The optimal dose of iodine based contrast agents used in contrast-enhanced spectral mammography (CESM) is unknown. If CESM, performed with lower dose of iodine based contrast agent, visualizes a tumor comparable to CESM with regular dose of contrast agent, patients can receive less contrast agent for CESM in future and thereby risking less side effects of the contrast agent.

In order to study whether CESM remains unchanged at smaller amounts of contrast administration, a second CESM exam will be performed within one week of the first with a an alternative amount of contrast, it being either 80%, 60% or 40% of the original contrast dose. The settings of the CESM unit will remain unchanged.

Inclusion Criteria:

• Female patient with histopathologically confirmed invasive breast cancer who recently underwent a clinical CESM exam without complications;
• Treated with primary surgery;
• Willing and able to undergo all study procedures;
• Has personally provided written informed consent.
• Age ≥ 18

Exclusion Criteria:

• Pregnancy
• Allergy for any of the ingredients of (Ultravist) contrast agent
• Being unable to give informed consent in person
• History of coronary arterial disease or unstable angina
• Acute or chronic severe renal insufficiency