Nuclear Medicine Mechanism Imaging and Therapy

**71**

**Chapter 4**

**Abstract**

radiopharmaceuticals

Theranostics: New Era

Radiopharmaceuticals

in Nuclear Medicine and

*Chanchal Deep Kaur, Koushlesh Kumar Mishra,* 

Malignancy and many inflammatory diseases have become a major concern for mankind over the years. The conventional therapy of these diseases lacks the effectiveness of the better diagnosis and targeted treatment of these diseases, but nuclear medicine can be regarded as a savior in the current scenario. Over the years, radioactivity of radioisotopes has been employed for treatment of many diseases. Nuclear medicines came up with radiopharmaceuticals that impart the ability to destroy specific diseased cells with high-energy-emitting radionuclides. Moreover, the emergence of theranostics, which is a combination of single drug used both for diagnostic as well as therapeutic purpose, has added a new feather in the field of nuclear medicines for providing a specific and personalized treatment to the patient. The current chapter discusses about techniques used for imaging of these radionuclides for better therapy and diagnosis of the root cause of the concerned disease by positron emission tomography (PET)/CT and single photon emission computed tomography (SPECT)/CT as well as the advantages and disadvantages associated with them. It also describes about applications of theranostics and nuclear imaging in cancer treatment and their future perspective.

**Keywords:** radionuclides, nuclear medicines, nuclear imaging, theranostics,

Scientist has discovered that earth contains many elements with varying configuration. These elements with varying configuration are called isotopes. Isotopes are atoms with same atomic number with varying atomic weight. Isotopes can be divided into two parts depending on the ability to emit radiation. One that does not emit radiations is called stable isotopes and other are called unstable isotopes. Unstable isotopes emit radiations to achieve a more stable configuration. These are called as radioisotopes. Instability of radioisotopes is due to presence of unstable combination of neutron and proton in their atoms and nucleus contains excess of energy. This characteristic of radioisotopes can be natural or instability can be created artificially by changing the atoms. Naturally radioisotope is uranium-238 and it accounts to 0.7% of total naturally occurring isotopes. Artificial radioisotopes are fluorine and molybdenum which are produced artificially by using cyclotrons and nuclear reactors respectively. Presently there are

**1. Introduction to radioisotopes and radiopharmaceuticals**

*Anil Sahu, Rajnikant Panik, Pankaj Kashyap,* 

*Saraswati Prasad Mishra and Anand Kumar*
