Operation

Phantom Preparation 2

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.

2.1.1Signal 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 = H2O 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

CuS04

1-2SmM

860-40 msec

625-38 msec

NiC12

1-25mM

806-59 msec

763-66 msec

Propanediol

0-100%

2134-217 msec

485-72 msec

MnC12

0.1-1mM

982-132 msec

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2.1.2Filling 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.

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Fluke 76-907, 76-908 user manual Phantom Preparation, 1Signal Producing Solution, 2Filling the Phantom

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