That kinda depends on what you’re wired for. Sometimes it helps to think of it like a power move, as if you’re baring your chest like a boxer preparing for a fight (but please do not punch your 80 year old doctor). I don’t want to advocate dissociating if that’s something you genuinely struggle with, but in specific circumstances it’s not always bad. Typically I try to reason myself out of modesty by thinking about myself with scientific detachment… the body I happen to inhabit is mammalian, it has all the features of a mammal, and my discomfort with it and my identity as an individual is separate from the mundanity of flesh.
When I had an echocardiogram done, I was wearing one of those paper gown things, and the doctor put holes in the paper for the ultrasound thing. You can ask if they could do that for yours.
The monitor’s readout itself is pretty interesting, even though you’ll probably have no idea what you’re looking at.
Also, keep in mind that the doctor has seen a LOT of people in various states of undress. Doctors, especially experienced doctors, don’t care.