• Radiation Oncology Journal
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• 제34권2호
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• pp.145-155
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• 2016

Purpose: Radiation therapy targeting axilla and groin lymph nodes improves regional disease control in locally advanced and high-risk skin cancers. However, trials generally used conventional two-dimensional radiotherapy (2D-RT), contributing towards relatively high rates of side effects from treatment. The goal of this study is to determine if three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or volumetric-modulated arc therapy (VMAT) may improve radiation delivery to the target while avoiding organs at risk in the clinical context of skin cancer regional nodal irradiation. Materials and Methods: Twenty patients with locally advanced/high-risk skin cancers underwent computed tomography simulation. The relevant axilla or groin planning target volumes and organs at risk were delineated using standard definitions. Paired t-tests were used to compare the mean values of several dose-volumetric parameters for each of the 4 techniques. Results: In the axilla, the largest improvement for 3D-CRT compared to 2D-RT was for homogeneity index (13.9 vs. 54.3), at the expense of higher lung $V_{20}$ (28.0% vs. 12.6%). In the groin, the largest improvements for 3D-CRT compared to 2D-RT were for anorectum $D_{max}$ (13.6 vs. 38.9 Gy), bowel $D_{200cc}$ (7.3 vs. 23.1 Gy), femur $D_{50}$ (34.6 vs. 57.2 Gy), and genitalia $D_{max}$ (37.6 vs. 51.1 Gy). IMRT had further improvements compared to 3D-CRT for humerus $D_{mean}$ (16.9 vs. 22.4 Gy), brachial plexus $D_5$ (57.4 vs. 61.3 Gy), bladder $D_5$ (26.8 vs. 36.5 Gy), and femur $D_{50}$ (18.7 vs. 34.6 Gy). Fewer differences were observed between IMRT and VMAT. Conclusion: Compared to 2D-RT and 3D-CRT, IMRT and VMAT had dosimetric advantages in the treatment of nodal regions of skin cancer patients.

• 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.

• 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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• 제34권3호
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• pp.193-201
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• 2016

Purpose: To assess the clinical outcomes of radiotherapy (RT) using two-dimensional (2D) and three-dimensional conformal RT (3D-CRT) for patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma to evaluate the effectiveness of involved field RT with moderate-dose and to evaluate the benefit of 3D-CRT comparing with 2D-RT. Materials and Methods: Between July 2003 and March 2015, 33 patients with stage IE and IIE gastric MALT lymphoma received RT were analyzed. Of 33 patients, 17 patients (51.5%) were Helicobacter pylori (HP) negative and 16 patients (48.5%) were HP positive but refractory to HP eradication (HPE). The 2D-RT (n = 14) and 3D-CRT (n = 19) were performed and total dose was 30.6 Gy/17 fractions. Of 11 patients who RT planning data were available, dose-volumetric parameters between 2D-RT and 3D-CRT plans was compared. Results: All patients reached complete remission (CR) eventually and median time to CR was 3 months (range, 1 to 15 months). No local relapse occurred and one patient died with second primary malignancy. Tumor response, survival, and toxicity were not significantly different between 2D-RT and 3D-CRT (p > 0.05, each). In analysis for dose-volumetric parameters, $D_{max}$ and CI for PTV were significantly lower in 3D-CRT plans than 2D-RT plans (p < 0.05, each) and $D_{mean}$ and V15 for right kidney and $D_{mean}$ for left kidney were significantly lower in 3D-CRT than 2D-RT (p < 0.05, each). Conclusion: Our data suggested that involved field RT with moderate-dose for gastric MALT lymphoma could be promising and 3D-CRT could be considered to improve the target coverage and reduce radiation dose to the both kidneys.

• 대한방사선치료학회지
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• 제26권1호
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• pp.91-98
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• 2014

