NEURACEQ Solution for injection Ref.[10070] Active ingredients: Florbetaben ¹⁸F

Neuraceq contains florbetaben F18, a molecular imaging agent that binds to β-amyloid plaques in the brain, and is intended for use with PET imaging. Chemically, florbetaben F18 is described as 4-[(E)2(4-{2-[2-(2-[¹⁸F] fluoroethoxy) ethoxy] ethoxy}phenyl)vinyl]-N-methylaniline. The molecular weight is 358.45 and the structural formula is:

Neuraceq is a sterile, non-pyrogenic radioactive diagnostic agent for intravenous injection. The clear solution is supplied ready to use. Each mL contains up to 3 micrograms and 50-5000 MBq (1.4 – 135 mCi) florbetaben F18 EOS, 4.4 mg ascorbic acid, 118 mg ethanol, 200 mg macrogol 400, 28.8 mg sodium ascorbate. The pH of the solution is between 4.5 and 7.

11.1 Physical Characteristics

Neuraceq is radiolabeled with [¹⁸F] fluorine (F18) that decays by positron (ß⁺) emission to O 18 and has a half-life of 109.8 minutes. The principal photons useful for diagnostic imaging are the coincident pair of 511 keV gamma photons resulting from the interaction of the emitted positron with an electron (Table 3).

Table 3. Principal Radiation Produced from Decay of Fluorine 18:

11.2 External Radiation

The point source air-kerma coefficient^a for F18 is 3.74E -17 Gy m²/(Bq s); this coefficient was formerly defined as the specific gamma-ray constant of 5.7 R/hr/mCi at 1 cm. The first half-value thickness of lead for F18-fluorine gamma rays is approximately 6 mm^b. The relative reduction of radiation emitted by F18-fluorine that results from various thicknesses of lead shielding is shown in Table 4. The use of ~8 cm of lead (Pb) will decrease the radiation transmission (i.e. exposure) by a factor of about 10,000.

Table 4. Radiation Attenuation of 511 keV Gamma Rays by Lead Shielding:

^a Eckerman KF and A Endo. MIRD: Radionuclide Data and Decay Schemes, 2nd Edition, 2008.
^b Derived from data in NCRP Report No. 49. 1998, Appendix C