) The mean score of desirable quality degree of head nurse was 3.18 Clinical nurses' score(3.38) was significantly higher than professors' (3.01) (p<0.01) 419 subjects (87.8%) responded that the insufficient of head nurse was improved by continuing relationship with instructor and being responsible from planing of clinical education. 7) The mean score of performance level of the desirable clinical education guide incollege was 2.91 Professors' score (2.96) was significantly higher than clinical nurses' (2.84) (p<0.01) 340 subjects (71.1%) responded that the possible resolution for poor performance was the more specified syllabus of clinical education and the satisfiable orientation for students. 8) The mean score of performance level of the desirable clinical education guide in hospital was 3.03 9) 141 subjects (29.6%) responded that the desirable clinical evaluator was the group of professor, head nurse, staff nurse. Response by working field of subjects was a significant difference (p< 0.05) 10) The mean score of performance level of the evaluation content needed in clinical education was 3.50 Clinical nurses' score (3.56) was significantly higher than professors' (3.45) (p<0.01) 11) 433 subjects (90.2%) responded that6 desirable evaluation method for clinical education was the presence. 12) The mean score of performance level about how personal difference among clinical educators was minimized was 2.89 and response by working field of subjects was not significant. The cause of poor performance was too much workload at clinical settings and too many students st colleges by 386 subjects (81.1%).

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A Case Study of Angular Momentum of Trunk and Lower extremity when Performing Uchimata by Posture and Voluntary Resistance Levels of Uke in Korean Judo Olympian[III] (유도 올림피언 허벅다리걸기 기술발휘 시 받기의 자세와 저항수준에 따른 몸통과 하지의 각운동량 분석 사례연구[III])

  • Kim, Eui-hwan;Kim, Sung-sup;Chung, Chae-Wook
    • Korean Journal of Applied Biomechanics
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    • v.15 no.4
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    • pp.191-203
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    • 2005
  • It was to study a following research of "A Kinematical Traits Analysis when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Uke in Judo[1]" and. "A Case Study of Center of Gravity(COG) when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Uke in Judo[II]". The purpose of this study was to analyze an angular momentum of trunk and lower extremity when performing uchimata by two postures and voluntary resistance levels(VRL) of uke(reciver) in Judo. The subjects, who were one male judoka(YH) for 1992 Barcelona Olympic Games Olympian(silver medalist), was filmed on two S-VHS 16mm video cameras(60fields/sec.) through 3-dimensional motion analysis methods, that postures of uke were shizenhontai (straight natural posture:NP) and jigohontai (straight defensive posture:DP), VRL of uke were 0% and 100%, respectively. The variables were angular momentum of trunk, lower extremity of attacking leg and supporting leg of tori(the thrower). The data of this study collection were digitized by SIMI Motion Program computed the mean values and the standard deviation calculated for each variables. When performing uchimata according to each posture and VRL of uke and classifying. From the data analysis and discussion, the conclusions were as follows : Angular momentum of trunk when performing uchimata was showed the largest among another angular momenta, and the posture displayed more different than resistant of uke(reciver), but the pattern similar in judo. Angular momentum of trunk of X axis was the largest and Y, Z axis order. Angular momentum of attacking the thigh-leg when performing uchimata was showed the largest among another angular momenta, and the posture displayed more different than resistant of uke(reciver), X axis and Y axis similar, but angular momentum of Z axis of thigh-leg the largest, in kake(application) event in 0% resistance of DP than other variables. Angular momentum in X,Y axis of attacking the lower-leg when performing uchimata was showed that the resistance level displayed more different than posture, but Z axis the largest, in kake(E3) phase in 0% resistance of DP than other variables as same thigh-leg, and the largest from tsukuri(set-up:E2) to kake(E3) phase. X and Z axis Angular momentum of supporting the thigh-leg were similar, regardless of posture and resistance of uke, but Y axis was resistance level. Angular momentum of supporting the thigh-leg was showed the largest in X axis, increased from EO event to E2, and decreased in E3, and angular momenta of Y, X axis were showed the largest in kuzushi(balance breaking) phase when performing uchimata. Angular momentum of supporting the lower leg were similar pattern, regardless of posture and resistance of uke, in Y axis, resistance displayed more difficult the position in NP, and showed opposite angular momentum in tsukuri phase. In conclusion, angular momentum of trunk when performing uchimata was showed the largest, and pattern was similar, regardless of posture than resistant of uke(reciver), magnitude and direction were different each other, and uchimata was Ashi -waza(foot and leg techniques) division but important of trunk action.

