Beta emitters and radiation protection

Abstract

Background. Beta emitters, such as 90Y, are increasingly being used for cancer treatment. However, beta emitters demand other precautions than gamma emitters during preparation and administration, especially concerning shielding. Aim. To discuss practical precautions for handling beta emitters in general, and specifically determine proper shielding for 90Y, while comparing to 177Lu and 131I. The aim is achieved through the application of physical principles combined with results from practical experience. Material and methods. Typical and maximal electron ranges were calculated for 131I, 177Lu, and 90Y, using data from a freely available database. Bremsstrahlung yields were calculated for 90Y shielded by lead, aluminium, or perspex. Bremsstrahlung spectrum from 90Y shielded by perspex was measured, and attenuation of spectrum by lead was calculated. Whole-body and finger doses to persons preparing 90Y-Zevalin were measured. Conclusions. Good laboratory practice is important to keep radiation doses low. To reduce bremsstrahlung, 90Y should not be shielded by lead but instead perspex (10 mm) or aluminium (5 mm). Bremsstrahlung radiation can be further reduced by adding a millimetre of lead on the outside of the primary shielding material. If suitable shielding is used and larger numbers of handlings are divided among several persons, then handling of beta emitters can be a safe procedure. © 2009 Informa UK Ltd. (Informa Healthcare, Taylor & Francis AS).