NYU Langone Medical Center.
J Appl Clin Med Phys. 2013 Sep 6;14(5):278-83. doi: 10.1120/jacmp.v14i5.4355.
Noncoplanar radiation fields from a linear accelerator can be used to deliver radiation dose distributions that are superior to those delivered using coplanar radiation fields. Noncoplanar radiation field arrangements are especially valuable when delivering stereotactic body radiation therapy (SBRT). Noncoplanar radiation fields, however, are geometrically more challenging to deliver than coplanar radiation fields, and are associated with a greater risk of collisions between the gantry, treatment couch, and patient. Knowledge of which treatment couch offset, treatment couch angle, and gantry angle combinations provide a collision-free radiotherapy delivery is useful in the treatment planning process, as the risk of requiring replanning due to improperly selected treatment parameters can be minimized. Such tables are by default specific to the linear accelerator make and model used for treatment. In this work a set of plots is presented indicating which combination of treatment couch lateral offsets (-10 cm to 10 cm), couch angles (270° to 90°), and gantry angles (0° to 360°), will result in collision-free radiation delivery using Siemens ONCOR linear accelerators equipped with a 160-leaf multileaf collimator and a 550 TxT treatment table, and a Elekta Infinity linear accelerator with an MLCi2 and Elekta iBEAM evo Couchtop EP. The patient was assumed to have a width of 50 cm and a height of 25 cm.
来自线性加速器的非共面射野可以用于提供优于共面射野的辐射剂量分布。在实施立体定向体部放射治疗（SBRT）时，非共面射野方案特别有价值。然而，与共面射野相比，非共面射野在几何上更具挑战性，并且与机架、治疗床和患者之间发生碰撞的风险更高。了解哪些治疗床偏移量、治疗床角度和机架角度组合可以提供无碰撞的放射治疗输送，这在治疗计划过程中是有用的，因为可以最小化由于选择不当的治疗参数而需要重新计划的风险。这些表格默认情况下是特定于用于治疗的线性加速器制造商和型号的。在这项工作中，提供了一组图，指出在使用配备有 160 叶多叶准直器和 550 TxT 治疗床的 Siemens ONCOR 线性加速器以及配备有 MLCi2 和 Elekta iBEAM evo Couchtop EP 的 Elekta Infinity 线性加速器时，哪些治疗床横向偏移量（-10 cm 至 10 cm）、床角度（270°至 90°）和机架角度（0°至 360°）的组合将导致无碰撞的放射输送。假设患者的宽度为 50 cm，高度为 25 cm。
