Fig. 8

An example (patient ID 20) of disagreement between tumor dose between predictive and post-treatment dosimetry. a, b Pre-treatment image (^99mTc-MAA-SPECT/CT). c, d Post-treatment image (⁹⁰Y-PET/MR); the tumor contoured in pink: predictive and post-treatment dose assessment were comparable (pre-treatment predicted: mean dose: 84 Gy, D50 = 83 Gy and V100 = 39%; post-treatment: mean dose: 95 Gy, D50 = 84 Gy and V100 = 44%); the tumor contoured in yellow: predictive dosimetry underestimated the tumor dose (pre-treatment predicted: mean dose: 33 Gy, D50 = 33 Gy and V100 = 0%; post-treatment measurement: mean dose: 130 Gy, D50 = 125 Gy and V100 = 67%); and the tumor contoured in red: predictive dosimetry over-estimated the tumor dose (pre-treatment predicted: mean dose: 165 Gy, D50 = 159 Gy and V100 = 86%; post-treatment: mean dose: 4 Gy, D50 = 2 Gy and V100 = 0%). e Dose-volume histogram of the described VOIs based on predictive and post-treatment dose assessments. In this case a different catheter positioning between MAA work-up and treatment resulted in flow variation. A preferential targeting of the tumor in the ventral part of the right liver lobe (red tumor) was observed in the work-up. On the other hand, after ⁹⁰Y-microsphere injection, a preferential targeting of the tumor in the dorsal part of the left liver lobe was obtained. This is one example of a potential pitfall in SIRT in general and a cause of discrepancy between ^99mTc-MAA and ⁹⁰Y-PET in particular