Figure 5. Dexrazoxane treatment. A single 20 Gy dose was administered to the entire rat heart to simulate RIHD; DZR treatment was administered for 12 weeks post-irradiation. Three randomly selected rats from each group were monitored using high-frequency echocardiography at 4, 8, 12, 16, 20, and 24 weeks post irradiation. All rats were euthanized at 24 weeks; serum and heart tissue samples were collected.