Implications of lung shunt fraction calculation discrepancy in Yttrium-90 radioembolization treatment from 2D planar vs 3D single photon emission CT imaging

The safety and efficacy of Yttrium-90 (Y-90) radio-embolization therapy is partly dependent on the lung shunt fraction (LSF). There may be a notable disparity between LSF when calculated using 2D planar imaging vs 3D single photon emission CT (SPECT); this can affect the total allowable Y-90 dose delivered and therefore change the effectiveness of the procedure. The case presented demonstrates an 81% decrease in LSF when calculated by SPECT as compared to 2D planar imaging. This case highlights the importance of considering the imaging technique and the potential discrepancies that can arise between planar and SPECT imaging in LSF assessment.