<<Chris Alston asked about obtaining NRPB reports>> I have passed the message on to the information office at the NRPB and asked them to contact Chris direct. For information the NRPB have a web site at http://www.nrpb.org.uk and their email address is information@nrpb.org.uk hope this is useful. Sharan Packer, Leeds, UK. (email sp@medphysics.leeds.ac.uk)