목 적 : 본 연구에서는 기존의 방사선 치료 기법인 3D-CRT 방법을 기반으로 치료 Energy와 Wedge를 변형 시킨 Hybrid 치료계획을 세워, open rectangular field를 사용한 2D-RT와 현재 가장 많이 시행되고 있는 방사선치료의 형태인 3D-CRT, 그리고 Hyrid paln 의 각각의 치료계획에 따른 선량분포, 선량-체적 히스토그램을 이용하여 산출된 값들을 비교, 분석하여 Hybrid 치료계획의 유용성을 평가하고자 한다. 대상 및 방법 : 본원에서 방사선 치료를 받은 환자 5명을 대상으로 전산화 단층촬영장치(RT-16GE)를 이용해 CT모의치료를 시행하여 영상을 획득하였다. 치료계획실에서는 이미지 관심영역표시는 종양은 CTV으로, 정상장기는 폐, 심장으로 나타냈다. 치료계획은(pinncle-ver 9.2)은 표적에는 충분한 선량을 정상장기에는 선량이 최소화 되도록 치료계획을 세웠다. 결 과 : Homogeneity Index의 선량비교는 2D-RT (open rectangular field): 38.32, TW(conformal wedge field): 32.01 FIF(field in field): 29.22, HYBRID(energy combine, wedge combine): 30.57으로 나타났다. 2D-RT, TW, FIF Hybrid $V_{75_-lung}$은 각각 112.33, 125.14, 121.3, 123.78. $V_{50_-lung}$은 155.43, 159.62, 157.96, 159.06. $V_{25_-lung}$은 199.86, 200.22, 198.65, 200.31. $V_{50_-heart}$는 각각 26.07, 27.1, 26.85, 27.17 $V_{30_-heart}$ 33.71, 34.37, 34.15, 34.65로 나타났다. 결 론 : HYBRID planning에서 표적에는 3D-CRT 에 비해 비교적 뛰어난 선량분포와 유방을 보호함을 보여주지만 폐와 심장에 많은 선량이 조사됨을 치료계획 시 주의해야 하고 앞으로 해결해야 할 과제라 생각된다. HYBRID 으로 Energy를 혼합하여 사용한다면, 타겟에 보다 더 적절한 coverage가 이루어질 수 있을 것으로 보인다. breast 뿐만 아닌 Lung cacner 치료와 같이 불균질한 부위의 치료에 적용한다면 보다 더 최적을 결과를 이루어낼 수 있을 것으로 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권12호
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• pp.5107-5111
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• 2016

Background: Epidemiological studies have indicated an increasing incidence of radiation induced secondary cancer (SC) in breast cancer patients after radiotherapy (RT), most commonly in the contra-lateral breast (CLB). The present study was conducted to estimate the SC risk in the CLB following 3D conformal radiotherapy techniques (3DCRT) including wedge field and forward intensity modulated radiotherapy (fIMRT) based on the organ equivalent dose (OED). Material and Methods: RT plans treating the chest wall with conformal wedge field and fIMRT plans were created for 30 breast cancer patients. The risks of radiation induced cancer were estimated for the CLB using dose-response models: a linear model, a linear-plateau model and a bell-shaped model with full dose response accounting for fractionated RT on the basis of OED. Results: The plans were found to be ranked quite differently according to the choice of model; calculations based on a linear dose response model fIMRT predict statistically significant lower risk compared to the enhanced dynamic wedge (EDW) technique (p-0.0089) and a non-significant difference between fIMRT and physical wedge (PW) techniques (p-0.054). The widely used plateau dose response model based estimation showed significantly lower SC risk associated with fIMRT technique compared to both wedge field techniques (fIMRT vs EDW p-0.013, fIMRT vs PW p-0.04). The full dose response model showed a non-significant difference between all three techniques in the view of second CLB cancer. Finally the bell shaped model predicted interestingly that PW is associated with significantly higher risk compared to both fIMRT and EDW techniques (fIMRT vs PW p-0.0003, EDW vs PW p-0.0032). Conclusion: In conclusion, the SC risk estimations of the CLB revealed that there is a clear relation between risk associated with wedge field and fIMRT technique depending on the choice of model selected for risk comparison.

• Radiation Oncology Journal
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• 제34권3호
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• pp.168-176
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• 2016

Purpose: The purpose of current study is to evaluate the response of the patients with portal vein thrombosis (PVT) or hepatic vein thrombosis (HVT) in hepatocellular carcinoma (HCC) treated with three-dimensional conformal radiation therapy (3D-CRT). In addition, survival of patients and potential prognostic factors of the survival was evaluated. Materials and Methods: Forty-seven patients with PVT or HVT in HCC, referred to our department for radiotherapy, were retrospectively reviewed. For 3D-CRT plans, a gross tumor volume (GTV) was defined as a hypodense filling defect area in the portal vein (PV) or hepatic vein (HV). Survival of patients, and response to radiation therapy (RT) were analyzed. Potential prognostic factors for survival and response to RT were evaluated. Results: The median survival time of 47 patients was 8 months, with 1-year survival rate of 15% and response rate of 40%. Changes in Child-Pugh score, response to RT, Eastern cooperative oncology group performance status (ECOG PS), hepatitis C antibody (HCVAb) positivity, and additional post RT treatment were statistically significant prognostic factors for survival in univariate analysis (p = 0.000, p = 0.018, p = 0.000, p = 0.013, and p = 0.047, respectively). Of these factors, changes in Child-Pugh score, and response to RT were significant for patients' prognosis in multivariate analysis (p = 0.001 and p = 0.035, respectively). Conclusion: RT could constitute a reasonable treatment option for patients with PVT or HVT in HCC with acceptable toxicity. Changes in Child-Pugh score, and response to RT were statistically significant factors of survival of patients.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7401-7405
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• 2014

