Influence of Dose Uniformity when Replicating a Gamma Knife Mouse Model of Radiation Necrosis with a Preclinical Irradiator.

Influence of Dose Uniformity when Replicating a Gamma Knife Mouse Model of Radiation Necrosis with a Preclinical Irradiator. Radiat Res. 2019 Feb 19;: Authors: Boria AJ, Perez-Torres CJ Abstract A common mouse model used for studying radiation necrosis is generated with the gamma knife, which has a non-uniform dose distribution. The goal of this study was to determine whether the lesion growth observed in this mouse model is a function of non-uniform dose distribution and/or lesion progression. Here, a model similar to the gamma knife mouse model was generated; using a preclinical irradiator, mice received single-fraction doses from 50 to 100 Gy to a sub-hemispheric portion of the brain. The development of necrosis was tracked for up to 26 weeks with a 7T Bruker magnetic resonance imaging (MRI) scanner using T2 and post-contrast T1 imaging. MRI findings were validated with histology, specifically H&E staining. Single small beam 50 Gy irradiations failed to produce necrosis in a 26-week span, while doses from 60 to 100 Gy produced necrosis in a timeframe ranging from 16 weeks to 2 weeks, respectively. Postmortem histology confirmed pathological development in regions corresponding with those that showed abnormal signal on MRI. The growth of the necrotic lesion observed in this gamma knife model was due in part to a non-uniform dose distribution rather than to the increased severity of the lesion. Interpretation of results from the...
Source: Radiation Research - Category: Physics Authors: Tags: Radiat Res Source Type: research