Nude?
Well, certainly not fully clothed ... ha ha.
The fun part of imagining things is you can play out endless combinations in your mind and see what tickles your fancy. For instance, fully nude is fine of course, but wearing underpants only, pulled down to the knees or ankles adds a bit of extra embarrassment and makes it more awkward to move around or keep your balance. Voila, more embarrassment. Or constantly pulling underpants, briefs or panties up and down in a simulation of 'protecting' the patient's modesty is also something that would of course probably increase feelings of exposure. Or maybe even better, not pulling them up correctly so that you are still partially exposed, or maybe perversely pulling up and bunching up briefs so they form a thong in back. Maybe even wearing jockstraps might be fun, though I have no experience with these.
Wearing a gown would also be fun, but then a sort of see-through gown, vaguely feminine, perhaps short enough to expose the genitals if you raise your arms, or full length to the ankles, which is then raised by an assistant to expose the necessary body parts in a simulation of something like extreme Victorian prudishness. Speaking of Victorian times, being made to wear a corset or a sort of back correction corset might also be nice to fantasize about, so that an exam and measuring would be about correcting spinal posture.
Maybe even wearing a sort of short skirt in lieu of traditional underpants might be arousing. That way an examining doctor could flip them up on the abdomen instead of pulling them down like briefs. Pretend he is being solicitous of modesty while of course increasing the embarrassment by introducing a hint of forced cross-dressing for male patients.
Just a few things here. I'm sure you can come up with many more variations I've never thought about ... 😃 😃