文摘
Purpose Hypericin (HYP) has been found avid to necrosis in small animal studies. We sought to evaluate the tissue distribution of 131I-HYP in a large animal model and to explore the theranostic utilities of 131I-HYP after radiofrequency ablation (RFA). Materials and methods This animal experiment was approved by the institutional ethics committee. Twenty-five male dogs were enrolled and subjected to transabdominal hepatic RFA. 131I-HYP was prepared by an electrophilic substitution method and intravenously administered at 0.5?mCi/kg. Systemic and regional distributions of 131I-HYP were monitored dynamically by single-photon emission computed tomography/computed tomography (SPECT-CT), gamma counting, autoradiography, and fluorescent and light microscopy at different time points up to 14?days. Experimental data were quantified and statistically analysed. Results Most of the tissues and organs retained 131I-HYP only transiently. 131I-HYP was mainly metabolised in the liver and excreted into the bile. 131I-HYP gradually accumulated in the RFA-induced necrosis with a peak concentration occurring within 2?days and lasting over 2?weeks as visualised by in vivo SPECT-CT and ex vivo autoradiography and fluorescent microscopy, and quantified by radioactivity and fluorescence measurements. Accumulation of 131I-HYP was low in both the necrosis centre and normal liver tissue. Conclusion 131I-HYP showed persistent high affinity to hepatic thermo-coagulative necrosis, but only a transient uptake by normal liver in dogs. Necrosis caused by RFA could be indicated by 131I-HYP on nuclear imaging, which suggests a supplementary measure for tumour detection and therapy.