99mTc-MAA overestimates the absorbed dose to the lungs in radioembolization: a quantitative evaluation in patients treated with 166Ho-microspheres

Purpose Radiation pneumonitis is a rare but serious complication of radioembolic therapy of liver tumours. Estimation of the mean absorbed dose to the lungs based on pretreatment diagnostic 99mTc-macroaggregated albumin (99mTc-MAA) imaging should prevent this, with administered activities adjusted accordingly. The accuracy of 99mTc-MAA-based lung absorbed dose estimates was evaluated and compared to absorbed dose estimates based on pretreatment diagnostic 166Ho-microsphere imaging and to the actual lung absorbed doses after 166Ho radioembolization.