Problems of management of patient biological waste in radionuclide diagnostics

Biological excretion from patients (urine) generated during radionuclide diagnostics enters directly into the hospital sewage system. The establishment of new clearance level according to Resolution of the Government of the Russian Federation No. 1069 of October 19, 2012 may entail amendments to regulatory documents for radionuclide diagnostics departments. One of these requirements is a mandatory dedicated sewage system. Establishment of the requirement may lead to an increase the cost of the radionuclide diagnostic examinations, and to a decrease the accessibility of radionuclide diagnostic. The aim of this study was to estimate the activity of radionuclides in patient urine after radionuclide diagnostic and activity concentration in sewage water in the hospital and in the transport tank of toilet for evaluation of paths of waste manage. Based on published literature data, models of biological excretion were constructed for the following radiopharmaceuticals: 99m Tc-pyrophosphate, 64 Cu-Labeled Monoclonal Antibody, 18 F-FDG, 68 Ga-PSMA-617. The activity of radionuclides in the patient waste in the hospital and in public transport during the patient transportation to home was calculated. Various scenarios of patient transportation were considered. The values of the excreted activity, activity concentration and dose rate at 1 m from the tank with sewage water for each type of transport were calculated. The calculated values of the radionuclide activity concentration in sewage water in transport tank of toilet for the majority scenarios exceed the clearance level (up to 180 times for 68 Ga-PSMA-617 when traveling by bus). According the regulatory requirements, it is necessary to collect patient excretions after radionuclide diagnostic examinations and hold it for decay. However, estimated effective doses of individuals from the public from contact with biological patient waste do not exceed the acceptable value. This is due to the short half-life of diagnostic radionuclides. The paths of management system of biological patient waste were proposed.