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Comparison of using CBCT with CT Simulator for Radiation dose of Treatment Planning (CBCT와 Simulation CT를 이용한 치료계획의 선량비교)

  • Kim, Dae-Young;Choi, Ji-Won;Cho, Jung-Keun
    • The Journal of the Korea Contents Association
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    • v.9 no.12
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    • pp.742-749
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    • 2009
  • The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

Distribution of Hydrometeors and Surface Emissivity Derived from Microwave Satellite Observations and Model Reanalyses (위성관측(MSU)과 모델 재분석 자료에서 조사된 대기물현상과 표면 방출율의 분포)

  • Kim, Tae-Yean;Yoo, Jung-Moon
    • Journal of the Korean earth science society
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    • v.23 no.7
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    • pp.552-564
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    • 2002
  • The data of satellite-observed Microwave Sounding Unit (MSU) channel 1 (Ch1) brightness temperature and General Circulation Model (GCM) reanalyses over the globe have been used to investigate low tropospheric hydrometeors and microwave surface emissivity during the period from January 1981 to December 1993. The average of GCM Ch1 temperature has been reconstructed from three kinds of reanalyses, based on the MSU weighting function. Since the GCM temperature mainly corresponds to the thermal state of the lower troposphere without the difference in the emissivity between ocean and land, it is higher in summer than in other seasons over the regions. The MSU temperature over the ocean shows its maximum at the ITCZ and the SPCZ due to hydrometeors. Over high latitude ocean, the temperature is enhanced because of sea ice emissivity, while it is reduced over the land. The seasonal displacement of the ITCZ and the SPCZ systematically appeared in the difference of Ch1 temperature between the GCM and the MSU. The difference values decrease in the regions of the ITCZ, the SPCZ, and the sea ice because of the increase of the MSU temperature. According to the local minima of the values, the ITCZ moves norhward to 9 N in fall, and the SPCZ moves southward to 12 S in boreal fall and winter. The sea ice in the northern hemisphere is extended southward to 53 N in winter, while the ice in the southern hemisphere, northward to 58 S in boreal summer. We also have discussed the separated contribution from hydrometeors and surface emissivity to the MSU Ch1 temperature, utilizing radiative transfer theory. The increase of 4-6K in the temperature over the ITCZ is inferred to result from hydrometeors of 1-1.5mm/day, and furthermore the increase of 10-30K over the high latitude ocean, ice emissivity of 0.6-0.9.

Development of Forest Road Network Model Using Digital Terrain Model (수치지형(數値地形)모델을 이용(利用)한 임도망(林道網) 배치(配置)모델의 개발(開發))

  • Lee, Jun Woo
    • Journal of Korean Society of Forest Science
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    • v.81 no.4
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    • pp.363-371
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    • 1992
  • This study was aimed at developing a computer model to determine rational road networks in mountainous forests. The computer model is composed of two major subroutines for digital terrain analyses and route selection. The digital terrain model(DTM) provides various information on topographic and vegetative characteristics of forest stands. The DTM also evaluates the effectiveness of road construction based on slope gradients. Using the results of digital terrain analyses, the route selection subroutine, heuristically, determines the optimal road layout satisfying the predefined road densities. The route selection subroutine uses the area-partitioning method in order to fully of roads. This method leads to unbiased road layouts in forest areas. The size of the unit partitiones area can be calculated as a function of the predefined road density. In addition, the user-defined road density of the area-partitioning method provides flexibility in applying the model to real situations. The rational road network can be easily achived for varying road densities, which would be an essential element for network design of forest roads. The optimality conditions are evaluated in conjuction with longitudinal gradients, investment efficiency earthwork quantity or the mixed criteria of these three. The performance of the model was measured and, then, compared with those of conventional ones in terns of average skidding distance, accessibility of stands, development index and circulated road network index. The results of the performance analysis indicate that selection of roading routes for network design using the digital terrain analysis and the area-partitioning method improves performance of the network design medel.

