Nuclear medicine is a discipline that uses nuclear technology to diagnose, treat and study diseases, and is divided into two main categories: treatment and diagnosis, both of which require the use of radioactive elements. Diagnosis is divided into the detection of the presence of a substance or the amount of a substance in a patient’s body through criteria such as blood to indicate whether or not they have a disease, and the examination of a variety of items through instruments, such as CT. Common treatments include iodine 131 internal irradiation therapy for thyroid cancer, strontium 89 therapy for bone metastases, and radioactive particle implantation therapy.