Objective: To assess the impact of nonuniform dose distribution within lesions and tumor-involved organs of patients receiving Zevalin®, and to discuss possible implications of equivalent uniform biological effective doses (EU-BED) on treatment efficacy and toxicity. MATLAB™ -based software for voxel-based dosimetry was adopted for this purpose. Methods: Eleven lesions from seven patients with either indolent or aggressive non-Hodgkin lymphoma were analyzed, along with four organs with disease. Absorbed doses were estimated by a direct integration of single-voxel kinetic data from serial tomographic images. After proper corrections, differential BED distributions and surviving cell fractions were estimated, allowing for the calculation of EU-BED. To quantify dose uniformity in each target area, a heterogeneity index was defined. Results: Average doses were below those prescribed by conventional radiotherapy to eradicate lymphoma lesions. Dose heterogeneity and effect on tumor control varied among lesions, with no apparent relation to tumor mass. Although radiation doses to involved organs were safe, unexpected liver toxicity occurred in one patient who presented with a pattern of diffuse infiltration. Conclusion: Voxel-based dosimetry and radiobiologic modeling can be successfully applied to lesions and tumor-involved organs, representing a methodological advance over estimation of mean absorbed doses. However, effects on tumor control and organ toxicity still cannot be easily predicted. © Copyright 2013, Mary Ann Liebert, Inc.

Quantification of dose nonuniformities by voxel-based dosimetry in patients receiving 90Y-ibritumomab-tiuxetan

Cicone F.
;
2013-01-01

Abstract

Objective: To assess the impact of nonuniform dose distribution within lesions and tumor-involved organs of patients receiving Zevalin®, and to discuss possible implications of equivalent uniform biological effective doses (EU-BED) on treatment efficacy and toxicity. MATLAB™ -based software for voxel-based dosimetry was adopted for this purpose. Methods: Eleven lesions from seven patients with either indolent or aggressive non-Hodgkin lymphoma were analyzed, along with four organs with disease. Absorbed doses were estimated by a direct integration of single-voxel kinetic data from serial tomographic images. After proper corrections, differential BED distributions and surviving cell fractions were estimated, allowing for the calculation of EU-BED. To quantify dose uniformity in each target area, a heterogeneity index was defined. Results: Average doses were below those prescribed by conventional radiotherapy to eradicate lymphoma lesions. Dose heterogeneity and effect on tumor control varied among lesions, with no apparent relation to tumor mass. Although radiation doses to involved organs were safe, unexpected liver toxicity occurred in one patient who presented with a pattern of diffuse infiltration. Conclusion: Voxel-based dosimetry and radiobiologic modeling can be successfully applied to lesions and tumor-involved organs, representing a methodological advance over estimation of mean absorbed doses. However, effects on tumor control and organ toxicity still cannot be easily predicted. © Copyright 2013, Mary Ann Liebert, Inc.
2013
BED
EUD
ibritumomab-tiuxetan
lymphomas
NHL
radioimmunotherapy
voxel-based dosimetry
zevalin
Adult
Aged
Antibodies, Monoclonal
Female
Humans
Lymphoma, Non-Hodgkin
Male
Middle Aged
Neoplasm Grading
Radionuclide Imaging
Radiotherapy Dosage
Tissue Distribution
Treatment Outcome
Yttrium Radioisotopes
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12317/64734
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