No part of this publication or site may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the Publisher, e-MED Limited, Permissions, PO Box 61053, London, SE16 7YZ. Tel: +44 (0)207 719 8989 Fax: +44 (0)560 126 4446, permissions@cancerimaging.org.