Biokinetic modelling of 89Zr-labelled monoclonalantibodies for dosimetry assessment in humans

Background: monoclonal antibodies have confirmed their merit asbiotherapeutics across a wide spectrum of diseases, including cancer, heartdisease, infection, and immune disorders. materials and methods: thedynamics of 89zr-labelled monoclonal antibodies (mab) after injection into thehuman body are modelled. this modified biokinetic model can be used fordose assessment not only for 89zr-labelled mab tumour visualization but alsofor diagnostic and radiation therapy with other mab-labelled radionuclides.the created modified biokinetic model is based on experimental data fromthe literature. the cumulative 89zr activity in organs and tissues per bq ofadministered activity is calculated with the winact program. results: for theorgans receiving the highest radiation exposure, the average absorbed doseswere estimated with idac 2.1 software. the results from the modelledcalculations are compared with new published experimental diagnosticresults from real patients. the calculations reveal that the organs whichreceived the highest dose were the spleen, liver, kidneys, and red bonemarrow (doses of 1.54, 1.33, 0.81 and 0.82 mgy/mbq, respectively). in themodified biokinetic model, the organs exhibiting the highest dose were theliver, gallbladder wall, spleen, pancreas, and kidneys (at 1.07, 0.77, 0.70, 54and 0.44 mgy/mbq, respectively), when the injection was associated withmonoclonal antibodies. conclusion: the developed biokinetic model is ingood agreement with direct measurements and can be considered a first stepfor simulating the radiopharmaceutical dosimetry of the 89zr isotope.