title: Thulium-170-labeled microparticles for local radiotherapy: preliminary studies.
abstract: The present article describes the preparation, characterization, and biological evaluation of Thulium-170 ((170)Tm) [T1/2 = 128.4 days; Eβmax = 968 keV; Eγ = 84 keV (3.26%)] labeled tin oxide microparticles for its possible use in radiation synovectomy (RSV) of medium-sized joints. (170)Tm was produced by irradiation of natural thulium oxide target. 170Tm-labeled microparticles were synthesized with high yield and radionuclidic purity (> 99%) along with excellent in vitro stability by following a simple process. Particle sizes and morphology of the radiolabeled particles were examined by light microscope, dynamic light scattering, and transmission electron microscope and found to be of stable spherical morphology within the range of 1.4-3.2 μm. The preparation was injected into the knee joints of healthy Beagle dogs intraarticularly for biological studies. Serial whole-body and regional images were taken by single-photon-emission computed tomography (SPECT) and SPECT-CT cameras up to 9 months postadministration, which showed very low leakage (< 8% of I.D.) of the instilled particles. The majority of leaked radiocolloid particles were found in inguinal lymph nodes during the 9 months of follow-up. All the animals tolerated the treatment well; the compound did not show any possible radiotoxicological effect. These preliminary studies showed that 170Tm-labeled microparticles could be a promising nontoxic and effective radiopharmaceutical for RSV applications or later local antitumor therapy.
authors.affiliation: 1 National "F.J.C." Research Institute for Radiobiology and Radiohygiene (NRIRR) , Budapest, Hungary .
authors.forename: Andras
authors.initials: A
authors.lastname: Polyak
authors.forename: Tapas
authors.initials: T
authors.lastname: Das
authors.forename: Sudipta
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Reka
authors.initials: R
authors.lastname: Kiraly
authors.forename: Gabriella
authors.initials: G
authors.lastname: Dabasi
authors.forename: Robert Peter
authors.initials: RP
authors.lastname: Joba
authors.forename: Csaba
authors.initials: C
authors.lastname: Jakab
authors.forename: Julianna
authors.initials: J
authors.lastname: Thuroczy
authors.forename: Zita
authors.initials: Z
authors.lastname: Postenyi
authors.forename: Veronika
authors.initials: V
authors.lastname: Haasz
authors.forename: Gergely
authors.initials: G
authors.lastname: Janoki
authors.forename: Gyozo A
authors.initials: GA
authors.lastname: Janoki
authors.forename: Maroor R A
authors.initials: MR
authors.lastname: Pillai
authors.forename: Lajos
authors.initials: L
authors.lastname: Balogh
mesh_terms: D000818:Animals; D004285:Dogs; D008297:Male; D010316:Particle Size; D011868:Radioisotopes / Q000008:administration & dosage* / Q000737:chemistry; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000737:chemistry; D013583:Synovial Membrane / Q000528:radiation effects; D013585:Synovitis / Q000532:radiotherapy; D013932:Thulium / Q000008:administration & dosage* / Q000737:chemistry; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals; D013932:Thulium; C033160:thulium oxide
keywords: Beagle dogs; Thulium-170; labeled microparticles; radiation synovectomy; radionuclide therapy; radiotherapy