Arbeitsgruppe Phantome
Phantom group - Introduction

It is obvious that all sub-projects within the first major part of the FORBILD fund, as they deal with the improvement of CT imaging, will at least partly make use of simulated CT raw data. E.g. it is clear to see that new algorithms examined for project II.2. must be validated with precisely defined and well known input data. In a similar form this argument applies to all other projects of part I.

During the first 4 months since FORBILD's kickoff a team FORBILD by members of all concerned sub-projects developed a series of phantoms:

• a group of 6 semi-anthropomorphic body sections providing simplified but realistic cross sections of typical regions of diagnostic interest.
• a group of physical phantoms (3 up to now) that can be used to derive quantitative measures of image quality like noise, resolution or artifact content.

Contributions were made by members of the SIEMENS Medical System research department and of the IMP in Erlangen. In detail the following people were - more or less - concerned with the phantom design:

(mail to phantom group)

Especially for the case of the semi-anthropomorphic phantoms our main goal was to supply a set of exactly defined geometrical objects that can be used by different teams working on various topics at different places with individual tools without sacrifying the comparability of results.

The results of the design sessions can be found in the following list:

For each phantom we provide the description of the actual design and the respective file that contains the list and the descriptions of the geometric objects the phantom is designed from. The syntax of the phantom geometry description file can be understood easily and is adapted to the CT simulation tool CT_SIM developed by SIEMENS Medical Systems (proprietary software for internal use only).

In addition we provide instructions for the simulation of noise and a preliminary table of tissues of interest. For the noise as well for the densities and CT values of various human tissues the same arguments apply as mentioned above: In the first place we try to achieve comparability of the results of different working groups. We did not stress too much on the question, if the shapes of "organs", the structure of noise or the exact HU values of special tissues are perfectly realistic.