A number of studies have demonstrated a link between radiotherapy of the chest area and subsequent cardiovascular disease, a relationship seen in breast cancer survivors specifically. The risk has been shown to persist, and even increase, long after the completion of radiation treatment. This pilot study will seek to determine whether there are a sufficient number of breast cancer patients with Coronary Artery Calcium who underwent breast radiation therapy in the BC Cancer Agency, in order to design a formal study to evaluate the impact of coronary calcification on radiation induced cardiac toxicity. These patients will then be categorized based on the extent of coronary calcification to determine if there is a correlation between these groups and radiation induced cardiac toxicity.