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James R
Sun. 13 Sep.09,
04:24
[Reply (5 of 21) to:
'MRI registry equations'
started by: 'Donna Nusser'
on Tue. 18 Aug.09]
 Category:
Basics and Physics
|
| MRI registry equations |
i don't know if it's just me but i feel the questions on the MIC course are way off topic sometimes. when i answer these questions myself, i feel like i know nothing cause the questions IMO are being asked in the "beating around the bush method"
i've been told that the registry is more basic than the questions they ask. pus they cover way too much than the ARRT exam question breakdown.
i'm going to use the black and yellow & lippincott book plus the answered question MIC from here on in.
can anyone who knows of or has taken the registry recently than can clarify this.
any advise or info will be greatly appreciated cause i'm pretty intimitaded by this test and i want it done by the end of this year
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|  View the whole thread | | |
n p
Fri. 11 Sep.09,
11:50
[Reply (3 of 12) to:
'90 excitation pulse vs 180 inversion pulse'
started by: 'Bjorn Redfors'
on Sat. 27 Jun.09]
Category:
Basics and Physics
|
| 90 excitation pulse vs 180 inversion pulse |
no hithesh n, that is a 180 rephasing pulse. thats not the question. the question is how is the net magnetization changed from the z plane to the -z plane without causing phase coherence, like the case of an inversion pulse. it is supposedly 2x as long or 2x as strong as the 90 degree pulse, but doesn't cause coherence. Why not is the question.
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hithesh n
Fri. 11 Sep.09,
08:33
[Reply (2 of 12) to:
'90 excitation pulse vs 180 inversion pulse'
started by: 'Bjorn Redfors'
on Sat. 27 Jun.09]
Category:
Basics and Physics
|
| 90 excitation pulse vs 180 inversion pulse |
Hi Bjorn,
I might be able to explain this even though its too late.
Initially a 90 excitation pulse is applied, the Hydrogen protons precess in the XY plane. Now they are spinning in sync in the XY or transverse plane. This is where they emit the RF signal.
But pretty soon, the neighboring hydrogen protons go out of sync, ie one is going faster and the other is going slower. This is similar to runners running a race in a track, they all start at the same time(assume) but after a couple of secs, some run faster than the other. The faster ones are in the front and the slower ones are in the back.
How do you bring them back into sync?
This is where the 180 excitation comes into play.
Now you apply a 180 pulse, this is equivalent to making the runners run in opposite direction. Now suddenly, the slower runners are gonna be in the front and faster ones in the back. Eventually the faster ones catchup and all of them are gonna be in sync. They go out of sync again.
They go out of sync bcoz the magnetic field applied is not uniform and due to material (tissues, bones etc). Local variations in the field causes the protons to go out of sync.
The 180 brings them in to coherence, not instantly but they do catch up and become coherent.
The 90, brings them into coherence almost instantly.
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waseem zafar
Thu. 3 Sep.09,
11:09
[Start of:
'MRI TECHNOLOGIST'
0 Reply]
Category:
Jobs
|
| MRI TECHNOLOGIST |
i am medical imaging technologist,i have passed BSc(HONS) Medical imaging technology in july 2007 from university of health sciences lahore.i have great experience of MRI(1.5T PHILIPS Magnetom,1.5T Siemens Avanto,Hitachi0.35T.ICAN PERFORM ALL TYPES OF SCANNING OF MRI INCLUDINGMRA,MRV,PERFUSION,DIFFUSION etc,
ihave also good experience of CT 64 SLICES TOSHIBA AQUILION,I CAN PERFORM ALL PERIPHERAL ANGIO,CARDIAC ANGIO,BIPHASIC AND OTHER CT PROCEDURES,I HAVE GREAT EXPERIENCE OF POSTPROCESSINF ON WORKSTATION OR VITREA,I CAN MAKE ALL 3D IMAGES ON VITREA.I AHVE EXPERINENCE OF NUCLEAR MEDICINE,AND FUJI CR SYSTEM,
I WANT TO WORK AT SAUDI ARABIA SO A I M LOOKING FOR THE JOB
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Christine Row
Tue. 1 Sep.09,
19:11
[Reply (1 of 4) to:
'Please recommend materials sensitive to T1-weighted MRI'
started by: 'Cindy Duan'
on Wed. 12 Aug.09]
Category:
Basics and Physics
|
| Please recommend materials sensitive to T1-weighted MRI |
Beside diluted contrast agents, you can use fat containing substances, for example fish-oil filled capsules.
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