Objectives: The purpose of this study is to evaluate the correlation between pretreatment planning technetium-99m (99mTc) macroaggregated albumin (MAA) SPECT images and posttreatment transarterial radioembolization (TARE) yttirum-90 (90Y) PET/CT images by comparing the ratios of tumor-to-normal liver counts. Methods: Fifty-two patients with advanced hepatic malignancy who underwent 90Y microsphere radioembolization from January 2010 to December 2012 were retrospectively reviewed. Patients had undergone 99mTc MAA intraarterial injection SPECT for a pretreatment evaluation of microsphere distribution and therapy planning. After the administration of 90Y microspheres, the patients underwent posttreatment 90Y PET/CT within 24 h. For semiquantitative analysis, the tumor-to-normal uptake ratios in 90Y PET/CT (TNR-yp) and 99mTc MAA SPECT (TNR-ms) as well as the tumor volumes measured in angiographic CT were obtained and analyzed. The relationship of TNR-yp and TNR-ms was evaluated by Spearman's rank correlation and Wilcoxon's matched pairs test. Results: In a total of 79 lesions of 52 patients, the distribution of microspheres was well demonstrated in both the SPECT and PET/CT images. A good correlation was observed of between TNR-ms and TNR-yp (rho value = 0.648, p < 0.001). The TNR-yp (median 2.78, interquartile range 2.43) tend to show significantly higher values than TNR-ms (median 2.49, interquartile range of 1.55) (p = 0.012). The TNR-yp showed weak correlation with tumor volume (rho = 0.230, p = 0.041). Conclusions: The 99mTc MAA SPECT showed a good correlation with 90Y PET/CT in TNR values, suggesting that 99mTc MAA can be used as an adequate pretreatment evaluation method. However, the 99mTc MAA SPECT image consistently shows lower TNR values compared to 90Y PET/CT, which means the possibility of underestimation of tumorous uptake in the partition dosimetry model using 99mTc MAA SPECT. Considering that 99mTc MAA is the only clinically available surrogate marker for distribution of microsphere, we recommend measurement of tumorous uptake using 90Y PET/CT should be included routinely in the posttherapeutic evaluation.
- Liver malignancy
- PET scan
- Single-photon emission computerized tomography
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging