Devices and methods are disclosed which relate to the calibration and quality assurance of motion tracking enabled radiation therapy machines. A phantom, capable of mimicking human breathing through inflation and deflation of the lungs, houses an independently moving target (tumor) that detects the amount of radiation received from the radiation therapy machine. This amount can be compared with a desired amount to determine if adjustment or repositioning is necessary. The servo-mechanism(s) of the motion tracking enabled radiation therapy machine(s) are adjusted in comparison of detected versus programmed motion of the respiring phantom having incorporated independently moving target that incorporated radiation dose detector(s). In the invention, motion tracking and irradiation mechanisms of the radiation therapy machine are adjusted to calibrate with reference to performance specifications of the radiation therapy machine.