用于治疗的发射电子和正电子的放射性镧系元素：剂量测定与生产方面

Electron- and positron-emitting radiolanthanides for therapy: aspects of dosimetry and production.

作者信息

Uusijärvi Helena, Bernhardt Peter, Rösch Frank, Maecke Helmut R, Forssell-Aronsson Eva

机构信息

Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, Göteborg, Sweden.

出版信息

J Nucl Med. 2006 May;47(5):807-14.

PMID:16644751

Abstract

UNLABELLED

All lanthanides have similar chemical properties regarding labeling. Therefore, radiolanthanides that have been used for therapy, such as (153)Sm and (177)Lu, 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 (TND) was calculated for different tumor sizes and compared with the TND values for (90)Y and (131)I. The normal tissue and tumors were simulated as an ellipsoid and spheres, respectively. The TND 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

(153)Sm, (161)Tb, (169)Er, (175)Yb, and (177)Lu had the highest TND values for most of the tumor sizes studied. Among these radiolanthanides, (161)Tb and (177)Lu are the only ones that can be produced no-carrier-added (nca) and with high specific activities. The Auger-electron emitters (161)Ho and (167)Tm had high TND values for tumors weighing less than 1 mg and can be produced nca and with high specific activities. (142)Pr, (145)Pr, and (166)Ho showed TND values similar to those of (90)Y. (166)Ho is generator produced and can be obtained nca and at high specific activities. (143)Pr, (149)Pm, (150)Eu, (159)Gd, (165)Dy, (176m)Lu, and (179)Lu had higher TND values than did (90)Y for all tumor sizes studied, but only (149)Pm can be produced nca and at high specific activities. The other electron-emitting radiolanthanides and the positron-emitting radiolanthanides showed low TND values for all tumor sizes because of the high photon contribution.

CONCLUSION

The low-energy electron emitters (161)Tb, (177)Lu, and (167)Tm might be suitable for radionuclide therapy. The Auger-electron emitter (161)Ho 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, (149)Pm or (166)Ho might be suitable for radionuclide therapy.

摘要

未标记

所有镧系元素在标记方面具有相似的化学性质。因此，已用于治疗的放射性镧系元素，如（153）Sm和（177）Lu，可能很容易被其他放射性镧系元素替代。这项工作的目的是参照剂量测定和生产可能性，研究发射电子和正电子的放射性镧系元素用于放射性核素治疗的适用性。

方法

选择半衰期为1小时至15天、具有稳定或长寿命子体且光子发射有限的放射性镧系元素。计算不同肿瘤大小下肿瘤与正常组织的吸收剂量率之比（TND），并与（90）Y和（131）I的TND值进行比较。正常组织和肿瘤分别模拟为椭球体和球体。TND值取决于放射性核素的物理参数、肿瘤大小以及肿瘤与正常组织中的活度浓度之比（TNC）。

结果

在研究的大多数肿瘤大小中，（153）Sm、（161）Tb、（169）Er、（175）Yb和（177）Lu的TND值最高。在这些放射性镧系元素中，（161）Tb和（177）Lu是仅有的可以无载体添加（nca）且具有高比活度生产的元素。俄歇电子发射体（161）Ho和（167）Tm对于重量小于1mg的肿瘤具有高TND值，并且可以nca且高比活度生产。（142）Pr、（145）Pr和（166）Ho的TND值与（90）Y相似。（166）Ho由发生器产生，可以nca且高比活度获得。对于研究的所有肿瘤大小，（143）Pr、（149）Pm、（150）Eu、（159）Gd、（165）Dy、（176m）Lu和（179）Lu的TND值高于（90）Y，但只有（149）Pm可以nca且高比活度生产。其他发射电子的放射性镧系元素和发射正电子的放射性镧系元素由于光子贡献高，在所有肿瘤大小下TND值都很低。