This is a prospective single-center interventional non-inferiority study where subjects are participating for one day for patients 18 years or older with melanoma, breast cancer or head & neck cancer (including melanoma of head and neck area) and scheduled for a surgical SN procedure in the NKI-AvL without any contra-indication for Sonazoid contrast agent, such as an allergy to eggs or egg products. The primary objective is to assess the sensitivity of CEUS for intra-operative SN localization compared to the gold standard (99mTc nanocolloid). Secondary objectives are the specificity of CEUS for intra-operative SN localization, the time required to localize the SNs using CEUS and intraoperative usability of the CEUS-system. The primary endpoint is the sensitivity of the CEUS SN localization method. The conventional gamma probe will be used as ground truth comparison.

Inclusion Criteria:

• Aged 18 years or older
• Patient has been diagnosed with cancer in the skin (melanoma), breast or head & neck (including melanoma of head and neck area)
• In case of a melanoma: it should be located in the limbs or head and neck area
• Scheduled for a surgical SN procedure at the NKI-AvL
• Patient provides written informed consent

Exclusion Criteria:

• Pregnancy
• Any known clinically significant acute hypersensitivity reaction to the study medication, such as eggs or egg products
• Other contra-indications for Sonazoid contrast agent, including arteriovenous cardiac or pulmonary shunt, serious coronary arterial disease and serious pulmonary disease