PART C: Equipment

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ficial lesions, they have been superseded for most treatments by linear electron accelerators,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.