I would definately recommend anyone who wants to be a Radiation Therapist contact the school they plan on attending and see if they offer a "shadow" program. "Shadow" programs offer the prospective student to "shadow" a Radiation Therapist for a day or longer, and provide immediate information valuable to the student about the career.
This is an excellent career in the medical field, it is a rewarding career as well as being a 9-5, M-F, job. It pays well and most hospitals and clinics have excellent benefits. The emotional and personal rewards you get from working with cancer patients also make this job truely enjoyable.