Linear accelerator

Mice were anesthetized with 2% isoflurane inhalation, and immobilized in a dedicated mouse holder with a lead shield that allowed for selective thoracic irradiation. Based on the published literatures (16 (link),23 (link)), we administrated the thoracic irradiation using a linear accelerator (Varian Medical Systems, Palo Alto, CA, USA) on the mice at a dose rate of 3 Gy/min with the regimen of 8 Gy ×3 on days 0, 1 and 2. The source-surface distance was 100 cm. The irradiation field was 4 cm × 2 cm. Mice were randomly assigned to different groups with the numbers of 5–12 for each time-point per group. Control mice underwent the same procedure and exposed to 0 Gy.

All patients received IMRT, which was delivered with a linear accelerator (Varian, Palo Alto, CA) using 6 MV photons. The prescribed doses were 68–70 Gy/30 fractions (fr) to the gross tumor volume of nasopharynx (GTVnx), 60–66 Gy/30 fr to the gross tumor volume of metastatic lymph nodes (GTVnd), 60 Gy/30 fr to the high-risk clinical target volume (CTV1), and 54 Gy/30 fr to the low-risk clinical target volume (CTV2), respectively. All of the following information has been detailed described in our previous published study: the IMRT technique, delineation method of the target volumes, dose limitation to the target volumes and organs at risk [21 (link)].
All stage I patients received IMRT alone, except one receiving concurrent chemotherapy for relatively large tumor volume (GTVnx-volume=30.4 cm³). Fifty patients with stage II disease received chemotherapy, 36 of them undertook concurrent chemotherapy (cisplatin, 80–100 mg/m²/day, intravenous infusion over 2 hours on days 1 and 22), three received cisplatin-based induction chemotherapy (IC), and 11 patients received cisplatin-based IC plus concurrent cisplatin chemotherapy.

Human ESCC cell lines Eca109 and TE‐1 were purchased from Shanghai Institute of Cell Research (Shanghai, China). All cells were cultured in DMEM supplemented with 10% FBS (Biological Industries, Kibbutz Beit‐Haemek, Israel) at 37°C in 5% CO₂. The cells were exposed to a single dose of X‐rays using a linear accelerator (RadSource, Suwanee, GA, USA) at a dose rate of 1.15 Gy/min and 160 kV X‐ray energy. Xenografted tumors in nude mice were exposed to a linear accelerator (Varian, Palo Alto, CA, USA) and irradiated at a dose rate of 4 Gy/min and 6 MeV X‐ray energy.

Cells (SW480 and SW620) were treated with different doses of radiation (0, 2, 4, and 6Gy) by a linear accelerator (Varian, Palo Alto, CA, USA) at a dose rate of 3.5 Gy/min.

5-8F cells and HNE2 cells in flask or plates were exposed to X-rays (2-8 Gy, 4Gy per minute), using a 6-MV photon beam from a linear accelerator (Varian Medical Systems, Inc) at the Department of Clinical Oncology of Xiangya Hospital (Changsha, China). The plates were covered with a tissue-equivalent gel to promote dose build-up.

Transfected NSCLC cells were irradiated with a linear accelerator (Varian Medical Systems, USA) at room temperature with different doses (0, 2, 4, 6, and 8 Gy, dose rate: 1 Gy/min). After 24–96 h, the cells were used for further analyses.