After the end of Cycles 2, 4 and 6, you will have a chest x-ray and either a CT scan, MRI scan, or PET scan to check the status of the cancer. You will then have a chest x-ray and either a CT scan, MRI scan, or PET scan after the end of every 3 cycles (Cycle 9, 12, 15, and so on) to check the status of the cancer.