Dipyridamole modulated Tc-99m sestamibi lung SPECT in small cell lung cancer

Purpose: In this study, the authors wanted to determine whether dipyridamol e-modulated MIBI (dipyridamole-MIBI) could enhance the prediction of the re sponse to chemotherapy in patients with small cell lung cancer. Methods: Twenty-seven patients with biopsy-proved small cell lung cancer (2 5 men, 2 women; mean age, 61+/-7 years) underwent dipyridamole-MIBI SPECT 3 to 7 days before starting chemotherapy (80 mg/m(2) etoposide and 80 mg/m(2 ) cisplatin every 3 or 4 weeks for at least two cycles), Tomographic images before and after dipyridamole (0.84 mg/kg) were acquired 1 hour after inje ction of 370 (10 mCi) and 1,110 (30 mCi) MBq MIBI, respectively, The respon se to chemotherapy was grouped as specified as complete response (CR), part ial (PR), no change (NC), or progressive disease (PD), according to the cha nge in tumor size on chest roentgenography and CT. Patients showing CR and PR were classified as responders, and those who showed NC and PD were consi dered nonresponders. Results: Among the 27 patients, 22 were responders (3 CR, 19 PR) and 5 were nonresponders (3 NC, 2 PD), The tumor-to-normal lung ratio (T:NL) of respo nders was significantly higher than that of nonresponders. The diagnostic a ccuracy of the T:NL ratio to differentiate responders and nonresponders was 33.3%, with a cutoff value of 2.5, which was significantly improved to 77. 8% when an increased T:NL ratio after dipyridamole was assigned to a nonres ponder. Furthermore, all patients with CR showed diminished T:NL ratios aft er dipyridamole, and all patients with NR showed an increased T:NL ratio af ter dipyridamole, Conclusion: Dipyridamole-MIBI SPECT could enhance the prediction of respons e to chemotherapy in patients with small cell lung cancer.