[HN Gopher] Taking digital X-ray shots for cheap
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Taking digital X-ray shots for cheap
Author : _Microft
Score : 85 points
Date : 2021-11-21 12:59 UTC (10 hours ago)
(HTM) web link (hackaday.io)
(TXT) w3m dump (hackaday.io)
| ad404b8a372f2b9 wrote:
| If the sensor is so small why are the X-ray machines at my
| hospital almost room sized? You know those huge mechanical arms
| hanging from the ceiling that look like they could crush you or
| irradiate you to death.
|
| Also can this project be used on flesh and will I accidentally
| cook myself doing it?
| willcipriano wrote:
| They have dental x-ray sensors[0] that are about 2 cm thick and
| 4 x 4 inches in size with a usb plug on the other end. You put
| them in the mouth and then can use a portable x-ray gun[1] to
| image the tooth to your laptop. No more films or anything like
| that.
|
| [0]https://www.atlasresell.com/used-dental-
| equipment/digital-x-...
|
| [1]https://www.kavo.com/en-us/imaging-solutions/kavo-nomad-
| pro-...
| blululu wrote:
| The size of an x-ray grows with power for two reasons: higher
| voltages require much more insulation, and higher energies
| require much more shielding. In medical contexts shielding is
| the big issue. I forget the exact figures but the mass
| attenuation coefficient for large energy is something like
| Z/E^3, so a dental x-ray at 15 kev will has much less radiation
| leakage than a chest x-ray at 150 kev. (Note that the beam is
| not monochromatic and the 1000x change in attenuation passes
| through an exponential decay relation so it is not a simple
| relation, but you need a lot of lead to keep the x-ray tech
| safe).
| jcrawfordor wrote:
| Besides offering much higher power levels, the bulk of most
| hospital X-ray equipment seems to just be positioning... i.e.
| the actual X-ray generator is fairly small (although things
| like a projected light illuminator to help the technician with
| aim make it bigger), but there's a lot of "accessory" equipment
| just to make it easy for the technician to position it in the
| right place and have it stay there. Ceiling tracks and a
| specially designed patient bed with a pretty x-ray transparent
| material that the sensor can be placed under, for example.
|
| Dental X-ray machines for example are very small, but I think
| it's because they operate at pretty low power and have pretty
| simple/consistent positioning requirements. Panoramic dental
| x-ray machines on the other hand are pretty big because of the
| specific positioning.
|
| On top of that I think a lot of hospitals just have pretty old
| X-ray machines... they're expensive and can operate for a long
| time with maintenance and tube replacements. I've seen clinics
| that upgraded their x-ray process to digital by using a
| standalone digital sensor like this, but are still using a 20+
| year old analog machine as the x-ray source. I think that's why
| this particular sensor doesn't accept triggering information
| over the digital interface... that seems kind of weird at first
| glance, but I assume it was designed as a drop-in replacement
| for film, so it would be used with an older machine that didn't
| have any kind of digital trigger output. Instead it just
| detects when the exposure has started. Presumably the manual
| told the technician what parameters they needed to use on the
| emitter for it to get a full scan.
|
| The author here mentioned using a hand-held X-ray emitter for
| sports medicine which I'm curious about because I've never seen
| such a thing. I assume the power and exposure time must be
| pretty limited, even the dental X-ray machines have a
| regulatory requirement that the operator be behind a shield
| during use---although the implementation is usually pretty lax,
| just putting the exposure button in the hallway outside the
| x-ray nook so they have to step outside briefly.
| SiempreViernes wrote:
| Just stepping away is in all likelihood exactly as much
| precaution as is needed: the machine itself ought to have
| shielding in all directions except the for the beam itself,
| so it doesn't emit significantly in the other directions
| anyway and getting some distance kills even that on its own.
|
| Honestly, going outside as a way to ensure you don't stand in
| the beam by mistake might be the most important part.
| willis936 wrote:
| I feel bad for sharing this because it's a master class in things
| to never do with HV and the creator made a follow-up video
| mocking commenters criticizing this, but it's similar and
| interesting.
|
| https://youtu.be/IiJAq53knwc
| tgsovlerkhgsel wrote:
| That's both hilarious and scary. For his own sake, I hope a lot
| of it is just a shtick and he is actually much more careful
| about safety than he admits.
| marcodiego wrote:
| How safe is playing with this?
| MegaDeKay wrote:
| The comments in the linked article have response to a question
| like this that states: "All safety precautions are complied
| with, also have a dosimeter for direct radiation warnings."
| neilv wrote:
| I only got partway through the entertaining video, before I had
| an impulse to pause it and check the YouTube comments about
| safety.
|
| There's so much of what seemed like poorly-informed belligerence
| in the YouTube comments, it felt like I was reading foreshadowing
| of tragedies.
| geocrasher wrote:
| Since when is "for cheap" the right way to say things. Ugh.
| Stampo00 wrote:
| According to Google Books Ngram Viewer, the first recorded
| usage of the phrase "for cheap" was noted in 1672, although
| that could be part of a longer phrase like "for cheap food".
|
| Usage peaked in 1876. I'm willing to bet that at least some of
| that usage mirrors how the author is using it.
|
| In conclusion, "for cheap" has been the "right way to say
| things" since before either of us were born.
|
| https://books.google.com/ngrams/graph?content=for+cheap&year...
| pbhjpbhj wrote:
| >In conclusion, "for cheap" has been the "right way to say
| things" since [...] //
|
| The more people that get it wrong the righter (sic) it is!
| :eyeroll:
| Stampo00 wrote:
| Why aren't you speaking Old English?
| fortran77 wrote:
| I'm able to solder Ball Grid Arrays at home, after a bit of
| practice, but I have no way to inspect them. I would love a cheap
| home Xray machine just for this purpose.
| _Microft wrote:
| Don't feel bad when you see what some people are able to build in
| hardware. It's their job (now) - the author is working at
| NeuraLink these days, building wireless charging for brain
| implants. (This is meant to say: they are really good at it)
|
| More of their stuff with with x-rays on Twitter:
|
| https://mobile.twitter.com/search?q=from%3Alucysrausch%20x-r...
| goldenkey wrote:
| Why would it matter if it was their job or not? My friend has
| been doing circuitry since he was a kid. He can run circles
| around me doing embedded while I can run circles around him
| when it comes to software. Our jobs are irrelevant, it's our
| initial interests that caused us to specialize. United, we
| build awesome stuff together. There's no reason to feel bad
| when people with different interests have way better skills in
| their specialties. Instead of feeling bad, form alliances and
| make awesome stuff together.
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