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First ever color X-ray on a human

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Re: First ever color X-ray on a human

#51

Post by klipt »

randcraw wrote: post #24

How much exposure to radiation is needed for this? Their brochure indicates 20-80 mGy/mSv. But a typical clinical head CT is only 2 mGy. AFAIK, exposures that high would not be acceptable for clinical human use. It's probably inevitable that a 'spectral' scanner requires greater exposure than clinical CT scanners since the intensity of a spectral X-ray source apparently varies during the scan. This implies slower sca…

I think regular CT already causes cancer in ~1/2000 uses. So 10x that dose would probably cause cancer in ~1/200 uses? That's pretty scary.

Re: First ever color X-ray on a human

#52

Post by stephengillie »

lars_thomas wrote: post #17

Photon counting sensors have been available for quite a while. This is unfortunately not new. It’s not ’color’ it’s multi channel imaging. X-ray tubes produce wide spectrum of x-rays, these type of sensors are able to put different bands to different buckets. Coloring is arbitrary and conveniently chosen in the example to look like visible wavelength response as if the patient was dissected. It does not work for more…

TV cameras originally produced color by taking black-and-white video through 3 different filters, transmitting these as a bundle, and outputting these to the electron scanner. The colors didn't get mixed until after they hit the TV screen, as the photons were traveling to our eyes.

Re: First ever color X-ray on a human

#53

Post by ISL »

stephengillie wrote: post #52
lars_thomas wrote: post #17

Photon counting sensors have been available for quite a while. This is unfortunately not new. It’s not ’color’ it’s multi channel imaging. X-ray tubes produce wide spectrum of x-rays, these type of sensors are able to put different bands to different buckets. Coloring is arbitrary and conveniently chosen in the example to look like visible wavelength response as if the patient was dissected. It does not work for more…

TV cameras originally produced color by taking black-and-white video through 3 different filters, transmitting these as a bundle, and outputting these to the electron scanner. The colors didn't get mixed until after they hit the TV screen, as the photons were traveling to our eyes.

That's still how most imaging sensors work. Few, if any, actually parse the photon energy from within the imaging pixel itself.

Re: First ever color X-ray on a human

#54

Post by tomp »

lars_thomas wrote: post #17

Photon counting sensors have been available for quite a while. This is unfortunately not new. It’s not ’color’ it’s multi channel imaging. X-ray tubes produce wide spectrum of x-rays, these type of sensors are able to put different bands to different buckets. Coloring is arbitrary and conveniently chosen in the example to look like visible wavelength response as if the patient was dissected. It does not work for more…

> I wish we could have a peek inside the patient as if we had opened it up but this is not yet that.

What's stopping us? Are you saying that there's no way to tell different kinds of tissues apart (e.g. not even with an MRI)? I imagine if we did, we could also add "color" (via post-processing) and enable a "dissection". Or are you saying it has something to do specifically with color?

Re: First ever color X-ray on a human

#55

Post by zwkrt »

tomp wrote: post #54
lars_thomas wrote: post #17

Photon counting sensors have been available for quite a while. This is unfortunately not new. It’s not ’color’ it’s multi channel imaging. X-ray tubes produce wide spectrum of x-rays, these type of sensors are able to put different bands to different buckets. Coloring is arbitrary and conveniently chosen in the example to look like visible wavelength response as if the patient was dissected. It does not work for more…

> I wish we could have a peek inside the patient as if we had opened it up but this is not yet that. What's stopping us? Are you saying that there's no way to tell different kinds of tissues apart (e.g. not even with an MRI)? I imagine if we did, we could also add "color" (via post-processing) and enable a "dissection". Or are you saying it has something to do specifically with color?

I think the point was that the x-ray 'colors' do not have 1:1 mapping with the colors that our eyes see. So the color is useful to discern different tissues and bones and stuff, but the colors won't look like the colors of those things in real life.

We see in a range of wavelengths 0.4--0.7 um. X-rays have no intersection with our visible range. Therefore the best you can do is define some function that maps x-rays into our color range, but things look very different in x-ray land than they do in color land. For starters, most things would be transparent if you could see x-rays (hence x-ray imaging!).

http://www.columbia.edu/~vjd1/electromag_spectrum.htm

Re: First ever color X-ray on a human

#57

Post by smt88 »

klipt wrote: post #51
randcraw wrote: post #24

How much exposure to radiation is needed for this? Their brochure indicates 20-80 mGy/mSv. But a typical clinical head CT is only 2 mGy. AFAIK, exposures that high would not be acceptable for clinical human use. It's probably inevitable that a 'spectral' scanner requires greater exposure than clinical CT scanners since the intensity of a spectral X-ray source apparently varies during the scan. This implies slower sca…

I think regular CT already causes cancer in ~1/2000 uses. So 10x that dose would probably cause cancer in ~1/200 uses? That's pretty scary.

That's assuming dosage has a linear relationship with instances of cancer. Scary regardless, though.

Re: First ever color X-ray on a human

#58

Post by thaumasiotes »

klipt wrote: post #50
ekun wrote: post #39

Earlier quoted context omitted.

Which similar to images we see of space where they have altered detectors' responses from different wavelengths of light to be images in the visible spectrum. So we produce beautiful images, but they aren't accurate to what space would look like to the naked eye.

Probably more useful than the naked eye in many cases. The colors our eyes can see mostly evolved to detect ripe fruit, not diseased tissue.

On the contrary, finding edible food is certainly important, but avoiding poisonous/diseased food is even more important.

Re: First ever color X-ray on a human

#59

Post by pharrington »

Create wrote: post #43
lars_thomas wrote: post #41

Earlier quoted context omitted.

Pretty much. Normal x-ray sensors are like camera sensors and produce an estimate of total energy of the photons / pixel. Photon counting sensors are able to estimate how many photons of certain energy range hit the sensor. So instead of value ’1023’ you might get ’63’ of 50kv. So poor mans spectroscopy. Naive way to produce ’color images’ would be to put those buckets to red green and blue channel and now different…

The way "color images" are produced is to map the Hounsfield scale to the visible colour spectrum: i.e. blood red, bone white, steel gray etc. https://en.wikipedia.org/wiki/Hounsfield_units#Value_in_part... CT machines have this calibrated as standard, DICOM images have the corresponding fields for the values. Any DICOM viewer will do this (i.e. 3D Slicer, ParaView, OsiriX etc.) As you say, there is nothing new in th…

To be more precise, CERN took part in Medipix3's development.

https://medipix.web.cern.ch/medipix3-collaboration-members

Yes, this is a PR release for tech using the Medipix3. If I understand correctly (which I very probably don't since this HN thread is the first time I've heard of this technology), this is analogous to faster/more accurate AI software being developed with some chip company's latest massively parallel processor - representative of real, but nowhere near groundbreaking, technological advancement.

Re: First ever color X-ray on a human

#60

Post by DEADBEEFC0FFEE »

thaumasiotes wrote: post #58
klipt wrote: post #50

Earlier quoted context omitted.

Probably more useful than the naked eye in many cases. The colors our eyes can see mostly evolved to detect ripe fruit, not diseased tissue.

On the contrary, finding edible food is certainly important, but avoiding poisonous/diseased food is even more important.

If we can detect ripe, surely we can infer not ripe.
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