title: The low-energy β(-) and electron emitter (161)Tb as an alternative to (177)Lu for targeted radionuclide therapy.
abstract: BACKGROUND
  The low-energy β(-) emitter (161)Tb is very similar to (177)Lu with respect to half-life, beta energy and chemical properties. However, (161)Tb also emits a significant amount of conversion and Auger electrons. Greater therapeutic effect can therefore be expected in comparison to (177)Lu. It also emits low-energy photons that are useful for gamma camera imaging.
  
  
  METHODS
  The (160)Gd(n,γ)(161)Gd→(161)Tb production route was used to produce (161)Tb by neutron irradiation of massive (160)Gd targets (up to 40 mg) in nuclear reactors. A semiautomated procedure based on cation exchange chromatography was developed and applied to isolate no carrier added (n.c.a.) (161)Tb from the bulk of the (160)Gd target and from its stable decay product (161)Dy. (161)Tb was used for radiolabeling DOTA-Tyr3-octreotate; the radiolabeling profile was compared to the commercially available n.c.a. (177)Lu. A (161)Tb Derenzo phantom was imaged using a small-animal single-photon emission computed tomography camera.
  
  
  RESULTS
  Up to 15 GBq of (161)Tb was produced by long-term irradiation of Gd targets. Using a cation exchange resin, we obtained 80%-90% of the available (161)Tb with high specific activity, radionuclide and chemical purity and in quantities sufficient for therapeutic applications. The (161)Tb obtained was of the quality required to prepare (161)Tb-DOTA-Tyr3-octreotate.
  
  
  CONCLUSIONS
  We were able to produce (161)Tb in n.c.a. form by irradiating highly enriched (160)Gd targets; it can be obtained in the quantity and quality required for the preparation of (161)Tb-labeled therapeutic agents.
authors.affiliation: Institute for Radiochemistry, Technical University of Munich, Walther-Meissner-Strasse 3, 85748 Garching, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lehenberger
authors.forename: Christoph
authors.initials: C
authors.lastname: Barkhausen
authors.forename: Susan
authors.initials: S
authors.lastname: Cohrs
authors.forename: Eliane
authors.initials: E
authors.lastname: Fischer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Grünberg
authors.forename: Alexander
authors.initials: A
authors.lastname: Hohn
authors.forename: Ulli
authors.initials: U
authors.lastname: Köster
authors.forename: Roger
authors.initials: R
authors.lastname: Schibli
authors.forename: Andreas
authors.initials: A
authors.lastname: Türler
authors.forename: Konstantin
authors.initials: K
authors.lastname: Zhernosekov
mesh_terms: D001610:Beta Particles / Q000627:therapeutic use*; D004583:Electrons; D006801:Humans; D008187:Lutetium / Q000737:chemistry* / Q000302:isolation & purification / Q000627:therapeutic use; D009688:Nuclear Reactors; D015282:Octreotide / Q000031:analogs & derivatives / Q000097:blood; D009942:Organometallic Compounds / Q000097:blood; D011854:Radiochemistry / Q000379:methods*; D011868:Radioisotopes / Q000737:chemistry* / Q000302:isolation & purification / Q000627:therapeutic use; D011878:Radiotherapy / Q000379:methods*; D013725:Terbium / Q000737:chemistry* / Q000302:isolation & purification / Q000627:therapeutic use
chemical_list: D009942:Organometallic Compounds; D011868:Radioisotopes; D013725:Terbium; D008187:Lutetium; C447941:lutetium Lu 177 dotatate; D015282:Octreotide