The purpose of this research study is to demonstrate that Deep Inspiration Breath Hold (DIBH), the technique used at the University of North Carolina (UNC) for left-side breast cancer radiation therapy, can reduce side effects to the heart.

The primary objective of this study is to estimate the rate of radiation-associated regional myocardial perfusion defects in patients 6 months after breast/chestwall radiation with DIBH for left-sided breast cancer. Cardiac perfusion will be assessed using SPECT cardiac perfusion scans pre- and 6 months post-radiation.

Inclusion Criteria:

• signed an Institutional Review Board (IRB)-approved informed consent document for protocol
• age >= 18 years
• histologically confirmed left-sided breast cancer scheduled to undergo curative intent radiation treatment post lumpectomy or mastectomy
• stage 0-III left-sided breast cancer (including DCIS)
• SPECT score of 0 at baseline
• radiation oncologist agrees target volume coverage will not be compromised via use of the DIBH technique along with conformal field shaping

Exclusion Criteria:

• active cardiac disease, defined as a history of angina, arrhythmias, myocardial infarction, congestive heart failure, or any other cardiac condition, which in the opinion of the treating physician would make this protocol unreasonably hazardous for the patient
• symptomatic pulmonary disease currently requiring regular medication including but not restricted to bronchodilators
• concurrent chemotherapy
• prior receipt of mediastinal radiation therapy
• pregnant or lactating women
• inability to understand and follow breathing instructions for the DIBH procedure

Women with left-sided breast cancer