Trying to better understand how much radiation i received from my first/only chest ct scan? ct tech told me the ctdi for my scan was 4.63?

Not enough to worry: A single CT does not produce enough radiation to cause any harm. You would receive more radiation at the beach .

CTDI is NOT Dose!: The CT Dose Index is a measure of the output of the CT scanner. Calculation of actual dose requires consideration of patient size and areas scanned. A radiation physicist can determine the actual dose from the CTDI and the factors mentioned above.