• Radiation Oncology Journal
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• 제20권1호
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• pp.68-72
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• 2002

최근 들어 새로운 방사선치료법인 강도변조방사선치료가 많은 종류의 종양치료에 적용되어 치료에 따른 부작용을 줄이고 치료율을 향상시키려는 노력들이 이루어지고 있다. 특히 전립선암에서 강도변조방사선치료법을 적용하여 삼차원입체조형치료에 비해 향상된 선량분포와 이로 인한 주위 정상조직의 방사선량을 줄임으로써 더욱 많은 양의 방사선을 전립선에 투여할 수 있고 이로 인하여 치료율의 상승을 기대할 수 있게 되었다. 저자들은 강도변조방사선치료를 전립선암에 적용하였기에 이에 대한 문헌고찰과 함께 치료과정을 보고하고자 한다.

• 한국의학물리학회지:의학물리
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• 제11권1호
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• pp.85-90
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• 2000

방사선치료에서 치료의 효과는 총선량, 치료회수, 1회 조사선량 등에 의해서 결정된다. 선량강도조절법을 사용하여 방사선치료를 행할 때 치료회수나 1회 조사선량을 고려하여 총선량에 미치는 효과를 살펴보고자 한다. 방사선치료의 목적은 암조직에는 충분한 선량을 조사하면서 주위 정상 조직에는 최소한의 선량을 조사되게 하여 치료성적의 향상으로 암환자의 생존율과 삶의 질을 높이는데 목적이 있다. 이러한 문제를 해결하기 위하여 많은 연구자들이 여러 가지 방법으로 해결하고자 노력한 결과 CT의 영상을 치료계획에 이용할 수 있게 되어 three dimensional conformal radiation therapy(3DCRT)를 개발하였다. 선량강도조절법을 시행하여 총선량을 75, 80, 85, 90Gy를 조사할 때, 처음부터 선량강도조절법을 사용하여 치료하는 경우와 일차적으로 45Gy를 조사하고 boost를 조사할 때 나머지 선량을 선량강도조절 법으로 사용하는 것을 TDF 환산법을 사용하여 비교하였다. 처음부터 선량강도조절법으로 치료할 경우에는 총선량에서 약 12.5 - 15 Gy 정도 감해서 조사하여야 하는 것으로 나타났다.

• Radiation Oncology Journal
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• 제35권1호
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• pp.32-38
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• 2017

Purpose: Several accelerated partial breast radiation (APBR) techniques have been investigated in patients with early-stage breast cancer (BC); however, the optimal treatment delivery techniques remain unclear. We evaluated the feasibility and toxicity of APBR delivered using intensity-modulated radiation therapy (IMRT) in elderly patients with stage I BC, using a novel fractionation schedule. Materials and Methods: Forty-two patients aged ${\geq}65$ years, with stage I BC who underwent breast conserving surgery were enrolled in a phase I/II study evaluating APBR using IMRT. Forty eligible patients received 40 Gy in 4 Gy daily fractions. Patients were assessed for treatment related toxicities, and cosmesis, before APBR, during, and after completion of the treatment. Results: The median age was 73 years, median tumor size 0.8 cm and the median follow-up was 54 months. The 5-year locoregional control was 97.5% and overall survival 90%. Erythema and skin pigmentation was the most common acute adverse event, reported by 27 patients (69%). Twenty-six patients (65%) reported mild pain, rated 1-4/10. This improved at last follow-up to only 2 (15%). Overall the patient and physician reported worst late toxicities were lower than the baseline and at last follow-up, patients and physicians rated cosmesis as excellent/good in 93% and 86 %, respectively. Conclusion: In this prospective trial, we observed an excellent rate of tumor control with daily APBR. The acceptable toxicity profile and cosmetic results of this study support the use of IMRT planned APBR with daily schedule in elderly patients with early stage BC.

• Radiation Oncology Journal
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• 제36권4호
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• pp.276-284
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• 2018

Purpose: Traditionally, three-dimensional conformal radiation therapy (3D-CRT) is used for neoadjuvant chemoradiation in locally advanced rectal cancer. Intensity-modulated radiation therapy (IMRT) was later developed for more conformal dose distribution, with the potential for reduced toxicity across many disease sites. We sought to use the National Cancer Database (NCDB) to examine trends and predictors for IMRT use in rectal cancer. Materials and Methods: We queried the NCDB from 2004 to 2015 for patients with rectal adenocarcinoma treated with neoadjuvant concurrent chemoradiation to standard doses followed by surgical resection. Odds ratios were used to determine predictors of IMRT use. Univariable and multivariable Cox regressions were used to determine potential predictors of overall survival (OS). Propensity matching was used to account for any indication bias. Results: Among 21,490 eligible patients, 3,131 were treated with IMRT. IMRT use increased from 1% in 2004 to 22% in 2014. Predictors for IMRT use included increased N stage, higher comorbidity score, more recent year, treatment at an academic facility, increased income, and higher educational level. On propensity-adjusted, multivariable analysis, male gender, increased distance to facility, higher comorbidity score, IMRT technique, government insurance, African-American race, and non-metro location were predictive of worse OS. Of note, the complete response rate at time of surgery was 28% with non-IMRT and 21% with IMRT. Conclusion: IMRT use has steadily increased in the treatment of rectal cancer, but still remains only a fraction of overall treatment technique, more often reserved for higher disease burden.

