title: Preparation and preliminary biological evaluation of 177Lu-labelled hydroxyapatite as a promising agent for radiation synovectomy of small joints.
abstract: OBJECTIVE
  Lutetium-(177)Lu) is considered to be a promising radionuclide for use in radiation synovectomy of small-sized joints owing to its favourable decay characteristics [t(1/2)=6.73 days, E(beta)(max)=0.49 MeV, E(gamma)=113 keV (6.4%), 208 keV (11%)] and feasible and cost-effective production route. Hydroxyapatite particles are regarded as one of the most suitable carriers for applications in radiation synovectomy, and labelling with (177)Lu has been envisaged. The present work describes the preparation and preliminary biological evaluation of (177)Lu-labelled hydroxyapatite particles.
  
  
  METHODS
  (177)Lu-labelled hydroxyapatite particles were prepared using (177)Lu produced by thermal neutron irradiation of a natural (2.6% (177)Lu) Lu(2)O(3) target and hydroxyapatite particles (particle size, 2-10 microm) prepared in-house. The biological efficacy of the radiolabelled preparation was tested by recording serial gamma scintigraphic images after injecting the agent in both normal and arthritic knee joints of Wistar rats.
  
  
  RESULTS
  (177)Lu-hydroxyapatite was prepared with high yield and high radiochemical purity (approximately 99%) and the radiolabelled particles showed excellent in-vitro stability at room temperature. Serial scintigraphic images of normal and arthritic Wistar rats showed complete retention of activity within the synovial cavity, with no measurable activity leaching out from the joint until 168 h post-injection.
  
  
  CONCLUSIONS
  Studies with (177)Lu-hydroxyapatite indicate its potential for use as an agent for radiation synovectomy of digital joints, as a viable alternative to (169)Er-based agents. The results also demonstrate the possibility of preparing a large number of patient doses of (177)Lu-hydroxyapatite from indigenously produced (177)Lu using a natural target.
authors.affiliation: Radiopharmaceuticals Division bRadiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, India.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Tapas
authors.initials: T
authors.lastname: Das
authors.forename: Sharmila
authors.initials: S
authors.lastname: Banerjee
authors.forename: Haladhar Dev
authors.initials: HD
authors.lastname: Sarma
authors.forename: Meera
authors.initials: M
authors.lastname: Venkatesh
mesh_terms: D000818:Animals; D004353:Drug Evaluation, Preclinical; D005240:Feasibility Studies; D007553:Isotope Labeling / Q000379:methods; D008187:Lutetium / Q000737:chemistry / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D008657:Metabolic Clearance Rate; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy*; D011868:Radioisotopes / Q000737:chemistry / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D013585:Synovitis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000532:radiotherapy; D016896:Treatment Outcome
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals; D008187:Lutetium