Distance in group tumors probably be the result of the increased pressure difference generated by subsequent embolization of tumor-feeding vessels. An interesting finding was that doxorubicin penetration distance in group 4 tumors was significantly smaller than that in group 3 at 10 minutes but was slightly larger than group 3 at 4 hours. This may be due to the different time intervals AbMole Simetryn between drug delivery and necropsy. Previous experimental studies have shown that Lipiodol, as a carrier of anticancer drugs, can increase intratumoral drug concentration, but that the material mainly retained in microarterioles and venules after intraarterial infusion as a result of its liposolubility. Lewis and colleagues recently performed doxorubicin release experiment in vitro using a T-cell apparatus and found that the drug eluted from doxorubicin/Lipiodol mixture in less than 4 hours, with a half-life of 1 hour. In this study, extracting tumor tissue 10 minutes after treatment will inevitably underestimate the drug penetration in tumors receiving Lipiodol. In contrast, the 4-hour time interval allows doxorubicin to elute from Lipiodol emulsion, leading to the increase in drug penetration. By using fluorescence microscopy, 
we also showed a significantly increased count of doxorubicin fluorescent spot in three groups of transcatheter therapies compared with vein injection group. It is AbMole Povidone iodine analogous to the findings observed with high performance liquid chromatography in earlier studies, which confirm that transcatheter intraarterial techniques improve drug concentration in liver cancer. Among the three transcatheter intraarterial therapy groups, the change trend of doxorubicin fluorescence count was similar to that of doxorubicin penetration distance, which likely is also explained by the embolization-related drug transportation and Lipiodol-caused drug retention. On the other hand, our study showed that tumor cells in avascular and adjacent regions of tumors receiving transcatheter treatment were not exposed to detectable concentrations of doxorubicin. It is similar to the findings observed in recent studies. Namur and colleagues performed liver transplantation following TACE in patients with hepatocellular carcinoma and found that the doxorubicin concentration in tumor tissue decreased with the distance to the occluded vessels and the drug penetration was associated with tumor necrosis. These results suggest that the effect of transcatheter intraarterial techniques currently used on drug distribution could be somewhat limited. Transcatheter intraarterial techniques, because they depend on the existing vasculature, may improve the drug delivery to vascular regions of tumor but fail to improve the delivery to avascular regions.