I r5ecently had a cat scan which showed a 4mm. kidney stone in my lower kidney. how large will it need to be before it can be broken up with some sort of lazer ? also I exercise regularly with a inverter. for now the stone is in a good spot, I was told by the Dr. didn t have questions at the time now I do. if I continue to use the inverter which puts me in a upside down position will I increase th possibility of the stone moving to a worst location? Thankyou for your time Bill