• Journal of the Korean Society of Radiology
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• v.6 no.2
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• pp.151-157
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• 2012

General treatment for cholangiocarcinoma is complete surgical resection. However recurrence is common in those patients. In most of cases the purpose of the treatment for patients with recurrent is palliative. Therefore we adopt intraluminal catheter to treat a recurrent patient with high-dose-rate intraluminal brachytherapy. This study aims to evaluate the treatment procedure and set-up reproducibility of intraluminal brachytherapy in the recurrent patient. Study patient was diagnosed at rcT1N0M0 and undergone intraluminal brachytherapy after Arrow Sheath insertion. 3 Gy was delivered in every fraction with a total dose of 30 Gy. We planned dose normalization at distal, proximal and central axis point of narrowed bile duct far from 1 cm. To evaluate set-up reproducibility, we measured distance between distal, proximal treatment target volume point and anterior surface of the thoracic vertebral body respectively for five times before every treatment with dummy seed insertion. Mean distance between distal, proximal treatment target volume point and anterior surface of 10th and 11th thoracic vertebral bodies is 0.5 cm, 6.1 cm and standard deviation is 0.06, 0.08 respectively. In addition, set-up reproducibility was maintained significantly. The patient has been alive with no evidence of disease recurrence for more than a year and has not yet reported severe complications. In conclusion, high-dose-rate intraluminal brachytherapy for unresectable recurrence of cholangiocarcinoma maintains high set-up reproducibility without severe side effects.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.627-635
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• 2017

Brachytherapy is generally performed in conjunction with external radiation therapy, and the treatment course is very complicated, which can lead to radiation accidents. In order to solve this problem, we designed the process map by applying the failure mode and effects analysis (FMEA) method to the Brachytherapy and scored the risk priority number (RPN) for each treatment course based on this process map. The process map consisted of five steps, Patient consulting", "Brachytherapy simulation", "CT simulation", "Brachytherapy treatment planning" and "Treatment". In order to calculate the RPN, doctor, medical physicist, dose planners, therapist, and nurse participated in the study and evaluated occurrence, severity, and lack of detectability at each detail step. Overall, the process map is preceded by a patient identification procedure at each treatment stage, which can be mistaken for another patient, and a different treatment plan may be established to cause a radiation accident. As a result of evaluating the RPN for the detailed steps based on the process map, overall "Patient consulting" and "Brachytherapy treatment planning" step were evaluated as high risk. The nurses showed a tendency to be different from each other, and the nurses had a risk of 55 points or more for all the procedures except "Treatment", and the "Brachytherapy simulation" step was the highest with 88.8 points. Since the treatment stage differs somewhat for each medical institution performing radiotherapy, it is thought that the risk management should be performed intensively by preparing the process map for each institution and calculating the risk RPN.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.155-159
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• 2015

We present a case of cervical cancer treated by concurrent chemoradiation. In radiation therapy part, the combination of the whole pelvic helical tomotherapy plus image-guided brachytherapy with megavoltage computed tomography of helical tomotherapy was performed. We propose this therapeutic approach could be considered in a curative setting in some problematic situation as our institution.

• Radiation Oncology Journal
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• v.2 no.1
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• pp.129-137
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• 1984

In brachytherapy, it is important to determine the positions of the radiation sources which are inserted into a patient and to estimate the dose resulting from the treatment. Calculation of the dose distribution throughout an implant is so laborious that it is rarely done by manual methods except for model cases. It is possible to calculate isodose distributions and tumor doses for individual patients by the use of a microcomputer. In this program, the dose rate and dose distributions are calculated by numerical integration of point source and the localization of radiation sources are obtained from two radiographs at right angles taken by a simulator developed for the treatment planning. By using microcomputer for brachytherapy, we obtained the result as following 1. Dose calculation and irradiation time for tumor could be calculated under one or five seconds after input data. 2. It was same value under$\pm2\%$ error between dose calculation by computer program and measurement dose. 3. It took about five minutes to reconstruct completely dose distribution for intracavitary irradiation. 4. Calculating by computer made remarkly reduction of dose errors compared with Quimby's calculation in interstitial radiation implantation. 5. It could calculate the biological isoffect dose for high and low dose rate activities.

• Progress in Medical Physics
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• v.15 no.2
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• pp.63-69
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• 2004

HDR brachytherapy administers a large dose of radiation in a short time compare with LDR, and its optimization for treatment is related to several complex factors, such as physical, radiation and optimization algorithms, so there is a need for these to be verified for accurate dose delivery. In our approach, a previous study concerning the phantom for dose verification has been modified, and a new pelvic phantom fabricated for the purpose of localization, including a structure enabling the use of a CT or MRI system. In addition, a comparison study was performed to verify an orthogonal method that is commonly used for brachytherapy localization by comparing target coordinates from a CT system. Since the developed phantom was designed to simulate the clinical setups of cervix cancer, it included an air-filled bladder and a rectum structure shaped sphere and cylinder An N-shaped localizer was used to obtain precision coordinates from both CT and films. Moreover, the IDL 5.5 software program for Windows was used to perform coordinates analysis based on an orthogonal algorithm. The film results showed differences within 1.0 mm of the selected target points compare with the CT coordinates. For these results, a Plato planning system (Nucletron, Netherlands) could be independently verified using this phantom and software. Furthermore, the new phantom and software will be efficient and powerful qualify assurance (QA) tools in the field of brachytherapy QA.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.69-75
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• 2013

