INTERRUPTED DEEP INSPIRATION WITH RESPIRATORY GATING (IDIRG): A NOVEL RADIOTHERAPY TECHNIQUE DESIGNED FOR LEFT BREAST CANCER PATIENTS NEEDING NODAL IRRADIATION AND NOT TOLERATING DEEP INSPIRATION BREATH HOLD (DIBH)

間斷性深吸氣搭配呼吸調控：治療需要淋巴結照射但不能配合深吸氣閉氣法的左側乳癌病患之放射治療新方法

蔡有倫(Yu-Lun Tsai) ； 游佩潔(Pei-Chieh Yu) ； 雷德(Louis Tak Lui) ； 蕭世禎(Su-Zun Shaw) ； 吳錦榕(Ching-Jung Wu)

《放射治療與腫瘤學》 23卷1期 (2016/03) Pp. 21-29

https://doi.org/10.6316/TRO/201623(1)21

摘要

目的：評估我們依據深吸氣閉氣法，所修改設計出的放射治療新方法--間斷性深吸氣搭配呼吸調控，比起傳統自由呼吸法，是否能減少需要淋巴結照射，但不能配合深吸氣閉氣法的左側乳癌病患的左側肺臟和心臟劑量。材料與方法：總共十二位術後需要淋巴結照射的左側乳癌病患被評估，其中五位接受間斷性深吸氣搭配呼吸調控法、七位使用傳統自由呼吸法。間斷性深吸氣搭配呼吸調控法最不同的地方在於電腦斷層模擬定位，包括使用瓦里安即時位置管理呼吸同步追蹤調控系統，監測病人所製造出連續且間斷的深吸氣，以及使用軸向電腦斷層而非一般常用的螺旋電腦斷層。目標繪畫包 括左側全乳、左側胸壁、局部淋巴結可能包含內乳淋巴結。治療計畫使用弧形調控放射計畫製作。結果：比較間斷性深吸氣搭配呼吸調控法和傳統自由呼吸法時，目標體績（855.85 毫升比836.83毫升，P值0.740）、目標包覆率（97.41%比96.99%，P值0.728）和最高劑量區（113.33%比114.42%，P值0.128）沒有統計顯著差異。至於左側肺臟和心臟的監測終點，間斷性深吸氣搭配呼吸調控法有顯著較大的總肺體積（3465.33毫升比 2065.14毫升，P值小於0.001）造成較少卻沒有達到統計顯著的左肺劑量（20 Gy體積：27.92% 比30.11%，P值0.156；10 Gy體積：47.42%比51.08%，P值0.199），以及顯著減少的心臟劑量包括全心臟（25 Gy體積：4.77% 比 17.09%，P值0.012；平均劑量：10.78 Gy比15.71 Gy，P值0.016）和左冠狀動脈前降枝（前百分之十劑量：31.80 Gy比50.41 Gy，P值0.004；平均劑量：24.46 Gy比 43.64 Gy，P值小於0.001）。結論：間斷性深吸氣搭配呼吸調控法，為我們為需要淋巴結照射，但不能配合深吸氣閉氣法的左側乳癌病患所設計出的放射治療新方法，比起傳統自由呼吸法，它可以提供擴張的肺臟體積，進而減少和長期心因性死亡相應對的心臟劑量。

關鍵字

乳癌 ； 放射治療 ； 間斷性深吸氣搭配呼吸調控

並列摘要

Purpose : To assess if the novel radiotherapy technique named interrupted deep inspiration with respiratory gating (IDIRG) modified from deep inspiration breath hold (DIBH) can reduce left pulmonary and cardiac dose compared to traditional free breath method (FB) in left breast cancer patients needing nodal irradiation and not tolerating DIBH. Materials and Methods : Twelve postoperative left breast cancer patients needing nodal irradiation were evaluated. Five used IDIRG technique and seven used the traditional FB method. The IDIRG method differs most from FB technique during the CT-simulation phase. Patients were asked to take interrupted deep inspiration breaths monitored by the Varian Real-time Position Management Respiratory Gating System (RPM). Axial CT was applied instead of routinely used Helical CT. Target delineation included the whole left breast, left chest wall, and regional lymph nodes with or without internal mamillary nodes. Treatment planning was made using volumetric modulated arc technique. Result : There was no statistically significant difference in IDIRG and FB in respect to target volume (855.85 ml vs 836.83 ml, p= 0.740), target coverage (97.41% vs 96.99%, p =0.728), and hotspot (113.33% vs 114.42%, p= 0.128). In terms of left pulmonary and cardiac endpoints, IDIRG showed significantly larger total lung volume (3465.33ml vs 2065.14ml, p ＜0.001) which translated into a lesser, but not statistically significant, left pulmonary dose (V20: 27.92% vs 30.11%, p= 0.156; V10: 47.42% vs 51.08%, p= 0.199), and significant reduction in cardiac dose including heart (V25: 4.77% vs 17.09%, p= 0.012; mean dose: 10.78 Gy vs 15.71 Gy, p= 0.016) and left anterior descending coronary artery (LAD) (D10: 31.80 Gy vs 50.41 Gy, p= 0.004; mean dose: 24.46 Gy vs 43.64 Gy, p＜ 0.001). Conclusions : IDIRG, a novel radiotherapy technique designed for patients with left breast cancer needing nodal irradiation and not tolerating DIBH, can provide expanded lung volume to reduce cardiac dose, corresponding to lower long-term cardiac mortality compared to the traditional FB method.

並列關鍵字

Breast cancer ； Radiotherapy ； Interrupted deep inspiration with respiratory gating