*9.1.1 A-production of radionuclides in the cyclotron*

The Cyclotrons are considered the most common type of accelerator which normally produce medical radionuclides through bombardment with charged particles. Its main usage is to accelerate charged particles in a circular fashion, cyclotrons used to take up less space than their linear counterparts.

The Cyclotrons typically accelerate charged particles to energies between 11 and 30 MeV, Despite the availability of the larger machines. Consequently, Cyclotrons can accelerate positive (e.g., protons, alpha particles) or negative (e.g., hydride ions) ions, but the majority of commercial machines manufactured today are negative ion.

#### **The most important steps fundamentals of cyclotrons:**


nuclides. The cyclotron was developed by with the purpose of accelerating particles such as protons or deuterons to achieve high levels of kinetic energy.


**Figure 4.** *The process of producing of radionuclides in cyclotron.*

energy needed to escape from them and collide with the target, where the nuclear reactions will take place.


Fluor-18: 18F - Carbon-11: 11C - Nitrogen-13: 13 N- Oxygen-15: 15O - Gallium-68: 68Ga - Scandium-44: 44Sc - Zirconium-89: 89Zr - Iodine-124: 124I See **Figure 5**.

*9.1.2 Production of radionuclides in the nuclear reactor*

The process of producing radionuclides in nuclear medicine generated in nuclear reactors has two kinds of nuclear reactions including an interaction with neutrons:



**Figure 5.** *Selected radionuclides produced by cyclotrons.* *New Trends in Preparation, Bio Distribution, and Pharmacokinetics of Radiopharmaceuticals… DOI: http://dx.doi.org/10.5772/intechopen.101069*

Each fission reaction releases a considerable amount of energy that is take out through heat exchangers to provide electricity in nuclear energy plants. When a fissionable heavy element target is interleaved into the core of the reactor, the heavy nuclides absorb thermal neutrons and experience the so-called fission reaction. Some fissionable heavy elements with an atomic number over 90 are: 235U, 239Pu, 237Np, 233U 232To. On the other hand, many clinically suitable radionuclides for instance 131I, 99Mo 133Xe and 137Cs are attained from the fission of 235 U See **Figures 6** and **7**.

**The diagram illustrates** the typical components found in radionuclide generator. It helps in the separation and elution of the daughter radionuclide and the parent radionuclide. This elution results in a product that is sterile and free of impurities thus making it immediately suitable for human injection See **Figure 8**.

#### *9.1.3 What are the main purpose of the radionuclide reactors?*

They are considered a source of radionuclides which used for the production of radiopharmaceuticals. The 99Mo → 99mTc reactor often referred to as a technetium reactor is the most important radionuclide reactor for radiopharmaceutical preparation that is why it gets its importance. The reactor is capable of supplying shortlived radionuclides (short half-lives) over a time period much longer than this short half-life. It is also a unique equilibrium that is establishment between a long-lived


#### **Figure 6.**

*Selected radionuclides produced by nuclear fission.*

**Figure 7.** *Radionuclide reactors.*

#### *Radiopharmaceuticals - Current Research for Better Diagnosis and Therapy*

**Figure 8.** *Radionuclide generator.*


#### **Figure 9.**

*Products of Radiocludes.*

"parent" radionuclide and its short-lived radioactive daughter. The second a ability to physically is the separation of the parent and daughter radionuclides to allow the daughter to be utilized for the preparation of short-lived radiopharmaceuticals. In the 99Mo → 99mTc reactor the parent is 99Mo with a half-life of 66 hours, which decays for producing the radioactive daughter 99mTc with a half-life of 6 hours. The *New Trends in Preparation, Bio Distribution, and Pharmacokinetics of Radiopharmaceuticals… DOI: http://dx.doi.org/10.5772/intechopen.101069*

separation of the parent and daughter is completed by simply washing the daughter from the reactor with sterile saline See **Figure 9** [5].
