Use of gated 13N-NH3 PET/CT to examine early myocardial perfusion alteration of beagles after radiotherapy

1666 Objectives Myocardial perfusion imaging has previously been used to evaluate the radiation induced heart diseases. However, clinical follow-up about radiation induced heart disease is affected by many factors, such as, individual differences, therapeutic protocols, and follow-up time, et al. In this study, we used gated myocardial perfusion imaging to observe the variation of perfusion of beagles irradiated anterior myocardium. Methods Eight adult male beagle weighting 13-14kg as the research object, a single 20 Gy radiation guided by imaging was used of which left anterior myocardial to induced heart injury, 13N-NH3 PET/CT scintigraphy were performed 1 week before and 3, 6 months after irradiation respectively. The ratio of the RAig / RAni(irradiated region /Nor-irradiated region) are quantitative analyzed, LVEF was calculated by software. Myocardial perfusion and functional were observed dynamically before radiotherapy and different periods of post-radiotherapy. Results Myocardial perfusion imaging was normal before irradiation. Myocardial perfusion imaging showed perfusion increased in the heart irradiated areas compared to non-irradiated areas 3 months after irradiation. With the follow-up time, perfusion reduced gradually in irradiation area 6 months after irradiation. The ratios of the RAig / RAni were 0.98±0.09, 1.21±0.15, 0.96±0.25 respectively at baseline, 3 months and 6 months after irradiation (P Conclusions 13N-NH3 PET/CT scintigraphy provide an method to monitor the early injury of radiation induced heart disease. 3 months after irradiation, myocardial perfusion increased is found for the first time in experimental study, the subsequent change of myocardial perfusion requiring further observation, and its clinical significance needs further study.