• 대한방사선치료학회지
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• 제6권1호
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• pp.67-70
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• 1994

The use of primary breast irraditation with advantage of improved cosmesis in breast cancer may be the potential risks of radiation for a change in the number of normal breast cancers and lung fibrosis. The magnitude of the scattered dose for a variety of radiation treatment techniques from patient of breast cancer and phantom was measured by adequate dosimeters. We can reduce the dose of the normal breast to treated with radiation by understanding the factors contributing to the unwanted dose and by determining ways to decrease this dose.

• 대한기관식도과학회지
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• 제4권1호
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• pp.91-95
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• 1998

Background： Laryngeal cancer, the most common malignancy of head and neck, is being detected and treated in earlier and more effectively due to introduction of endoscope, continuous development of radiographic technology, and advancement in new surgical techniques such as laser surgery and conservation laryngeal surgery Objectives To compare the different treatment results for early laryngeal cancer to determine which methos provides the good prognosis. Materials and Methods： Retrospective study was done for 135 patients with early laryngeal squamous cell carcinoma(Stage I or II) who were treated at our institute between 1989 to 1996. There were 105 patients with glottic cancer(Stage I: 68 patients, Stage II：37 Patients) and 30 patients with supraglottic cancer(Stage I: 12 patients, Stage II：18 patients) Initial treatment included radiation therapy for 54 patients, endoscopic laser surgery for 8 patients, laryngofissure and cordectomy for 8 patients, vertical partial laryngectomy for 37 patients, supraglottic laryngecomy for 14 patients and supracricoid laryngectomy for 5 patiens, and total laryngectomy for 9 patients. Results : Salvage treatments, such as total laryngectomy, conservation laryngeal surgery, radiation therapy and neck dissection were performed for initial treatment failure with 9 patients after radiation therapy, 8 patients after conservation laryngeal surgery, 2 patients after endoscopic laser and 3 patients after total laryngectomy. Overall 3-year survival rate for glottic 71 was 92.4%, glottic f 84.3%, supraglottic 7172.7%, and supraglottic f was 63.%%. However, survival rate of the same stage was variable according to the choice of initial treatment. Conclusion New classification of the early laryngeal cancer was necessary and helpful for the choice of the initial treatment.

• Radiation Oncology Journal
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• 제7권1호
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• pp.101-112
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• 1989

The treatment planning and dosimetry of small fields for stereotactic radiosurgery with 10 MV x-ray isocentrically mounted linear accelerator is presented. Special consideration in this study was given to the variation of absorbed dose with field size, the central axis percent depth doses and the combined moving beam dose distribution. The collimator scatter correction factors of small fields $(1\times1\~3\times3cm^2)$ were measured with ion chamber at a target chamber distance of 300cm where the projected fields were larger than the polystyrene buildup caps and it was calibrated with the tissue equivalent solid state detectors of small size (TLD, PLD, ESR and semiconductors). The central axis percent depth doses for $1\timesl\;and\;3\times3cm^2$ fields could be derived with the same acuracy by interpolating between measured values for larger fields and calculated zero area data, and it was also calibrated with semiconductor detectors. The agreement between experimental and calculated data was found to be under $2\%$ within the fields. The three dimensional dose planning of stereotactic focusing irradiation on small size tumor regions was performed with dose planning computer system (Therac 2300) and was verified with film dosimetry. The more the number of strips and the wider the angle of arc rotation, the larger were the dose delivered on tumor and the less the dose to surrounding the normal tissues. The circular cone, we designed, improves the alignment, minimizes the penumbra of the beam and formats ball shape of treatment area without stellate patterns. These dosimetric techniques can provide adequate physics background for stereotactic radiosurgery with small radiation fields and 10MV x-ray beam.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.449-455
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• 2022

The rapid rise in the application of novel treatment techniques, such as intensity-modulated radiotherapy (IMRT), motivated us to survey the status of Korea's radiation safety management and the shielding designs of facilities employing medical linear accelerators (LINACs). To this end, a questionnaire was used to collect information on LINAC facilities and treatments, workload, shielding design, shielding management, and path of obtaining shielding information. Out of 100 domestic institutions, 52 responded to the survey. Approximately 70% of the institutions utilized IMRT for more than 60% of their cases, and an IMRT factor of 5 was adopted by 75% of these institutions. Over 80% of the institutions accounted for the applied time-averaged dose rate per week and instantaneous dose equivalent rates in their shielding designs. Approximately 45% of the institutions obtained important shielding information via a radiation shielding design company and the NCRP-151 report. Overall, most facilities were shown to follow the standards recommended by the relevant international agencies. However, the requirement to establish standardized shielding design information and clarify ambiguous paths for information acquisition was also highlighted. Therefore, the study's results can be used as a foundation for establishing a safety control system and for creating adequate shielding designs.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2005년도 제30회 춘계학술대회
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• pp.59-63
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• 2005

