Apple's iPhone 7 Plus decided to add another lense to be able to make better pictures. Meanwhile Walabot who started with wanting to build a breast cancer detection technology released a 600$ device that can look 10cm into walls. Thermal imaging also got cheaper.
I think it would be possible to build a 1500$ device that could combine those technologies and also add a laser that can shift color. A device like this could bring medicine forward a lot.
A lot of area's besides medicine could likely also profit from a relatively cheap 3D scanner that can look inside objects.
Developing it would require Musk-level capital investments but I think it would advance medicine a lot if a company would both provide the hardware and develop software to make the best job possible at body scanning.
I think that many physiotherapists could do a better job if they would have body scanners.
The BMI is a horrible metric and having cheap body scanners would move us past the BMI and provide us with better targets for weight management.
In many cases I wouldn't need to go to the doctor if a good body scanner can tell me what's up with me. If the scanner can tell me whether my teeth are alright, I don't have to go to the dentist.
If I can get a body scan for mammogram from a person who isn't a breast surgery salesman as in the status quo, a false positive is also less likely to get me to do risky treatment.