NOD-SCID mice irradiation with medical accelerators: Dosimetric and radiobiological results

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Abstract

Purpose: Preclinical studies normally requires dedicated instruments due to the small anatomical scales involved, but the possibility of using clinical devices for this purpose may be of economical, scientific and translational interest.In the present work the accurate description of treatment planning, dosimetric results, radiotoxicity and tumor response of the irradiation of NOD-SCID mice were presented. Two medical linear accelerators, TrueBeam STx and Tomotherapy Hi-ART, were compared. NOD-SCID mice irradiation with Tomotherapy isa novelty, as well as the comparison of different irradiation techniques, devices and dose fractionations.Methods: Human derived glioblastoma multiforme neurospheres were injected in immunocompromised NOD-SCID mice to establish xenograft models. Mice were anaesthetized and placed in a plexiglas cagepieboth to perform CT scan for treatment planning purposes and for the irradiation. Three fractionation schedules were evaluated: 4 Gy/1 fraction, 4 Gy/2 fractions and 6 Gy/3 fractions. Tomotherapy planningparameters, the presence of a bolus layer and the irradiation time were reported.After irradiation, mice were examined daily and sacrificed when they showed signs of suffering or whentumor volume reached the established endpoint. Outcomes regarding both radiotoxicity and tumorresponse were evaluated comparing irradiated mice as respect to their controls.Results: Survival analysis showed that Tomotherapy irradiation with 6 Gy/3 fractions with a bolus layerprolong mice survival (log-rank test, p < 0.02). Tumor volume and mice survival were significantlydifferent in irradiated xenografts as compared to their controls (t-test, p < 0.03; log-rank, p < 0.05).Conclusion: The radiobiological potential of Tomotherapy in inducing tumor growth stabilization isdemonstrated.
Original languageEnglish
JournalPhysica Medica
Publication statusPublished - 2016

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