Applications of Ultrasound in Breast Cancer

For decades, whole breast radiation therapy has been standard treatment for breast cancer patients following lumpectomy. The goal of radiation treatment is to kill any remaining cancerous cells around the lumpectomy cavity while limiting the dose to normal, healthy tissues, such as the heart and lungs. Recently, partial breast irradiation (PBI) has gained momentum in efforts to reduce the overall treatment time and limit the volume of breast and normal tissues being irradiated. This involves targeting only the lumpectomy cavity surrounded by a small margin to account for variability in daily treatments. Imaging Limitations CT imaging has been the standard tool used for radiation treatment planning and has provided clinicians with great anatomic detail. However, CT is limited in its ability to visualize certain soft tissues, such as lumpectomy cavities, and its ability to distinguish them from adjacent normal tissue. Uncertainty in identifying the borders of the lumpectomy cavity can cause either undertreatment of areas at risk or unnecessary overexposure of healthy tissue to radiation in some patients. In addition, another challenge is the fact that a lumpectomy cavity can move and change shape as the tissue heals in the weeks following surgery. Traditionally, physicians have relied on the surgery scar to serve as a marker to localize the lumpectomy cavity. Several studies have found that locating the lumpectomy cavity based solely on this scar may result in a partial miss of the cavity in over 50% of cases. While the radiation oncology community widely recognizes inconsistent set up of patients on the radiation table and changes to the lumpectomy cavity over time, one practical solution to this problem...