whereMnandMtare the masses of the normal (nontumoral) liver and tumor, respectively,ris the target:normal liver ratio of the average radioactivity concentration in the tumor compared with the nontumoral liver, andLis the lung shunt fraction, that is, the ratio of the [99mTc]-macroaggregated albumin (MAA) total counts in the lungs compared with the total counts in the lungs plus the normal liver. The gene discussed is ALB; the disease is neoplasm.