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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
23
Mechanically ventilation will be done through facial masks connected to a respirator. Volunteers/patients are fully conscious during the ventilation.
Dynamic MRI acquisition are specific dynamic sequences intended to visualise the motion of internal structures (anatomical structures or tumour) under non-invasive mechanically-assisted ventilation
In order to perform in-silico planning, 4D-CT will be acquired on patients under non-invasive mechanically-assisted ventilation
Cliniques Universitaires Saint-Luc
Brussels, Belgium
Measure in millimeters of the internal motion during non-invasive mechanically assisted ventilation, based on MRI images
This analysis will be based on dynamic MRI analysis made with healthy volunteers and also patients on non-invasive mechanically assisted ventilation. A well defined anatomical structure will be selected for the healthy volunteers while the tumor will be tracked in patients.
Time frame: within 12 months
Tolerance assessment
During all these acquisitions, the tolerance to the non-invasive mechanically assisted ventilation will be assessed by all the participants through a 5-steps scale.
Time frame: within 12 months
Internal motion reproducibility with non-invasive mechanically assisted ventilation.
This analysis will be done by comparing the motion of the internal structures/tumors at two different time points (MRI acquisition at two different time points). All these acquisitions will obviously be done in the same conditions on non-invasive mechanically assisted ventilation. Motion reproducibility will be analysed by comparing the baseline positions of anatomical structures/tumors on MRI images and the measures in millimeters of motion of the same anatomical structures/tumors.
Time frame: Within 12 months
Dosimetric comparison
This dosimetric comparison will be done in order to assess the impact of non-invasive mechanically-assisted ventilation on dose planning and delivery. Difference in dose (in Gy) to organ at risks will specially be compared through the DVH (dose-volume histogram) analysis.
Time frame: within 12 months
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