Randy, it is typically hospitals that offer radiotherapy. The thing to look for is e. g. a department of oncology as in below address

Department of Radiation Oncology, Massachusetts General Hospital, Harvard University Medical School, Boston 02114, USA.

Though the therapy itself is very easy to apply, it still makes sense to look for someone who has experience with radiotherapy. Just having the equipment might not be sufficient, with little experience doctors might have difficulties to calculate the dosis correctly or wouldn't know which area to expose and which to shield (we show an example of a radiated area on our web site www.dupuytren-online.info).

Possibly we could also arrange a contact with an experienced German hospital that could provide advice to a US colleague if needed.

Wishing you good luck

Wolfgang