• 대한두경부종양학회지
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• 제37권1호
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• pp.1-10
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• 2021

Intensity-modulated radiation therapy (IMRT) using X-rays is a standard technique implemented for treating head and neck cancer (HN C). Compared to 3D conformal RT, IMRT can significantly reduce the radiation dose to surrounding normal tissues by using a highly conformal dose to the tumor. Proton therapy is a type of RT that uses positively charged particles named protons. Proton therapy has a unique energy deposit (i.e., Bragg peak) and greater biological effectiveness than that of therapy using X-rays. These inherent properties of proton therapy make the technique advantageous for HNC treatment. Recently, advanced techniques such as intensity-modulated proton therapy have further decreased the dose to normal organs with a higher conformal dose to the tumor. The usage of proton therapy for HNC is becoming widespread as the number of operational proton therapy centers has increased worldwide. This paper aims to present the current clinical evidence of proton therapy utility to HNC clinicians through a literature review. It also discusses the challenges associated with proton therapy and prospective development of the technique.

• Radiation Oncology Journal
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• 제37권4호
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• pp.232-248
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• 2019

Proton beams have been used for cancer treatment for more than 28 years, and several technological advancements have been made to achieve improved clinical outcomes by delivering more accurate and conformal doses to the target cancer cells while minimizing the dose to normal tissues. The state-of-the-art intensity modulated proton therapy is now prevailing as a major treatment technique in proton facilities worldwide, but still faces many challenges in being applied to the lung. Thus, in this article, the current status of proton therapy technique is reviewed and issues regarding the relevant uncertainty in proton therapy in the lung are summarized.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
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• pp.72-74
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• 2004

세기변조방사선치료(IMRT)의 정확한 선량을 검증하기위해 본원에서는 최적화 기법을 이용한 2차원 선량 검증 알고리즘을 개발하여 임상에 적용하고 있다. 이에 대한 계속적인 연구로 최적화 알고리즘을 3차원으로 확장하고, 3차원 아크릴 팬톰을 제작하여 필름을 이용한 3차원 IMRT 선량검증 시스템을 개발하였다.

• Journal of Chest Surgery
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• 제53권4호
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• pp.184-190
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• 2020

Radiation therapy (RT) has improved patient outcomes, but treatment-related complication rates remain high. In the conventional 2-dimensional and 3-dimensional conformal RT (3D-CRT) era, there was little room for toxicity reduction because of the need to balance the estimated toxicity to organs at risk (OARs), derived from dose-volume histogram data for organs including the lung, heart, spinal cord, and liver, with the planning target volume (PTV) dose. Intensity-modulated RT (IMRT) is an advanced form of conformal RT that utilizes computer-controlled linear accelerators to deliver precise radiation doses to the PTV. The dosimetric advantages of IMRT enable better sparing of normal tissues and OARs than is possible with 3D-CRT. A major breakthrough in the treatment of esophageal cancer (EC), whether early or locally advanced, is the use of proton beam therapy (PBT). Protons deposit their highest dose of radiation at the tumor, while leaving none behind; the resulting effective dose reduction to healthy tissues and OARs considerably reduces acute and delayed RT-related toxicity. In recent studies, PBT has been found to alleviate severe lymphopenia resulting from combined chemo-radiation, opening up the possibility of reducing immune suppression, which might be associated with a poor prognosis in cases of locally advanced EC.

• 한국의학물리학회지:의학물리
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• 제19권2호
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• pp.89-94
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• 2008

토모치료기는 선형가속기에서 사용되는 세기 변조방사선치료와 Mega-voltage Computed Tomography (MVCT) 3차원 영상정보에 의한 영상유도방사선치료(Image Guide Radiation Therapy, IGRT)가 가능하고 나선식 빔 조사를 통해 표적과 정상조직에 효율적으로 선량(dose)을 집중하고 분산할 수 있다는 장점을 가진다. 이에 본 논문에서는 2006년 9월부터 운용을 시작한 국립암센터의 토모치료기를 이용하여 10명의 두경부암 환자를 대상으로 토모치료계획과 선형가속기기반 세기변조방사선치료계획의 선량분포를 비교하였으며 또한, 영상유도 방사선치료장치가 구비되지 못하여 환자의 위치보정이 부정확한 구형 세기변조방사선치료기에 대해 표적의 움직임에 따라 균일성(Homogeneity)과 정상조직부작용율(Normal Tissue Complication Probability, NTCP)이 상대적으로 어떻게 변화하는지 연구하였다. 이 연구를 위하여 토모치료기의 치료계획용 시스템인 Hi-Art (Hi-Art2_2_4 2.2.4.15, TomoTherapy Incorporated, 1240 Doming Way, Madison, WI S3717-1954, USA)와 선형가속기기반 세기변조방사선치료계획용 시스템인 CadPlan (CadPlan R.6.4.7, Varian Medical System Inc. 3100 Hansen Way, Palo Alto, CA 94304-1129, USA)을 이용한 역치료계획(inverse Planning)이 수행되었으며 치료계획은 각각의 환자에 대해 같은 표적과 최적화조건을 가지도록 고려되었다. 총 10명의 환자를 대상으로 한 연구결과, 환자의 신체내 외부가 완전히 고정되어 있는 이상적인 경우에 대해서 토모치료기를 이용한 치료계획이 선형가속기에 의한 세기 변조 방식보다 표적에 대해 보다 높고 일정한 선량분포를 주면서도 주변 장기의 선량이 선량체적 히스토그램(Dose Volume Histogram, DVH)에서 오히려 감소함을 보여 주었다 또한 토모치료기의 MVCT를 이용하여 한 달간 토모 환자의 표적위치변화를 측정하였고, 이를 토대로 평균 표적위치변화를 고려하였을 경우 선형가속기기반 세기변조방사선치료계획인 CadPlan에서 표적의 등가균질선량(Equivalant Uniform Dose, EUD)이 감소하고 정상조직의 부작용율의 발생가능성이 상대적으로 증가함을 발견하였다.

