Bachelorarbeit - Physikzentrum der RWTH Aachen

Results
In this thesis the influence of movements on CT measurement has been studied. For
that, a thorax phantom and water-filled balls of different sizes that are movable within
the phantom came into use to simulate a moving lung tumor. The movements have been
measured using a CT. The aims of the study are to determine whether known, given
movements can be recognized in the measurements and how movements influence the
measured volumes of the balls.
The results of the study of the movement are that movements can be recognized with
high accuracy for all ball sizes. This is of advantage for practical work, because it means
that small tumors or tumors in an early stage can be detected and therefore diagnosed
even though movement occurs.
As results of the study of the volumes can be stated that a method which is able to
measure volumes of moving objects with an accuracy of 7% has been developed. For
that, three different ball sizes with different movement forms and different movement
amplitudes came in use for measurements. For the smallest and largest ball size, volumes
could be measurement with a high accuracy, but the error of the measurement of the
middle-sized ball is unexpectedly high. Further study is necessary on that issue. The error
of the whole method is dominated by that of the middle-sized ball volume. Therefore,
for improving the method as a whole, the volume determination of the middle-sized
ball has to be improved. Whether the overall accuracy is sufficient for clinical use has
to be determined in further studies. Nonetheless, the clinical diagnoseability, which is
important for clinical work, is given for all object sizes and movements.
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