Department of Radiation Oncology, Geneva University Hospital, Geneva, Switzerland.
Radiother Oncol. 2010 Mar;94(3):334-8. doi: 10.1016/j.radonc.2009.11.009. Epub 2009 Dec 18.
To evaluate the feasibility and dosimetric optimization potential of a unilateral two-field intensity-modulated radiotherapy (IMRT) technique in the curative treatment of lateralized tonsil cancer.
Six patients with lateralized tonsillar carcinoma were treated unilaterally with a two-field IMRT technique (oblique-anterior and oblique-posterior fields, with or without collimator and couch rotation). Alternative IMRT plans using seven non-opposed coplanar fields were compared with the two-field plans for each patient.
Planning target volume (PTV) coverage was excellent with the two-field technique, using a relatively low number of monitor units (MU) (median, 441; range, 309-550). Dose constraints were respected for all organs at risk (OAR). Mean doses to contralateral parotid and submandibular glands were 3.9 and 17.7 Gy, respectively. Seven-field IMRT provided similar PTV coverage, with statistically significant better dose homogeneity and conformality. However, the mean delivered dose to the contralateral parotid (3.9 vs. 9.0 Gy, p=0.001) as well as the mean number of MU (437 vs. 814, p=0.002) and consequently machine time were lower with two-field IMRT.
Unilateral two-field IMRT is a simple and feasible technique providing excellent tumor coverage and optimal OAR sparing while reducing the number of MU and treatment time.
评估单侧两野调强放疗（IMRT）技术在侧方扁桃体癌根治性治疗中的可行性和剂量优化潜力。
对 6 例侧方扁桃体癌患者采用两野 IMRT 技术（斜前野和斜后野，有或无准直器和治疗床旋转）进行单侧治疗。对每位患者的两野计划进行了与七野非对野共面野计划的比较。
两野技术的计划靶区（PTV）覆盖良好，使用相对较少的机器跳数（MU）（中位数 441；范围 309-550）。所有危及器官（OAR）的剂量限制均得到尊重。对侧腮腺和颌下腺的平均剂量分别为 3.9 和 17.7 Gy。七野 IMRT 提供了相似的 PTV 覆盖，具有统计学意义上更好的剂量均匀性和适形性。然而，两野 IMRT 的对侧腮腺（3.9 与 9.0 Gy，p=0.001）以及平均 MU （437 与 814，p=0.002）和机器时间均较低。
单侧两野 IMRT 是一种简单可行的技术，可提供优异的肿瘤覆盖和最佳的 OAR 保护，同时减少 MU 数量和治疗时间。
