I took needlepoint in with me for the chemo sessions but couldn't do it partly because of the drip in my arm and partly because it was frowned upon. I don't think they like you to even try to move your hands around too much. Whether this is because it increases blood flow or not I have no idea. You could take a book or a magazine. We had the TV on in my room, though I couldn't understand it, being all in Greek. You might be able to strike up a conversation with someone next to you. Someone else in there had an iPad and watched films with headphones on. Mostly I just nodded off and slept.
For the radiotherapy I recommend drinking liquid Aloe Vera every day. Apparently radiotherapy is a little bit like having sunburn inside your digestive system and Aloe Vera helps with the burns.
There's nothing you can do during brachy, but it only lasts a matter of seconds. If you have a book or knitting for your time in the waiting room that should do you fine.