title: Determination of individual organ masses for (90)Y-anti-CD66 radioimmunotherapy: influence on therapy planning.
abstract: Dosimetry is important in the development of radioactive pharmaceuticals, especially for optimizing radionuclide therapy with respect to risk-benefit analysis. To calculate the applied absorbed doses in the target and risk organs standard phantom masses are frequently used. However, deviations to the true organ mass can lead to suboptimal decisions in dose finding studies. To estimate the magnitude of deviations introduced when using standard phantom masses instead of individual organ masses, we investigated 10 patients treated with radioimmunotherapy using (90)Y labelled anti-CD66 antibody. The use of standard phantom masses instead of individually measured organ masses results in mean deviations for liver, spleen and kidneys of 2% (Min. -22%, Max. 34%), -3% (Min. -34, Max. 100%) und -8% (Min. -37, Max. 38%), respectively. For the administered therapeutic activity differences of -16% (Min. -45%, Max. 4%) were observed depending on the used organ mass. These results demonstrate that using standard phantom masses for dosimetry before radionuclide therapy is not adequate.
authors: Klinik für Nuklearmedizin, Universität Ulm, Germany. thomas.kull@uniklinik-ulm.de
authors: Thomas
authors: T
authors: Kull
authors: P
authors: P
authors: Kletting
authors: S N
authors: SN
authors: Reske
authors: Gerhard
authors: G
authors: Glatting
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015703:Antigens, CD / Q000276:immunology*; D001682:Biological Availability; D015815:Cell Adhesion Molecules / Q000276:immunology*; D003198:Computer Simulation; D006801:Humans; D007158:Immunologic Techniques; D019047:Phantoms, Imaging; D016499:Radioimmunotherapy / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014018:Tissue Distribution; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D015021:Yttrium Radioisotopes