Efficacy of synovectomy in haemophilic patients with 153Sm-hydroxyapatite

Introduction - We preconized the use of 153Sm-Hydroxyapatite (HYP) in the synoviorthesis of haemophilic patients (pts) by physical, chemical and biological characteristics. The real efficacy is beeing confirmed by the actual experience over the previous results. These are the first results with 153Sm-HYP in our literature review. Material and Methods - Fiftheen pts. were treated, all males, with ages between 15 and 31 years (average = 22,8 years old), with an intraarticular injection of 185MBq (5mCi) of 153Sm-HYP, totalizing 29 joints: 12 knees, 11 elbows, 4 ankles and 2 shoulders. The 153Sm, produced by IPEN/CNEN - São Paulo, targeted hydroxyapatite particles with a diameter between 1-10µm, radiochemical purity superior to 95 percent and stability of 96,6 percent 1440min after the labeling process. The intraarticular punction was made after local antiseptic, aspirating synovial fluid, injecting 0,5 ml of radioactive solution and flushing the tract with a saline with a total volume no greater than 1,5 ml. The images were obtained 2 and 24h after injection in all pts in a large field of view gamma-camera. The clinical evaluation was made before and one year after it, using objective (range of motion, joint tenderness, degree of joint effusion) and subjective criteria (joint pain by visual scale and joint aspect). The response were graded: 1 - Excellent (E); 2 - Good (G); 3 - Mild (M); 4 - Bad (B); 5 - Worse (W). The reduction in clotting factor use and heamarthroses were others aspects evaluated. Results - The scintigrafies showed homogeneous distribution of the material in joints (2h) and no articular scape (24h). The was a reduction of 34 percent in the clotting factor use and of 51,4 percent in haemarthroses including the poor responses in knees. The results by patients were: 53,3 percent E, 20 percent G, 13,3 percent M, 13,3 percent B, 0 percent W and by joints were 47,75 with excellent and good responses and 84,75 percent when included the mild group. The...

[166Dy]Dy/166Ho hydroxide macroaggregates: an in vivo generator system for radiation synovectomy.

Radiation synovectomy is an effective treatment in patients suffering from inflammatory-rheumatoid and degenerative joint diseases. The aim of this work was to examine the feasibility of preparing dysprosium-166 (166Dy)/holmium-166(166Ho) hydroxide macroaggregates ([166Dy]Dy/166Ho-HM) as an in vivo generator for radiation synovectomy evaluating whether the stability of 166Dy-HM and 166Ho-HM complexes is maintained when the daughter 166Ho is formed. The Monte Carlo (MCNP4B) theoretical depth dose profile for the in vivo [166Dy]Dy/166Ho generator system in a joint model was calculated and compared with that produced by 90Y, 153Sm and 166Ho. 166Dy was obtained by neutron irradiation of enriched 164Dy2O3 in a Triga Mark III reactor. Macroaggregates were prepared by reaction of [166Dy]DyCl3 with 0.5 M NaOH in an ultrasonic bath. [166Dy]Dy/166Ho-HM was obtained with radiochemical purity >99.5% and with the majority of particles in the 2-5 microm range. In vitro studies demonstrated that the radio-macroaggregates are stable in saline solution and human serum without a significant change in the particle size over 14 d, suggesting that no translocation of the daughter nucleus occurs subsequent to beta- decay of 166Dy. Biological studies in normal rats demonstrated high retention in the knee joint even 7 d after [166Dy]Dy/166Ho-HM administration. The Monte Carlo (MCNP4B) theoretical depth dose profiles in a joint model, showed that the in vivo [166Dy]Dy/166Ho generator system would produce 25% and 50% less radiation dose to the articular cartilage and bone surface, respectively, than that produced by 90Y or pure 166Ho in a treatment with the same therapeutic dose to the synovium surface. Despite that 153Sm showed the best depth dose profile sparing doses to healthy tissues, the use of 166Dy could provide the advantage of being applied in patients that cannot be reached within a few hours from a nuclear reactor and to produce less radiation exposure to the medical personnel during the radiopharmaceutical administration.