• The Journal of Korean Society for Radiation Therapy
• /
• v.13 no.1
• /
• pp.122-125
• /
• 2001

I. 목적 : Primus의 Multi Leaf Collimator는 X측이 29쌍으로 이루어 져 있으며 그중27쌍의 leaf은 1cm이고 2쌍은 6.5cm의 leaf으로 구성되어있다. 이러한 이유로 Paraaortic node를 포함하는 자궁경부암 치료시 현재는 Y가 27cm 이상인 경우는 차폐블럭을 제작하여 치료를 시행하나 차폐 블럭의 제작에 따른 업무의 지연과 차폐 블럭이 무거워져 치료시 환자에게 떨어질 위험을 제거 하기 위해 Asymmetric Field로 Multi Leaf Collimator를 사용한 결과를 보고하고자 한다. II. 재료 및 방법 : 모의 치료(Ximatron, Varian, USA)시 $Y_1$측을 15cm을 기준으로 하여 $Y_2$측을 변경하면서 Field size를 결정한다. ($Y_2$측은 20cm가 최대, 즉 Y측은 35cm까지 적용) 이러한 방법으로 Multi Leaf Collimator를 사용한 환자와 기존의 차폐블럭을 제작하여 치료한 환자와의 업무 개선사항을 확인하기 위하여 실제 공작실 업무 담당자의 블럭 제작 시간과 Beam Shaper를 이 용해 Multi Leaf Collimator를 입력하는 시간을 상호 비교하여 단축된 시간을 조사하였다. III. 결과 : 차폐블럭을 대신해 Multi Leaf Collimator를 이용함으로써 치료실에서 환자에 대한 위험요소(차폐블럭이 무겁다)를 사전에 제거 할 수 있었고 공작실에서 블럭 제작 시간과 LANTIS를 이용해 MLC를 입력하는 시간을 실측 한 결과업무의 시간이 120분에서 5분으로 단축되는 효과가 있었다. 전산화 계획 실에서 선량 계산시 OAR Factor값을 고려하여야 한다. IV. 결론 : Paraaortic node를 포함한 자궁경부암 환자의 차폐부위는 모양이 거의 일직선이기 때문에 Mu]ti Leaf Collimator를 사용하기에 용이 한 치료 부위이다. 하지만 큰 Field size로 인한 불편함이 있었다. 이러한 제 약성을 Asymmetric Field를 이용해서 Multi Leaf Collimator의 사용을 가능하게 하고 차폐 블록의 제작과정과 치료 시에 발생되는 근무자의 업무의 손실을 줄이고 환자에 대한 위험성 을 해결하였다.

• The Journal of the Korea Contents Association
• /
• v.8 no.11
• /
• pp.235-241
• /
• 2008

If the target volume cannot be included with one field at head and neck cancer, we commonly used two or more field. It is very important to irradiate uniform dose at junction area of the fields. However, according to body shape of patient or general condition of patient, skin junction area can be matched incorrect, So overdose area or underdose area can be appeared in the junction area. This study researched therapy technique which can give uniform dose at skin junction owing to applying the edge block of lateral field at head and neck cancer. We measured the changed distance and rotational angle between central line of anterior supraclavicle lymph node and low margin of right lateral field on simulation process using the shielding block of variable rotation. As a result, the changed distance between central line of anterior supraclavicle lymph node and low margin of right lateral field was below 2mm to ${\pm}$10cm distance at central line of Y axis, changed angle was average 1.28 degree. But by using it the shielding block of variable rotation, the incorrect match at junction can be minimized. We think that this technique is very efficient one to apply this technique at head and neck cancered by the movement of organs can be not included, Therefore we have to pay attention on the process to imput MLC layer

• The Journal of Korean Society for Radiation Therapy
• /
• v.33
• /
• pp.127-135
• /
• 2021

Purpose : The purpose of the study is to evaluate the efficiency of Vertical MLC VMAT plan(VMV plan) Using 273° and 350° collimator angle compare to Complemental MLC VMAT plan(CMV plan) using 20° and 340° collimator angle for nasopharyngeal carcinoma. Materials & Methods : Thirty patients treated for nasopharyngeal carcinoma with the VMAT technique were retrospectively selected. Those cases were planned by Eclipse, PO and AcurosXB Algorithm with two 6MV 360° arcs and Each arc has 273° and 350° of collimator angle. The Complemental MLC VMAT plans are based on existing treatment plans. Those plans have the same parameters of existing treatment plans but collimator angle. For dosimetric evaluation, the dose-volumetric(DV) parameters of the planning target volume (PTV) and organs at risk (OARs) were calculated for all VMAT plans. MCSv(Modulation complexity score of VMAT), MU and treatment time were also compared. In addition, Pearson's correlation analysis was performed to confirm whether there was a correlation between the difference in the MCSv and the difference in each evaluation index of the two treatment plans. Result : In the case of PTV evaluation index, the CI of PTV_67.5 was improved by 3.76% in the VMV Plan, then for OAR, the dose reduction effect of the spinal cord (-14.05%) and brain stem (-9.34%) was remarkable. In addition, the parotid glands (left parotid : -5.38%, right : -5.97%) and visual organs (left optic nerve: -4.88%, right optic nerve: -5.80%, optic chiasm : -6.12%, left lens: -6.12%, right lens: -5.26%), auditory organs (left: -11.74%, right: -12.31%) and thyroid gland (-2.02%) were also confirmed. The difference in MCSv of the two treatment plans showed a significant negative (-) correlation with the difference in CI (r=-0.55) of PTV_54 and the difference in CI (r=-0.43) of PTV_48. Spinal cord (r=0.40), brain stem (r=0.34), and both salivary glands (left: r=0.36, right: r=0.37) showed a positive (+) correlation. (For all the values, p<.05) Conclusion : Compared to the CMV plan, the VMV plan is considered to be helpful in improving the quality of the treatment plan by allowing the MLC to be modulated more efficiently

