MEDICAL DOSIMETRY – INTERNAL DOSIMETRY STUDIES IN NUCLEAR MEDICINE EXAMS
The use of radiopharmaceuticals implies calculation of absorbed doses according to the MIRD and ICRP methodologies. Particularly in children, parameters such as weight and age are thought to be important and determinant for dose calculations. This work consisted in determining the absorbed doses in 20 pediatric patients after intravenous administration of radiopharmaceutical 99mTc-DMSA and 99mTc-MAG3 for diagnostic purposes. Gamma camera and in vivo measurements were used to assess the biokinetic data. The specific absorbed fraction (SAF) values were estimated via Monte Carlo simulations and scaled VOXEL phantoms. Deviations from the reference values were found, mainly related to children specific anatomy. SAF values are dependent on body and organ mass, kidney dimensions and velocity of excretion, among other anatomical and physiological parameters.
Anthropomorphic (voxel) computational phantoms used to model for pediatric patients (upper left) and time evolution of the activity after administration of radiophamaceuticals in Nuclear Medicine exams, obtained using state-of-the-art biokinetic models and reference methodologies (MIRD, ICRP).
Contact person: Pedro Teles
See more details in:
Teles, P., et al. (2017). Assessment of the absorbed dose in the kidney of nuclear nephrology paediatric patients using ICRP biokinetic data and Monte Carlo simulations with mass-scaled paediatric Voxel phantoms. Radiation Protection Dosimetry 174 (1), 121-135. doi: 10.1093/rpd/ncw096.