The Contents and Satisfation of Home Care Progral Delivered by Seoul Nurses Association (서울시 간호사회 가정간호시범사업 서비스 내용 및 만족도 분석)

  • Lim, Nan-Young;Kim, Keum-Soon;Kim, Young-lm;Kim, Kwuy-Bun;Kim, Si-Hyun;Park, Ho-Ran
    • The Korean Nurse
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    • v.36 no.1
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    • pp.59-76
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    • 1997
  • The purposes of this study were to identify the contents and satisfaction level of the patients received home care service, and to compare the differences of the contents by the characteristics of the patients. Seventy eight patients received home care service from 1st Jan. to 30th Sept., 1996 were data-collected to analyze the contents and outcomes of home care service. Sixty-nine patients currently receiving home care service were participated to evaluate the satisfaction level of home care service. The data were analyzed using mean, standard deviation, $x^2$ test, and ANOVA by SPSS $PC^+$ program. The findings of this study were as follow : 1. The contents & outcomes of home care service 1) The mean age of the subjects was 64.4 years: 58% of them were female. Those who living in Seoul were 83% and the rest of the subjects was living in Kyung-Gi. 2) The subjects who had one diagnosis were 41%. Over 60% of them had the disease of neurologic & sensory system. 3) The mean number of visit was 6. Only one visit was 22%. The mean time of care was 79 minutes. Duration of visit from 31 minutes to 60 minutes were 47 %. The subjects who terminated the visit because of death were 67.3%. 62% of the persons who referred them to the home care service were nurses. 4) The pain after the service was more relieved than before. The amounts of intake, the degree of bed sore, edema & fracture after the service were more improved than before. Health status after the service was improved in general. 5) There were significant differences between initial and last conscious level in tracheostomy care & oxygen inhalation care. There was significant difference between initial and last degree of activity in blood sugar check. 6) There were significant differences on the number of visit in assessment of the status, evaluation & observation, vital sign check, skin care, injection, medication, bed sore care, colostomy care, relaxation therapy for pain relief, patient education, family care, exercise therapy, position change, supply of disinfected equipments and infection control. There were significant differences on visiting time in nasogastric tube care, drainage tube care and oxygen inhalation care. 2. The satisfaction level of home care service 1) 50% were male. Over 60 years of the subjects was 61 %. Those who living in Seoul were 82%. 2) The subjects who had one or two diagnosis were 32% respectively. 55% of the persons who referred them to the home care service were nurses. 3) Total level of satisfaction of home care service was very high. 4) The older the age, the higher the satisfaction level. The larger the number of visit, the higher the satisfaction level. 5) The subjects who were in cloudy state were higher level of satisfaction than in alert or coma state. The subjects whose activity were normal or who needed assistance were higher level of satisfaction than bedridden or immobilized subjects. These findings suggested that the patients had substantial need for posthospital care. They tended to be elderly and to have experienced the wide range of health problems associated with aging, chronicity, including limitations in activities, and other serious health problems. So, the nationwide home care systems beyond the limit of demonstration program by local association and the development of the effective financial system of home based health care are necessary for the clients who are in need of home care.

