**1. Introduction**

It is very effective to provide an introduction to this chapter of the field of nuclear medicine and how radioisotopes are used in nuclear medicine for both diagnostic and therapeutic applications. Radiopharmaceuticals are compounds that administered intravenously whether diagnostic or therapeutic applications [1]. Diagnostic applications in nuclear medicine use low activity tracer levels of generally gamma- or positron-emitting radioisotopes which are generally produced in nuclear reactors and accelerators. In other hands, therapeutic applications use particle-emitting radionuclides for induction of radio toxicity to kill cells in the intended tissue. It is also noted that in the form of radioactive sources, therapeutic radioisotopes are also used in other clinical specialties will be discussed in this chapter. As well as this chapter focuses on the description of radioactive materials which are used for nuclear medicine therapy and how they are produced.

Improving the utilization of radiopharmaceuticals in the development of pharmaceutical drug delivery systems, the behavior of the tracers administered by various ways must be investigated. The main aim of radio pharmacology is to study the chemical properties of radiotracers and their interactions with living organisms. Radiopharmaceuticals are unique medicinal formulations containing radioisotopes which are used in major clinical areas for diagnosis and/or therapy. Radiopharmaceuticals is currently considered the cornerstone of nuclear medicine. That is why there is a requirement for new radiopharmaceuticals that could be utilized to explore more subtle mechanisms of body functions.

This part of chapter which presented in the symposium reflect current and future developments in diagnostic and therapeutic agents as it deals with (Tc-99 m), highlighting its continuing importance to nuclear medicine and the role of imaging as an important tool. The emerging interest in therapeutic radiopharmaceuticals based on beta emitting short lived isotopes such as Iodine (I-131).

It worth mentioning that The properties of bio distribution and pharmacokinetics play a major role in affecting and defining the efficacy and safety for the treatment with a medicine. Currently, several image guided modalities have been applied in nuclear medicine such as Single-Photon Emission Computed Tomography (SPECT), (SPECT/CT), Tomography Computed Tomography (PET/ CT), and Positron Emission.

The use of radionuclides for medical applications has continued to grow at a very rapid pace. That is why, it is required to learn more about The use of radiotracers for nuclear medicine imaging as well as discussing in this part of chapter the different methods of preparation, bio distribution and pharmacokinetics of radio pharmaceuticals for diagnosis and research.

### **2. What is radiopharmaceutical?**

Radiopharmaceuticals can be defined as a chemicals substances that contain radioactive atoms within its structure and suitable for administration to human used for either diagnose or treat diseases [2].

Radiopharmaceuticals can be categorized into:


#### **3. Nuclear medicine and radiopharmaceuticals**

Radiopharmaceuticals can be categorized into two groups:


*New Trends in Preparation, Bio Distribution, and Pharmacokinetics of Radiopharmaceuticals… DOI: http://dx.doi.org/10.5772/intechopen.101069*

Cameras in nuclear medicine are suitable for identifying radioactive particles. The type of camera can be defined by The type of radiation emitted:

