Lung Shunt Fraction

The lung shunt fraction (LSF) measurement before selektive intraarterielle Radiotherapie (SIRT) using [^99mTc]MAA is performed with a planar whole-body scan post-injection. Regions of interest are defined over the liver and lungs. The result is derived from the ratio of lung counts to the total counts (lungs plus liver), expressed as a percentage of the injected activity. This quantifies the risk of pulmonary radiation during therapy.