99mTc MAA SPECT/CT pre-treatment based surrogate dosimetry and hepatotoxicity in patients following 90Y radioembolization: association of non-tumor liver dose and clinical markers of radioembolization induced liver disease (REILD).

BACKGROUND

Radiation induced liver damage can occur in healthy non-tumor liver tissue as a complication of radioembolization. In this study, we investigated the application of personalized dosimetry software with the surrogate radiotracer 99mTechnetium (99mTc) macroaggregated albumin (MAA) to maximize the radiation dose to hepatic malignant lesions while minimizing the dose to non-tumor liver. We correlated clinical outcomes with dosimetry findings to elucidate important factors in optimizing patient outcomes.

METHODS

In this retrospective study, we obtained clinical follow-up in 43 patients who received radioembolization with 90Yttrium (90Y) microspheres as treatment for primary and metastatic hepatic malignancies and who had mapping with 99mTc MAA by single photon emission computed tomography. We investigated the predictive accuracy of voxel-based dosimetry from pre-treatment mapping with respect to clinical outcomes following 90Y treatment. Specifically, we analyzed correlations between pre-treatment mapping dosimetry and the incidence of radioembolization induced liver disease (REILD), a known complication from radioembolization with 90Y microspheres. Outcomes of reduced hepatic function-such as inadequate albumin production, hyperbilirubinemia, elevated international normalized ratio (INR), and new medically uncontrolled ascites were used as quantitative clinical markers of REILD.

RESULTS

Non-tumor liver radiation dose was correlated with REILD, odds ratio (OR) =3.446 (P=0.020). Interestingly, a history of prior hepatic chemotherapy was associated with a decreased risk, OR =0.099 (P=0.046). History of cirrhosis was associated with REILD; however, this was not significant, OR of 3.495 with (P=0.156). Differences, however, between predicted and delivered absorbed radiation doses did not significantly predict the occurrence of REILD, OR =0.198 (P=0.169). Type of microsphere was also not significantly associated with REILD, OR =0.111 (P=0.079).

CONCLUSIONS

The findings of this study support the use of 99mTc MAA pre-treatment mapping as a valuable tool to predict the absorbed dose in normal liver tissue from 90Y radioembolization. This approach thus allows for a more personalized and calculated treatment plan.