hello!
im having a problem with a CTI ct scan. when i scan a qa phantom in a gridline portion, the image is like a double, it has a shadow on the lines.. this cti is originaly has a 6.3mhu tube and i downgrade it to 3.5mhu.
i already did all the modification.
the scanner it works perfectly but only the image has a problem.
im using the existing apps. sotware 4.4.19..
thank you....
Hello John,
the first thing I have to say is that I never had the chance to work on CTi CT systems, so please consider this while reading my message.
That said, I can tell You that on Toshiba systems (like X-series and A-series) You can encounter this same problem when You replace an X-Ray tube (which You did, is that so?) and You don't make a proper X-ray tube - detector alignment.
So, have You done this kind of alignment after the tube replacement?
Just my two cents...
hi Ivano,
thank you in advance, the tube was properly align but the detector not yet been touch.. but anyway i will try to re check the detector alignment..
i will let you know...
hi Carlos,
thank you for the reply,. i will check the mechanical adjustment, maybe your right, the gantry balance is not correct. bec the 6.3mhu is bigger than the 3.5mhu.
Hello John,
I agree with Carlos: You might have a balancing problem.
I thought You already covered that aspect, when You wrote "i already did all the modification". I can tell You that on Toshiba CT systems You have to balance the rotating section everytime You replace a tube with a different model, because of course they have different weights. You do this removing/adding special heavy metal plates in precise places, so that the rotating section will be perfectly balanced (You know that because when You switch off the motor brake You have no self-rotation).
Hope this helps, best luck.
hello every body,
this are the update that i performed.
i did gantry balancing according to the GE hsa cti manual. all the four angles(0,90,180,270) are already balanced.
i did detector centering by performing beam on window and radial alignment.
i did iso alignment.
i run qcal without error and calibrate the machine.
result: same problem.
i decided to put back the original 6.3mhu tube so i can verify if its the balanced,detector centering are the problems,and i surprised that the image has no problem(not adouble image).i did not run any calibration(just the aircal only). and the gantry is not balance.
what could be the possible problem?
thank you all.
I ran into a problem similar to this. We replaced a x-ray tube with one having different charactoristics, did not setup the idle filament current. It was so high that during an exposure, we had a ghost image. Who thinks of setting up, or even checking the idle filament current?
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john dismaya
CTI image problem
November 25, 2011 11:57
hello!
im having a problem with a CTI ct scan. when i scan a qa phantom in a gridline portion, the image is like a double, it has a shadow on the lines.. this cti is originaly has a 6.3mhu tube and i downgrade it to 3.5mhu.
i already did all the modification.
the scanner it works perfectly but only the image has a problem.
im using the existing apps. sotware 4.4.19..
thank you....
john.
to rate and post a comment
Ivano Murat
Re: CTI image problem
November 26, 2011 06:02
Hello John,
the first thing I have to say is that I never had the chance to work on CTi CT systems, so please consider this while reading my message.
That said, I can tell You that on Toshiba systems (like X-series and A-series) You can encounter this same problem when You replace an X-Ray tube (which You did, is that so?) and You don't make a proper X-ray tube - detector alignment.
So, have You done this kind of alignment after the tube replacement?
Just my two cents...
Best regards,
Ivano Murat
to rate and post a comment
john dismaya
Re: CTI image problem
November 28, 2011 08:48
hi Ivano,
thank you in advance, the tube was properly align but the detector not yet been touch.. but anyway i will try to re check the detector alignment..
i will let you know...
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Carlos Duran
Re: CTI image problem
November 26, 2011 10:40
Your problem is about mechanical adjustment between tube and detector...does not matter the H.U. Capacity.
However, keep in mind the rotational balance issue.
Additionally, the H.U. Behavior is software-calculated. You MUST tell to software the new H.U. Capacity even more if you downgraded the H.u. Capacity.
Cordially,
Carlos duran
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john dismaya
Re: CTI image problem
November 28, 2011 08:48
hi Carlos,
thank you for the reply,. i will check the mechanical adjustment, maybe your right, the gantry balance is not correct. bec the 6.3mhu is bigger than the 3.5mhu.
john...
to rate and post a comment
Ivano Murat
Re: CTI image problem
November 29, 2011 01:33
Hello John,
I agree with Carlos: You might have a balancing problem.
I thought You already covered that aspect, when You wrote "i already did all the modification". I can tell You that on Toshiba CT systems You have to balance the rotating section everytime You replace a tube with a different model, because of course they have different weights. You do this removing/adding special heavy metal plates in precise places, so that the rotating section will be perfectly balanced (You know that because when You switch off the motor brake You have no self-rotation).
Hope this helps, best luck.
Ivano Murat
to rate and post a comment
john dismaya
Re: CTI image problem
December 14, 2011 10:43
hello every body,
this are the update that i performed.
i did gantry balancing according to the GE hsa cti manual. all the four angles(0,90,180,270) are already balanced.
i did detector centering by performing beam on window and radial alignment.
i did iso alignment.
i run qcal without error and calibrate the machine.
result: same problem.
i decided to put back the original 6.3mhu tube so i can verify if its the balanced,detector centering are the problems,and i surprised that the image has no problem(not adouble image).i did not run any calibration(just the aircal only). and the gantry is not balance.
what could be the possible problem?
thank you all.
result
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Robert Budach
Re: CTI image problem
December 15, 2011 08:40
I ran into a problem similar to this. We replaced a x-ray tube with one having different charactoristics, did not setup the idle filament current. It was so high that during an exposure, we had a ghost image. Who thinks of setting up, or even checking the idle filament current?
Drove us crazy. Never heard of such a thing.
to rate and post a comment