The word radiotherapy is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 20
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (48 words)
adapter, adaptor, adopter, aerator, airdate, airdrop, airhead, airport, apteria, arrayed, atrophy, atropia, daytrip, dietary, diopter, dioptre, drapery, eardrop, hardier, hardtop, hayride, hoarder, hoarier, hydrate, opiated, parader, parotid, paydirt, peridot, pirated, pithead, portray, pothead, praetor, prorate, radiary, radiate, rapider, readapt, readopt, tardier, tarried, therapy, thready, thyroid, tiaraed, topiary, typhoid