• Radiation Oncology Journal
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• 제31권2호
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• pp.104-110
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• 2013

Purpose: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Materials and Methods: Sixteen patients were studied. Prostate ($PTV_P$), right pelvic ($PTV_{RtLN}$) and left pelvic lymph nodes ($PTV_{LtLN}$), and organs at risk were contoured. $PTV_P$, $PTV_{RtLN}$, and $PTV_{LtLN}$ received 50.40 Gy followed by a boost to $PTV_B$ of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose ($D_{MEAN}$) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Results: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The $D_{MEAN}$ of bladder was within 2% of each other. The rectum $D_{MEAN}$ in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). Conclusion: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

• 대한방사선치료학회지
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• 제28권2호
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• pp.123-130
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• 2016

목 적 : Computerized imaging reference systems 동적팬텀을이용한 cone-beamcomputed tomography(CBCT) 영상과 four-dimensionalcomputed tomography(4DCT) 영상의 체적을 비교분석 하고자 한다. 대상 및 방법 : 동적팬텀 내에 직경 1, 2, 3 cm 노드를 각각 삽입하고, CT simulator와 TruebeamSTx X-ray Imaging system을 이용하여 4DCT 영상과 CBCT 영상을 얻었다. 4DCT 영상은 maximum intensity projection(MIP), minimum intensity projection(MinIP), 그리고 average intensity projection(AVG)영상으로 재구성 하고 노드의 체적은 Eclipse system의 CT ranger tool로 CT number를 설정하여 측정하였다. 결 과 : CBCT를 기준으로 노드1, 2, 3 cm의 체적을 비교하였을 때 4DCT의 MIP는 0.54~2.33, 5.16~8.06, 9.03~20.11 ml, MinIP는 0.00~1.48, 0.00~8.47, 1.42~24.85 ml, AVG는 0.00~1.17, 0.00~2.19, 0.04~3.35 ml의 차이를 보였다. 결 론 : 노드의 체적을 비교한 결과 CBCT 영상은 4DCT의 AVG 영상과 유사한 것으로 확인되었다.

• 대한방사선치료학회지
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• 제2권1호
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• pp.31-40
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• 1987

In the case of designing a high dose rate remote controlled afterloading treatment room with existing hospital facilities. We must construct the effective protective barriers so as to reduce the primary and scattered radiation up to the maximum permissible dose level. It is difficult to reinforce the barrier thickness of the shielding requirements because of the limited space and the problem of the existing building structure at the surrounding area. Therefore we can reduce the intensity of primary radiation to the required degree at the location of interest with installing the appropriate I shaped Pb barriers between the radiation source and the shielding wall of the concrete. As a result, it was possible to reduce the intensity of the primary radiation below the M.P.D level by using additional Pb barriers instead of increasing thickness of concrete wall.

• 대한기계학회논문집B
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• 제30권9호
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• pp.891-897
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• 2006

The SRS method is applied to a turbulent flame with radiation/turbulence interaction to invert the temperature and concentration profile. The flame is conditioned as optically thin per each fluctuation length and the flame spectral intensity is measured for inversion. From inversion result, we find that SRS can successfully invert the coupled temperature/concentration fluctuation amplitudes. For two cases of experiments, inverted values are within approximately 1% over the full range of fluctuation amplitude. However, SRS cannot find the detailed local fluctuation parameters such as pattern and phase, etc. as far as they do not affect the resulting radiation intensity. Important available parameters are the mean temperature and the temperature fluctuation amplitude. The radiation/turbulence interaction effect is verified to play an important role in the radiation.

• Radiation Oncology Journal
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• 제36권4호
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• pp.254-264
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• 2018

This article reviewed new trends and controversial issues, including the intensification of chemotherapy and recent brachytherapy (BT) advances, and also reviewed recent consensuses from different societies on the management of locally advanced cervical cancer (LACC). Intensive chemotherapy during and after radiation therapy (RT) was not recommended as a standard treatment due to severe toxicities reported by several studies. The use of positron emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) for pelvic RT planning has increased the clinical utilization of intensity-modulated radiation therapy (IMRT) for the evaluation of pelvic lymph node metastasis and pelvic bone marrow. Recent RT techniques for LACC patients mainly aim to minimize toxicities by sparing the normal bladder and rectum tissues and shortening the overall treatment time by administering a simultaneous integrated boost for metastatic pelvic lymph node in pelvic IMRT followed by MRI-based image guided adaptive BT.

• Radiation Oncology Journal
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• 제30권3호
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• pp.146-151
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• 2012

Purpose: This treatment planning study was undertaken to evaluate the impact of beam angle configuration of intensity-modulated radiotherapy (IMRT) on the dose of the normal liver in hepatocellular carcinoma (HCC). Materials and Methods: The computed tomography datasets of 25 patients treated with IMRT for HCC were selected. Two IMRT plans using five beams were made in each patient; beams with equidistance of $72^{\circ}$ (Plan I), and beams with a $30^{\circ}$ angle of separation entering the body near the tumor (Plan II). Both plans were generated using the same constraints in each patient. Conformity index (CI), homogeneity index (HI), gamma index, mean dose of the normal liver (Dmean_NL), Dmean_NL difference between the two plans, and percentage normal liver volumes receiving at least 10, 20, and 30 Gy (V10, V20, and V30) were evaluated and compared. Results: Dmean_NL, V10, and V20 were significantly better for Plan II. The Dmean_NL was significantly lower for peripheral (p = 0.001) and central tumors (p = 0.034). Dmean_NL differences between the two plans increased in proportion to gross tumor volume to normal liver volume ratios (p = 0.002). CI, HI, and gamma indices were not significantly different for the two plans. Conclusion: The IMRT plan based on beams with narrow separations reduced the irradiated dose of the normal liver, which would allow radiation dose escalation for HCC.