But researchers at the Netherlands Cancer Institute discovered a new set of salivary glands around 1.5in in length while scanning for prostate cancer cells using using a combination of CT scans and positron emission tomography (PET) scans called PSMA PET-CT.
Doctors using radiotherapy to treat head and neck cancers try to avoid the three main salivary glands because damaging them can leave patients struggling to eat, speak or swallow.