Effect of urinary excretion on radiation dose in patients having PET/CT scans

Abstract

Objectives: 18Fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography/ computed tomography(PET/CT) is commonly used for diagnosis, staging and re-staging of cancers and for determining theeffectiveness of treatment. Because of renal, ureteral and urinary involvement of 18F-FDG radiopharmaceuticalafter its injection, patients subject to radioactivity during its effective half-life. The aim of the present studywas to determine the degree of association between effective dose levels of patients and bladder emptying ofpatients having PET/CT scans.Methods: The present retrospective study included 108 patients (43 females and 65 males, average age: 60.9± 12.7 years). Effective dose level as mSv/h was determined from a distance of 1 m in all patients before andafter bladder emptying at the first hour following 18F-FDG injection. Radioactivity excretion amounts werecompared based on gender, age, body mass index, fasting blood sugar level and clinical diagnosis.Results: Amount of radioactivity decreased by 22.75% ± 14.77% after bladder emptying. No association wasfound between urinary excretion level and age, gender, fasting blood sugar and body mass index (p > 0.05).Conclusions: Active emptying of bladder in patients having PET/CT scans where 18F-FDG radiopharmaceuticalis involved is an effective method for the radiation safety of both health workers and patients.