High Pitched Sound from Throttle Body

I purchased a stethoscope and identified a high pitched sound coming from the throttle body of my 2010 Prius. I've read threads that the source is normal from the inverter, however I'm certain the sound is originating from the throttle body part. What would cause this high pitched sound? I'm planning on cleaning it and report if this corrects itself.

 

Cleaned the throttle body, still can hear a high pitched buzzing originating from it.