* Participants will have a TOBI scan prior to starting their cancer treatment and again on day 8 after their first treatment. Participants will also be asked if they would volunteer to undergoing one or more additional TOBI scans on days 2-7 after they begin cancer treatment. These additional scans are optional. Participants will also have a scan on the first day of each treatment cycle.
* TOBI scans will be performed at the Gillette Center for Breast Cancer at the Massachusetts General Hospital.
* For the scan, each breast is placed between 2 plastic plates in order to spread the tissue apart, similar to the procedure for a mammogram. The TOBI scanner is attached to these plates. We will apply mild pressure to compress the breast and the breast will be scanned using light waves. Each scan will take about 3 minutes.
