Transarterial Radioembolization (TARE) Agents beyond 90Y-Microspheres.

Liver malignancies, either primary tumours (mainly hepatocellular carcinoma and cholangiocarcinoma) or secondary hepatic metastases, are a major cause of death, with an increasing incidence. Among them, hepatocellular carcinoma (HCC) presents with a dark prognosis because of underlying liver diseases and an often late diagnosis. A curative surgical treatment can therefore only be proposed in 20 to 30% of the patients. However, new treatment options for intermediate to advanced stages, such as internal radionuclide therapy, seem particularly attractive. Transarterial radioembolization (TARE), which consists in the use of intra-arterial injection of a radiolabelled embolising agent, has led to very promising results. TARE with 90Y-loaded microspheres is now becoming an established procedure to treat liver tumours, with two commercially available products (namely, SIR-Sphere® and TheraSphere®). However, this technology remains expensive and is thus not available everywhere. The aim of this review is to describe TARE alternative technologies currently developed and investigated in clinical trials, with special emphasis on HCC.

Molecular imaging of vascular cell adhesion molecule-1 expression in experimental atherosclerotic plaques with radiolabelled B2702-p.

PURPOSE: VCAM-1 plays a major role in the chronic inflammatory processes present in vulnerable atherosclerotic plaques. The residues 75-84 (B2702-p) and 84-75/75-84 (B2702-rp) of the major histocompatibility complex-1 (MHC-1) molecule B2702 were previously shown to bind specifically to VCAM-1. We hypothesised that radiolabelled B2702-p and B2702-rp might have potential for the molecular imaging of vascular cell adhesion molecule-1 (VCAM-1) expression in atherosclerotic plaques. METHODS: Preliminary biodistribution studies indicated that 125I-B2702-rp was unsuitable for in vivo imaging owing to extremely high lung uptake. 123I- or 99mTc-labelled B2702-p was injected intravenously to Watanabe heritable hyperlipidaemic rabbits (WHHL, n=6) and control animals (n=6). After 180 min, aortas were harvested for ex vivo autoradiographic imaging, gamma-well counting, VCAM-1 immunohistology and Sudan IV lipid staining. RESULTS: Robust VCAM-1 immunostaining was observed in Sudan IV-positive and to a lesser extent in Sudan IV-negative areas of WHHL animals, whereas no expression was detected in control animals. Significant 2.9-fold and 1.9-fold increases in 123I-B2702-p and 99mTc-B2702-p aortic-to-blood ratios, respectively, were observed between WHHL and control animals (p<0.05). Tracer uptake on ex vivo images co-localised with atherosclerotic plaques. Image quantification indicated a graded increase in 123I-B2702-p and 99mTc-B2702-p activities from control to Sudan IV-negative and to Sudan IV-positive areas, consistent with the observed pattern of VCAM-1 expression. Sudan IV-positive to control area tracer activity ratios were 17.0+/-9.0 and 5.9+/-1.8 for 123I-B2702-p and 99mTc-B2702-p, respectively. CONCLUSION: Radiolabelled B2702-p is a potentially useful radiotracer for the molecular imaging of VCAM-1 in atherosclerosis.