PET Radiopharmaceuticals

• Nitrogen 13
• F18
• Rb 82

Postive Ion Cyclotron: proton accelerated

• Negative Ion Cyclotron: proton+2 e
• -tungsten filament heated>ionizes H+ gas intro protons that gain 2 electrons> negative ions get pulled into cyclotron by magnetic device.

Ernest Lawrence in 1930

• Vacuum
• Ion Source
• Radiofrequency System
• Magnetic System
• Extraction System

Removes air, atoms or molecules

Creates plasma from which the negative ions are extracted to form the ion beam for acceleration

ARC power supply=plasma created by electrical current

Bias power supply=H- pulled from the plasma thru a small slit and then thru the puller in to the main acceleration region

Accelerates the ion beam

**Alternating current accelerates H- ions**

Controls the path of the ion beam w/n the cyclotron

• Carbon extraction foil is catches beam of H-
• THEN
• Beam strikes foil and becomes positive
• THEN
• Beam is diverted towards the target

To identify true events

• 1. Positron Range
• 2. Residual kinetic energy and momentum (how far it travels)

• 1. F18 Fluoride Production
• 2. Trap and release of F18 fluoride ion
• 3. Prep of F18 fluoride ion
• 4. Radiolabeling
• 5. Hydrolysis
• 6. Purification

Proton Bombardment of O18 water (target material) with F18

Transfer to chemistry module

• 1. Load O18 and F18 to chemistry module
• 2. Rinse with Potassium Carbonate
• (O+F)+K= (K+F) + O

• F18 will stick to resin and become purified (K+F18)
• The water will washout and can be recycled

• Must have no water (anhydrous)**Important b/c H2O forms bonds with fluoride so F18 won't be able to to bind**
• Must be in solution (soluble)
• Must be reactive

1. Remove K by adding Kryptofix 222 (forms a cage around K so it doesn't react with fluoride)

2.Add acetonitrile and azeotropic distillation to get rid of water

3.Add more acetonitrile to resolublize the dried F18 complex

• C2 is at the nucleus of the triflate group
• F- is a nucleophile (nucleus loving)
• F18 displaces the C2 triflate group to form glucose

**The acetyl groups protect the hydroxyl groups which force the F18 to remove C2**

Use NaOH to remove acetate groups to yield FDG molecule

Neutralize using acid or base

• Eliminates:
• Unreacted F18 ion
• Unhydrolyzed F18
• K222
• Acetonitrile
• Microbial Contamination