• Progress in Medical Physics
• /
• v.14 no.4
• /
• pp.225-233
• /
• 2003

The goal of a radiation treatment plan is to deliver a homogeneous dose to a target with minimal irradiation of the adjacent normal tissues. Dose uniformity is especially important for stereotactic radiosurgery using a linear accelerator. The dose uniformity and high dose delivery of a single spherical dose distribution exceed 70％. This also results with a similar stereotactic radiosurgical plan using a Gamma Knife. The dose distribution produced in a stereotactic radiosurgical plan using a Gamma Knife and Linear accelerator is spherical, and the application of the sphere packing arrangement in a real radiosurgical plan requires much time and skill. In this study, we found a characteristic of dose distribution with transformation of beam parameters that must be considered in a radiosurgical plan for effective radiosurgery. First, we assumed a cylinder type tumor model and a cube type tumor model. Secondly, the results of the tumor models were compared and analyzed with dose profiles and DVH_(Dose Volume Histogram) representative dose distribution. We found the optimal composition of beam parameters_(i.e. collimator size, number of isocenter, gap of isocenters etc.), which allowed the tumor models to be involved in the isodose curve at a high level. In conclusion, the characteristics found in this study are helpful for improving the effectiveness and speed of a radiosurgical plan for stereotactic radiosurgery.

• The Journal of Korean Society for Radiation Therapy
• /
• v.34
• /
• pp.31-42
• /
• 2022

Purpose: This study measures and compares the surface dose values in the virtual target volume using Tomotherapy, Halcyon, and TrueBeam equipment using 6MV-Flattening Filter-Free(FFF) energy. Materials and Methods: CT scan was performed under three conditions of without bolus, 0.5 cm bolus, and 1 cm bolus using an IMRT phantom (IBA, Germany). The Planning Target Volume (PTV) was set at the virtual target depth, and the treatment plan was established at 200 cGy at a time. For surface dosimetry, the Gafchromic EBT3 film was placed in the same section as the treatment planning system and repeated measurements were performed 10 times and then analyzed. Result: As a result of measuring the surface dose for each equipment, without, 0.5 cm, 1 cm bolus is in this order, and the result of Tomotherapy is 115.2±2.0 cGy, 194.4±3.3 cGy, 200.7±2.9 cGy, The result in Halcyon was 104.7±3.0 cGy, 180.1±10.8 cGy, 187.0±10.1 cGy, and the result in TrueBeam was 92.4±3.2 cGy, 148.6±5.7 cGy, 155.8±6.1 cGy, In all three conditions, the same as the treatment planning system, Tomotherapy, Halcyon, TreuBeam was measured highly in that order. Conclusion: Higher surface doses were measured in Tomotherapy and Halcyon compared to TrueBeam equipment. If the characteristics of each equipment are considered according to the treatment site and treatment purpose, it is expected that the treatment efficiency of the patient will increase as well as the treatment satisfaction of the patient.

• The Journal of Korean Society for Radiation Therapy
• /
• v.20 no.2
• /
• pp.91-102
• /
• 2008

Purpose: To enlarge the efficiency of operation and establish a constituency for development of new radiotherapy treatment through database which is established by arranging and indexing radiotherapy related affairs in well organized manner to have easy access by the user. Materials and Methods: In this study, Access program provided by Microsoft (MS Office Access) was used to operate the data base. The data of radiation oncology was distinguished by a business logs and maintenance expenditure in addition to stock management of accessories with respect to affairs and machinery management. Data for education and research was distinguished by education material for department duties, user manual and related thesis depending upon its property. Registration of data was designed to have input form according to its subject and the information of data was designed to be inspected by making a report. Number of machine failure in addition to its respective repairing hours from machine maintenance expenditure in a period of January 2008 to April 2009 was analyzed with the result of initial system usage and one year after the usage. Results: Radiation oncology database system was accomplished by distinguishing work related and research related criteria. The data are arranged and collected according to its subjects and classes, and can be accessed by searching the required data through referring the descriptions from each criteria. 32.3% of total average time was reduced on analyzing repairing hours by acquiring number of machine failure in addition to its type in a period of January 2008 to April 2009 through machine maintenance expenditure. Conclusion: On distinguishing and indexing present and past data upon its subjective criteria through the database system for radiation oncology, the use of information can be easily accessed to enlarge the efficiency of operation, and in further, can be a constituency for improvement of work process by acquiring various information required for new radiotherapy treatment in real time.