• Radiation Oncology Journal
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• 제36권3호
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• pp.200-209
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• 2018

Purpose: To evaluate the effectiveness and feasibility of chemoradiotherapy (CRT) using simultaneous integrated boost-intensity modulated radiotherapy (SIB-IMRT) in locally advanced pancreatic cancer (LAPC) patients. Materials and Methods: Between January 2011 and May 2015, 47 LAPC patients received CRT using SIB-IMRT. Prior to SIB-IMRT, 37 patients (78.7%) received induction chemotherapy (IC-CRT group) and remaining 10 patients (21.3%) did not received induction chemotherapy (CRT group). During SIB-IMRT, all patients received concomitant chemotherapy, with gemcitabine (n = 37) and capecitabine (n = 10). Results: At the time of analysis, 45 patients had died and 2 patients remained alive and the median follow-up time was 14.2 months (range, 3.3 to 51.4 months). For all patients, the median times of local progression-free survival (LPFS), progression-free survival (PFS), and overall survival (OS) were 18.1, 10.3, and 14.2 months, respectively. The median time of LPFS between IC-CRT and CRT groups was similar (18.1 months vs. 18.3 months, p = 0.711). IC-CRT group had a higher trend in PFS (10.9 months vs. 4.1 months, p = 0.054) and had significantly higher OS (15.4 months vs. 9.5 months, p = 0.007) than CRT group. In multivariate analysis, the use of induction chemotherapy and tumor response were significant factors associated with OS (p < 0.05, each). During SIB-IMRT, toxicity of grade ≥3 was observed in 7 patients (14.9%) in all patients. Conclusions: CRT using SIB-IMRT is feasible and promising in LAPC patients.

• 한국의학물리학회지:의학물리
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• 제24권3호
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• pp.154-161
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• 2013

본 연구는 총 10명의 전립선 암 환자를 대상으로 세기조절방사선치료(IMRT), 균일스캐닝양성자치료(USPT), 그리고 세기조절양성자치료(IMPT)기술을 이용한 치료계획의 결과를 비교, 평가 하였다. 각 치료 계획은 타깃 체적의 95%에 70 Gy가 28회 분할 조사되도록 하였으며 세기조절방사선치료(IMRT)에서는 step-and-shoot 기법을 이용하여 총 7개의 빔을 사용하여 방사선을 조사하였고, 균일세기양성자치료(USPT)와 세기조절양성자치료(IMPT)에서는 동일한 방사선 가중치의 측방향대향조사면(lateral opposing field)를 사용하여 타깃에 처방선량이 전달되도록 하였다. 한편, 세기조절양성자치료(IMPT)의 최적화를 위해 IMRT치료와 유사한 Inverse planning을 수행하였다. 결과 비교를 위해 타깃의 균질성지수(homogeneity index) 및 동형지수(conformity index)와 정상조직의 정상조직합병증확률(NTCP)을 계산하였다. 비록 치료기법간에 균질성지수(homogeneity index), 동형지수(conformity index)차이가 크지 않았지만, 직장의 경우 각 세기조절방사선치료(IMRT), 균일스캐닝 양성자치료(USPT) 및 세기조절양성자치료(IMPT)에서 2.233, 3.326 및 1.707로 계산되었다. 또한 방광의 정상조직합병증확률(NTCP)는 0.008, 0.003, 및 0.002를 나타내었다. 직장과 방광의 NTCP 값이 IMPT을 사용할 때 유의하게 낮은 값을 보이는 것을 확인하였다. 본 연구를 통해 전립선 암의 방사선 치료 시 세기조절방사선치료(IMRT)보다 양성자를 이용한 방사선 치료, 특히 최적화된 세기조절양성자치료(IMPT)가 치료 효과를 높일 수 있는 치료계획이 될 수 있음을 확인할 수 있었다.

