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Registered Member #1143
Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721
Hello. is it really possible to make good quality CT scanner by using high quality X ray beam, green intensifying screen, stepper motor with low angle/step ratio, good quality camera and every thing synchronized by uC. Question just one, is it possible to make high detail pictures with intensifying screen in short time, if yes, how ?
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
Well if you were to make it, I'd bet you'd be the first in the world to DIY such a thing!
Problem with an intensifying screen is that the light is dim, so you need long exposures. If time isn't an issue you could certainly make the machine, but if you need to make an exposure in x amount of seconds you're SOL.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Linas wrote ...
Question just one, is it possible to make high detail pictures with intensifying screen in short time, if yes, how ?
Intensifying screens are the imaging technology of the last century, and not worth developing into a system, any more than some new refinement to 35 mm film technology. Resolution is inherently poor and noisy. Images are acceptable for macro imaging - 1:1 - but beyond this you have what is called 'empty magnification' in microscopy - i.e. the images increase in size, but no new details are revealed.
It's your own responsibility to know and follow the radiation safety regulations in your own nation or jurisdiction, so keep your dosimeter calibration certificates up to date!
Registered Member #1143
Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721
Grenadier wrote ...
Well if you were to make it, I'd bet you'd be the first in the world to DIY such a thing!
Problem with an intensifying screen is that the light is dim, so you need long exposures. If time isn't an issue you could certainly make the machine, but if you need to make an exposure in x amount of seconds you're SOL.
i can easy boost my X ray machine power loosing high energy photons to 500W or so, with good camera i should get nice pictures and fast. but what about details ? i guess shorter is better, but i get less energy photons, and as far as i know, high energy high detail. and what about tube_object, object_screen distance ? does any one have a theory then the best picture is produced ? ( or should i do it hard way by experiments )
Registered Member #1143
Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721
hboy007 wrote ...
how about an array of scintillator/WLS fibers that end up glued to a CCD camera sensor? at one end?
or just get good and thin layer intensifying emulsion on CCD sensor, but i need to get good camera, and also get emulsion for high detail conversion.That sounds expensive also, i will get 3x3xZ cm active scanning space, that is not very good, but acceptable
Registered Member #1667
Joined: Sat Aug 30 2008, 09:57PM
Location:
Posts: 374
Well, scintillator fibre could be arranged as a line of pillars that harvest several radiation lengths. As a bonus, photon yield drops for oblique angles, damping secondary and tertiary radiation a bit.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
If you intend to use a CCD, even DSLR cameras have relatively small ccds so yes you will have a small scanning space.
You'll also have to make a lead pinhole to take advantage of that small space, because x-ray tube focal spots are relatively large. A lead pinhole will allow for sharper images at the expense of increased exposure time.
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HomeMade CT [update_first _3D_pictures]
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