  Difficulties in obtaining good phantoms, improvements in technologies of
voxel localization, better sequences for water and fat suppression has brought
us to define a minimal Protocol of home-made quality controls of MRS systems.
Measurements, defined in the proposed protocol, have, as main goal, to
establish if peaks quantification predicts realistic concentration values,
meaning that, the occurrence of this event is a sufficient condition to declare
that MRS system works good. Moreover, stability measurements helps in a correct
data understanding. It is, indeed, realistic to think that environmental
condition can introduce casual errors in the working good system. Discrepancies
in the working good condition, under stochastic variability (environment), have
to be related to systematic errors introduced by the set of pre and/or
post-processing operations and/or by any forms of MRS bad-working tool that
differs from the previous. The quality control minimal protocol has been
executed on a Philips-Achieva MRS system utilizing a phantom supplied by the
manufacturer. The minimal protocol consists of two steps: reproducibility and
performance tests. The reproducibility of the MRS measurements helps in
quantifying the stability of the system. The performance test enables to
establish if the system is able to reproduce concentrations in a realistic way.
In both cases good results have been obtained: fluctuations of measured values
are below 9% and quantification of concentration is consistent with the known
values.
