Therapeutic Potential of 90Y- and 131I-Labeled Anti-CD20 Monoclonal Antibody in Treating Non-Hodgkins Lymphoma with Pulmonary Involvement: A Monte Carlo–Based Dosimetric Analysis

摘要

Pulmonary involvement is common in patients with non-Hodgkin's lymphoma (NHL). ⁹⁰Y- and ¹³¹I-anti-CD20 antibodies (ibritumomab tiuxetan and tositumomab, respectively) have been approved for the treatment of refractory low-grade follicular NHL. In this work, we used Monte Carlo–based dosimetry to compare the potential of ⁹⁰Y and ¹³¹I, based purely on their emission properties, in targeted therapy for NHL lung metastases of various nodule sizes and tumor burdens.MethodsLung metastases were simulated as spheres, with radii ranging from 0.2 to 5.0 cm, which were randomly distributed in a voxelized adult male lung phantom. Total tumor burden was varied from 0.2 to 1,641 g. Tumor uptake and retention kinetics of the 2 radionuclides were assumed equivalent; a uniform distribution of activity within tumors was assumed. Absorbed dose to tumors and lung parenchyma per unit activity in lung tumors was calculated by a Monte Carlo–based system using the MCNP4B package. Therapeutic efficacy was defined as the ratio of mean absorbed dose in the tumor to that in normal lung. Dosimetric analysis was also performed for a lung-surface distribution of tumor nodules mimicking pleural metastatic disease.