Varian 600cd

Radiotherapy was performed using a Varian 600CD (Varian Medical Systems, Palo Alto, CA) linear accelerator with 6 MV X-ray photon beams. Five separated radiation fields with a size of 2 cm × 2 cm each on the isocenter plane (source to the isocenter plane is 100 cm) were simultaneously formed by utilizing the jaw collimator and the multileaf collimator (MLC). The gantry and collimation angles were 0 degrees to guarantee the beam incident vertically downward. The tumor-bearing mice were anesthetized and placed in customized controlling devices, and they were placed on a 10cm thick solid water phantom with a source-to-tumor distance of 100 cm. To ensure an adequate dose, the tumor of each mouse was placed within 1 cm × 1 cm of the center of each radiation field while the rest of the body was placed away from the radiation fields as far as possible, and a 1.5 cm thick phantom for dose build-up was placed above the mice. Single fraction radiotherapy of 20 Gy dose treatment was applied with a 5 Gy/min absorbed dose rate. All experiments were carried out under the supervision of medical physicists and engineers. A schematic summary of the device and regimen was shown in Figure S7B.

All patients were treated with the intensity modulated radiation therapy technique randomly using the Varian-600CD (Varian Medical Systems, Palo Alto, CA, USA) or Helical TomoTherapy (Accuray Inc., Sunnyvale, CA, USA) linac with a prescribed dose of 70 to 80 Gy in 33 to 36 fractions. The treatment plans were designed on Pinnacle³ 9.0 treatment planning systems (Philips, Fitchburg, WI, USA) or TomoTherapy Planning System (Accuray Inc., Madison, WI, USA) using computed tomography datasets with a 3-mm slice thickness. The beam energy for all plans was 6 megavolt, and the ultimate goal of optimization for an individual patient plan was that the dose to organs at risk (OARs) can be kept as low as possible while maintaining optimal target coverage and dose uniformity to the target. Twelve of 20 patients received RT concurrent with chemotherapy, depending on their grade of disease.