Purpose: Transbronchial brachytherapy used in the two-dimensional treatment planning difficult to identify the location of the tumor in the affected area to determine the process analysis. In this study, we have done a comparative analysis for the patient's treatment planning using a CT simulator. Materials and Methods: The analysis was performed by the patients who visited the hospital to June 2012. The patient carried out CT-image by CT simulator, and we were plan to compare with a two-dimensional and threedimensional treatment planning using a Oncentra Brachy planning system (Nucletron, Netherland). Results: The location of the catheter was confirmed the each time on a treatment planning for fractionated transbronchial brachytherapy. GTV volumes were $3.5cm^3$ and $3.3cm^3$. Also easy to determine the dose distribution of the tumor, the errors of a dose delivery were confirmed dose distribution of the prescibed dose for GTV. In the first treatment was 92% and the second was 88%. Conclusion: In order to compensate for the problem through a two-dimensional treatment planning, it is necessary to be tested process for the accurate identification and analysis of the treatment volume and dose distribution. Quantitatively determine the dose delivery error process that is reflected to the treatment planning is required.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.1
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• pp.7-12
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• 2011

Purpose: To analyze availability of MR images before and after external beam radiotherapy in brachytherapy, we will acquire MR images before and after external beam radiotherapy and compare the change of direction of uterine cavity and analyze the accuracy of applicator insertion. Materials and Methods: From January 2009 to December 2010, we compared MR images before and after external beam radiotherapy for uterine cervical cancer only with radical purpose treatment. MR images which was acquired after external beam radiotherapy has done with inserted status of CT/MR applicator. Results: As a consequence, the tumor was markedly reduced after external beam radiotherapy. The change of anteflexion of uterus turned into retroflexion of the uterine cavity was 17.1%. The case of wrong insertion of tandem include direction or length was 14.3%. Conclusion: According to MR images taken after external beam radiotherapy, we recognized not only reduced the tumor volume but the marked change of exact direction or length of the uterine cavity. So the confirmation of accurate insertion based on MR images before brachytherapy could be very helpful for optimal brachytherapy treatment planning with reduced applicator insertion errors.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.119-125
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• 2006

Purpose: To measure the dose for dose optimization at the reference point (A, B) and the critical organ with multi Purpose brachytherapy phantom (MPBP). For this wort the MPBP was custom made, and designed to reconstruct the treatment applicator using multi function applicator (MFA) in the same way as the treatment of patient. Materials and Methods: Dose measurements were made at the reference points (A, B) and the bladder with thermoluminescence dosimeter (TLD) for four patients with tandem and ovoid of uterine cervix cancer using the phantom. In Phantom, Total 20 times of the measurements were made with 5 times a patient. Results: The results of TLD measurements in MPBP phantom showed the relative error ranging from -3.2% to 3.8% at A point, and -1.4% to 4% at B point and 1.3% to 7.15% at the bladder of reference point. Conclusion: The reproducibility of dose measurement under the same condition as the treatment could be achieved using the custom-made MFA in phantom and the dose at the reference point (A, B) and bladder could be analyzed accurately. The measured dose acquired in MPBP can apply for the dose optimization.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.123-128
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• 1996

Purpose : This is a retrospective study to compare the Palliation rates, survival rates and complications of low dose rate and high dose rate endobronchial brachytherapy in the management of malignant airway obstruction. Materials and methods : Forty three consecutive patients with malignant airway compromise from primary or metastatic lung tumors were treated with low dose rate(LDR) endobronchial Iridium-192 insertion(21 patients) between October 1988 and June 1992, and high dose rate(HDR) endobronchial brachytherapy(22 patients) between August 1992 and April 1994 with palliative aim Flexible fiberoptic bronchoscopy under fluoroscopic control was utilized in all 91 procedures. Twenty seven LDR Procedures delivered a dose of 5-7.5 Gy to a 1.0 cm radius respectively. Results : Subjective and objective responses to treatments were evaluated on follow-up examinations by clinical examination, chest x-rays and CT scan of the chest on some patients. Fifteen of 21 LDR patients and 19 of 22 HDR Patients showed subjective improvement in terms of better breathing and less Productive cough as well as complete disappearance of hemoptysis. Objective improvement on chest x-rays and CT scan of the chest had been demonstrated on 8 LDR Patients and 10 HDR patients. Conclusion : The technique of LDR and HDR endobronchial brachytherapy is simple and well tolerated procedure with minimal morbidity It Provides excellent palliation by keeping airway Patent in these short life-spanned patients.

• Progress in Medical Physics
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• v.20 no.1
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• pp.7-13
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• 2009

This work is for the preliminary study for the calibration of an $^{192}Ir$ brachytherapy source based on an absorbed dose to water standards. In order to calibrate brachytherapy sources based on absorbed dose to water standards using a clyndirical ionization chamber, the beam quality correction factor $k_{Q,Q_0}$ is needed. In this study $k_{Q,Q_0}s$ were determined by both Monte carlo simulation and semiexperimental methods because of the realistic difficulties to use primary standards to measure an absolute dose at a specified distance. The 5 different serial numbers of the PTW30013 chamber type were selected for this study. While chamber to chamber variations ran up to maximum 4.0% with the generic $k^{gen}_{Q,Q_0}$, the chamber to chamber variations were within a maximum deviation of 0.5% with the individual $k^{ind}_{Q,Q_0}$. The results show why and how important ionization chambers must be calibrated individually for the calibration of $^{192}Ir$ brachytherapy sources based on absorbed dose to water standards. We hope that in the near future users will be able to calibrate the brachytherapy sources in terms of an absorbed dose to water, the quantity of interest in the treatment, instead of an air kerma strength just as the calibration in the high energy photon and electron beam.