title: Modeling the time dependent distribution of a new (153)Sm complex for targeted radiotherapy purpose.
abstract: BACKGROUND
  For radioimmunotherapy purposes, a chemical complex with high absorption in cancer tumor is required. New chemicals are to be examined for their concentration in tumor and healthy organs. These are labeled with β-emitting radioisotopes to irradiate the tumor while deposited inside it.
  
  
  OBJECTIVE
  To study the capability of recently developed chemical complex in targeting cancer tumor and investigate the distribution of (153)Sm-TPTTC in rat organs as function of time.
  
  
  METHODS
  The chemical complex - [Tris(1,10-phenanthroline)Samarium(III)] trithiocyanate was prepared and labeled with (153)Sm radioisotope. The labeled complex was injected to a population of tumor bearing mice. In 2, 4, 24, 48, 96 h after injection the animals were sacrificed and the concentration of Samarium complex was measured in various organs such as blood, heart, intestine, colon, liver, spleen, kidney, sternum and bone.
  
  
  RESULTS
  The concentration of the radiopharmaceutical in various organs was measured at different times. The temporal behavior of biodistribution of (153)Sm-TPTTC was modeled and drawn as function of time.
  
  
  CONCLUSIONS
  It is shown that (153)Sm-TPTTC is concentrated in tumor tissue and liver much more than in other organs. The variation of pharmaceutical concentration in all organs is described with summation of eight exponential terms and it approximates our experimental data with precision better than 2%.
authors.affiliation: Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, P.O. Box 14515-775, Iran.
authors.forename: Dariush
authors.initials: D
authors.lastname: Sardari
authors.affiliation: Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, P.O. Box 14515-775, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Hakimi
keywords: Biodistribution; Cancer targeted radiotherapy; Compartmental analysis; Mathematical modeling