Radiopharmaceutical study on Iodine-131-labelled hypericin in a canine model of hepatic RFA-induced coagulative necrosis.

Abstract

PURPOSE:

Hypericin (HYP) has been found avid to necrosis in small animal studies. We sought to evaluate the tissue distribution of (131)I-HYP in a large animal model and to explore the theranostic utilities of (131)I-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. (131)I-HYP was prepared by an electrophilic substitution method and intravenously administered at 0.5 mCi/kg. Systemic and regional distributions of (131)I-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 (131)I-HYP only transiently. (131)I-HYP was mainly metabolised in the liver and excreted into the bile. (131)I-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 (131)I-HYP was low in both the necrosis centre and normal liver tissue.

CONCLUSION:

(131)I-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 (131)I-HYP on nuclear imaging, which suggests a supplementary measure for tumour detection and therapy.

• Authors: Xiaojun Qi, Haibo Shao, Jian Zhang, Ziping Sun, Yicheng Ni, Ke Xu
• Journal: La Radiologia medica (Radiol Med) Vol. 120 Issue 2 Pg. 213-21 (Feb 2015) ISSN: 1826-6983 [Electronic] Italy
• PMID: 25012473 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anthracenes
• Radiopharmaceuticals
• Perylene
• hypericin

Topics

• Animals
• Anthracenes
• Catheter Ablation
• Dogs
• Liver (diagnostic imaging, metabolism, pathology, surgery)
• Male
• Necrosis
• Perylene (analogs & derivatives, pharmacokinetics)
• Radiopharmaceuticals (pharmacokinetics)
• Tissue Distribution
• Tomography, Emission-Computed, Single-Photon