Patient-specific, 3-dimensional dosimetry in non-Hodgkin's lymphoma patients treated with 131I-anti-B1 antibody: Assessment of tumor dose-response Journal Article


Authors: Sgouros, G.; Squeri, S.; Ballangrud, A. M.; Kolbert, K. S.; Teitcher, J. B.; Panageas, K. S.; Finn, R. D.; Divgi, C. R.; Larson, S. M.; Zelenetz, A. D.
Article Title: Patient-specific, 3-dimensional dosimetry in non-Hodgkin's lymphoma patients treated with 131I-anti-B1 antibody: Assessment of tumor dose-response
Abstract: A comprehensive, SPECT-based, patient-specific 3-dimensional (3D) dosimetry analysis has been performed using 3D-ID, a previously developed software package. The role of the total-body tumor burden, individual lesion size, tumor absorbed dose, and the spatial distribution of the absorbed dose on response and on the time course of tumor shrinkage has been examined in patients with lymphoma treated by radioimmunotherapy. METHODS: Data from 15 patients participating in a phase II study of (131)I-labeled anti-B1 antibody (tositumomab) were used. Patients were administered a tracer dose of (131)I for imaging and pharmacokinetics. Dose estimates from the tracer studies were used to prescribe the therapeutic administration such that the whole-body absorbed dose did not exceed 75 cGy. All patients received a fixed mass amount of antibody for both the tracer and the therapeutic administrations. SPECT and planar imaging were performed 3-4 d after the therapeutic administration. CT or MRI scans were available on all patients. Total tumor burden was assessed by drawing contours around all lymphoma lesions identified on whole-body CT or MRI. Mean absorbed doses were estimated for selected, index lesions by conventional dosimetry and also by 3D SPECT-based dosimetry. Using a patient-specific dosimetry package, 3D-ID, dose-volume histograms were also generated to assess the spatial distribution of absorbed dose. This approach made it possible to obtain estimates of the minimum and maximum absorbed doses for individual tumors in addition to the mean. RESULTS: Mean absorbed dose estimates obtained by patient-specific SPECT-based dosimetry using 3D-ID were within 2%-5% of estimates obtained by conventional dosimetry. None of the absorbed dose parameters (mean, minimum, maximum, uniformity) were found to have a significant correlation with tumor response. The total-body tumor burden did not impact on overall response or toxicity. CONCLUSION: This analysis represents the first full reported implementation of a patient-specific 3D dosimetry package. The absence of a dose-response relationship for tumors is surprising and suggests that absorbed dose is not the sole determinant of tumor response in these patients. The absence of a correlation between the total-body tumor burden and overall response or toxicity suggests that tailoring the milligram amount of administered antibody to patient tumor burden is not likely to improve response or reduce toxicity.
Keywords: treatment outcome; clinical trial; antineoplastic agents; methodology; antineoplastic agent; sensitivity and specificity; vascular neoplasms; phase 2 clinical trial; thrombocyte; validation study; radiation exposure; radiation response; dose-response relationship, radiation; monoclonal antibody; antibodies, monoclonal; nonhodgkin lymphoma; lymphoma, non-hodgkin; three dimensional imaging; imaging, three-dimensional; multicenter study; vascular tumor; scintiscanning; radiometry; radiotherapy planning, computer-assisted; radioimmunotherapy; whole body counting; whole-body counting; computer assisted radiotherapy; single photon emission computer tomography; blood platelets; tomography, emission-computed, single-photon; iodine 131 anti b1 antibody; iodine-131 anti-b1 antibody; humans; human; male; female; article
Journal Title: Journal of Nuclear Medicine
Volume: 44
Issue: 2
ISSN: 0161-5505
Publisher: Society of Nuclear Medicine  
Date Published: 2003-02-01
Start Page: 260
End Page: 268
Language: English
PUBMED: 12571219
PROVIDER: scopus
DOI/URL:
Notes: Export Date: 12 September 2014 -- Source: Scopus