Showing papers on "Radiation-induced lung injury published in 2004"

Proton and hyperpolarized helium magnetic resonance imaging of radiation-induced lung injury in rats.

Abstract: Purpose To assess the usefulness of hyperpolarized helium ( 3 He) MRI, including apparent diffusion coefficient measurements, in the detection and evaluation of radiation-induced lung injury in rats. Methods and materials Female Fischer-344 rats were treated to the right lung with fractionated dose of 40 Gy (5 × 8 Gy) using 4-MV photons. Conventional proton ( 1 H) and hyperpolarized ( 3 He) MRI were used to image the lungs 3–6 months after radiation treatment. Apparent diffusion coefficient (ADC) maps of hyperpolarized 3 He in the lungs were calculated using a nonlinear, least-squares fitting routine on a pixel-by-pixel basis. After imaging, lungs were processed for histologic assessment of damage. Results The effect of radiation was time dependent with progressive right lung damage ranging from mild to moderate at 3 months to severe fibrosis with structural deformation at 6 months after radiation. There was a significant decrease in the apparent diffusion coefficient of hyperpolarized 3 He gas in radiation-treated lungs. Areas of decreased ADC in the lungs correlated with fibrosis shown by histology. Conclusion This is the first study to show that hyperpolarized 3 He MRI can detect radiation-induced lung injury noninvasively. Reduced hyperpolarized 3 He ADC values postradiation likely reflect reduced alveolar volumes associated with fibrosis of the interstitium. Future studies at earlier time points may determine whether this noninvasive imaging technique can detect lung damage before clinical symptoms. Development of this new approach of magnetic resonance lung imaging in the rat model of radiation-induced lung injury will increase the ability to develop appropriate algorithms and more accurate models of the normal tissue complication probability.

Defining the pathway of radiation induced lung toxicity in mice overexpressing extracellular superoxide dismutase

Abstract: Purpose/Objective: Radiation induced lung injury is mediated by reactive oxygen species. Superoxide dismutase is involved in the processing of these free radicals. Overexpression of extracellular superoxide dismutase (EC-SOD) has been shown to protect against radiation induced lung injury. The purpose of this study is to evaluate if the transforming growth factor beta (TGF )/smad3 signal transduction pathway is involved in the pathogenesis of radiation induced lung toxicity.