That study combines High Frequency Percussive Ventilation (HFPV) with radiotherapy treatment in patients with tumors that are moving with respiration like breast or lung cancers. The use of a High Frequency Percussive Ventilation system leads to the cessation of respiratory motions while administering radiotherapy (RT) to tumors which allows a reduction of the amount of irradiated normal tissues and which potentially decrease radiation-induced collateral damages.