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A study of the impact of using a nursing care standards on the quality of nursing care in gastrectomy patients (위절제술환자의 간호실무표준 사용이 간호의 질에 미치는 영향)

  • Woo, Young-Ja
    • Journal of Korean Academy of Nursing Administration
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    • v.2 no.2
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    • pp.97-107
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    • 1996
  • Nursing standards determine the type and extent of services that are delivered to the patients and define quality care and communicate the institution's expectations of care. Thus, taking the standard of care and incorporating it into a welldefined indicator of excellent patient care becomes one of the first activities in setting up the nursing service's quality assurance process. The purpose of this study was to determine the impact of using a nursing care standards for the quality of nursing care in gastrectomy patients. The subjects were composed of fourty-two under going gastrectomy patients with stomach cancer in general surgery nursing care unit of K University Hospital in Pusan. The data was collected from January 3 to April 13,1996. The subjects were divided into a control group - those admitted from Jan.3 to Feb.12 and an experimental group those admitted from Feb.18 to April 13. The instruments used for this study were a nursing care standards in gastrectomy patients developed by the investigator and an evaluation tool for the quality of nursing care in abdominal surgery patients developed by Byoung-Sook Lee in 1995. The data was analized by means of chi-square test, t-test and Cronbach-alpha test with the SAS System. The result was as follows : The hypothesis, that scores of the quality of nursing care in the experimental group would be higher than that of the control group. was supported(t=-6.12, p=0.00). The detailed results of each standards of evaluation tool were as follows : The mean score of the experimental group was significantly higher than that of the control group in audit standard 1:'Collection of basic data of the patients', (t=-3.76, p=0.00). The mean score of the experimental group was significantly higher than that of the control group in audit standard 2 : 'Defining nursing diagnoses(or nursing problems)', (t= (-), p= (-) ). The mean score of the experimental group was significantly higher than that of the control group in audit standard 3:'Estabilishment of nursing care plan according to nursing diagnoses(or nursing problems)',(t= (-), p= (-) ). The mean score of the experimental group was significantly higher than that of the control group in audit stndard 4:'Implimentation of nursing care plan', (t=-2.38, p=0.01). The mean score of the experimental group was significantly higher than that of the control group in audit standard 8 : 'Increase of the knowledge of health related to surgery',(t=-2.40, p=0.01). No significant differences between the mean scores of the experimental group and that of the control group in audit standard 5 : 'Recover and maintain of the physical function', audit standard 6:'Prevention of the post-operative complication', audit standard 7 : 'Decrease of discomfort caused by operation', and audit standard 9 : 'Patient satisfaction in nursing care' were found. The standards of evaluation tool were devided into two dimension. One was process dimension which contains four standards(audit standard 1 to 4), the other was outcome dimension which contains five standards(audit standard 5 to 9). The mean score of the experimental group was significantly higher than that of the control group in process dimension (t=-12.30, p=0.00), but no significant difference between the mean scores of the experimental group and that of the control group in outcome dimension was found. From these results, it is concluded that using a nursing care standards in gastrectomy patients promotes quality of nursing care and nursing care standards of various fields are necessary for effective nursing care.

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A Study on the Deduction of the Forest Play Activity and Space through Preschooler Participatory Workshop (유아참여 워크숍을 통한 숲놀이 활동 및 공간 요소의 도출에 관한 연구)

  • Kang, Taesun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.46 no.5
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    • pp.69-81
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    • 2018
  • Recently, user participatory workshops have been applied as a way to plan landscape spaces that reflects the needs and demands of the users. It is also required to improve the quality of the FECC (Forest Experience Center for Children), which is growing rapidly. Therefore, the purpose of this study is to deduct the design elements (forest play activities and space), the basic needs, and the demands of users in making the FECC a preschooler participatory workshop. For this, materials for preschooler participation were selected, and a step-by-step workshop was conducted to satisfy the demands of the preschooler's development. First, in the pre-workshops phase, design elements standards were deducted through the preschooler participatory results (41 children aged 6 and 7, Kindergarten). Second, in the main workshop phase, the design elements to be introduced on the site (Songsan-mulbit FECC) were deducted through the participating preschooler's selection and those results were analyzed. The materials used at the preschooler participatory process were 'drawing a picture' in the pre-workshop phase, and the design elements and the standard types charts were the forest play activity pictogram chart, and the forest play space general images chart in the main workshop. As for results, frst, there are 38 standard types of forest play activities that have been deducted. It consists of 27 cognitive activities (functional 16, constructive 4, symbolic 4, game on rule 3), 9 games (sensory 5, other 4), and two social play activities (solo, group). There are 21 standard types of forest play spaces. They consist of 8 play facility spaces (5 facility, 3 natural), 2 water spaces, and 11 spaces of 5 types. Second, as a result of applying the results to the site, the forest play activities to be introduced on the site were selected, and the functional play was most selected. Additionally, climbing and water play were most selected as the unit activities. Also, functional, constructive, symbolic, games based on rules were selected, even in the preschooler's development play. In the case of the forest play spaces to be introduced in the site, the preschooler's selection results by sex and age tended to be similar to the preschooler's comprehensive selection results, but the boys preferred function and adventure spaces more than the girls, while the girls preferred rest spaces more than the boys. This result is similar to the previous study results, which directly observed the preschooler's forest play behavior, and analysis that the preschooler recognized the site and selected the design elements introduced on the site. Therefore, the participatory workshop process and the materials process in this study are analyzed and applied to the purpose of the study. It is valuable as a case to be applied in design of the FECC from this point forward.

