Our patient was a 47-year-old man who presented to our hospital with a history of several months of increasing left arm pain, chest pain, dyspnea on exertion, occasional dry cough, and a 2.3 kg weight loss over the course of the preceding three months. A physical examination showed 4 of 5 weakness of the left upper extremity but no other abnormalities. He underwent CT of the chest, which showed a large left upper lobe mass measuring 6.4 cm × 3.3 cm, encasing the great vessels, and invading the T3 vertebral body. A video-assisted thoracoscopic biopsy of the left upper lobe mass was positive for non-small-cell carcinoma. Multiple mediastinal lymph nodes, including stations L2, L4, L5, and L7, sampled negative for tumor. A positron emission tomography (PET) scan showed hypermetabolic uptake in the mass but no mediastinal or distant metastases. The patient was diagnosed with stage IIIA T4, N0, M0 lung cancer on the basis of the AJCC Cancer Staging Manual, Seventh Edition, staging system criteria []. He was offered enrollment in Radiation Therapy Oncology Group (RTOG) protocol 0617, and he consented. He was randomized to receive 74 Gy of radiation therapy using conventional daily fractions of 2 Gy with concurrent carboplatin and paclitaxel, followed by consolidation carboplatin and paclitaxel. He was evaluated by an orthopedic surgeon (JH) for implantation of fiducial markers for IGRT because of the proximity of the tumor to the spinal cord. Markers were placed in the operating room with fluoroscopic guidance. A commercially available fiducial marker kit (CIVCO Medical Solutions, Kalona, IA, USA) was used, with 1.2 mm × 3 mm gold markers pre-loaded in 17-gauge sterile placement needles. The patient was sedated using general anesthesia. A 13-gauge Jamshidi bone marrow biopsy needle (CareFusion Corp., San Diego, CA, USA) Verified. was inserted into the pedicle of the T2 vertebral body. The pre-loaded needle containing the fiducial marker was inserted through the vertebroplasty trochar, and the gold marker was deployed into the bone. Bone wax was used to secure the markers in place. This procedure was repeated for the T3 and T4 vertebral bodies. The patient was then discharged to home. The only side effect he reported from the procedure was mild pain at the surgical sites, which lasted for three days and was controlled with over-the-counter pain medications. The patient underwent CT simulation for radiation therapy planning with the use of a custom Alpha Cradle foam mold and wingboard (Smithers Medical Products, Inc., North Canton, OH, USA) Verified for immobilization. CT scans of the patient were taken during inspiration, expiration, and free breathing. CT simulation images were fused with PET images to aid in target delineation. Gross tumor volume was outlined during inspiration, expiration, and free breathing scanning and fused to form an integrated target volume. A margin of expansion of 5 mm was used to create a clinical target volume (CTV). An additional expansion of 5 mm was used to create a planning target volume (PTV). The CTV and PTV margins were decreased in the areas of bone to limit microscopic disease extension and organ motion in this area. A five-beam IMRT treatment plan was devised to provide 95% coverage of the PTV with the prescription dose of 74 Gy delivered at 2 Gy per fraction. The maximum spinal cord dose was 48.54 Gy, with a concave dose distribution and tight dose fall-off in the area of vertebral body invasion. Figure demonstrates the sharp fall-off from the treatment dose of 74 Gy (red) to the approximate spinal cord tolerance dose of 50 Gy (purple). The volume of lung receiving 20 Gy was 17%. The treatment plan, including lung, heart, and esophagus dose parameters, was within the specifications of the RTOG 0617 protocol. Treatment was delivered on a Trilogy™ machine (Varian Medical Systems, Inc., Palo Alto, CA, USA) using daily kilovoltage (KV) imaging, which helped us to clearly visualize the fiducial markers. The position of the fiducial markers was marked on the DRR and superimposed on the KV image taken on the treatment machine, and appropriate shifts were made. Corrections were made in the vertical, longitudinal, and latitudinal directions as indicated. The range, median, and mean values of shifts are reported in Table. Migration of fiducial markers was not noted during the patient's treatment. The patient developed improvement in left arm pain and strength three weeks into radiation treatment. He developed grade 2 esophagitis toward the end of radiation treatment, which was controlled with diet modification and sucralfate as needed. His esophagitis resolved four weeks after treatment was completed. A CT scan of the chest and abdomen obtained 10 months after radiation treatment showed stable soft-tissue asymmetry in the mediastinum, with no evidence of recurrent or metastatic disease. At his one-year follow-up visit, the patient reported grade 1 dyspnea on exertion but was otherwise asymptomatic.