Ajani Abdallah A, Qureshi Muhammad M, Kovalchuk Nataliya, Orlina Lawrence, Sakai Osamu, Truong Minh Tam
Department of Radiation Oncology, Boston Medical Center and Boston University School of Medicine, Boston, MA, USA.
Med Dosim. 2013 Autumn;38(3):238-42. doi: 10.1016/j.meddos.2013.01.007. Epub 2013 Apr 1.
To evaluate the change in volume and movement of the parotid gland measured by serial contrast-enhanced computed tomography scans in patients with head and neck cancer treated with parotid-sparing intensity-modulated radiotherapy (IMRT). A prospective study was performed on 13 patients with head and neck cancer undergoing dose-painted IMRT to 69.96Gy in 33 fractions. Serial computed tomography scans were performed at baseline, weeks 2, 4, and 6 of radiotherapy (RT), and at 6 weeks post-RT. The parotid volume was contoured at each scan, and the movement of the medial and lateral borders was measured. The patient's body weight was recorded at each corresponding week during RT. Regression analyses were performed to ascertain the rate of change during treatment as a percent change per fraction in parotid volume and distance relative to baseline. The mean parotid volume decreased by 37.3% from baseline to week 6 of RT. The overall rate of change in parotid volume during RT was-1.30% per fraction (-1.67% and-0.91% per fraction in≥31Gy and<31Gy mean planned parotid dose groups, respectively, p = 0.0004). The movement of parotid borders was greater in the≥31Gy mean parotid dose group compared with the<31Gy group (0.22% per fraction and 0.14% per fraction for the lateral border and 0.19% per fraction and 0.06% per fraction for the medial border, respectively). The median change in body weight was-7.4% (range, 0.75% to-17.5%) during RT. A positive correlation was noted between change in body weight and parotid volume during the course of RT (Spearman correlation coefficient, r = 0.66, p<0.01). Head and neck IMRT results in a volume loss of the parotid gland, which is related to the planned parotid dose, and the patient's weight loss during RT.
为了评估接受保留腮腺调强放疗（IMRT）的头颈癌患者中，通过系列增强CT扫描测量腮腺的体积和移动变化情况。对13例接受剂量勾画IMRT、分33次给予69.96Gy照射的头颈癌患者进行了一项前瞻性研究。在放疗（RT）的基线、第2周、第4周和第6周以及放疗后6周进行系列CT扫描。每次扫描时勾画腮腺体积，并测量内侧和外侧边界的移动情况。在放疗期间的每个相应周记录患者体重。进行回归分析以确定治疗期间腮腺体积和距离相对于基线的变化率，以每分次变化百分比表示。从基线到放疗第6周，腮腺平均体积减少了37.3%。放疗期间腮腺体积的总体变化率为每分次-1.30%（平均计划腮腺剂量≥31Gy和＜31Gy组分别为每分次-1.67%和-0.91%，p = 0.0004）。平均腮腺剂量≥31Gy组腮腺边界的移动比＜31Gy组更大（外侧边界分别为每分次0.22%和0.14%，内侧边界分别为每分次0.19%和0.06%）。放疗期间体重的中位数变化为-7.4%（范围为0.75%至-17.5%）。放疗过程中体重变化与腮腺体积之间存在正相关（Spearman相关系数，r = 0.66，p＜0.01）。头颈IMRT导致腮腺体积丢失，这与计划的腮腺剂量以及患者放疗期间的体重减轻有关。