Behavior of wall and nearby tunnel due to deformation of strut of braced wall using laboratory model test (실내모형시험을 통한 흙막이벽체 버팀대 변형에 따른 흙막이벽체 및 인접터널의 거동)

  • Ahn, Sung Joo;Lee, Sang Duk
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.3
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    • pp.593-608
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    • 2018
  • If a problem occurs in the strut during the construction of the braced wall, they may cause excessive deformation of the braced wall. Therefore, in this study, the behavior of the braced wall and existing tunnel adjacent to excavation were investigated assuming that the support function of strut is lost during construction process. For this purpose, a series of model test was performed. As a result of the study, the earth pressure in the ground behind wall was rearranged due to the deformation of the braced wall, and the ground displacements caused the deformation of adjacent tunnels. When the struts located on the nearest side wall from the tunnel were removed, the deformation of the braced wall and the tunnel deformation were the largest. The magnitude of transferred earth pressure depended on the location of tunnel. The increase of the cover depth of tunnel from 0.65D to 2.65D caused the increase of the earth pressure by 25.6%. As the distance between braced wall and tunnel was increased from 0.5D to 1.0D, the transferred earth pressure increased by 16% on average. Horizontal displacements of braced wall by the removal of the strut tended to concentrate around the removed struts, and the horizontal displacement increased as the strut removal position is lowered. The tunnel displacement was maximum, when the cover depth of tunnel was 1.15D and the horizontal distance between braced wall and the side of tunnel was 0.5D. The minimal displacement occurred, when the cover depth of tunnel was 2.65D and the horizontal distance between braced wall and the side of tunnel was 1.0D. The difference between the maximum displacement and the minimum displacement was about 2 times, and the displacement was considered to be the largest when it was in the range of 1.15D to 1.65D and the horizontal distance of 0.5D.

Manufacturing Location and Linkages in the Suburb of Metropolitan Pusan (부산시 근교의 공업입지와 지역적 연계)

