When your child needs a medical test done such as an X-ray, CT or MRI, insist on one of the following: 1) being in the room, 2) leaving the door open and being just outside the door or 3) if there is a viewing window, stay where you can clearly see your child. Don't allow the technician to tell you that you can't stay due to exposure. There's no reason why you can't stand with the technician.
I had an opportunity to talk with a mother whose son was sexually abused while getting a routine medical test done at a local hospital. She was just on the other side of a closed door. The technician had been released from another hospital for alleged sexual abuse and the records were sealed, allowing him to get another job where he had regular private access to young children.