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A Kinematic Analysis of Uchi-mata(inner thigh reaping throw) by Kumi-kata types in Judo (유도 맞잡기 타입에 따른 허벅다리걸기의 Kinematic 분석[I])

  • Kim, Eui-Hwan;Cho, Dong-Hee;Kwon, Moon-Seok
    • Korean Journal of Applied Biomechanics
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    • v.12 no.1
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    • pp.63-87
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    • 2002
  • The purpose of this study was to analyze the kinematic variables when Uchi-mata(inner thigh reaping throw) performing by Kumi-kata(engagement position, basic hold) types A, B(A: grasping part-behind neck lapel, B: chest lapel) in Judo with three dimensional analysis technique DLT method by videography. The subjects were four male judokas who have been training in Yong-In University(YIU), on Korean Representative level and Uchi-mata is their tokui-nage(favorite technique), the throwing form was filmed on two S-VHS 16mm video camera( 30frame/sec. Panasonic). Kinematic variables were temporal, posture, and COG. The data collection was performing by Uchi-mata. Six good trials were collected for each condition (type A, B) among over 10 trials. The mean values and the standard deviation for each variable were obtained and used as basic factors for examining characteristics of Uchi-mata by Kumi-kata types. The results of this analysis were as follows : 1) Temporal variables The total time elapsed(TE) by Uchi-mata of types A, B were 1.45, 1.56 sec. respectively. Types A shorter than B. 2) Posture variables In performing of Uchi-mata, the range of flexion in type A, left elbow was $45^{\circ}$ and B was $89^{\circ}$ from Event 2(E2) to Event 6(E6). Type A and B were quite different in right elbow angle in Event1(E1). Left shoulder angle of type A was extended and type B was flexed in E4. Both types right shoulder angles were showed similar pattern. Also both hip angles(right/left) were showed similar pattern. When type A performed Uchi-mata the knee-angle of supporting foot showed $142^{\circ}$in the 1st stage of kake phase[KP], and extended to $147^{\circ}$in the 2nd stage of KP. And the foot-ankle angle of supporting foot showed $83^{\circ}$in the 1st stage of KP, and extended to $86^{\circ}$in the 2nd stage of KP. moreover, The knee angle of attacking foot showed $126^{\circ}$in the 1st stage of KP, and extended to $132^{\circ}$in the 2nd stage of KP, and the foot-ankle angle of attacking foot showed $106^{\circ}$in the 1st stage of KP, and extended to $121^{\circ}$in the 2nd stage of KP. When type B performed Uchi-mata the knee-angle of supporting foot showed $144^{\circ}$in the 1st stage of KP, and extended to $154^{\circ}$in the 2nd stage of KP. And the foot-ankle angle of supporting foot showed $83^{\circ}$in the 1st stage of KP, and extended to $92^{\circ}$in the 2nd stage of KP. moreover, The knee angle of attacking foot showed $132^{\circ}$in the 1st stage of KP, and extended to $140^{\circ}$in the 2nd stage of KP, and the foot-ankle angle of attacking foot showed $103^{\circ}$in the 1st stage of KP, and extended to $115^{\circ}$in the 2nd stage of KP. During Uchi-mata performing, type A showed pulling pattern and type B showed lift-pulling pattern. As Kumi-kata types, it were different to upper body(elbow, shoulder angle), but mostly similar to lower body(hip, knee, ankle angle) on both types. 3) C. O. G. variables When the subjects performed Uchi-mata, COG of type A, B up and down in vertical aspect was 71cm, 73.8cm in height from the foot in the 2nd stage of KP. As Kumi-kata types, it were different on medial-lateral direction aspect but weren't different in Kuzushi phase on vertical direction aspect.

