Ct scan

Hi everyone, I have rrms, I have had mri for years. I find myself this year highly anxious regarding going in the mri. So unfortunately I cancelled my mri in October, due to really bad anxiety regarding the head coil and mri. I have had numerous headaches mostly when I wake up in the morning. I say another neurologist regarding this, as was told it isn't to do with ms. I have a ct scan next week on the brain regarding the headaches. I find myself anxious regarding radiation from the ct scan, I need to know why I keep getting headaches. I know the ct scan can't help with what is going on with my ms. Has anyone else had a ct scan before ? Any help appreciated thankyou.