**12.2 Nuclear imaging**

Nuclear imaging is essential for the detection of cancer. Using fragments reduces nuclear exposure to radiation. The bifunctional connector connects antibody fragment and radionuclide, and such complexity easily accumulates at the tumor and gives clear visualization [54]. This method can be used to measure the absorption of drugs and the expression of receptors. One issue with the complex is increased radiation in the kidney due to complex breakdown and retention of radionuclide in the kidney [37].
