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microchanelled radiography CT scans are 20 times less carcinogenic

put a chunk of microchanneled bismuth between the radiation source n the image CCD, then just have software connect the micro "bokeh" of less than 1mm each to create an interpretive image with 1/25 the usual radiation
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Science magazine had a blurb, as well as a paper about a researcher who estimated that 1 of every 1000 persons with a computed tomography body scan got cancer. thus of about 2.4 million scans, 24,000 lethal cancers were being caused each year (an amount comparable to the 30,000 annual road deaths). This is a very simple approach to reducing that risk 20 or 100 times. place a big chunk of bismuth with numerous very tiny microchannels in front of the radiation source. The radographic photions only travel linear paths through the microchannels to pass through the body to reach the imaging surface.

think of each square millimeter of a radiograph as a grid "#" if you just created a microchanel at the center, then 1/9th the radiation absorbed dose is transmitted, yet the intensity of activation (amplitude) on "film", or more likely a semiconductor imaging surface is preserved at that one place. Then software just draws lines between all the known data points to make a millimeter accurate "interpretive" CT scan Now thats just 1/9th the radiatuion dose. It is pretty simple to go with the idea the a 5 on a side square would also function, giving 1/25th the usual radiation absorbed dose. Also the physician can always specify different bismuth microchannel chunks if they prefer anything from a 9th, a quarter or even a full dosing image.

a slightly fancier approach uses the multiplier effect to create CT scans with just 1/100th the previous amount of radaition. (1/25th * 1/4th = 1/100th) That is to have the software guess what it is looking at with each pixel of a scanning radiographic beam. if the last 3 pixels, as well as mapping derived shape (sort of like OCR or nudity autodetection) suggest a soft tissue type then the energy to the radiation source is reduced, to provide the more minimal amount of energy required to image that kind of tissue). Its possible that permits a quarter of the usual radiation dose. alternatively, I think (but do not actually know) that actual cancer risk from radiation is related to highest energy, thus its possible that say ten 1/10th strength radioactive photons reaching the CCD imager as 100 microsecond pulses has half or a quarter the risk of one dose of radiation ten times larger.

Update: I think this could work with X-rays, just put a plate with lots of holes in it in front of the x ray source, then use the lower resolution that is capable of doing effective imaging.

as always my ideas are public domain

beanangel, Oct 26 2012

Science Magazine link http://www.sciencem...f-81fc-861836d61860
[beanangel, Oct 26 2012]

This link actually has some non-login text http://www.aboutcan...sk_brenner_2007.htm
[beanangel, Oct 26 2012]


       Hang on. I got the impression that, in all CT systems, all the X-rays going through the patient are registered. In other words, all the X-ray energy delivered into the patient contributes to the final image.   

       If this is true, then channelling the X-rays will just create a narrower beam, requiring a longer scan and the same total exposure. No?
MaxwellBuchanan, Oct 26 2012

       Its interpretive. kind of like replacing a watercolor with a pointillist painting, where the software draws the lines between the   

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       "pointillisms" to recreate the look of an orginal watercolor. the tiny areas of radiation are the result of the microchanneled bismuth chunk   

       It is true that the resolution is 1mm rather than say 1/25th of a mm, its just that I think think a human clinician is looking at larger detail than the 1/10 of a millimeter size
beanangel, Oct 26 2012

       Right, for those giant hairline fractures.   

       Actually, my understanding is that one of the advantages of CT (and MRI) is the high level of detail they provide, revealing things such as stress fractures that don't show up on normal X-rays.   

       I'm not sure how this idea is any different from taking a low-res picture and scaling it up. You're just using the computer to interpolate detail that doesn't exist, the same as if you just doubled the resolution of the image in Photoshop. In fact, it's worse than that, because it might mask details that are too small to be resolved in the image, giving the impression that there's nothing wrong with an area that may have a problem. Big [-] on this one.
ytk, Oct 26 2012

       CT also doesn't use point results (I think). It use the distortion/diffraction to produce it's image. This means that narrowing of the input beam will produce an impressionist image, not pointillist, since there will be less total data still covering the entire scanned area.
MechE, Oct 26 2012

       //CT also doesn't use point results (I think).// True, but it probably could.   

       However, [ytk] is right, I think. You might as well use a lower intensity and get a noisier, less contrasty, image.   

       In the end, you put a certain amount of X-rays into a person and get a certain amount of data out. Whether you reduce the overall intensity or image fewer points with higher intensity and then interpolate, the end result won't be much different.   

       Actually there might be one difference. The relationship between carcinogenicity and radiation dose is non-linear and (I think - not sure; [EDIT - the jury is out]) it flattens a little at high doses. Therefore, imaging a few points at high (normal) intensity may actually be worse than making a continuous image at low intensity, if the total delivered dose is the same.   

       Ultimately, the solution is either to use a different imaging technique, or to improve the sensitivity of the detectors (which, I imagine, people are working hard to do).
MaxwellBuchanan, Oct 26 2012

       // improve the sensitivity of the detectors //   

       Umm .. there are quantum noise limits on the sensetivity of the detectors. And CT (to a certain extent) relies on scattering. Yes, ionising radiation dose is stochastic. Much like a flash photo taken in darkness, the quality of the image is dependant on both the duration and the intensity of the flash. It all depends on how the detector integrates the incident energy.
8th of 7, Oct 26 2012

       // a researcher who estimated that 1 of every 1000 persons with a computed tomography body scan got cancer. thus of about 2.4 million scans, 24,000 lethal cancers were being caused each year //   

       Let's take a look at some of the assumptions you're making here:   

       1) a single researcher making a fairly general statement does not make something true. There's a 'researcher' who's spent most of his life 'proving' that the Great Pyramid at Giza is actually an ancient landing pad for giant alien spaceships. His work is taken so seriously that it has led to a feature-length documentary called 'Stargate' and a ground-breaking investigative journalism series called 'Stargate SG-1'.   

       2) 'cancer' does not necessarily mean 'deadly cancer'. My aunt had cancer; some doctors cut it out of her and replaced it with a rather attractive pouch of saline (I say this objectively, mind you). Now my aunt no longer has cancer, and she is not dead.   

       3) 'estimate' does not mean 'exact figure'. By scooping up a bucketful of gravel and examining the contents I can estimate that for every ten rocks in my driveway, one of them will be black, but there's no way to come up with a specific ratio unless I count all of the rocks in my driveway.   

       Science, [beany], science!
Alterother, Oct 26 2012

       What [Alterother] said, except that the bit about // the Great Pyramid at Giza is actually an ancient landing pad for giant alien spaceships // which is actually correct, but only by pure coincidence.   

       // replaced it with a rather attractive pouch of saline //   


       Was it expensive? Is it socially acceptably to have the entire person replaced with a more attractive bag of saline? Just curious … no- one specific in mind, you understand …   

8th of 7, Oct 26 2012

       they don't use CCDs or at least the scanners in any of the hospitals I've come across don't. There's work going on to implement electron miltiplier CCDs.. EM CCDs, which with a quantum efficiency of >90%, gives you a 20% drop in the amount of radiation necessary.
bs0u0155, Oct 28 2012


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