ABSTRACT
Patient data acquisition is the first step in the treatment planning process. It is required for
three different purposes:
In all cases, it is essential that the patient position be defined at the beginning and main-
tained throughout the whole treatment planning and delivery process. This will be addressed in
Section 30.2. Patient data for treatment planning is often based on data acquired using a single
imaging modality with the aim of achieving the goals listed above. The most commonmethods
are described in Section 30.3. A full chapter is dedicated to the use of Magnetic Resonance
(MR) imaging for treatment planning, which is becoming increasingly important (see Chapter
31). With some imaging modalities, such as positron emission tomography (PET), and to
some extent MR, the geometric accuracy and the lack of electron density information makes it
necessary to co-register the data with CT. The methods used to register image sets obtained
from different modalities are described briefly in Section 31.6.2 in the context of the use of
Magnetic Resonance Imaging in radiotherapy.
