～(99m)Tc-HL91 Hypoxic Imagingin Predicting The Radiosensibility Of Nasopharyngeal Carcinoma

Objective: To investigate the value of ^99mTc-HL91 imaging in predicting the radiosensibility of tumors by comparing the imaging of nasopharyngeal carcinoma patients with the effects of radiotherapy.Methods: Thirty patients with untreated nasopharyngeal carcinoma underwent ^99mTc-HL91 SPECT imaging at 1h and 4h postin jection of ^99mTc-HL91. ROI technique was used to calculate the tumor -to-normal tissue ratio (T/B) . Routine radiotherapy was given to all subjects after imaging. The effects of radiotherapy were evaluated 4 weeks later by the radiotherapists according to the standard of WHO. Then the data of ^99mTc-HL91 imaging and radiotherapeutic responses were analized.Results:1. The ^99mTc-HL91 uptake ratios of T/B in thirty patients at 1 h and 4 h imaging were 1.370±0.207 and 1.883±0.358, respectively. There was a significant difference between T/B value of the two phases (P＜0. 001) .2. The follow-up results demonstrated that the average T/B value at 1 h phase in the group of effective radiotherapy (CR+PR) and ineffective radiotherapy (NC+PD) were 1.273±0.196 and 1.498±0. 147, respectively. There was a significant difference between T/B value of the two group (P＜0. 001, 2 tails).The T/B average value of the two groups at 4h phase were 1.679±0.232 and 2.152±0.318, respectively. There was a significant difference between T/B value of the two group (p＜0.001, 2 tails).Conclusions:1. In nasopharyngeal carcinoma patients delayed imaging at 4 h demonstrated higher tumor uptake of ^99mTc-HLg1 and the image with better quality can be acquired at delayed phase.2. The uptake extent of ^99mTc-HL91 by nasopharyngeal carcinoma may be related to the hypoxic state of tumor tissue and thus it may predict the radiosensibility of nasopharyngeal carcinoma. It is suggested that ^99mTc-HL91 scintigraphy may be potentially helpful for working out radiotherapy strategy in the patients with nasopharyngeal carcinoma.