DOSIMETRY OF I-131-LABELED ANTIFERRITIN IN HEPATOMA - SPECIFIC ACTIVITIES IN THE TUMOR AND LIVER

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 67  (7-8) , 647-658
Abstract
Dosimetric studies are reported for 22 patients with hepatoma who received treatment with 131I-labeled antiferritin IgG. Studies included liver and tumor volume computations based on computerized axial tomographic scan analysis, in-vivo quantitation of the activity deposited in hepatic tumors and normal liver tissue, and effective half-life [t1/2] measurements of the activity in the tumor, liver and total body. Administered activities of polyclonal and affinity-column purified 131I-labeled antiferritin IgG ranged from 32-157 mCi. Tumor volumes at the time of radioimmunoglobulin infusion ranged from 220-3020 cm3, and total liver volumes ranged from 900-4620 cm3. For tumor volumes ranging from 220-1700 cm3, the maximum tumor activity was linearly proportional to tumor volume but independent of antiferritin preparations and administered activities. In this range of tumor volumes, the mean value of tumor-to-liver ratios of specific activities was 4.8:1. Hepatomas ranging from 2290-3020 cm3 had reduced tumor uptake of radiolabeled antiferritin IgG and had a tumor-to-liver ratio of specific activities of 1.6:1. For all patients studied, there was a linear relationship between the volume of normal liver tissue and the maximum activity deposited. These data, in conjunction with toxicity studies and tumor effective t1/2 measurements, led to the present treatment regimen of administering 30 mCi of polyclonal antiferritin IgG on day 0 and 20 mCi on day 5 following the 1st injection. This has resulted in the same range of absorbed dose to the tumor as was achieved with larger administered activities, but with a significant reduction of total-body irradiation to the patient.