2.2. Radioactive Blood Sampling

Peripheral blood specimens were collected by venipuncture into BD Vacutainer EDTA tubes at different time intervals (6, 22, 46, 69, and 92 h) after the ¹³¹I therapeutic dose administration. The volume of blood was 2 mL. It should be noted that all blood samples collected after the ¹³¹I intake were radioactive. Therefore, they were labeled with a sticker displaying the international symbol of radioactivity. A separate procedure for the radioactive biological samples of collection, transport, processing, and removal was prepared. This procedure followed the rules in force developed by the guidelines of the Dosimetry Committee of the European Nuclear Medicine Association (EANM) [19] and ISO 15189: 2013/ISO 15190: 2005 (requirements for quality and competence in medical laboratories/requirements for safety in medical laboratories).