Depending on what kind of cancer your treatments are for, you may need to change or remove some clothing in preparation for radiation. I had rectal/colon cancer and my appt time started with going to changing room to remove some clothing before treatments so techs could align radiation to appropriate places they had marked on my body, so actual radiation time was definitely not 30 min. After a couple of appts, I wore a dress, and found out that I could just remove my underwear in the radiation room and they just lifted up my dress when I got onto the gurney.This was so much quicker and easier than going to changing room! So keep that in mind, unless they have told you that actual radiation will be 30 min, it probably won't be. But don't hesitate to call their office and ask them. Best of luck to you.