You guys also put your washing machine in the kitchen. In the US the washing machine goes in a different room, which means you have to run a lot more plumbing. Combination machines are also extremely rare, and people don't really air dry clothes much, so you need space for both a washer and dryer.
Plus a unit with an in-unit washer and dryer generally costs more than a similarly sized unit, and part of that space is taken up by a washer/dryer.
Yeah, it's definitely an interesting question. I took two full years of biomedical ethics, and I think you could make a pretty strong claim for either side.
I personally think that performing a basic reading of an ultrasound or an ECG/EKG would be fairly simple with some training, but I also have a lot of experience reading raw data. I have a few friends who are Radiologists, and I'm going to have to ask them what they think. I'm really not sure what they'd think about all this, and I'm definitely open to the possibility that I'm massively overestimating my ability to interpret even "simple" diagnostic data.
I agree to a certain extent. I think it would mostly be useful in developing areas where you might have someone who has training to make simple diagnostic calls (should this person be put on a 2 day bus ride to a hospital), but doesn't have the tools to make the diagnosis.
Basically, places where buying $10k of diagnostic tools wouldn't be tenable, either because of the price, or because they would get stolen or damaged before they could "pay off".
Places where I think this might be useful are places like Nepal, Sudan, Pakistan, India, Niger, Mongolia, etc. Places that have low development and population densities.
I think a DIY instrument would be especially useful in India, given the fact that it has low development levels but a lot of highly educated individuals and a strong central government.
That being said, this is all speculation. I don't know enough about ANY of those areas to say whether people there would actually find tools like this useful. I'm definitely not suggesting we start filling shipping containers with cheap instruments and shipping them abroad.
I just looked at the Wikipedia page for SAR. I think what you are doing requires a lot more signal processing than an ultrasound. At it's most basic, an ultrasound is really just a 1d graph of signal intensity. You should look at some old ultrasounds, it's pretty obvious how low the resolution is.
I'm sure you know more about signal processing than I do, but trust me when I say a simple diagnostic ultrasound is a pretty rudimentary bit of kit. Most medical imaging is pretty simple actually (not accounting for signal acquisition). Radiologists are trained to read fairly abstract charts, and they want as little processing as possible. Imagine if a CT machine tried lining up images, rather than presenting the raw slices. That might make sense for mapping data, but if you were trying to diagnose a displacement of something, like a broken bone, having the image "fixed" wouldn't do you much good.
That's part of the reason why older ultrasound images of babies are so inscrutable to the casual observer. Since the technician is slowly sweeping a 1d or 2d array by hand, the printed image ends up looking pretty weird if the baby moves. An ultrasound can be 100 db inside the womb[1], so the baby tends to start moving when the ultrasound is performed. The horrible images aren't much of a problem, because the images they give to the parents aren't really used for diagnosis. They use the monitor for that purpose. If there is something the tech wants to explore further, they just look at that area some more.
Based on my limited knowledge of SAR, it seems like the processing is way more important because you are working with data that has been captured in the past.
You can have a basic ultrasound with only on channel. The following patent is from 1985, and has a pretty good overview of the field at the time. It appears that most if not all untrasound transducers at the time were large single channel instruments.
This patent, from 1989, indicates that most ultrasound transducers are either single element or linear arrays. It was the earliest patent I could find with a cursory look that had a 3 dimentional array.
Regardless, even Wikipedia suggests that most of the arrays used for medical imaging use either a single element or a phased array:
To generate a 2D-image, the ultrasonic beam is swept. A transducer may be swept mechanically by rotating or swinging. Or a 1D phased array transducer may be used to sweep the beam electronically. The received data is processed and used to construct the image. The image is then a 2D representation of the slice into the body.
3D images can be generated by acquiring a series of adjacent 2D images. Commonly a specialised probe that mechanically scans a conventional 2D-image transducer is used. However, since the mechanical scanning is slow, it is difficult to make 3D images of moving tissues. Recently, 2D phased array transducers that can sweep the beam in 3D have been developed. These can image faster and can even be used to make live 3D images of a beating heart.
