Complications of cholecystitis and/or biliary colic may also include cholangitis, sepsis, pancreatitis, hepatitis, and choledocholithiasis (10%). In addition, Gallbladder perforation occurs in 10% of patients with cholecystitis. When perforation is localized, it may be seen as pericholecystic fluid by ultrasonography.
Half-life is defined as the time it takes for one half of a radioactive element to decay into a daughter isotope. As radioactive isotopes of elements decay, they lose their radio activity and become a brand new element known as a daughter isotope.
Radioactive elements with a half-life of several hours are generally used. Read more about radiation therapy here. A sample of Uranium atoms has about a 50% chance of undergoing radioactive decay at any time. Within the Uranium-238 decay cycle, half-life can range from billions of years to mere seconds.