Rectal Balloon for the Immobilization of the Prostate Internal Motion (전립선암의 방사선치료 시 직장풍선의 유용성 평가)

  • Lee Sang-Kyu;Beak Jong-Geal;Kim Joo-Ho;Jeon Byong-Chul;Cho Jeong-Hee;Kim Dong-Wook;Na Soo-Kyong;Song Tae-Soo;Cho Jae-Ho
    • The Journal of Korean Society for Radiation Therapy
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    • v.17 no.2
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    • pp.113-124
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    • 2005
  • Purpose : The using of endo-rectal balloon has proposed as optimal method that minimized the motion of prostate and the dose of rectum wall volume for treated prostate cancer patients, so we make the customized rectal balloon device. In this study, we analyzed the efficiency of the Self-customized rectal balloon in the aspects of its reproducibility. Materials and Methods : In 5 patients, for treatment planning, each patient was acquired CT slice images in state of with and without rectal balloon. Also they had CT scanning samely repeated third times in during radiation treatment (IMRT). In each case, we analyzed the deviation of rectal ballon position and verified the isodose distribution of rectum wall at closed prostate. Results : Using the rectal balloon, we minimized the planning target volume (PTV) by decreased the internal motion of prostate and overcome the dose limit of radiation therapy in prostate cancer by increased the gap between the rectum wall and high dose region. Conclusion : The using of rectal balloon, although, was reluctant to treat by patients. View a point of immobilization of prostate internal motion and dose escalation of GTV (gross tumor volume), its using consider large efficients for treated prostate cancer patients.

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Study of Respiration Simulating Phantom using Thermocouple-based Respiration Monitoring Mask (열전쌍마스크를 이용한 호흡모사팬톰 연구)

  • Lim, Sang-Wook;Park, Sung-Ho;Yi, Byong-Yong;Lee, Sang-Hoon;Cho, Sam-Ju;Huh, Hyun-Do;Shin, Seong-Soo;Kim, Jong-Hoon;Lee, Sang-Wook;Kwon, Soo-Il;Choi, Eun-Kyung;Ahn, Seung-Do
    • Radiation Oncology Journal
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    • v.23 no.4
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    • pp.217-222
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    • 2005
  • Purpose: To develop the respiration simulating phantom with thermocouple for evaluating 4D radiotherapy such as gated radiotherapy breathing control radiotherapy and dynamic tumor tracking radiotherapy. Materials and Methods: The respiration monitoring mask(ReMM) with thermocouple was developed to monitor the patient's irregular respiration. The signal from ReMM controls the simulating phantom as organ motion of patients in real-time. The organ and the phantom motion were compared with its respiratory curves to evaluate the simulating phantom. ReMM was used to measure patients' respiration, and the movement of simulating phantom was measured by using $RPM^{(R)}$. The fluoroscope was used to monitor the patient's diaphragm motion. relative to the organ motion, respectively. The standard deviation of discrepancy between the respiratory curve and the organ motion was 8.52% of motion range. Conclusion: Patients felt comfortable with ReMM. The relationship between the signal from ReMM and the organ motion shows strong correlation. The phantom simulates the organ motion in real-time according to the respiratory signal from the ReMM. It is expected that the simulating phantom with ReMM could be used to verify the 4D radiotherapy.

The fracture resistance of heat pressed ceramics with wire reinforcement (금속선 강화에 따른 열 가압 도재의 파절저항)

