Does working in the radiation oncology department expose me to enough radiation to make it more likely i'll get cancer?

No. Its too small to measure. Risk for various professions have been reported. Such that dying from this is much less likely than a construction worker for example. Also the radiation exposure is virtually nil since radiation is produced electrically (versus cobalt machines) and workers are outside the room. Being inside the room with radioactive substances increases your risk.
Follow guidelines. Early radiation therapy workers died from cancers in the work place. That is why osha and others have strict guidelines on radiation exposure. If you are close enough to the source of radiation that you pick up stray radiation, you work place has strict rules and procedures for you to follow to avoid excess exposure. This would include a radiation monitoring device in the form of a badge.
Minimal. People working in the radiation department get some of the lowest amounts of radiation exposure amongst any specialty since so much shielding and so many precautions are are taken. The cardiologists and people working the radiology and cath labs get far more exposure. Working in those departments can b more concerning if you do not follow recommended monitoring guidelines as far as wearing badge.