In the proposed research study, we are investigating the feasibility of integrating automated planning tools to MR images acquired using a novel MR-guided linac, for on-line adaptive radiation treatment. However, these on-line automation tools require further technical refinement and clinical validation. The goal of this research proposal is to develop an on-line MR-guided radiation therapy process for adapting breast IMRT treatment. Such an approach will provide early stage breast cancer patients timely access to high-quality adaptive treatments without exposure to additional ionizing radiation.

Inclusion Criteria:

• Patients who will receive standard two-field tangential whole breast radiation therapy with dose prescription of 4240 cGy in 16 fractions, 5000 cGy in 25 fractions or 4000 cGy in 16 fractions.
• Female patients with any stage of breast cancer.
• Patients with prior treatment such as surgery or chemotherapy for any type of cancer.
• Able to provide a written informed consent.
• ≥ 18 years of age.

Exclusion Criteria:

• Patients who will not receive 4240 cGy in 16 fractions, 5000 cGy in 25 fractions, or 4000 cGy in 16 fractions
• Males.
• Patients who received partial breast radiation and not the standard dose.
• Patients who are unable to provide informed consent.
• < 18 years of age.