The Effect of Pentoxifylline in Improving Tumor Hypoxia Assessed by Tc-HL91-NI

Received 5/20/2008; revised 5/30/2008; accepted 7/1/2008. For correspondence and reprints contact: Guang-Uei Hung, M.D., Department of Nuclear Medicine, Chang-Bing Show Chwan Hospital. 6 Lugong Road, Lukang Township, Changhua 500, Taiwan. Tel: (886)4-7813888 ext. 70161, E-mail: [email protected] Purpose: Tc-HL-NI is a novel hypoxia-imaging agent synthesized by the Institute of Nuclear Energy Research (INER). Pentoxifylline (PTX) is a peripheral vasodilator and has been found to improve tumor hypoxia and to enhance response to radiotherapy. The purpose of the study was to evaluate the feasibility of using Tc-HL91-NI for assessing the effect of PTX in modifying tumor hypoxia. Methods: The human breast cancer-bearing nude mice were pretreated with 100 mg of PTX as the study group. Tc-HL91-NI was administered intravenously and whole body scan was performed at 2 h post-injection. The uptake ratios of tumor-to-background (T/B) were measured. Parallel studies without PTX pretreatment were performed as control group for comparison. Results: There was relatively higher uptake of TcHL91-NI in tumor compared to the contralateral thigh. In addition, the tumor uptake of Tc-HL91-NI was significantly reduced in PTX treated group than controls. The T/B ratios of Tc-HL91-NI were 1.95 0.34 and 3.53 0.55 for PTX and control groups, respectively (P = 0.01). Conclusions: The preliminary results suggested that Tc-HL91-NI prepared by INER could be used to noninvasively evaluate the effect of PTX in improving tumor hypoxia in vivo. Further human trials should be warranted before its clinical applications.