Mechanical ventilation can be used to impose a completely regular pattern of breathing frequency and inflation volume on the patient for as long as required. This would considerably improve the reproducibility of the internal motion parameters, and thus facilitate the implementation of respiratory-synchronized techniques such as gating, tracking and four-digital optimization.

This will be a three-phase analysis :

First, different ventilation modes will be tested and compared on healthy volunteers. This phase will be analysed with a ventilator and with dynamic MRI in order to measure the movement of anatomical structures in each ventilation mode (intra-fraction analysis). Further, we will repeat these exams in order to compare them with the first ones, in order to analyse the reproducibility and baseline shifts (inter-fraction analysis).

Here are the different ventilation modes

• spontaneous breathing
• physiologic ventilation mode :
• shallow ventilation mode
• slow ventilation mode
• Jet Ventilation mode

Second phase will be done with patients that are intended to have a radiation treatment for thoracic or upper abdominal tumors. All the previous ventilation modes will be analysed during repeated MRI, again in order to perform intra- and inter-fraction analysis of the tumor motion.

Third phase also concerned patients intended to have a radiation treatment. It will be an in-silico-planning analysis in order to quantify dosimetric outcomes of these ventilation modes.

Inclusion Criteria:

• No comorbidity for healthy volunteers
• Cancer patients with either lung or upper abdomen (liver/pancreas) tumours treated with radiation therapy.

Exclusion Criteria:

• severe lung disease or emphysema
• previous history of pneumothorax
• claustrophobia

Not decided at this moment