MSc-thesis project physics and applied physics
Proton radiography: an imaging tool for medical applications
Proton radiotherapy allows to reduce the radiation dose to the healthy tissues that
are inevitably also irradiated during radiotherapy. Therefore proton radiotherapy
should lead to a better treatment outcome (higher cure probability, less and/or less
severe complications) than the conventional radiotherapy with photons for a
significant fraction of the cancer patients treated with radiotherapy.
The planning of a proton radiotherapy treatment is, however, significantly more
complex than that of a conventional radiotherapy treatment. Also, the quality of the
treatment plan is much more sensitive to the quality of the information on the
properties of the tissues that the protons traverse on their way to the tumor. This
information is mainly obtained from X-ray CT imaging and has to be interpreted using
a model because the interaction of X-rays with tissue is different from that of protons.
In the framework of the research programme on proton radiotherapy that is
associated with the planned clinical facility for proton radiotherapy at the UMCG
campus, KVI has in collaboration with Nikhef and INCAS3 started a study on imaging
with protons instead of X-rays to improve the quality of the information for the
planning of proton radiotherapy treatments.
We will develop a proof of principle detector system that will be used to assess the
capabilities of proton radiography imaging to provide better quality information than
X-ray CT imaging. This detector system consists of two tracking detectors that
measure the 3D-trajectory of individual protons before and after their passage
through the patient’s body and a so-called calorimeter that measures the remaining
energy of the protons.
For the design of the detector system and the development of the data analysis
algorithm, extensive simulations of the detection of the protons and their interaction
in the patient’s body are needed. The reconstruction of a 2D-map of the average
tissue density from the measurements is relatively straightforward. However, it is also
possible to obtain depth information using more sophisticated ray-tracing techniques,
a kind of “software microscope” that can be focussed at different depths in the
sample.
We are looking for an MSc-student in physics with an interest in computational
physics and medical applications of physics to do her/his MSc-thesis research in this
project. She/he will contribute to the design of the detector system, the development
of the data analysis and the study of the optimum measurement conditions. The work
will mainly consist of large scale simulations using GEANT4. In addition she/he will
participate in prototype tests and their analysis.
Further information can be obtained from
Sytze Brandenburg
Kernfysisch Versneller Instituut
email brandenburg@kvi.nl
phone 050-3632573 (office)
050-3633599 (secretariat)