Antimatter is used practically in medical imaging. A PET scan stands for Positron Emission Tomography, and as we know a positron is a particle of antimatter. During a PET scan, a molecule very much like glucose (sugar) called FDG or Fludeoxyglucose (18F) is put into the body. This molecule is like glucose, so it goes where ever glucose would go. However, it has a fluorine-18 isotope in it, which emits positrons.
So positrons leave the FDG, but positrons are antimatter and annihilate anytime they encounter an electron (which is matter). This happens, and gamma photons are produced. These gamma photons can be detected outside the body. So, the annihilation event between matter and antimatter can be used to map where the FDG goes and how much of it there is.