I read your question and I understand your concern. However a CT is not always necessary after every head injury. If she feels well she doesn t have to do it at all, avoiding an unnecessary expensive exam and futile radiation. If a CT is performed anyway it is usually done during the first 24 hours when complications usually occur, if those have passed and she s fine there s little chance of hemorrhagic complications, especially in a young person. Symptoms noted by her or others which could indicate brain injury are: -Drowsiness -Vomiting -Intense or progressively growing in intensity headache -Marked or progressively worsening dizziness with difficulty walking and standing -Confusion, abnormal behavior -Weakness of the limbs on one side -Doubling of vision or other visual problems -Seizures So to sum it up if she develops symptoms CT is urgent, should not wait, if she feels fine skip CT altogether. I hope to have been of help.