ABSTRACT
Kilovoltage X-Ray Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Tony Greener
Chapter 11
Linear Accelerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Les Loverock (with Philip Mayles, Alan McKenzie, David Thwaites, and Peter Williams)
Chapter 12
Cobalt Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
John Saunders
Chapter 13
Simulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Jean-Claude Rosenwald
Chapter 14
Portal Imaging Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Cephas Mubata
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
This part deals with the equipment used in external beam radiotherapy. The treatment
devices used for radiation production are either kilovoltage x-ray units, or megavoltage linear
accelerators, or cobalt-60 machines. Kilovoltage x-ray units, described in Chapter 10 were histori-
cally the first to be used and they played an important role in the early development of
radiotherapy, mainly between 1910 and 1950. Although still useful for the treatment of super-
ficial lesions, they have been superseded for most treatments by linear electron accelerators,
emitting megavoltage x-ray beams and possibly electron beams. These accelerators, which
started to be used clinically in the late 1960s, are described in Chapter 11 with a brief reference
to betatrons and microtrons, which were other types of electron accelerator developed for
radiotherapy. Cobalt-60 machines, described in Chapter 12, provide penetrating g-ray beams
emitted from a radioactive source. They were introduced as a replacement for kilovoltage x-ray
units in the 1950s. It is only in the last decade of the past century that the superiority of linear
accelerators became evident and that the number of cobalt-60 machines started to decrease all
over the world, except in developing countries where they are still considered as the best
option, mainly because of their reliability. Equipment for radiotherapy using proton or high
LET particle beams are dealt with in Chapter 46 and Chapter 49 respectively.