• 대한방사선치료학회:학술대회논문집
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• 1996.06a
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• pp.9-11
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• 1996

• The Journal of Korean Society for Radiation Therapy
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• v.6 no.1
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• pp.107-110
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• 1994

• The Journal of Korean Society for Radiation Therapy
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• v.7 no.1
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• pp.167-175
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• 1995

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.58-58
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• 2003

목적 : 본 연구에서는 C-arm과 CT에 사용 가능한 자궁경부암용 팬톰을 개발하고 이를 이용하여 기존의 필름 방법에 기반한 위치 확인 방법과 CT 재구성 방법의 정확성을 비교 연구하고자 한다. 정확성이 검증된 후에는 두 방법의 장점을 이용하기 위해 CT로 재구성된 좌표를 필름의 좌표로 변환시켜 현재 사용되고 있는 필름에 기반한 근접 치료 계획 시행에 도움을 주고자 한다. 방법 : 자체 제작한 자궁경부암용 팬톰은 인체 등가 물질인 물과 아크릴을 사용하였고, 크게 localizer 부분과 팬톰 부분으로 구성되어 있다. 또한, 실제 자궁경부암 환자의 임상적인 구조를 모사하여 제작하였다. 자궁경부암 치료시 중요 장기인 방광과 직장을 구와 원기둥으로 설계하였고, 고선량율 applicator는 아크릴 판의 흠으로 고정시켜 제작하였기 때문에 CT 촬영시 applicator를 제거한 영상에서도 applicator의 구조가 정확하게 묘사될 수 있도록 제작하였다. 두 시스템에서 재구성된 좌표를 비교하기 위해 각각의 시스템에서의 얻은 재구성 좌표와 팬톰 자체의 localizer와 재구성 알고리즘을 바탕으로 개발된 프로그램을 이용하여 얻은 좌표로 두 재구성 좌표의 비교 연구를 수행하였다. 정확성이 검증되고 장기의 정보가 담긴 CT의 좌표는 자체 개발된 프로그램으로 2 차원의 필름 좌표로 변환되었다. 본 연구에 사용된 모든 프로그램은 ILD 5.5를 사용하여 개발되었다. 결과 : 두 시스템의 좌표 비교 결과 x, y 축은 차이가 2mm 이내로 비교적 정확한 실험 결과를 얻을 수 있었고, z 축의 경우 CT 슬라이드의 굵기에 따라 2mm-3mm 이내의 차이가 있음을 관찰할 수 있었다. z 축을 제외한 좌표의 차이는 획득한 영상에서 컴퓨터로 좌표를 옮기는 localizer 좌표 선택 과정에 발생했을 것으로 예상된다. 또한, 이 검증된 좌표와 개발된 프로그램을 이용하여 우리는 CT의 좌표를 2차원의 필름 좌표로 정확하게 변환할 수 있었다. 결론 : 이 연구로부터 기존의 C-arm 재구성 방법과 CT 재구성 방법의 비교를 통해 각 치료 기기의 신뢰성을 직접 확인할 수 있었으며, 비교를 통해 검증된 CT의 좌표를 필름 좌표로 변환시킴으로서, 각 시스템의 장점만을 결합한 효과적인 치료 계획을 세울 수 있는 가능성을 제시하였다. 또한 물과 아크릴을 사용한 비교적 간단하고 경제적인 방법으로 C-arm, CT 그리고 MRI에 모두 이용 가능한 팬톰을 제작하여 쉽고 정확하게 위치를 확인할 수 있었다. 더 나아가, 본 연구에서 제작된 자궁경부암 팬톰은 근접치료를 포함하여 관련 팬톰 개발에 도움을 줄 수 있을 것으로 예상된다.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.228-236
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• 2002

Purpose : Although high-dose-rate (HDR) brachytherapy regimens have been practiced with a variety of modalities and various degrees of success, few studies on the subject have been conducted. The purpose of this study was to compare the results of local control and late complication rate according to different HDR brachytherapy fractionation regimens in uterine cervical cancer patients. Methods and Materials : From November 1992 to March 1998, 224 patients with uterine conical cancer were treated with external beam irradiation and HDR brachytherapy. In external pelvic radiation therapy, the radiation dose was $45\~54\;Gy$ (median dose 54 Gy) with daily fraction size 1.8 Gy, five times per week. In HDR brachytherapy, 122 patients (Group A) were treated with three times weekly with 3 Gy to line-A (isodose line of 2 cm radius from source) and 102 patients (Group B) underwent the HDR brachytherapy twice weekly with 4 or 4.5 Gy to line-A after external beam irradiation. Iridium-192 was used as the source of HDR brachytherapy. Late complication was assessed from grade 1 to 5 using the RTOG morbidity grading system. Results : The local control rate (LCR) at 5 years was $80\%$ in group A and $84\%$ in group B (p=0.4523). In the patients treated with radiation therapy alone, LCR at 5 years was $60.9\%$ in group A and $76.9\%$ in group B (p=0.2557). In post-operative radiation therapy patients, LCR at 5 years was $92.6\%$ In group A and $91.6\%$ in group B (p=0.8867). The incidence of late complication was $18\%$ (22 patients) and $29.4\%$ (30 patients), of bladder complication was $9.8\%$ (12 patients) and $14.7\%$ (15 patients), and of rectal complication was $9.8\%$ (12 patients) and $21.6\%$ (22 patients), in group A and B, respectively. Lower fraction sized HDR brachytherapy was associated with decrease in late complication (p=0.0405) (rectal complication, p=0.0147; bladder complication, p=0.115). The same result was observed in postoperative radiation therapy patients (p=0.0860) and radiation only treated patients (0=0.0370). Conclusion : For radiation only treated patients, a greater number of itemized studies on the proper fraction size of HDR brachytherapy, with consideration for stages and prognostic factors, are required. In postoperative radiation therapy, the fraction size of HDR brachytherapy did not have much effect on local control, yet the incidence of late complication increased with the elevation in fraction size. We suggest that HDR brachytherapy three times weekly with 3 Gy could be an alternative method of therapy.

