On-line adaptive deep inspiration breath-hold treatment

A system for performing treatment fractions of a radiation therapy process, the system comprising:

• an X-ray imager;
• a treatment-delivering X-ray source configured to direct treatment X-rays to a target volume of patient anatomy;
• an imaging X-ray source configured to direct imaging X-rays through the target volume and toward the X-ray imager;
• and
• a processor configured to:
• while a patient is disposed in a first position for a first treatment fraction of the radiation therapy process and maintains a first inspiration level, acquire a first set of projection images of a target volume associated with the patient;
• based on a treatment planning digital volume associated with the radiation therapy process and the first set of projection images of the target volume associated with the patient, generate a synthetic digital volume that includes the target volume;
• based on a treatment plan associated with the treatment planning digital volume and on the synthetic digital volume, generate a second modified treatment fraction of the radiation therapy process that is based on the first treatment fraction of the radiation therapy process;
• and
• while the patient remains in the first position for the first treatment fraction of the radiation therapy process and maintains at least the first inspiration level, cause the second modified treatment fraction of the radiation therapy process to be performed.