• 한국의학물리학회지:의학물리
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• 제32권2호
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• pp.25-39
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• 2021

Brachytherapy, along with external beam radiation therapy (EBRT), is an essential and effective radiation treatment process. In brachytherapy, in contrast to EBRT, the radiation source is radioisotopes. Because these isotopes can be positioned inside or near the tumor, it is possible to protect other organs around the tumor while delivering an extremely high-dose of treatment to the tumor. Brachytherapy has a long history of more than 100 years. In the early 1900s, the radioisotopes used for brachytherapy were only radium or radon isotopes extracted from nature. Over time, however, various radioisotopes have been artificially produced. As radioisotopes have high radioactivity and miniature size, the application of brachytherapy has expanded to high-dose-rate brachytherapy. Recently, advanced treatment techniques used in EBRT, such as image guidance and intensity modulation techniques, have been applied to brachytherapy. Three-dimensional images, such as ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography are used for accurate delineation of treatment targets and normal organs. Intensity-modulated brachytherapy is anticipated to be performed in the near future, and it is anticipated that the treatment outcomes of applicable cancers will be greatly improved by this treatment's excellent dose delivery characteristics.

• 대한방사선기술학회지:방사선기술과학
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• 제37권4호
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• pp.331-339
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• 2014

현재 상용화되어 있는 양성자치료의 치료계획장비를 이용하여 방사선회전조사와 같은 치료계획을 양성자치료에 사용하여 대동맥 주위 림프절 종양에 대해 양성자회전치료와 양성자치료, 세기조절방사선치료를 이용하여 선량 평가를 하였다. 대동맥주위 림프절 종양 환자 9명을 대상으로 양성자회전치료, 양성자치료, 세기조절방사선치료의 방사선치료계획을 세워 각각의 선량 체적 히스토그램을 이용하여 선량 평가를 하였다. 양성자회전치료의 치료계획방법으로는 250~120까지 5도 간격으로 48개의 빔을 사용하였으며, 양성자치료와 세기조절방사선치료는 각각 2~3, 4~5개의 빔을 사용하였다. 모든 방사선 치료계획 시스템은 Eclipse planning system(Varian Medical system, Inc., Palo Alto, CA, USA)을 사용하였으며, 양성자회전치료는 아직 개발이 안된 치료장치이므로 치료계획방법에서 기계적, 물리적인 요소를 양성자치료계획과 동일하게 시행하였다. 선량분석방법으로는 정상장기(간, 신장, 소장, 위, 십이지장)와 종양의 선량 체적 히스토그램(dose-volume histogram: DVH)을 이용하여 생물학적 인자인 normal tissue complication probabilities(NTCP), organ equivalent dose(OED)와 mean dose를 각각의 치료계획방법을 비교 분석 평가하였다. 그 결과 양성자회전치료가 복부에 위치한 small bowel, duodenum, stomach의 볼륨 90%가 받는 선량에서의 결과는 다른 치료계획에 비해 높은 결과를 나타내고 있다. NTCP의 결과에서 양성자회전치료가 liver를 제외한 나머지 장기에서 가장 낮은 결과를 보여주고 있다. 하지만 복부에 위치한 정상장기에 받는 선량이 다른 치료계획에 비해 높아 치료계획 시 주위가 요하며, 물리적, 기계적인 요소는 양성자치료와 동일하다는 전제조건으로 양성자회전치료와 유사한 장비가 제작되어 상용화 되었을 때에 본 연구의 결과와는 다를 거라 사료된다. 현실적으로 아직 불가능한 치료방법이지만 앞으로 추가적인 양성자회전치료의 연구와 기술개발이 되어 상용화가 되면 기존의 특수방사선치료인 세기조절방사선치료, 양성자치료, 세기조절회전치료보다 효과적이고 안전한 치료방법이 될 거라고 사료된다.

• Radiation Oncology Journal
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• 제36권3호
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• pp.182-191
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• 2018

Purpose: To investigate the clinical outcome of proton therapy (PT) in patients with chordoma. Materials and Methods: Fifty-eight patients with chordoma treated with PT between June 2007 and December 2015 at the National Cancer Center, Korea, were retrospectively analyzed. The median total dose was 69.6 cobalt gray equivalent (CGE; range, 64.8 to 79.2 CGE). Local progression-free survival (LPFS), distant metastasis-free survival (DMFS), overall survival (OS), and disease-specific survival (DSS) rates were calculated by the Kaplan-Meier method. Results: With the median follow-up of 42.8 months (range, 4 to 174 months), the 5-year LPFS, DMFS, OS, and DSS rates were 87.9%, 86.7%, 88.3%, and 92.9%, respectively. The tumor location was associated with the patterns of failure: the LPFS rates were lower for cervical tumors (57.1%) than for non-cervical tumors (93.1%) (p = 0.02), and the DMFS rates were lower for sacral tumors (53.5%) than for non-sacral tumors (100%) (p = 0.001). The total dose was associated with both the LPFS rate and DMFS rate. The initial tumor size was associated with the DMFS rate, but was not associated with the LPFS rate. Three patients had grade 3 late toxicity with none ≥grade 4. Conclusion: PT is an effective and safe treatment in patients with chordomas. The tumor location was associated with the patterns of failure: local failure was common in cervical tumors, and distant failure was common in sacral tumors. Further refinement of PT, such as the utilization of intensity modulated PT for cervical tumors, is warranted to improve the outcome.