Setup and intra-fractional motion measurements using surface scanning in head and neck cancer patients

The standard method for immobilization during radiation treatment for head and
neck cancer patients is using a 5-point thermoplastic mask. The use of an
individual patient mask results in small setup errors and intra-fractional
motion, resulting in a small margin for setup uncertainties. Despite the use of
a mask, variations are still seen in patient setup. In addition, many patients
experience the mask as uncomfortable, or even stressful. Therefore, an ideal
alternative for accurate setup of head and neck patients might be a method
without using a mask, but instead applying optical surface scanning for
accurate patient setup and intra-fractional motion monitoring.

The aim of the study is to investigate the clinical feasibility of irradiation
without a mask for head and neck cancer patients. Optical surface scanning will
be used and the set-up accuracy, intra-fractional motion, patient friendliness,
and clinically possible treatment margins are studied.

This is a preliminary study to the clinical feasibility of irradiation without
a mask for head and neck cancer patients. All subjects participating in the
study undergo a simulated radiation treatment once a week before the real
treatment, and optical surface scanning is used for set-up and intra-fractional
motion monitoring.

The intervention in this study includes a simulated radiation treatment for
head and neck cancer patients. Patient set-up is performed using optical
surface scanning without the use of a thermoplastic mask. Online imaging is
used to correct the setup. Patients are instructed to lie as still as possible
on the treatment couch. For intra-fractional motion monitoring again the
optical surface scanner is used. The surface scanner used for this study is
IDENTIFY (Varian), which constructs a 3D-reconstruction of a subject. The
actual position of the patient is compared to a daily made reference image and
the deviation is presented on a screen. After the simulated session and the
actual treatment, the patient fills in a questionnaire.

Participation in the study means subjects undergo an additional, simulated
treatment session, prior to the actual treatment session, once a week during in
total in 7 fractions. Moreover the patient is asked to fill in a questionnaire.
The extra time amounts to 20 minutes per simulated session. The patient
receives some additional dose due to the online imaging. No risks are
associated with participation.