ความเป็นไปได้ในการเพิ่มระยะห่างของหัวใจกับผนังทรวงอกและความสัมพันธ์ของแอมพลิจูดการหายใจกับระยะห่างของหัวใจกับผนังทรวงอกในการฉายรังสีมะเร็งเต้านมซ้ายโดยการใช้อุปกรณ์กดหน้าท้อง

Abstract

In radiotherapy for left sided breast cancer, the radiation dose of heart and left anterior descending artery (LAD) are major concerns. This study investigated the use of the Abdominal Compression (AC) and moderate deep inspiration breath hold technique (mDIBH+AC) in left side breast cancer radiotherapy. The primary objective was to evaluate an increasing of the heart to chest wall distance by using mDIBH+AC along with the relationship between respiratory amplitude and the heart to chest wall distance. The secondary objective was to assess the radiation doses delivered to the heart and LAD and times of deep inspiration breath hold. Eleven patients with left sided breast cancer were enrolled in our study. CT simulation and record respiratory signal with Anzai Belt system in 3 data sets: Free breath (FB), Deep inspiration breath hold (DIBH) and moderate deep inspiration breath hold with abdominal compression (mDIBH+AC) were done in each patient. Respiratory signal was analyzed with Fourier Transform technique. The time of breath hold was compared between DIBH and mDIBH+AC. Then, the heart to chest wall distance and radiation doses of the heart and LAD from the radiation treatment plans were evaluated. The average heart to chest wall distances were 0.46, 0.99 and 0.97 cm. for FB, DIBH and mDIBH+AC, respectively. We found a moderate positive correlation between respiratory amplitude and the heart to chest wall distance with a statistically significant Pearson correlation coefficient 0.623. Using mDIBH+AC reduced Dmean, Dmax,V20Gy and V30Gy of the heart by 6.64%, 4.23%, 31.17% and 53.33%, respectively and Dmean, Dmax and D2% on LAD by 18.39 %, 16.31% and 14.39%, respectively when compared with FB. Besides, most patients (63.6%) revealed a longer time of breath hold than DIBH. From our study, the AC is effective to increase the heart to chest wall distance including reducing radiation dose to the heart and LAD compared with FB. Moreover, the advantage of AC is improving of reproducibility and stability of mDIBH.