호흡 움직임은 종양에 대한 방사선치료의 부정확한 방사선조사가 유도되도록 복부 및 흉부에서 움직임을 야기한다. 그러므로 치료시 이러한 움직임에 대한 정확한 계산은 정상조직에는 저 선량을 조사되도록 CTV의 마진을 줄일 수 있고 방사선치료에 발생되는 부작용을 줄일 수 있다. Intrafraction motion을 고려하는 기술로는 호흡 멈춤, 호흡동조, 4차원 또는 종양추적 기술이 있다. 호흡동조 방법은 환자의 호흡 신호가 호흡주기의 일정한 범위에 위치할 때 주기적으로 빔을 조사하고 그 범위를 벗어날 때는 빔을 조사하지 않는 방법이다. 이러한 기술은 내부장기 움직임과 상관관계가 있는 호흡 움직임 신호의 획득이 요구된다. 호흡동조 방사선치료를 위한 예비연구로 본 연구자들은 호흡 움직임 신호 측정을 수행하였다. 환자의 호흡 움직임 신호 측정을 위해서, 호흡측정시스템을 3 가지 센서, 4 채널 데이터 획득 시스템, 신호처리용 컴퓨터로 구성하였다. 2명의 환자를 대상으로 본 연구자들은 호흡측정시스템을 가지고 호흡주기 및 파형을 평가하였다. 그 결과 호흡주기는 시간의 함수에 따라 일반적으로 정확한 대칭 형태는 아니지만 주기적인 형태로 측정되었다. 호흡측정 시스템은 기대했던 만큼 환자의 호흡을 잘 추적하였으며 실험에 적용하기 위해 쉽게 컨트롤 할 수 있었다.

• Radiation Oncology Journal
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• 제16권4호
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• pp.399-408
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• 1998

목적 : 본 연구는 비인강암 환자의 방사선치료에서 기존의 2차원적 치료계획과 3차원 입체조형 치료계획을 비교 분석하여 3차원적 치료계획의 우월성을 입증하고자 하였다. 대상 및 방법 : 병기가 T4인 환자를 대상으로 하였으며, 두 치료계획 모두 기존의 2차원적 치료방법으로 50.4Gy가 조사된 후 추가조사하는 과정을 2차원적 치료계획과 3차원적 치료계획으로 구분하여 수립하였다. 치료계획의 비교는 선량통계, 선량체적히스토그람, 국소제어율, 그리고 정상조직손상확률을 이용하여 시행하였다. 결과 : 3차원적 치료계획에서 2차원적 치료계획과 비교하여 계획용표적체적의 선량균일성이 더욱 향상되었으며 평균선량도 15.2$\%$의 증가를 보였다. 또한 종양 주위의 정상 장기인 측두엽, 뇌간, 이하선 및 측두하악골관절에 조사되는 평균선량은 3차원적 치료계획에서 낮았다. 종양제어확률은 3차원적 치료계획에서 2차원적 치료계획에서보다도 6$\%$ 증가하였으나 정상조직손상확률은 측두엽, 뇌간, 이하선, 측두하악골관절, 그리고 시신경교차 등 대부분의 정상장기에서 낮았다. 결론 : 3차원 입체조형치료계획은 2차원적 치료계획에 비교하여 종양의 국소제어율을 증가시킬수 있는 우월한 치료법임이 증명되었으나 임상적으로도 같은 결과를 가져올 지는 향후 전향적인 임상 연구가 요구된다.

• 대한의용생체공학회:의공학회지
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• 제16권3호
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• pp.337-344
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• 1995

방사선 치료에 있어서 치료전 및 치료도중에 치료부위를 확인하기 위한 수단으로 보편적으로 사용되고 있는 포탈필름은 높은 에너지를 이용하여 촬영되는 것이므로 영상이 매우 흐리며 어둡다는 구조적인 문제점이 있다. 이러한 영상을 개선하기 위하여는 치료필드와 그 주변필드로 영상을 먼저 분할한 후, 각 필드 별로 영상처리를 해야만 한다. 본 연구에서는 소벨 탐지자, 레이블링 기법을 이용하여 최적의 문턱치를 찾아내어 포탈영상을 분할 한 후 형태학적 세선화기법들을 적용하여 포탈영상 분할하는 알고리즘을 제안하였다. 이 알고리즘은 포탈영상에서 불필요한 에지들은 제거하고 치료필드 에지만을 탐지하며 촬영조건이 수시로 변하는 임상적 환경에서 얻어지는 포탈영상들에 적용하여도 균일한 결과를 얻을 수 있다.

