title: Importance of bladder radioactivity for radiation safety in nuclear medicine.
abstract: OBJECTIVE
  Most of the radiopharmaceuticals used in nuclear medicine are excreted via the urinary system. This study evaluated the importance of a reduction in bladder radioactivity for radiation safety.
  
  
  METHODS
  The study group of 135 patients underwent several organ scintigraphies [40/135; thyroid scintigraphy (TS), 30/135; whole body bone scintigraphy (WBS), 35/135; myocardial perfusion scintigraphy (MPS) and 30/135; renal scintigraphy (RS)] by a technologist within 1 month. In full and empty conditions, static bladder images and external dose rate measurements at 0.25, 0.50, 1, 1.5 and 2 m distances were obtained and decline ratios were calculated from these two data sets.
  
  
  RESULTS
  External radiation dose rates were highest in patients undergoing MPS. External dose rates at 0.25 m distance for TS, TKS, MPS and BS were measured to be 56, 106, 191 and 72 μSv h-1 for full bladder and 29, 55, 103 and 37 μSv h-1 for empty bladder, respectively. For TS, WBS, MPS and RS, respectively, average decline ratios were calculated to be 52%, 55%, 53% and 54% in the scintigraphic assessment and 49%, 51%, 49%, 50% and 50% in the assessment with Geiger counter.
  
  
  CONCLUSIONS
  Decline in bladder radioactivity is important in terms of radiation safety. Patients should be encouraged for micturition after each scintigraphic test. Spending time together with radioactive patients at distances less than 1 m should be kept to a minimum where possible.
  
  
  BACKGROUND
  None declared.
authors.affiliation: Department of Nuclear Medicine, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey.
authors.forename: Salih Sinan
authors.initials: SS
authors.lastname: Gültekin
authors.affiliation: Department of Nuclear Medicine, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey.
authors.forename: Turan
authors.initials: T
authors.lastname: Sahmaran
keywords: Radiation protection; Radionuclide imaging; ionizing radiation; radiation effects; radiation monitoring