Gadolinium oxyorthosilicate (known as GSO) is a type of scintillating inorganic crystal used for imaging in nuclear medicine and for calorimetry in particle physics. Gadolinium oxyorthosilicate (known as GSO) is a type of scintillating inorganic crystal used for imaging in nuclear medicine and for calorimetry in particle physics. The formula is Gd2SiO5.Its main properties are shown below: