[1] IAEA, Div Radiat Transport & Waste Safety, Radiat Protect Patients Unit, Radiat Safety & Monitoring Sect, A-1400 Vienna, Austria
[2] St James Hosp, Trinity Coll, Dublin 8, Ireland
[3] IAEA, Div Human Hlth, Dosimetry & Med Radiat Phys Sect, A-1400 Vienna, Austria