  • Jo, Deuk-Won;Dong, Jin-Keun;Oh, Sang-Chun;Kim, Yu-Lee
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.2
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    • pp.191-198
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    • 2009
  • Statement of problem: Ceramics have been important materials for the restoration of teeth. The demands of patients for tooth-colored restorations and the availability of various dental ceramics has driven the increased use of new types of dental ceramic materials. Improved physical properties of theses materials have expanded its use even in posterior crowns and fixed partial dentures. However, ceramic still has limitation such as low loading capability. This is critical for long-span bridge, because bridge is more subject to tensile force. Purpose: The wire reinforced ceramic was designed to increase the fracture resistance of ceramic restoration. The purpose of this study was to evaluate the fracture resistance of wire reinforced ceramic. Material and methods: Heat pressed ceramic(ingot No.200 : IPS Empress 2, Ivoclar Vivadent, Liechtenstein) and Ni-Cr wire(Alfa Aesar, Johnson Matthey Company, USA) of 0.41 mm diameter were used in this study. Five groups of twelve uniform sized ceramic specimens(width 4 mm, thickness 2 mm, length 15 mm) were fabricated. Each group had different wire arrangement. Wireless ceramic was used as control group. The experimental groups were divided according to wire number and position. One, two and three strands of wires were positioned on the longitudinal axis of specimen. In another experimental group, three strands of wires positioned on the longitudinal axis and five strands of wires positioned on the transverse axis. Three-point bending test was done with universal testing machine(Z020, Zwick, Germany) to compare the flexural modulus, flexural strength, strain at fracture and fracture toughness of each group. Fractured ceramic specimens were cross-sectioned with caborundum disc and grinded with sandpaper to observe interface between ceramic and Ni-Cr wire. The interface between ceramic and Ni-Cr wire was analyzed with scanning electron microscope(JSM-6360, JEOL, Japan) under platinum coating. Results: The results obtained were as follows: 1. The average and standard deviation in flexural modulus, flexural strength and fracture toughness showed no statistical differences between control and experimental groups. However, strain was significantly increased in wire inserted ceramics(P<.001). 2. Control group showed wedge fracture aspects across specimen, while experimental groups showed cracks across specimen. 3. Scanning electron microscopic image of cross-sectioned and longitudinally-sectioned specimens showed no gap at the interface between ceramic and Ni-Cr wire. Conclusion: The results of this study showed that wire inserted ceramics have a high strain characteristic. However, wire inserted ceramics was not enough to use at posterior area of mouth in relation to flexural modulus and flexural strength. Therefore, we need further studies.

Dose Distribution and Image Quality in the Gantry Aperture for CT Examinations (전산화단층촬영 검사 시 Gantry Aperture 내의 선량분포와 영상의 질)

  • Cho, Pyong-Kon;Kim, You-Hyun;Choi, Jong-Hak;Lee, Ki-Yeol;Kim, Hyung-Cheol;Kim, Jang-Seob;Shin, Dong-Chul;Lee, Sung-Hyun;Lee, Jun-Hyub;Shin, Gwi-Soon
    • Journal of radiological science and technology
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    • v.32 no.4
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    • pp.453-460
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    • 2009
  • The purpose of this study was to determine the dose distribution and image quality according to slice thickness and BC(beam collimation) in the gantry aperture. CT scans were performed with a 64-slice MDCT(Brilliance 64, Philips, Cleveland, USA) scanner. To determine the dose distribution according to BC, a ionization chamber was placed at isocenter and 5, 10, 15, 20, 25 and 30 cm positions from the isocenter in the 12, 3, 6 and 9 o'clock directions. The dose distribution for phantom scan was also measured using CT head and body dose phantom with five holes at the center of the phantom and the positions of the 12, 3, 6 and 9 o'clock directions. The image noise measurement for different BCs was performed using an AAPM CT phantom. Water-filled block of the phantom was moved by 5 cm or 10 cm to the 12 o'clock direction, and the image noise was measured at the center of the phantom, and the points of 12, 3, 6 and 9 o'clock direction respectively. Some points were placed beyond the scan field of view (SFOV), so that measurement was not possible at that points. The results are as follows: The CTDIw showed a larger decrease as the source goes farther from the iso-center or the BC became wider. The CTDIw depends on the BC width more than the number of the channel of a detector array. The value of CTDIW decreased with increasing BC, but the value decreased 16.6~31.9% in the head phantom scan in air scan and 51.0~64.5% in the body phantom scan. The value of the noise was 3.9~5.9 in the head and 5.3~7.4 in the body except for BC of $2{\times}0.5\;mm$, regardless of the degree of deviation from the iso-center. When a subject was located within the SFOV, the position did not significantly affect image quality even if the subject was out of the center.

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