The Estimation Value of Tc-MAA in Comparison with Y-PET/MR-based Dosimetry in Selective Internal Radiation Therapy (SIRT) for Liver Malignancies.

AIM

This study intended to compare the radiation dose estimates to target and nontarget liver compartments from Tc-MAA SPECT/CT and Y-PET/MR scans in liver tumors treated by Y-glass microspheres.

MATERIALS AND METHODS

Dose estimation was performed for twenty-three eligible patients (13M, 10F) after Tc-MAA simulation using SPECT/CT imaging, and over Y-PET/MR images after Y-microsphere therapy. SimplicitY™ software was used for voxel-based dosimetry over the liver parenchyma. Dose estimates were obtained for whole healthy liver (HL), healthy injected liver (HIL), and tumor volumes. Pearson correlation, Bland-Altman plot, and Wilcoxon signed-ranks test were used for statistical analysis.

RESULTS

The mean tumor dose was 270 ± 111 Gy, the whole liver parenchyma dose was 26 ± 12 Gy, and the healthy injected liver dose was 55 ± 18 Gy from Tc-MAA simulation. Y-PET/MR dosimetry yielded a mean tumor dose of 271 ± 125 Gy, a HIL mean dose of 54±18 Gy, and a liver parenchyma dose of 25 ± 12 Gy. An excellent agreement was demonstrated between tumor doses (R2=0.90) and liver doses (R2=0.87), while the agreement was less for HIL doses (R2=0.80). Wilcoxon signed-ranks test yielded no significant difference between the dose estimates for all liver compartments.

CONCLUSION

It was deduced that Tc-MAA SPECT/CT simulation provides valuable dose prediction in Y-glass microsphere therapy. Despite the difference in volume measurements and dose estimates with Y-PET/MR, the predictive value of the Tc-MAA simulation was not affected.