Preserving the phantoms
The hydrogel based phantoms must not dry. The surface should always be covered with preservative fluid. The fluid can be drained off before freight, but never let the phantoms stay dry for more than few days.
If fluid disappears by desiccation it should be replaced with distilled or demineralised water.
The phantoms should be inspected once every month and the preservative fluid replaced every 3 months.
The hydrogel based phantoms are fine substrates for growth of fungus and bacteria, so it is important to kill or reduce microorganisms.
If phantoms are attacked by microorganisms it can be disinfected with 0,5% solution of H2O2 in water.
The ingredients for long time preserving are not critical as long as it works.
Some elder phantoms are preserved with:
-0,5% Acnibio OCS (K-Sorbat + Na-Benzoate) + 1% citric acid. It is no longer available from the manufactory. A small quantity is stil in stock for preserving the old phantoms.
Now all new phantoms are preserved with 0,2% Grotan BA21.
Please notice Grotan BA21 is alkaline and it neutralises the acid that is important for Na-Benzoate to work.
For some phantoms the speed of sound is critical. To maintain a speed of sound of 1540 m/sec it is recommended to use either
9 % glycerol or 6,5 % PEG MW 400. Glycerol and PEG can be
mixed. It is not critical to continue with the one, that is
mentioned on the label on the phantom.
These preservative fluids are available:
Refill1540ACN
Refill1500GRO
Refill1540GRO