Room: AAPM ePoster Library
Purpose: To study the effect of tumor involvement on resin Yttrium-90 (Y90) activity determination for metastatic liver cancer treatment.
Methods: 102 cases of resin Y90 microsphere treatment were studied. Body surface area (BSA) method, a widely used method, was used in the calculation of resin Y90 activity for the treatments. The total activity (TA) was calculated as a summation of activities obtained from body-surface-area based calculation and tumor involvement TI (ratio between tumor volume and liver volume). TI and TA of each case were evaluated. The contributions of TI to TA, i.e., the effect of TI on TA, were calculated with the ratio of TI/TA in each case, and were analyzed for the 102 cases.
Results: TI accounted for a small portion of TA. Among the 102 cases, the average contribution of TI to TA was 4.1 (standard deviation 4.4%). The contributions were < 5.8% in 75% of the cases, < 2.2% in 50% of the cases, and < 1.0% in 25% of the cases.
Conclusion: Overall the effect of tumor involvement on the activity determination was small. The BSA method could be simplified, i.e., TI could be neglected in the activity determination in quite a number of cases, e.g., in 25% of the cases in the study. Contouring tumor and liver structures for TI calculation, which was time consuming, could thus be avoided, and the efficiency of the workflow for resin Y90 procedures could be improved.