PT  - JOURNAL ARTICLE
AU  - Helena Uusijärvi
AU  - Peter Bernhardt
AU  - Frank Rösch
AU  - Helmut R. Maecke
AU  - Eva Forssell-Aronsson
TI  - Electron- and Positron-Emitting Radiolanthanides for Therapy: Aspects of Dosimetry and Production
DP  - 2006 May 01
TA  - Journal of Nuclear Medicine
PG  - 807--814
VI  - 47
IP  - 5
4099  - http://jnm.snmjournals.org/content/47/5/807.short
4100  - http://jnm.snmjournals.org/content/47/5/807.full
SO  - J Nucl Med2006 May 01; 47
AB  - All lanthanides have similar chemical properties regarding labeling. Therefore, radiolanthanides that have been used for therapy, such as 153Sm and 177Lu, might easily be replaced with other radiolanthanides. The aim of this work was to investigate the suitability of electron- and positron-emitting radiolanthanides for radionuclide therapy with reference to dosimetry and production possibilities. Methods: Radiolanthanides with half-lives of 1 h to 15 d, stable or long-lived daughters, and limited photon emission were selected. The ratio of the absorbed dose rate to the tumors and the normal tissue (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document}) was calculated for different tumor sizes and compared with the \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values for 90Y and 131I. The normal tissue and tumors were simulated as an ellipsoid and spheres, respectively. The \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values depend on the physical parameters of the radionuclides, the tumor size, and the ratio between the activity concentrations in the tumor and normal tissue (TNC). Results: 153Sm, 161Tb, 169Er, 175Yb, and 177Lu had the highest \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values for most of the tumor sizes studied. Among these radiolanthanides, 161Tb and 177Lu are the only ones that can be produced no-carrier-added (nca) and with high specific activities. The Auger-electron emitters 161Ho and 167Tm had high \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values for tumors weighing less than 1 mg and can be produced nca and with high specific activities. 142Pr, 145Pr, and 166Ho showed \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values similar to those of 90Y. 166Ho is generator produced and can be obtained nca and at high specific activities. 143Pr, 149Pm, 150Eu, 159Gd, 165Dy, 176mLu, and 179Lu had higher \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values than did 90Y for all tumor sizes studied, but only 149Pm can be produced nca and at high specific activities. The other electron-emitting radiolanthanides and the positron-emitting radiolanthanides showed low \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{TN{\dot{D}}}\) \end{document} values for all tumor sizes because of the high photon contribution. Conclusion: The low-energy electron emitters 161Tb, 177Lu, and 167Tm might be suitable for radionuclide therapy. The Auger-electron emitter 161Ho might not be suitable for systemic radionuclide therapy (intravenous injection) because of its short half-life but might be suitable for local therapy (e.g., in body cavities). If higher electron energy is needed, 149Pm or 166Ho might be suitable for radionuclide therapy.