[Rtk-users] Preprocessing

[Jonathan Mason]

Good afternoon RTK users,

I have access to "raw data" from a Varian OBI scanner, and have
experimented with RTK for performing its reconstruction. However, it is
not really "raw" in the sense that the coefficients are proportional to
the photon flux recorded at a given sensor, but is instead proportional
to the Hounsfield attenuation along that path. With this data, it means
that one can reconstruct using FDK and other iterative techniques, which
assume a linear model, but the connection to the underlying physics is
abstract.

The problem I then have when trying to develop reconstruction
techniques, is that I do not know whether I am really correcting for
physical distortions or just correcting for Varian's preprocessing,
which has been finely tuned for its own FDK method.

My question is whether anybody has dug into the steps that manufacturers
such as Varian or Elekta perform to arrive at these projection images?
And if they think that if reverse engineered, could provide a richer set
of information to facilitate advanced strategies.

Best wishes,

Jonathan Mason

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