Background and purpose: Neoadjuvant chemotherapy with docetaxel was gaining more attention in the treatment for locoregionally advanced nasopharyngeal carcinoma (NPC). The prediction of the sensitivity to neoadjuvant chemotherapy with docetaxel could enable c

linicians to individualize treatment protocols for NPC. Recently we found that

99m

Tc-MIBI imaging in NPC could predict tumor response to chemotherapy with cisplatin plus 5-FU. However

there was no study to support similar findings in NPC patients receiving chemotherapy containing docetaxel. This study was to evaluate the value of double-phase

99m

Tc-MIBI SPECT/CT in predicting response to neoadjuvant chemotherapy with docetaxel-based regimen for nasopharyngeal carcinoma. Methods: Thirty-one nasopharyngeal carcinoma patients participated in this prospective study. Before treatment

early and delayed singlephoton emission computed tomography/compute tomography (SPECT/CT) images were obtained instantly and 2 hours after an intravenous injection of 25-30 mCi

99m

Tc-MIBI. All patients received neoadjuvant chemotherapy consisting of docetaxel

cisplatin plus 5-FU for two cycles. The relationships between efficacy of neoadjuvant chemotherapy and the early uptake ratio

late uptake ratio and washout rate of

99m

Tc-MIBI were evaluated. Results: According to the MRI

the early uptake of

99m

Tc-MIBI (2.67±0.83) in the lesions which were sensitive to chemotherapy was significantly higher compared with that (1.69±0.46) in the insensitive lesions(P=0.003). The difference of the late uptake between the sensitive(1.46±0.39) and the insensitive (1.06±0.62) was also statistically significant (P=0.026). However

the washout rate of

99m

Tc-MIBI was not significantly different between the two groups (P=0.23). Through ROC curve analysis

the AUC for early uptake of

99m

Tc-MIBI and late uptake were 0.84. The sensitivity

specificity

positive predictive value and negative predictive value were 74.2%

87.5%

95.8% and 46.7% for early uptake when the cut off value of 1.97 was used. Conclusion: The uptake of 99mTc-MIBI in both early phase and late phase could predict the efficacy of neoadjuvant chemotherapy with docetaxel-based regimen.