Mathew Boby, Chakraborty Sudipta, Das Tapas, Sarma H D, Banerjee Sharmila, Samuel Grace, Venkatesh Meera, Pillai M R A
Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Appl Radiat Isot. 2004 May;60(5):635-42. doi: 10.1016/j.apradiso.2003.09.016.
Ytterbium-175 (T1/2 = 4.2 d, Ebeta(max) = 480 keV) has radionuclidic properties suitable to be used in palliative therapy of bone metastases. 175Yb can be produced in moderate specific activity and good radionuclidic purity by thermal neutron bombardment of natural Yb target. The analysis of the neutron irradiated sample exhibited the presence of 96.2% 175Yb along with 2.1% 169Yb and 1.7% 177Lu at 6 h post-EOB. Four polyaminomethylene phosphonic acid ligands, ethylenediamine tetramethylene phosphonic acid, propylenediamine tetramethylene phosphonic acid, triethylenetetramine hexamethylene phosphonic acid and diethylenetriamine pentamethylene phosphonic acid were synthesized and radiolabeled with 175Yb. Complexation parameters were optimized to achieve maximum yields (92-99%). All complexes were found to retain their stability at room temperature even after 10d of preparation. Biodistribution studies of the complexes carried out in Wistar rats showed significant bone uptake (3-4.4%/g in tibia at 3h post-injection) with rapid clearance from blood and minimum uptake in soft tissues for all the complexes (bone/blood ratio approximately 40-150 and bone/muscles ratio approximately 40-400 at 3 h post-injection). These studies suggest that 175Yb complexes with the phosphonate ligands have potential for use in palliative treatment of painful bone metastases.
镱 - 175（半衰期(T_{1/2}=4.2)天，最大β能量(E_{β(max)} = 480)keV）具有适合用于骨转移姑息治疗的放射性核素性质。通过对天然镱靶进行热中子轰击，可以制备出比活度适中且放射性核素纯度良好的(^{175}Yb)。对中子辐照样品的分析表明，在放化结束后6小时，样品中含有96.2%的(^{175}Yb)，以及2.1%的(^{169}Yb)和1.7%的(^{177}Lu)。合成了四种聚氨基亚甲基膦酸配体，即乙二胺四亚甲基膦酸、丙二胺四亚甲基膦酸、三乙烯四胺六亚甲基膦酸和二乙烯三胺五亚甲基膦酸，并将它们用(^{175}Yb)进行放射性标记。优化络合参数以实现最大产率（92 - 99%）。发现所有络合物即使在制备10天后在室温下仍保持其稳定性。在Wistar大鼠中进行的络合物生物分布研究表明，所有络合物均显示出显著的骨摄取（注射后3小时胫骨摄取量为3 - 4.4%/克），血液清除迅速，软组织摄取最少（注射后3小时骨/血比值约为40 - 150，骨/肌肉比值约为40 - 400）。这些研究表明，镱 - 175与膦酸配体形成的络合物具有用于疼痛性骨转移姑息治疗的潜力。
