A study of CT perfusion imaging before and after radiotherapy for solid lung cancer

Objective: To analyze the perfusion status of lung cancer before radiotherapy and the relationship between changes in CT perfusion parameters after radiotherapy and the efficacy of radiotherapy. Methods Twenty-eight patients clinically and pathologically diagnosed with lung cancer were enrolled as subjects. Those patients received CT perfusion imaging scan and perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS) were calculated. We use linear correlation analysis for relation between value of CT perfusion imaging and the target volume of lung cancer before radiotherapy, t-test for difference between the remission groups and non-remission groups, compared paired sample t-test for value of CT perfusion imaging before and after radiotherapy. Results: According to the efficacy of radiotherapy, 28 patients with lung cancer were divided into response group (n = 16) and non-response group (n = 12). The response group had significantly smaller tumor sizes before and after radiotherapy than the non-response group (58.72 ± 22.95 cm³ vs. 24.53 ± 13.79 cm³, P = 0.000). However, there was no significant correlation of target volume before radiotherapy with any perfusion parameter (P = 0.628). The response group had significantly larger BF and BV than the non-response group before radiotherapy (1.23 ± 1.36 vs. 6.42 ± 2.57, P = 0.024 and 1.23 ± 0.31 vs. 0.59 ± 0.18, = 0.041), suggesting a low perfusion state of tumor tissue in the non-response group. However, there were no significant differences in MTT and PS between the two groups (0.93 ± 0.58 vs. 0.93 ± 0.66, P = 0.851 and 1.46 ± 0.83 vs. 1.17 ± 0.56, P = 0.141). All the 28 patients had significantly smaller BF, BV, MTT, and PS after 0.53 ± 0.30, P = 0.007; 1.34 ± 0.73 vs. 0.74 ± 0.44, P = 0.001). Conclusions: CT perfusion imaging can predict the efficacy of radiotherapy for lung cancer, which may guide the planning and implementation of precise radiotherapy for lung cancer. (authors)