• 대한두개안면성형외과학회지
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• 제22권5호
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• pp.247-253
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• 2021

Background: Radiation therapy (RT) is frequently used for supportive treatment and management of advanced head and neck cancers. This study performed a retrospective review of the treatment methods that were used for intractable draining fistulas in seven patients who had received RT for head and neck cancers. Treatment methods used for two of the seven patients are presented in detail. Methods: From 2009 to 2020, seven patients underwent reconstructive surgery for intractable fistulas which occurred after RT for head and neck cancers. Patient characteristics, medical history, treatment method, and treatment outcome were reviewed for each case. The type of surgery performed, failure rate, and treatment period were also analyzed. Results: In this study, a total of seven patients received additional management for radiation-induced fistulas. Patients underwent a mean of 3.3±1.4 surgeries (maximum: six surgeries) to resolve their fistulas. The mean time interval from the first surgery to the last surgery for the patients to achieve resolution of the fistula was 8.7 months. Loco-regional flaps have performed an average of 1.9±1.5 times. However, all loco-regional flaps failed. Instead, the patients' intractable fistulas were resolved with the use of distant flaps or free tissue transfers. Conclusion: Fistulas that develop after head and neck cancer treatment following RT are difficult to treat with simple loco-regional flap procedures. Therefore, more aggressive treatment techniques, such as distant flap or free tissue transfer, may be needed to shorten patients' treatment periods and avoid unnecessary surgeries.

• Radiation Oncology Journal
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• 제6권2호
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• pp.283-288
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• 1988

초기 유방암의 치료는 근치적 절제술이 오랫동안 주된 치료방법으로써 선택되어 왔으나, 근래에는 여성의 유방을 보존하고 미용효과를 기대할 수 있는 보조적 절제술 후 근치적 방사선치료법이 개발되어 지대한 관심과 상당한 논란이 거듭되어 왔다. 이러한 논란을 해결하기 위하여 그동안 세계적으로 많은 후향성 또는 전향성 분석을 시행하여 두 치료방법사이의 치료효과를 비교하여 본 결과, 국소치료율, 재발을, 그리고 생존율에 있어서 큰 차이를 보이지 않았다. 이와 같은 치료성적의 결과를 토대로 하여 최근에는 보조적 절제술 후 근치적 방사선치료법이 여성들의 유방을 보존하고 미용효과를 향상시킬 수 있을 뿐만 아니라 국소치료율, 재발율, 생존율도 근치적 절제술의 성적과 대동소이하므로 초기 유방암의 치료에 활발히 이용되기에 이르렀다. 본원에서도 이러한 추세에 따라서 보조적 절제술 후 근치적 방사선치료를 시행한 초기 유방암 1예를 보고하면서 아울러 많은 문헌고찰과 함께 향후 치료방침을 세우고자 한다.

• Radiation Oncology Journal
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• 제35권1호
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• pp.16-24
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• 2017

Locally advanced non-small cell lung cancer (LA-NSCLC) is composed of heterogeneous subgroups that require a multidisciplinary team approach in order to ensure optimal therapy for each patient. Since 2010, the National Comprehensive Cancer Network has recommended chemoradiation therapy (CRT) for bulky mediastinal disease and surgical combination for those patients with single-station N2 involvement who respond to neoadjuvant therapy. According to lung cancer tumor boards, thoracic surgeons make a decision on the resectability of the tumor, if it is determined to be unresectable, concurrent CRT (CCRT) is considered the next choice. However, the survival benefit of CCRT over sequential CRT or radiotherapy alone carries the risk of additional toxicity. Considering severe adverse events that may lead to death, fit patients who are able to tolerate CCRT must be identified by multidisciplinary tumor board. Decelerated approaches, such as sequential CRT or high-dose radiation alone may be a valuable alternative for patients who are not eligible for CCRT. As a new treatment strategy, investigators are interested in the application of the innovative radiation techniques, trimodality therapy combining surgery after high-dose definitive CCRT, and the combination of radiation with targeted or immunotherapy agents. The updated results and on-going studies are thoroughly reviewed in this article.