Abstract: Objective: To explore the value of multislice CT perfusion scanning in the prediction of the radiotherapy sensitivity in nasopharyngeal carcinoma. Methods: The spiral CT dynamic scanning in 52 patients with nasopharyngeal carcinoma were implemented before treatment. The perfusion data of nasopharyngeal carcinoma and inviolate wing muscle were calculated through the time-density curve. All patients were treated with radiation therapy， the CT scanning of the nasopharynx were reexamined when the external exposure arrived at DT50 Gy. The relationship between maximum cross-sectional area of tumor，blood flow(BF),blood volume(BV),mean transit time(MTT),permeability surface(PS) and tumor regression function parameters and tumor regression rate(Rs0 - 50 ) were measured before reatment and at the DT50 Gy of external exposure. Results: The BF，BV，MTT and PS of 52 patients with nasopharyngeal tumor were(385. 79 39. 08) mlmin - 1100 g - 1,(14. 49 16. 29) ml /100 g，(3. 34 1. 5) s and(65. 13 10. 02) mlmin - 1100 g - 1， respectively. The correlation analysis showed that there were not relevant relationships between the BF，BV，MTT，PS and tumor area and Rs0 - 50(P ＞ 0. 05). Rs0 - 50 less than or equal Objective: To 0. 75 and more than 0. 75 were set as low sensitive group and high sensitive group， respectively. The BV and BF in high sensitive group were significantly higher than those in low sensitive group(P ＜ 0. 01),while PS was just the opposite(P ＜ 0. 01). Conclusions: The BV and BF of CT perfusion parameters in nasopharyngeal tumor can predict their sensitivity Objective: To radiotherapy