비소세포성 폐암에서 호흡동기방사선치료 적용 환자군의 선택을 위한 예측인자들의 분석 = The Analysis of Predictive Factors for the Identification of Patients Who Could Benefit from Respiratory-Gated Radiotherapy in Non-Small Cell Lung Cancer

국문 초록 (Abstract)

목 적: 비소세포성 폐암에서 호흡동기방사선치료의 이득을 평가하고 이런 치료법의 적용으로 이득이 있을 환자들을 선택하기 위한 예측인자들을 선정하기 위하여 방사선치료를 위해 시행되었던 4-dimensional computed tomography (4DCT) 영상들을 후향적으로 분석하였다. 대상 및 방법: 15명의 병기 1∼3기 비소세포성 폐암 환자들에서 3 종류의 다른 계획용표적체적(PTV)을 사용하여 치료계획들이 수립되었다. 즉 PTVroutine은 동기창(gating window)의 중심에 해당되는 단일 bin의 육안적종양체적 (GTV)에 통상적인 균일 margin을 적용해 구성하였고 환자 특이적인 PTVall phases는 호흡주기 내 모든 6 bins의 복합 GTV로부터 구성되었다. 그리고 호흡동기치료에 사용된 PTVgating은 호기말단(end-exhalation)에서 3 연속적인 bins의 복합 GTV로부터 구성되었다. 결 과: PTVroutine에 비해 PTVall phases는 43.2%의 PTV 감소율을 나타냈고, PTVgating은 PTVall phases와 비교해서 9.5%의 추가적인 PTV 감소율을 보였다. PTVroutine과 비교해서 PTVall phases와 PTVgating의 사용은 평균폐선량(MLD)을 각각 18.1%와 21.6% 감소시켰고 V20은 각각 18.2%와 22.0% 감소되었다. 종양 움직임과 용적 분석들을 통해 선택된 3D 움직임벡터, 호흡동기로 인한 3D 움직임의 감소크기와 PTV 감소율, 그리고 두 극단의 호흡단계 GTV들 간에 서로 중복되는 용적의 비율 같은 예측인자들은 호흡동기로 인한 추가적인 MLD, V20 감소율들과 유의한상관성을 보였다. 결 론: 4DCT를 이용한 환자 특이적 PTV의 사용과 비교해서 호흡동기로 인한 추가적인 이득은 크지 않았으나, 이러한 이득은 예측인자들에 따라 분명한 상관성과 차이를 보였다. 이런 예측인자들은 호흡동기방사선치료에 적합한환자들을 선택하기 위해 유용할 것이다.

다국어 초록 (Multilingual Abstract)

Purpose: 4DCT scans performed for radiotherapy were retrospectively analyzed to assess the possible benefits
of respiratory gating in non-small cell lung cancer (NSCLC) and established the predictive factors for identifying patients who could benefit from this approach. Materials and Methods: Three treatment planning was performed for 15 patients with stage I∼III NSCLC using different planning target volumes (PTVs) as follows: 1) PTVroutine, derived from the addition of conventional uniform margins to gross tumor volume (GTV) of a single bin, 2) PTVall phases (patient-specific PTV), derived from the composite GTV of all 6 bins of the 4DCT, and 3) PTVgating, derived from the composite GTV of 3 consecutive bins at end-exhalation. Results: The reductions in PTV were 43.2% and 9.5%, respectively, for the PTVall phases vs. PTVroutine and PTVgating vs. PTVall phases. Compared to PTVroutine, the use of PTVall phases and PTVgating reduced the mean lung dose (MLD) by 18.1% and 21.6%, and V20 by 18.2% and 22.0%, respectively. Significant correlations were seen between certain predictive factors selected from the tumor mobility and volume analysis, such as the 3D mobility vector, the reduction in 3D mobility and PTV with gating, and the ratio of GTV overlap between 2 extreme bins and additional reductions in both MLD and V20 with gating. Conclusion: The additional benefits with gating compared to the use of patient-specific PTV were modest; however, there were distinct correlations and differences according to the predictive factors. Therefore, these predictive factors might be useful for identifying patients who could benefit from respiratory-gated radiotherapy.