Background: Postoperative chemoradiotherapy is accepted as standard treatment for stage IB-IV, M0 gastric cancer. Radiotherapy (RT) planning of gastric cancer is important because of the low radiation tolerance of surrounding critical organs. The purpose of this study was to compare the dosimetric aspects of 2-dimensional (2D) and 3-dimensional (3D) treatment plans, with the twin aims of evaluating the adequacy of 2D planning fields on coverage of planning target volume (PTV) and 3D conformal plans for both covering PTV and reducing the normal tissue doses. Materials and Methods: Thirty-six patients with stage II-IV gastric adenocarcinoma were treated with adjuvant chemoradiotherapy using 3DRT. For each patient, a second 2D treatment plan was generated. The two techniques were compared for target volume coverage and dose to normal tissues using dose volume histogram (DVH) analysis. Results: 3DRT provides more adequate coverage of the target volume. Comparative DVHs for the left kidney and spinal cord demonstrate lower radiation doses with the 3D technique. Conclusions: 3DRT produced better dose distributions and reduced radiation doses to left kidney and spinal cord compared to the 2D technique. For this reason it can be predicted that 3DRT will result in better tumor control and less normal tissue complications.

• 한국방사선학회논문지
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• 제7권6호
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• pp.409-414
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• 2013

본 연구에서는 전립샘암 환자에게 방사선 치료법인 3차원 입체조형법과 세기조절치료법을 각각 적용 할 경우 선량분포의 차이를 관찰하여 치료기법의 우수성을 평가하고자 하였다. 실험대상자 10명의 컴퓨터 단층 모의치료영상을 얻어 종양학과 전문의가 종양용적 및 정상장기를 구분하고 종양용적에 흡수선량을 80 Gy로 설정한 후 각각 다른 치료계획을 수립하였다. 그 결과 선량분포윤곽은 세기조절치료법이 우수 하였고 종양조직의 흡수선량은 세기조절치료법이 처방선량에 근접(100.2%)하였으며 정상조직 흡수율(방광, 직장, 소장, 좌 우 대퇴골두) 또한 우수하였다. 즉, 전립샘암의 방사선 치료시 세기조절방사선치료가 입체조형치료법보다 선량적인 면에서 양호한 것으로 분석되었다.

• Radiation Oncology Journal
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• 제24권2호
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• pp.81-87
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• 2006

목적: 3차원 입체조형 방사선치료를 시행 받은 코인두암 환자에서 설문조사를 이용하여 구강건조증의 시간경과에 따른 변화양상을 분석하고자 하였다. 대상 및 방법: 2000년 12월부터 2005년 8월까지 코인두암 환자에서 3차원 입체조형 방사선치료를 적용한 환자 51명을 설문조사의 대상으로 하였다. 3차원 입체조형 방사선치료는 3회의 컴퓨터 단층촬영(Computed tomography: CT)모의치료를 이용한 3단계 치료계획을 시행하는 순차적 조사영역 축소방법을 사용하였고, 총 선량 72 Gy를 목표로 하였다. 구강건조증은 일상생활에서 중요한 4가지 항목으로 구성된 설문점수(xerostomia questionnaire score: XQS)를 측정하였으며, 방사선치료 후 경과시간, 성별, 나이, 병기, 항암치료의 병용유무, 그리고 이하선의 평균 방사선량 등에 따르는 차이를 분석하였다. 결과: 항암치료를 병용한 환자가 40명, 방사선치료 단독환자가 11명이었으며, 방사선치료 후 설문조사까지 경과 시간은 중앙값 20 ($1{\sim}58$)개월이었다. 전체 환자에서 XQS 점수의 평균은 8.4점(최하 6점, 최고 14점, 표준편차 1.9)이었다. 방사선치료 후 경과시간에 따라 XQS 점수는 통계적으로 유의하게 감소하는 경향을 보였다($X^2$=-0.484, p<0.05). 성별, 나이, 병기에 따라 XQS 점수의 차이는 없었고, 항암치료를 병용한 환자에서 방사선치료 단돈 환자와 비교하여 XQS 점수가 유의하게 높았다(p=0.001). 전체 이하선의 평균선량은 35 Gy 미만에서 35 Gy 이상보다 XQS 점수가 통계적으로 유의하게 낮았다(p=0.05). 결론: 코인두암 환자에서 3차원 입체조형 방사선치료 후 측정한 XQS 점수는 방사선치료 후 시간경과에 따라 감소하는 양상을 보였으며, 항암치료를 병용함으로써 더 악화되는 경향이 있고, 이하선에 조사되는 평균선량을 35Gy 미만으로 하는 것이 구강건조증 증상완화에 도움이 될 수 있겠다.