A Study of Disappearing Markers for Daily Radiation Treatment Delivery for Breast Cancer Patients.

This study is testing a new type of temporary skin marker — called a "disappearing marker" — used to guide where radiation therapy is aimed during breast cancer treatment. Unlike permanent tattoos currently used to line up patients for radiation, this marker gradually fades, which may be preferred by many patients. Researchers want to see whether these temporary markers work just as accurately. **You may be eligible if...** - You are 18 years or older and assigned female at birth - You have been diagnosed with breast cancer (stage 0 through III) and are planning to receive radiation therapy after surgery - Your general health is reasonably good (Karnofsky performance score 70% or higher) - You have not received prior radiation to the affected breast **You may NOT be eligible if...** - You have previously had radiation to the affected breast - You have a known allergy to tattoo ink - You have active chronic skin diseases such as psoriasis (controlled skin conditions are acceptable) - You are pregnant or breastfeeding - Your BMI is above 44.5 Note: The first 6 participants must have a darker skin tone (Fitzpatrick scale 5 or 6). Talk to your doctor to see if this trial is right for you.