목차 (Table of Contents)

• 서 론
• 대상 및 방법
• 결 과
• 고안 및 결론

참고문헌 (Reference)

• 1 신은혁, "호흡연습장치를 적용한 호흡교정법의 영향 평가" 대한방사선종양학회 26 (26): 181-188, 2008
• 2 Underberg RW, "Use of maximum intensity projections (MIP) for target volume generation in 4DCT scans for lung cancer" 63 : 253-260, 2005
• 3 van Sornsen de Koste JR, "Tumor location cannot predict the mobility of lung tumors: a 3D analysis of data generated from multiple CT scans" 56 : 348-354, 2003
• 4 Keall PJ, "The management of respiratory motion in radiation oncology report of AAPM Task Group 76" 33 : 3874-3900, 2006
• 5 Onimaru R, "The effect of tumor location and respiratory function on tumor movement estimated by real-time tracking radiotherapy (RTRT) system" 63 : 164-169, 2005
• 6 Jiang SB, "Technical aspects of image-guided respirationgated radiation therapy" 31 : 141-151, 2006
• 7 Li XA, "Technical and dosimetric aspects of respiratory gating using a pressure-sensor motion monitoring system" 33 : 145-154, 2006
• 8 Stevens CW, "Respiratory-driven lung tumor motion is independent of tumor size, tumor location, and pulmonary function" 51 : 62-68, 2001
• 9 Jiang SB, "Radiotherapy of mobile tumors" 16 : 239-248, 2006
• 10 Seppenwoolde Y, "Precise and real-time measurement of 3D tumor motion in lung due to breathing and heartbeat, measured during radiotherapy" 53 : 822-834, 2002
• 11 Salazar OM, "Once-weekly, high-dose stereotactic body radiotherapy for lung cancer: 6-year analysis of 60 early-stage, 42 locally advanced, and 7 metastatic lung cancers" 72 : 707-715, 2008
• 12 Guckenberger M, "Influence of retrospective sorting on image quality in respiratory correlated computed tomography" 85 : 223-231, 2007
• 13 Underberg RW, "Fourdimensional CT scans for treatment planning in stereotactic radiotherapy for stage I lung cancer" 60 : 1283-1290, 2004
• 14 Rietzel E, "Four-dimensional computed tomography: image formation and clinical protocol" 32 : 874-889, 2005
• 15 Allen AM, "Evaluation of the influence of breathing on the movement and modeling of lung tumors" 58 : 1251-1257, 2004
• 16 Bortfeld T, "Effects of motion on the total dose distribution" 14 : 41-51, 2004
• 17 van Sornsen de Koste JR, "Dosimetric consequences of tumor mobility in radiotherapy of stage I non-small cell lung cancer: an analysis of data generated using 'slow' CT scans" 61 : 93-99, 2001
• 18 Rietzel E, "Design of 4D treatment planning target volumes" 66 : 287-295, 2006
• 19 Mageras GS, "Deep inspiration breath hold and respiratory gating strategies for reducing organ motion in radiation treatment" 14 : 65-75, 2004
• 20 Starkschall G, "Correlation of gross tumor volume excursion with potential benefits of respiratory gating" 60 : 1291-1297, 2004
• 21 Hara R, "Clinical outcomes of single-fraction stereotactic radiation therapy of lung tumors" 106 : 1347-1352, 2006
• 22 Graham MV, "Clinical dose-volume histogram analysis for pneumonitis after 3D treatment for non-small cell lung cancer (NSCLC)" 45 : 323-329, 1999
• 23 Underberg RW, "Benefit of respiration-gated stereotactic radiotherapy for stage I lung cancer: an analysis of 4DCT datasets" 62 : 554-560, 2005
• 24 George R, "Audio-visual biofeedback for respiratory-gated radiotherapy: impact of audio instruction and audio-visual biofeedback on respiratory-gated radiotherapy" 65 : 924-933, 2006
• 25 Liu HH, "Assessing respiration-induced tumor motion and internal target volume using four-dimensional computed tomography for radiotherapy of lung cancer" 68 : 531-540, 2007
• 26 Wu J, "An evaluation of planning techniques for stereotactic body radiation therapy in lung tumors" 87 : 35-43, 2008
• 27 Kleshneva T, "An algorithm for automatic determination of the respiratory phases in fourdimensional computed tomography" 51 : N269-276, 2006
• 28 Burnett SS, "A study of tumor motion management in the conformal radiotherapy of lung cancer" 86 : 77-85, 2008
• 29 Bradley J, "A review of radiation dose escalation trials for non-small cell lung cancer within the Radiation Therapy Oncology Group" 32 (32): S111-S113, 2005
• 30 Underberg RW, "A dosimetric analysis of respiration-gated radiotherapy in patients with stage III lung cancer" 1 : 8-, 2006
• 31 Slotman BJ, "4D imaging for target definition in stereotactic radiotherapy for lung cancer" 45 : 966-972, 2006
• 32 Keall P, "4-dimensional computed tomography imaging and treatment planning" 14 : 81-90, 2004