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Operation
Phantom Preparation
2
2-1
Section 2
Operation
2.1 Phantom Preparation
The phantoms can be shipped filled with solutions or solutions can be shipped separately. Each user can
also prepare a solution.
2.1.1 Signal Producing Solution
At each operating field strength, AAPM recommends that the chosen NMR material should exhibit the
following characteristics:
100 msec < T1 < 1200 msec
400 msec > T2 > 50 msec
proton density = H
2
O density
One of the following solutions is suggested as a signal producing solution. It should be noted that
relaxation times are both temperature and field strength dependent. The relaxation rates (inverse of
relaxation times) are approximately linear with ion concentration.
Agent Concentration T1 T2
CuS0
4
1-2SmM 860-40 msec 625-38 msec
NiC
12
1-25mM 806-59 msec 763-66 msec
Propanediol 0-100% 2134-217 msec 485-72 msec
MnC
12
0.1-1mM 982-132 msec --
2.1.2 Filling the Phantom
Degassed water should be used to make MR solution. Water can be degassed by boiling and cooling.
The following amount of water should be prepared:
Cubical Phantom: 4,000 cc/4 liters
Flood Phantom: 12,000 cc/12 liters
Once the solution has been prepared, it is recommended that several drops of wetting agent be added to
reduce surface tension and that some hydrochloric acid be added as a fungicide. As the solution is
poured into the phantom one should watch for air bubbles, especially any trapped in the resolution
section. It is recommended that the phantom be placed in a vacuum chamber for several hours to remove
the trapped bubbles.