Can i get radiation therapy even though i have a cardiac defibrillator?

Depends which organ: The distance between defibrlllator and the organ being treated is the key. Usually 5 centimeter or more is safe, closer than that the defibrillator needs to be moved. Usually you don't want it in direct field of radiation.

Yes: As dr. Shirazi stated you can't directly radiate a defibrillator. With many new radiation techniques there are many angles used, so the medical physicist needs to do a calculation on the dose given to the defibrillator. We contact the cardiologist and get the make and model of the unit, which are getting better in how much radiation they can take. This way we limit the radiation to the unit.