Influence of Couch Tracking Motion
Condition: Respiratory Amplitude
Study type: Interventional

Summary: 
      Tumor motion increases the uncertainty in Radiation Oncology. Couch tracking can compensate
      for this uncertainty. However it is not known if the couch motion influences the respiratory
      pattern of the patients. This will be evaluated in this study on healthy volunteers.
    

Detailed description: 
      Radiation therapy is one of the main options in cancer treatments, alongside surgery and
      chemotherapy. Its efficacy largely depends on the absorbed radiation dose of the tumor cells.
      However, the irradiation of healthy cells results in negative side effects for the patient.
      Therefore, a big challenge in radiation therapy is to irradiate the tumor with sufficient
      dose, while keeping the irradiation of the healthy tissue reasonably low. Currently, the
      radiation treatment is planned by defining a volume enclosing the tumor, but with added
      margins to account for any uncertainties. These margins ensure that the tumor receives the
      prescribed dose.

      Tumor motion contributes to the uncertainties. The tumor motions of tumors in different sites
      have different causes, but for this project the focus is on thoracic, liver, and adrenal
      gland tumors. The motion of these tumor types is mainly caused by the patient's respiration.
      So, the tumor motion pattern depends on the respiration pattern of the patient. The motion of
      lung tumors has been reported to have a peak-to-peak amplitude of up to 24 mm. Currently, the
      tumor motion is handled by enlarging the margins, such that the tumor is always inside the
      defined volume. But enlarging the margins also results in an increase of irradiated volume
      consisting of healthy tissue.

      Tumor motion mitigation is concerned with reducing the margin increase caused by the motion
      of the tumor. There are several approaches to tumor motion mitigation and the one under
      consideration in this project is the tumor tracking approach, the technically most difficult
      approach. In tumor tracking the tumor motion is continuously compensated by moving the
      radiation source modifying the radiation beam, or moving the patient, which is denoted as
      couch tracking.

      In couch tracking, the patient is moved by the robotic treatment couch. Such robotic
      treatment couches are in use with conventional, widely available C-arm linear accelerators,
      and, therefore, are readily available for implementing couch tracking. The patient is placed
      on a couch which moves in the opposite direction of the tumor motion. The goal is to minimize
      the patient's tumor motion relative to the radiation, which in turn allows the margins to be
      decreased. The margin decrease might ultimately lead to a reduction of side effects, e.g.
      pneumonitis.

      The motion of the couch depends on the motion of the tumor, which in turn depends on the
      respiration of the patient. However, the couch motion may influence the patient's well being
      or the patient's respiration. So the question arises: Does the motion of the couch have an
      influence on the respiration behavior? And also: Does the motion of the couch have an
      influence on the well being (motion sickness)? And are the well-being and the respiration
      behavior connected? If the respiration behavior does depend on the couch motion, it may be
      necessary to control the respiration behavior. Additionally, in the study, the investigators
      will check an assumption in couch tracking, namely that the patient's body is rigidly fixed
      to the couch. If this assumption does not hold, the motion of the patient's body relative to
      the couch will have to be taken into account in couch tracking.
    

Intervention name(s): Protura Treatment table
Intervention type(s): Device
Intervention description(s): The treatment couch will be moved according to the respiratory motion of the patient. As a reference first the respiration will be measured without couch motion, than the couch will be switched on and we will evaluate if the respiration changes due to the motion of the couch. This procedure will be repeated once.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science