Durante, M.

La Tessa, C.

Lang, P. M.

Merrill, F.

Prall, M.

Shestov, L.

Varentsov, D.

GSI Repository

First high-energy proton tomography of a mouseC. La Tessa1, M. Durante1,2, P. M. Lang2, F. Merrill3, M. Prall1, L. Shestov1, and D. Varentsov11GSI, Darmstadt, Germany; 2TU Darmstadt, Germany; 3Los Alamos National Laboratory, NM, USARelativistic protons have been proposed as an alterna-tive to low-energy ions in the treatment of cancer and noncancer diseases [1]. The increase of the primary beam en-ergy to the GeV region will overcome several limitationsof Bragg-Peak therapy with protons, such as the broaden-ing of the primary beam due to multiple scattering and un-certainties on the particle range and Relative Biological Ef-fectiveness (RBE). These processes lead to a reduced dosegradient between the tumor volume and the surroundingtissue and thus to an increase of side effects. The mainadvantage of relativistic protons is that the beam crossingthe patient can be exploited for imaging purposes. Pro-ton radiography was investigated for many years becauseof its low radiation dose and high density resolution, butuntil recently the image blurring caused by scattering waslimiting its practical applications in medicine. In the pastyears, the Los Alamos National Laboratory (LANL) sys-tem based on a magnetic lens after the object for imagingand chromatic aberration corrections pushed the techniqueto unprecedented time and spatial resolution [2]. This tech-nique exploits differences in the lateral scattering of the pri-mary ions due to the material thickness and density theyencounter. The application of this methodology to medicalimagining has been tested at the pRad facility (LANL) inDecember 2012. The experiment was performed within theframework of the PANTERA (Proton Therapy and Radio-graphy) project. Radiographies of simple (plastic tissue-equivalent targets) and complex (antropomorphic phantom,zebra ﬁshes) geometries were acquired using 800 MeVprotons. Furthermore, the ﬁrst proton tomography of aformalin-preserved mouse was obtained. First preliminaryresults of the latter target are shown in this report.The experimentThe mouse was placed with its main axis perpendicu-lar to the beam direction. A rotational stage was used toallow a 360 degrees movement of the sample with a 0.5 de-grees step. Examples of the mouse proﬁle acquired in theorthogonal and parallel direction with respect to the beamaxis are reported in Figs. 1 and 2. The former has beenobtained from a direct acquisition of the target radiographywhile the latter was achieved through a more advanced dataanalysis. Using ﬁltered backprojection (employing a rampﬁlter), tomographic slices were reconstructed from trans-mission images, of which Fig. 2 is an example. The shapeof the mouse can be clearly distinguished in the full picture(Fig. 1). Furthermore, internal bony structures are well vis-ible especially in the parallel reconstruction (Fig. 2).Figure 1: Proﬁle of the mouse acquired in the directionorthogonal to the beam axis.Figure 2: Tomographic reconstruction of a mouse slice ac-quired in the direction parallel to the beam axis. The imagecontains a section of the head, where the skull bones (darkareas) and nasal cavities (light areas) are visible.ConclusionsThe application of relativistic protons to diagnostic hasshown promising results. Further tests on live animals areplanned at pRad in 2013 and at the proton microscopePRIOR located in the FAIR facility, where energies above1 GeV will be available. The experiments will focus on op-timizing the technique for the image of lesions implantedin the animals and couple the irradiation with standard ra-diotherapy.References[1] M. Durante and H. Sto¨cker, J. Phys.: Conf. Ser. 373 (2012),012016.[2] F. E. Merrill et al., Rev Sci Instr 82 (2011), 103709.HEALTH-58 GSI SCIENTIFIC REPORT 2012482

First high-energy proton tomography of a mouse

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First high-energy proton tomography of a mouse

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