Medical Imaging Signals and Systems, by Jerry Prince and Jonathan Links, Prentice Hall, 2nd edition
Available as hardcopy in the bookstore or at Amazon.
Other Recommended Reference Books
Fundamentals of Medical Imaging, by Paul Suetens, Cambridge Press, Second Edition (2009) ISBN 978-0-521-51915-1.
Available at the bookstore or at Amazon as a Kindle electronic edition.
Also in the Engineering library as hardcopy or viewable online only one person at a time.