Point being, I think you are wrong. I'm not an EE, so I can't speak towards signal processing, but I am a biologist by training, and I don't see a clear reason why sonar principles wouldn't work. We are basically a bag of salt water.
Also, I am familiar enough with ultrasound to be sure that models with only a single transducer are very common. Hospitals and the like might be using the fancy-pants multi-dimensional arrays now, but the units we used to image things in college were definitely not multi-dimension. For one thing, they were older than the patent that demonstrated multi-dimensional arrays.
I actually chose biology over computer science because of problems like this[1]. Now, I don't think I have all the knowledge necessary to build an ultrasound myself, but at least I have the ability to read the literature and make sense of it, and I can understand the language radiologists and doctors use to describe an ultrasound.
I don't think the programming would actually be that hard. It's basically sonar for people. There are tons of builds of devices that use time-of-flight to produce images. I think you could actually get something reasonable working pretty quickly if you had access to testing apparatus and a radiologist.
I don't have the skills to build the ultrasound machine myself, but I'm not an EE. I don't think the programming is a huge barrier though.
Quick edit: I would probably try emulating a system with physical lenses first. It seems like an easier problem. There was an article on Hackaday a while back about a guy who built a phased array radar in his garage, but it seems harder than the physical lens version:
Oh, definitely. I don't want to suggest the added inaccuracy is a trivial problem. It just seems like access to a diagnostic test with a lower resolution is better than no test at all.
The way I see it, the benefit of cheaper diagnostic technology is the difference between no access (or extremely limited) to that technology and access to an inferior but otherwise capable technology.
I've been researching diagnostic medical equipment a lot recently, and it seems like the biggest barrier to homebrew medical diagnostic equipment is attitudinal. Discussion about building your own equipment are almost immediately sidetracked by FUD about how dangerous it is.
Proper medical devices have loads of safety features! They have isolated power supplies! They are tested in harsh environments! They fail in a predictable manner! There are regulations that need to be followed! New devices are still expensive because they are better!
Yes, electricity can kill you.
Yes, improper medical advice can kill you.
Yes, malfunctioning diagnostic equipment can lead to an incorrect diagnosis, which, yes, can kill you.
Yes, medical regulations exist and protect us from harm.
While a homebrew machine would not be able to compete with the latest and greatest, I'd hazard that even rudimentary diagnostic equipment could save thousands of lives a year in the developing world. These technologies are not new -- the medical ultrasound has been around for more than 60 years, and the EKG has been around for nearly 100. It seems insane that cost is still such a barrier for the machines used for medical diagnostics, when the price of other technologies has fallen so much in the same period of time.
I bought myself a Rigol DS1054Z, and I realized that I paid $400 for an oscilloscope that would have cost millions of dollars 30 years ago. I thought about the experiments I had done on neurons using the 50 year old oscilloscopes as part of my degree, and I realized that an ECG/EKG can be replicated pretty easily with an oscilloscope. It turns out, building an ECG is pretty trivial. It's not a 12-lead ECG, but it's also something I built out of parts I had on hand.
I don't see why other medical technology should be any different. Yes, unregulated medical technology is dangerous, but the risk doesn't seem to outweigh the potential benefit. If the parts to build these devices is cheaper and more accessible than they ever have been, and the equipment needed to build, test and calibrate the devices is cheaper and more accessible than ever, it seems like the devices themselves should be cheaper and more accessible than ever. I think there is a place for a $20k ultrasound, but when you live hours or days from an ultrasound, a cheaper option could save lives, even if the primary purpose is directing people to get a follow-up with the more capable machine.
Plus a unit with an in-unit washer and dryer generally costs more than a similarly sized unit, and part of that space is taken up by a washer/dryer.