ABSTRACT
Objective To explore whether the degree of 99Tcm-methoxyisobutylisonitrile (MIBI) uptake in non-small cell lung cancer (NSCLC) could be correlated with the treatment response to three-dimensional conformal radiotherapy.Methods A total of 102 patients with NSCLC were studied with 99Tcm-MIBI SPECT before radiotherapy.The patients were classified by a follow-up CT as responders (complete or partial remission) and non-responders (stable or progressive disease).After intravenous administration of 740 MBq 99Tcm-MIBI, SPECT imaging at 10-30 min (early) and 2-3 h (delayed) were performed.Region of interest (ROI) was placed over the tumors and contralateral normal lung tissue.The uptake ratio of tumor to contralateral normal lung (T/N) was obtained from both early (ER) and delayed (DR) SPECT images.The retention index (RI) was measured as:RI = (DR - ER)/ER×100%.Statistical analysis was performed by two independent-sample t-test and Mann-Whitney U test using software SPSS 13.0.Results 99Tcm-MIBI uptake was significantly higher in responders than in non-responders:2.36 ±0.17 vs 1.82 ±0.14 (ER) and 2.48 ± 0.20 vs 1.94 ± 0.16 (DR), respectively (t = - 13.1,- 12.7, both P＜ 0.05).The median RI in the responders group was also significantly higher than that in the non-responders group (6.60% vs 5.13%, z = - 6.83, P ＜ 0.05).Conclusion ER, DR and RI of 99Tcm-MIBI SPECT might be useful to estimate the treatment response to three-dimensional conformal radiotherapy in patients with NSCLC.