Samarium-145: A new brachytherapy source

R. G. Fairchild, J. Kalef-Ezra, S. Packer, L. Wielopolski, B. H. Laster, J. S. Robertson, L. Mausner, C. Kanellitsas

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


A new radiation source has been produced for brachytherapy, with radiation energies slightly above those of 125I, and a T1/2 of 340 d. This source, 145Sm, is produced by neutron irradiation of 144Sm (96.5% enriched). Decay is by electron capture with 140 K X-rays per 100 disintegrations in the energy region between 38-45 keV, plus 13 gamma -rays at 61 keV. These sources are encapsulated in Ti tubes, approximately 0.8 mm*4.5 mm, and have been developed for temporary implantation in brain and ocular tumours. The 38-61 keV photons should make such sources easy to shield, while providing a dose distribution from source arrays somewhat more homogeneous than that from 125I. In addition, the 340 d half life of 145Sm permits its use for times significantly longer than that of 60 d 125I. While the 145Sm sources have been designed primarily for implantation in a brain tumour, they should be useful for almost any conventional brachytherapy application.

Original languageEnglish
Article number005
Pages (from-to)847-858
Number of pages12
JournalPhysics in Medicine and Biology
Issue number7
StatePublished - 1 Dec 1987
Externally publishedYes

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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