Clinical uses of radiopharmaceuticals imply the administration of radioactive substances that are mainly excreted through urine. The Nuclear Medicine Department at the Instituto Nacional de Cancerología (INC-COL) in Bogota, Colombia, administers radiopharmaceuticals for diagnostics and treatment to many patients, resulting in tens of cubic meters of radioactive waste water (WW) every day. As Colombian regulatory limits for liquid radioactive discharges to the sewer system are lower than in other countries, longer WW decay times are required, even when an in-house waste water treatment plant (WWTP) is used. To fulfill the requirements for controlled disposal of radioactive discharges, a complementary abatement system was implemented to retain WW for periods as long as 360 d, and was connected to the hospital´s WWTP. These holding times can cause major changes in the WW physicochemical parameters, reaching levels higher than acceptable. In this study, we evaluate the decontamination and decay efficiency of the retention system using water quality parameters and the amount of radioactivity in the effluents stored in the tanks and the WWTP. According to the results, to maintain the physicochemical parameters below acceptable levels, biological and chemical treatment of decayed WW is necessary before discharging it into urban waste water. Using the principles of dilution, retention, and decay, an integral radioactive WW management system was implemented favoring the quality of discharges and activity levels to the sewer system, with efficiencies close to 100% for WW from discharges in diagnostic procedures ranging from 98% (131I) to 100% (177Lu) for WW from discharges in therapeutic procedures. Activity concentration assessment in medically-derived radionuclides using an in-house waste water treatment plant (WWTP) and a complementary abatement system; an in-house WWTP could be used as an abatement system for short-lived radionuclides; and a tank-based abatement system attached to the in-house WWTP showed higher efficiencies for long-lived radionuclides and adequate physicochemical parameters for the discharge to the city sewage system.

Basado en la implementación del plan de aseguramiento de la calidad, el objetivo principal de este estudio es realizar el seguimiento y análisis de las verificaciones funcionales realizadas a los equipos detectores de radiación ionizante del Servicio de Medicina Nuclear y del Servicio de Radiofarmacia del Instituto Nacional de Cancerología E. S. E. (INC). Los equipos de estudio fueron dieciséis detectores tipo Geiger-Müller, fijos y portátiles, con fuentes certificadas selladas tipo gotero y planas para la recolección de mediciones realizadas por un periodo de tres años. Como resultado, se encontraron comportamientos variables siempre en el rango del 20 % del error porcentual existentes entre el valor medido y el valor de referencia de cada equipo. El estudio permite concluir que los detectores muestran un comportamiento esperado dentro de la reproducibilidad propia del detector y las desviaciones propias de los diferentes operadores; sin embargo, y con el fin de minimizar las variaciones, es imprescindible contar con un programa de aseguramiento de la calidad de los equipos detectores de radiación que vele por la idoneidad de las medidas realizadas.