Real-Time MRI-Guided 3-Fraction Accelerated Partial Breast Irradiation in Early Breast Cancer

This study is testing a shorter, more targeted type of radiation treatment called accelerated partial breast irradiation (APBI) delivered in just 3 sessions using real-time MRI guidance. It is designed for people with early-stage breast cancer who have already had a lumpectomy (surgery to remove the tumor while keeping the breast). MRI guidance helps doctors focus radiation precisely on the area where cancer was, reducing exposure to surrounding healthy tissue. **You may be eligible if...** - You have had a lumpectomy for early-stage breast cancer - The area where the tumor was removed is clearly visible on MRI and CT scans - You have no contraindications to MRI scans - Your pregnancy test is negative (if applicable) - Your tumor meets specific size, margin, and grade criteria **You may NOT be eligible if...** - You have had prior radiation to the same breast - You have metal implants or other MRI incompatible devices - You are pregnant - Your cancer has spread to lymph nodes or beyond - Your tumor cavity is too close to the skin or chest wall Talk to your doctor to see if this trial is right for you.