The uptake and clearance of 131I activity for inpatients undergoing cancer therapy were determined from routine external dose survey measurements. A bi-exponential behavior was found, with the two time constants representing the iodine dynamics in the thyroid on one hand and in the rest of the body on the other. The external dose at 1 m from the patient was correlated to the activity in the thyroid remnant and inside the body, the averaged value being 52.8 ± 11.4 μSv GBq−1 h−1. The temporal evolution of activity in the body, the urinary system and the thyroid remnant area were determined taking into account the clearance from thyroid and whole body (effective retention constants averages 0.23 ± 0.14 d−1 and 1.46 ± 0.34 d−1) and the uptake in thyroid (3.15 ± 3.36%). Applications of this study in the public and environmental radiation protection areas are presented.
* Hospital Universitario del Río Hortega, E-47010 Valladolid, Spain; † Departamento de Física Teórica, Atómica y Optica, Universidad de Valladolid, Spain; ‡ Unidad Académica de Estudios Nucleares de la Universidad Autónoma de Zacatecas, México; § Departamento de Física Teórica, Atómica y Optica, Universidad de Valladolid, Spain; ** Hospital Universitario Ramón y Cajal, Madrid, Spain; †† Hospital Clínico Universitario de Valladolid, Spain.
For correspondence contact: R. Barquero, Hospital Universitario del Río Hortega, E-47010 Valladolid, Spain, or email at firstname.lastname@example.org.
(Manuscript accepted 30 January 2008)