physics testing on GE 64

papa · Posted: Fri Nov 02, 2007 11:04 am Post subject: physics testing on GE 64

ok, dumb questions.....

we had the physics testing for the ACR accredidation on the GE 64. the physicist failed us on the low contrast resolution, and a ring artifact. he told me that since this is a brand new scanner, he would expect better image quality from it.

had my GE service engineer come out to recalibrate the scanner, and he told me that everything is within GE specs.
-the phantom that the physicists use for ACR won't give the propper images, and they need to use the image analysis tool for the low contrast resolution.
-the ring artifact is from scanning the phantom helically at a smaller DFOV. if he were to test it at a larger FOV, he would not see the ring.

so who do i believe, GE or the physicist?

Question

_________________
Mr. Green

papa RT(R)(CT) Mr. Green

Delusional Radiology
never meddle in the affairs of a dragon, for you are crunchy, and taste good with ketchup

papa · Posted: Mon Nov 05, 2007 2:57 pm Post subject:

ok, another thing wrong ( i always thought GE was better than this)

another failed part of the ACR was the HU for water. when i had the GE service engineer in, we tried to duplicate the problem, but could not tell what values the physicist was using (helical/axial etc.)

well, today I just scanned every damn thing. I found out that on my 100 kV 5.0 mm axial scans, i was getting like a -6.0 for water, and on my 120 kV 1.25 mm images, they were going as far out as -7.2.

told this to my service engineer, and he said that he would check with his supervisor, and that this may be normal for the "new technology in the GE VCT 64".

who thinks i'm getting a hose job?

Evil or Very Mad

_________________
Mr. Green

papa RT(R)(CT) Mr. Green

Delusional Radiology
never meddle in the affairs of a dragon, for you are crunchy, and taste good with ketchup

CigarPete · Power User Joined: 21 May 2007 Posts: 118

well papa..

welcome to the world of the middleman. I would get the physicist in touch with the service guy.. and let them hash it out... a lot of physicists are smarter than this tho..

I would never let the service guys yank me around.. I show them the report and say tell them this needs to be fixed.. GE is famous for tihs stuff... if there are issues getting the service guy to fix what's wrong then ask him for the name of his supervisor and call that guy.. If GE has one thing it's certainly personel in management roles.

I hate these kinds of fights..

Good Luck
Pete