"A class of proteins that controls visual system development in the young brain also appears to affect vulnerability to Alzheimer's disease in the aging brain. The proteins, which are found in humans and mice, join a limited roster of molecules"...
(flutemetamol F 18) for Injection
Vizamyl contains flutemetamol F 18, a molecular imaging agent that binds to β-amyloid aggregates, and is intended for use with PET imaging of the brain. Chemically, flutemetamol F 18, is described as 2-[3-[18F]fluoro-4-(methylamino) phenyl]-6-benzothiazolol. It has the molecular formula C14H1118FN2OS, molecular weight 273.32, and the following structural formula:
Vizamyl is a sterile, non-pyrogenic, clear, colorless to slightly yellow radioactive solution for intravenous injection. Each milliliter (mL) of the no-carrier added Vizamyl product solution contains 150 MBq (4.05 mCi) of flutemetamol F 18 at reference date and time and up to 2 micrograms of flutemetamol. Each mL of the Vizamyl solution also contains 70 microliters ethanol, 9.0 mg sodium chloride and 4.98 mg polysorbate 80 (w/v) in 0.014 M aqueous phosphate buffer. The pH of the solution is between 6.0 and 8.5.
Fluorine-18 (F 18) is a cyclotron-produced radionuclide that decays by positron emission (ß+ decay, 96.7%) and orbital electron capture (3.3%) to stable oxygen-18 with a physical half-life of 109.8 minutes. The positron can undergo annihilation with an electron to produce two gamma rays; the energy of each gamma ray is 511 keV (Table 3).
Table 3: Principal Radiation
Emission Data – Fluorine-18
The point source air-kerma rate constant for F-18 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 (Pb) for F 18 gamma rays is approximately 6 mm. The relative reduction of radiation emitted by F-18 that results from various thicknesses of lead shielding is shown in Table 4. The use of ~8 cm of 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
|Shielding Thickness cm of lead (Pb)||Coefficient of Attenuation|
Last reviewed on RxList: 12/18/2014
This monograph has been modified to include the generic and brand name in many instances.
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