Irradiation of mouse brains at University Proton Therapy Dresden (UPTD): Treatment planning, dose verification and biological assessment of radiation damage


Irradiation of mouse brains at University Proton Therapy Dresden (UPTD): Treatment planning, dose verification and biological assessment of radiation damage

Müller, J.; Suckert, T.; Beyreuther, E.; Tillner, F.; Krause, M.; Enghardt, W.; Dietrich, A.; Bütof, R.; Lühr, A.; von Neubeck, C.

Proton therapy holds the potential to spare tumor-surrounding tissue and is therefore frequently used in brain tumor treatment. Clear indications from in vitro experiments show that the clinically applied relative biological effectiveness of 1.1 is higher towards the distal edge of the proton Bragg peak. Due to planning margins and range uncertainties the Bragg peak is typically placed in normal tissue and might increase neurological toxicities. Clinical evidence for radiation induced brain necrosis is yet scarce, nonetheless, needs critical evaluation. Sophisticated in vivo studies might be able to close this knowledge gap when designed to mirror the clinical exposure scenario.
Here, the setup for in vivo experiments together with the first results of mouse brain irradiation at the experimental beam line [1] of the UPTD will be presented. Absolute dosimetry in treatment position was done with ionization chambers and EBT3 radiochromic films. The anesthetized mice were fixed in an in-house developed multi-modality bed suitable for imaging and irradiation. Following CT for target delineation and proton radiography [2] for treatment positioning, mice were irradiated with a lateral collimated proton beam of 2 mm in diameter to the proximal hemisphere of the brain. Following radiation, mouse brains were excised and analyzed for DNA and tissue damage. Matching photon experiments with SAIGRT [3] are currently underway allowing in the future a direct comparison of treatment related side effects in the brain.
[1] Helmbrecht et al. J Instrum 2016
[2] Müller et al. Acta Oncologica 2017
[3] Tillner et al. Phys Med Biol 2016

  • Contribution to proceedings
    PTCOG 57 - 57th Annual Conference of the Particle Therapy Co-operative Group, 21.-26.05.2018, Cincinnati, USA

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Publ.-Id: 26856