• The Journal of Korean Society for Radiation Therapy
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• v.12 no.1
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• pp.1-7
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• 2000

• Progress in Medical Physics
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• v.26 no.4
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• pp.280-285
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• 2015

In radiation therapy fields, a brachytherapy is a treatment that kills lesion of cells by inserting a radioisotope that keeps emitting radiation into the body. We currently verify the consistency of radiation treatment plan and dose distribution through film/screen system (F/S system), provide therapy after checking dose. When we check dose distribution, F/S systems have radiation signal distortion because there is low resolution by penumbra depending on the condition of film developed. In this study, We fabricated a $HgI_2$ Semiconductor radiation sensor for base study in order that we verify the real dose distribution weather it's same as plans or not in brachytherapy. Also, we attempt to evaluate the feasibility of QA system by utilizing and evaluating the sensor to brachytherapy source. As shown in the result of detected signal with various source-to-detector distance (SDD), we quantitatively verified the real range of treatment which is also equivalent to treatment plans because only the low signal estimated as scatters was measured beyond the range of treatment. And the result of experiment that we access reproducibility on the same condition of ${\gamma}$-ray, we have made sure that the CV (coefficient of variation) is within 1.5 percent so we consider that the $HgI_2$ sensor is available at QA of brachytherapy based on the result.

• The Journal of Korean Society for Radiation Therapy
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• v.15 no.1
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• pp.29-33
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• 2003

I. Purpose Brachytherapy is the main component in treatment of patients with uterine cervical cancer. The reproducibility of applicator position in the same patient at repeated treatments was very important for accurate dose delivery. It was aimed to evaluate the change of applicator location between each high dose rate(HDR) brachytherapy insertion in the patients with uterine cervical cancer. II. Materials and Methods From January 1999 to October 2001, total 52 patients were treated with external beam radiotherapy and HDR brachytherapy (Microselectron, Nucletron). During six to seven times of brachytherapy, all patients had three treatment plans. From the orthogonal radiographs, we measured the following variables; height from upper border of pubic bone to os (HPO), distance from sacral promontory to tip of tandem (DST), distance from coccyx to os (DCO), distance from tip of right ovoid to os (DRO), distance from tip of left ovoid to os (DLO), and distance from center of the first tandem source to ovoid (DTO). To evaluate the reproducibility of applicator position, it was calculated the standard deviation of differences between three insertions for the 7 parameters in each patient. III. Results The ranges of standard deviations of interfractional differences for the variables were as follows. 1)HPO : $0{\sim}0.79cm$ 2)DST : $0{\sim}0.9cm$ 3)DCO : $0.06{\sim}0.76cm$ 4)DRO : $0{\sim}0.53cm$ 5)DLO : $0{\sim}0.45cm$ 6) DTO $0{\sim}0.36cm$ IV. Conclusions There was some change in applicator position on repeated implants in our study. But variation of the interfractional differences was minimal; in all parameters, there were less than 1 cm. We are continued to try for reducing the geometric variation between each procedure.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.25-32
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• 2004

Purpose : Evaluate the efficacies and toxicities of concurrent chemoradiotherapy (CCRT), with or without intraluminal brachytherapy (ILB), using a retrospective analysis in esophageal carcinomas with respect to survival. Materials and Methods : From April 1995 to July 2001, a total of 65 patients, diagnosed with an esophageal carcinoma, were treated by CCRT, with 21 also treated by ILB after CCRT. External radiotherapy was peformed using 6 or 10 MV X-rays, with a dose range of $46.8~\69.6$ Gy (median; 59.4). The ILB was peformed using high-dose-rate brachytherapy with Ir-192. The fractionation of ILB was 3 Gy by 4, or 5 Gy by 2 fractions. Cisplatin $(75\;mg/m^2)$ was given on each first day of weeks 1, 5, 9 and 13, and 5-FU $(1,000\;mg/m^2)$ as a continuous infusion for the first 4 days of each course. Results : The median survival time of all patients was 15 months, and the 1, 2 and 3-year survival rates were 55.4, 29.2 and $20.7\%$, respectively. The 2-year survival rates of the patients with and without ILB were 33.3 and $27.3\%$, respectively (p=0.80). The 2-year survival rates of the patients with a complete, partial and no response were 44.1, 13.8 and $0\%$, respectively (p=0.02). The response to treatment was the only significant factor affecting the overall survival from a multivariate analysis. Conclusion : This study has shown that the survival outcomes of CCRT were much better than previous results with radiotherapy alone. However, the addition of ILB after CCRT showed no advantage over that of CCRT alone.

• 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.