  Proton therapy is a cancer treatment technique currently in growth worldwide.
It offers advantages with respect to conventional X-ray and $\gamma$-ray
radiotherapy, in particular, a better control of the dose deposition allowing
to reach a higher conformity in the treatments. Therefore, it causes less
damage to the surrounding healthy tissue and less secondary effects. However,
in order to take full advantage of its potential, improvements in treatment
planning and dose verification are required. A new prototype of proton Computed
Tomography scanner is proposed to design more accurate and precise treatment
plans for proton therapy. Here, results obtained from an experiment performed
using a 100-MeV proton beam at the CCB facility in Krakow (Poland) are
presented. Proton radiographs of PMMA samples of 50-mm thickness with spatial
patterns in aluminum were taken. Their properties were studied, including
reproduction of the dimensions, spatial resolution and sensitivity to different
materials. They demonstrate the capabilities of the system to produce images
with protons. Structures of up to 2 mm are nicely resolved and the sensitivity
of the system was enough to distinguish thicknesses of 10 mm of aluminum or
PMMA. This constitutes a first step to validate the device as a proton
radiography scanner previous to the future tests as a proton CT scanner.
