Why can't my father be around my children while he's having radiation therapy for his prostate?

Seeds /y radioactive: Radioactive seed implant of prostate makes your father slightly radioactive for about 6 months when the amount of radioactivity has decreased significantly. Children have young organs prone to injury from radiation. Other forms of radiation like external beam radiation, imrt, igrt, cyberknife, high-dose-rate brachy therapy do not make your father radioactive. No risk to be around children.

Depends: If he is taking daily radiation from a machine in the radiation department he can be around children. If he had surgery to implant radioactive seeds then he can be in the room with them as long as those under 13 do not sit on his lap or right next to him. Children and pregnant women keep a distance of a couple of feet if he had this implant.

Seems unusual: If he is having external beam, he brings hom no harmful radiation to others. If he had seeds implanted, children would need to sit on his lap to get enough exposure to cause concern. Probably a misunderstanding. Talk to the radiation doctor directly about this, .