Lung perfusion PET / CT is a new imaging modality based on the use of the same cold molecules as those used for a conventional perfusion lung scan. Similartly, perfusion images are obtained after intravenous administration of human albumin macroaggregates, which are embolized in pulmonary capillaries according to pulmonary blood flow. However, these cold molecules are radiolabeled, not with Technetium99m, but with Gallium68, a ß + isotope, allowing image acquisition with PET technology. The same physiological processes are therefore observed with conventional scintigraphy PET imaging, but PET is an intrinsically superior technique for image acquisition, with greater sensitivity, better spatial and temporal resolutions and the possibility to perform respiratory-gated acquisition, allowing a better definition of the pulmonary functional volumes.
The aim is to evaluate the feasability of functional lung avoidance planification using lung perfusion PET/CT imaging during SBRT.
Patients will benefit from a pre-treatment functional assessment including PET/CT imaging.
The treatment planning will be carried out in 2 stages:
* First, an anatomical planning will be carried out, blinded to the PET results.
* Then, a functional planning, respecting the standard constraints applied during anatomical planning, but also incorporating a new "functional lung volume" constraint defined by PET/CT images, will be carried out.
A follow-up will be carried out for 12 months, including repeated perfusion PET/CT imaging at 3 and 12 months.