  • Lim, Yeong-Dae
    • Journal of the Korean association of regional geographers
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    • v.6 no.1
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    • pp.1-28
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    • 2000
  • The purpose of this study is to clarify the suburbanization of manufacturing, and location and linkages of decentralized manufacturing from Metropolitan Pusan by means of case study on manufacturing location and linkages in the suburb of Metropolitan Pusan. Kimhae city and Yangsan-Gun toward which heavy decentralization of manufacturing from the Metropolitan Pusan has been done. Both hard data and soft data were used as the basic data. Hard data are the statistical data in statistical yearbooks and firm list in directories. The former consists of the number of establishments and employees classified by product type, firm size and unit area. The latter consists of owner's names, addresses, employee number, products and headquarters of firms. Soft data are the results of the interviews with the 242 owners of firms in the four case study areas selected by Proportional Stratified Sampling Method. The major findings are as follows: 1. The spatial variations of manufacturing in the suburb was regularized in the latter half of 1970's. The primary processes to decentralize manufacturing from Metropolitan Pusan were the birth, relocation and establishment of branches of the firms. Among them the relocation of small outer-oriented single-location firms from Pusan was the most important. 2. The spatial variations undergoing spatial expansion of manufacturing distribution and increase of agglomeration degree of manufacturing, proceeded from the adjacents of Metropolitan Pusan to the outer areas along the main transportation route. 3. The main factors which caused manufacturing to decentralize from the Metropolitan Pusan were firm policy and land for this policy. The main locational factors which induced the decentralizing manufacturing into the suburb were land, market and transportation. 4. The strength of linkages with the outside of the study area is stronger than that of linkages with the inside. There is distance-decay-function in the strength of linkages with the outside, and linkages with short distant areas are stronger than those with long distant areas. 5. The ranges of spatial linkages in procurement of materials, in subcontraction and in marketing are wider than those in ordering. 6. The main factors which cause the formation of linkages are different by types of linkages: monopolistic and oligopolistic supply are important in procurement linkages; characteristics of products and the subsequent marketing difficulties, in subcontraction linkages; fluctuation, cost reduction, insufficient facility and characteristics of products, in ordering linkages; subcontract, characteristics of product and the subsequent marketing difficulties, in marketing linkages. 7. The changes of linkages owing to locational changes of firms were great, and were greater in long distant areas than in short distant areas. 8. The main factor influencing on the changes of linkages was the easiness in the transportation of goods, movement of labour and contacts with customers. In conclusion, some facts described above were proved to be consistent with the results of proceeding studies in the other areas: influence of relocation of decentralizing firms on the suburbanization; the factors of manufacturing decentralization; spatial characteristics of linkages; linkage changes owing to relocation of firms. Some were proved to be partly consistent: locational factors inducing decentralized manufacturing into the suburb were proved to be inconsistent. I think that the results of previous studies on the other areas can be applicable to the explanation on the decentralization of Metropolitan manufacturing from the viewpoint of the suburb. For the better explanation on the decentralization of Metropolitan manufacturing, more empirical case studies on the suburbanization of manufacturing are necessary.

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A Study for Drying of Sewage Sludge through Immersion Frying Using Used Oil (폐유를 이용한 하수슬러지 유중 건조 연구)

  • Shin, Mi-Soo;Kim, Hey-Suk;Hong, Ji-Eun;Jang, Dong-Soon;Ohm, Tae-In
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.7
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    • pp.694-699
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    • 2008
  • Considering the severe regulation associated with sludge treatment such as direct landfill and ocean dumping, there is no doubt in that an advanced study for the proper treatment of sludge is urgently needed in near feature. As one of viable method for sludge treatment, fry-drying of sludge by waste oil has been investigated in this study. The fundamental mechanism of this drying method lies in the phenomenon of rapid moisture escape in the sludge pore toward oil media. This is caused by the severe pressure gradient formed by the rapid oil heating between sludge and oil. As part of research effort of fry-drying using waste oil, a series of basic study has been made experimentally to obtain typical drying curves as function of important parameters such as drying temperature, drying time, oil type and geometrical shape of sludge formed. Based on this study, a number of useful conclusion can be drawn as following. The fry-drying method by oil immersion was found quite effective in the removal efficiency of sludge moisture, in general, the moisture content decreases significantly after 10 minutes and the whole moisture content was less than 5% after 14 minutes regardless of the drying temperature. The increase of oil temperature up to 140$^{\circ}C$ favors significantly for the removal of moisture but there was no visible difference above 140$^{\circ}C$. As expected, the decrease of diameter in sludge was efficient in drying due to the increased surface area per unit volume. Further, the effect of oil property by the change of oil type was noted. To be specific, for the case of engine oil the efficiency was found to be remarkably delayed in moisture evaporation compared with that of vegetable oil due to the increased viscosity of engine oil. It produced a result of increasing the evaporation of moisture largely relatively high in the drying temperature over 140$^{\circ}C$ compared with the drying temperature 120$^{\circ}C$ drying temperature as the drying time passed. Accordingly, the drying temperature is considered desirable as keeping over 140$^{\circ}C$ regardless of a sort of used oil.

THE CURRENT STATUS OF BIOMEDICAL ENGINEERING IN THE USA

  • Webster, John G.
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.05
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    • pp.27-47
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    • 1992
  • Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.

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Comparison of using CBCT with CT simulator for radiation dose of treatment planning (CBCT와 Simulation CT를 이용한 치료계획의 선량비교)

  • Cho, jung-keun;Kim, dae-young;Han, tae-jong
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.1159-1166
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    • 2009
  • The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

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