@fwpoole, I'm so sorry to hear that the big "C" has struck twice – lymphoma and now throat cancer. I moved your message to the Head & Neck Cancers group where you can meet others like @karly@skoshi, @margieinia@fxdwing and @catlyn. They can also share their treatment experiences.
Fwpoole, I can understand your reluctance to have radiation therapy given your brother-in-law's experience and your claustrophobia. Remember that not all radiation is the same. Your brother-in-law's experience will not be yours. Before dismissing radiation therapy, I personally think it is worth having a heart-to-heart with your radiation oncologist. Explain to him you concerns and reluctance. Find out what alternatives there might be. Ask what would be the prognosis without radiation. How do they help people who are anxious about closed spaces? Etc.
The final decision is always yours, but I recommend having all the information to make an informed decision, including perhaps a second opinion. Have you thought of getting a second opinion? When do you start chemo?