• The Journal of the Korea Contents Association
• /
• v.9 no.11
• /
• pp.254-261
• /
• 2009

This study suggested that the table of CT-simulator and the laser alignment system using diagnostic CT scanner have an efficient method for improvement in alignment between the planned target center of traverse image with CT scanner. It was conducted on the daily QA when presented in the AAPM TG66 with correcting the laser alignment system using geometric trigonometric functions and investigated the effectiveness of correction methods as compared with those before and after correction. Before correction error was 3.82mm between the planned target center of image, the table longitudinal axis was twisted with 0.436o. The laser alignment system using geometric trigonometric functions in after correction was satisfied with tolerance limits of ${\pm}2mm$ when occurred about 0.7mm in errors between the planned target center. The table correction to satisfy the geometric accuracy is very inefficient over against the time and economic loss as well as technical limits in the case of application as only radiation therapy associated with CT-simulator with diagnostic CT scanner in use. But, the method which corrects the laser alignment system is economic and relatively simple with possibility of getting well geometric accuracy and we suppose that it is efficient method for applying in the clinic.

• The Journal of Korean Society for Radiation Therapy
• /
• v.16 no.2
• /
• pp.63-67
• /
• 2004

Purpose : New therapy technique appeared in 3D-CRT or IMRT according to a radiation treatment developing and worked. Such treatment technique requires the radiation irradiation of many direction. It has many restriction at radiation irradiation of many direction to the linear acceleration deception of now actually. Consequently We make new fix device and measure consequently the improvement of the activate range. Method and Material : We upload the fix device on a linear accelerator Couch. We fixed Gantry at 45, 90, 135 and Couch is spin and measure the clearance of the equipment. Couch is fixed at 0 45 90 and measures the clearance of Gantry. We upload the Extended head holder(EHH) on a linear accelerator Couch. and We measure with the experiment of the front. Result : The action range did not have big difference to increase Gantry45. but The activate range of Couch increases the angle in Gantry 90 and Gantry 135 when it uses EHH. The activate range of Gantry increases the angle in Couch 45 when it uses EHH. We showed good activate situation all in Couch 0 and Couch 90. The utility of EHH could keep a behind radiation diminution. Conclusion : The radiation irradiation of many direction comes to be possible the utility of the fix instrument(EHH). The safety space between the patient and equipment or between equipment and equipment increased the utility of the fix device. Also, The manufacture is possible imports to rather cheap price. and We could bring the frugality of the treatment expendable supplies.

• The KIPS Transactions:PartD
• /
• v.14D no.1 s.111
• /
• pp.121-130
• /
• 2007

in a software development, the design or architecture prior to implementing the software is essential for the success. This paper presents a case that we successfully designed a software architecture of radiation monitoring system (RMS) for HANARO research reactor currently operating in KAERI by applying the quality attribute-driven design method which is modified from the attribute-driven design (ADD) introduced by Bass[1]. The quality attribute-driven design method consists of following procedures: eliciting functionality and quality requirements of system as architecture drivers, selecting tactics to satisfy the drivers, determining architectures based on the tactics, and implementing and validating the architectures. The availability, maintainability, and interchangeability were elicited as duality requirements, hot-standby dual servers and weak-coupled modulization were selected as tactics, and client-server structure and object-oriented data processing structure were determined at architectures for the RMS. The architecture was implemented using Adroit which is a commercial off-the-shelf software tool and was validated based on performing the function-oriented testing. We found that the design method in this paper is an efficient method for a project which has constraints such as low budget and short period of development time. The architecture will be reused for the development of other RMS in KAERI. Further works are necessary to quantitatively evaluate the architecture.

• Journal of the Korean Society of Radiology
• /
• v.13 no.1
• /
• pp.119-124
• /
• 2019

Radiation therapy using flattening filter free beam can prevent beam attenuation caused by flattening filter and can improve treatment efficiency. However, accurate dose control is not established for nonuniform iso dose distributions. In this study, curved dosimeter based on photoconductive material $HgI_2$ was fabricated and its reproducibility and linearity were evaluated at 6 MV photon energy to verify its performance. In order to show the usefulness of the curved measurement, the signals measured on the flat substrate and the curved substrate were compared in the flattening filter free beam using the acrylic filter. As a result, the reproducibility of the unit cell dosimeter was evaluated as SE 0.613%, and the linearity was evaluated as R-sq 0.9999. The usability evaluation of the array curve dosimeter demonstrated its usefulness by indicating a curvature error rate of 11.073%p and a reduced error rate.