PURPOSE: To study the dosimetric characteristics of a non-internalizing and an internalizing monoclonal antibody (MAb) labeled with (131)I, (125)I or (123)I, which targets a typical lymphoma B-cell. MATERIALS AND METHODS: Using our hybrid Monte Carlo (MC) code which combines detailed- and condensed-history electron track simulation we carry out transport calculations of Auger and beta electrons for different intracellular distributions of radioactivity. RESULTS: Assuming permanent retention of the MAb in cells, (125)I gave the highest absorbed dose and (123)I the highest absorbed dose rate. Under the more realistic scenario of biologic excretion from the cells, (123)I resulted in the highest absorbed dose and absorbed dose rate. CONCLUSION: The present dosimetric analysis shows that biological half-life, subcellular localization, and the proper account of low-energy electrons is critical in assessing the energy deposition inside the targeted cells from the three iodide radioisotopes examined. From a dosimetric point of view and under the present approximations (123)I might be superior to the other two radioiodides in the treatment of microscopic disease in B-cell lymphoma patients.
PURPOSE: To study the dosimetric characteristics of a non-internalizing and an internalizing monoclonal antibody (MAb) labeled with (131)I, (125)I or (123)I, which targets a typical lymphoma B-cell. MATERIALS AND METHODS: Using our hybrid Monte Carlo (MC) code which combines detailed- and condensed-history electron track simulation we carry out transport calculations of Auger and beta electrons for different intracellular distributions of radioactivity. RESULTS: Assuming permanent retention of the MAb in cells, (125)I gave the highest absorbed dose and (123)I the highest absorbed dose rate. Under the more realistic scenario of biologic excretion from the cells, (123)I resulted in the highest absorbed dose and absorbed dose rate. CONCLUSION: The present dosimetric analysis shows that biological half-life, subcellular localization, and the proper account of low-energy electrons is critical in assessing the energy deposition inside the targeted cells from the three iodide radioisotopes examined. From a dosimetric point of view and under the present approximations (123)I might be superior to the other two radioiodides in the treatment of microscopic disease in B-cell lymphomapatients.
Authors: Joseph Grudzinski; Ian Marsh; Benjamin Titz; Justin Jeffery; Marc Longino; Kevin Kozak; Kristofer Lange; Jason Larrabee; Ashley Weichmann; Amy Moser; Bryan Bednarz Journal: Cancer Biother Radiopharm Date: 2018-04 Impact factor: 3.099