早期左側乳癌放射治療自創右側躺姿勢之經驗分享

The experience of homemade right decubitus position for early-stage left breast cancer treatment

蕭琇文(Hsiu-Wen Hsiao) ； 張哲銘(Che-Ming Chang) ； 王天佑(Tien-Yu Wang) ； 陳鈺蟬(Yu-Chan Chen) ； 黃昭明(Chao-Ming Huang) ； 莊和達(Ho-Da Chuang) ； 林錦雄(Chin-Hsiung Lin) ； 康淑娌(Shu-Li Kang) ； 陳鳳鴒(Fong-Lin Chen) ； 吳立夫(Li-Fu Wu) ； 蔡玉真(Yu-Chen Tsai)

《放射治療與腫瘤學》 25卷2期 (2018/06) Pp. 75-86

https://doi.org/10.6316/TRO.201806_25(2)0002

摘要

目的：比較自創右側躺姿勢與一般傳統治療平躺姿勢之心臟和肺臟劑量，來評估自創固定裝置之右側躺姿勢，對於早期左側乳癌放射治療病人之效益。材料與方法：本研究集結二十一位和信治癌中心醫院早期左側乳癌病人的資訊結果，依據腫瘤床的部位分類，可分為8個上內側（UIQ）、5個上外側（UOQ）、4個中心部位（Center）、2個下內側（LIQ）與2個下外側（LOQ）。每位病人皆收取右側躺姿勢與平躺姿勢之兩組影像。對於右側躺姿勢，使用自製二十度傾斜之發泡劑模具（alpha cradle）及自製腳部固定設備；對於平躺姿勢，使用一般治療之模具，病人雙手皆上舉，頭轉向非治療之對側方向。在相同之計畫靶體積包覆程度下，經由(1)乳房體積(2)照野內最大心臟距離（MHD）；(3)照野內最大心臟長度（MHL）；(4)照野中心肺距離（CLD）；(5)腫瘤區域等方面，探討心臟劑量（V_5, V_(10), V_(25)及平均劑量）與肺部劑量（V_5, V_(10), V_(20)及平均劑量）之差異，評估自創右側躺姿勢相較於一般傳統平躺姿勢之優缺點。結果：心臟劑量與乳房體積沒有相關聯性；但隨著右側躺姿勢，MHD、MHL減少，心臟劑量皆有減少之現象，平均劑量最大可減少約48.2%±14.0%之比率，V_5可減少7.6%±6.0%，V_(10)可減少4.2%±2.4%，V_(25)可減少1.9%±1.3%。然而，並非所有之右側躺姿勢相較於平躺姿勢，其CLD值皆會減小，故右側躺姿勢肺部劑量不一定會減少。腫瘤區域在下內側（LIQ）部位，隨右側躺姿勢，心臟平均劑量與V_5、V_(10)、V_(25)都能更有效地減少；上側部位（UIQ, UOQ）心臟劑量之V_(10)、V_(25)較低；腫瘤在中央區域位置（Central）之病人，其右側躺姿勢肺部劑量反而較平躺姿勢增加，但增加幅度不多，平均劑量增加16.4厘格雷（cGy），體積-劑量因子增加在1%範圍內。結論：本研究自製之右側躺姿勢能有效降低心臟之劑量，現今已普遍使用於和信治癌中心醫院，早期左側乳癌病人之術後全乳放射治療。

關鍵字

自創右側躺姿勢 ； 照野內最大心臟距離 ； 照野內最大心臟長度 ； 照野中心肺距離

並列摘要

Purpose: To evaluate the effectiveness of homemade immobilization equipment of right decubitus position for left breast cancer treatment by comparing the heart and lung doses of right decubitus position with those of supine position. Materials and Methods: Twenty-one early-stage left breast cancer patients of Koo Foundation Sun Yat-Sen Cancer Center (KFSYSCC) were collected in this study. Based on the location of the tumor bed, 8 Upper Inner Quadrant (UIQ), 5 Upper Outer Quadrant (UOQ), 4 Central, 2 Lower Inner Quadrant (LIQ) and 2 Lower Outer Quadrant (LOQ) sites were classified. Two sets of CT images (right decubitus and supine position) were acquired. Homemade alpha-cradle with 20 degrees tilt and homemade immobilization device of legs were used for the right decubitus position while the routine treatment position with both arms raised and head turned to the opposite side of treatment side was set for the supine position. Heart dose (V_5, V_(10), V_(25) and mean dose) and lung dose (V_5, V_(10), V_(20) and mean dose) of right decubitus position were compared with those of supine position by using parameters of breast volume, Maximum Heart Distance (MHD), Maximum Heart Length (MHL) and Central Lung Distance (CLD) in the same condition of Planning Target Volume (PTV) coverage. Results: There was no correlation between breast volume and heart dose. Heart dose could be decreased by using right decubitus position because of decreased MHD and MHL. Under this condition, the maximum decreased mean heart dose, V_5, V_(10) and V_(25) were 48.2% ± 14.0%, 7.6% ± 6.0%, 4.2% ± 2.4% and 1.9% ± 1.3%, respectively. CLD was not always decreased in the right decubitus position compared to the supine position. Therefore, lung dose was not always decreased by using the right decubitus position. Heart dose was decreased effectively for tumor in the LIQ. Heart dose for tumor in the UIQ or UOQ was lower than that in other position. For tumor in the Central position, lung dose was a little bit increased by using the right decubitus position. The mean dose of lung was increased 16.4 cGy and the Dose-Volume value was increased within 1%. Conclusion: Heart dose can be decreased effectively by using right decubitus position. Homemade immobilization equipment for right decubitus position is now routinely used for early-stage left breast cancer treatment at KFSYSCC.

並列關鍵字

Homemade immobilization device for right decubitus position ； Maximum Heart Distance (MHD) ； Maximum Heart Length (MHL) ； Central Lung Distance (CLD)