datscan - Medication Listings

11.1 Chemical Characteristics DATSCAN (ioflupane I 123 injection) is a sterile, pyrogen-free radioactive diagnostic agent for intravenous use. DATSCAN is a clear and colorless solution supplied in single-dose vials. Each milliliter contains 0.07 to 0.13 mcg ioflupane, 74 MBq (2 mCi) of iodine-123 (as ioflupane I 123) at calibration time, 5.8 mg acetic acid, 8.2 mg sodium acetate and 0.05 mL (5%) ethanol. The pH of the solution is between 4.2 and 5.2. The chemical name for ioflupane I 123 is N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-[ 123 I]iodophenyl)nortropane and it has the following structural formula: Chemical Structure 11.2 Physical Characteristics Iodine-123 is a cyclotron-produced radionuclide that decays to tellurium-123 by electron capture and has a physical half-life of 13.2 hours. The photon that is useful for detection and imaging studies is listed in Table 2. Table 2 Principal Radiation Emission Data – Iodine-123 Radiation Energy Level (keV) Abundance (%) Gamma 159 83 11.3 External Radiation The specific gamma-ray constant for iodine-123 is 1.6 R/mCi-hr at 1 cm. The first half-value thickness of lead (Pb) for iodine-123 is 0.04 cm. The relative transmission of radiation emitted by the radionuclide that results from interposition of various thicknesses of Pb is shown in Table 3 (e.g., the use of 2.16 cm Pb will decrease the external radiation exposure by a factor of about 1,000). Table 3 Reduction in In-air Collision Kerma Caused by Lead Shielding Calculation based on attenuation and energy-transfer coefficients obtained from National Institute of Standards & Technology Internal Report NISTIR 5632. Shield Thickness cm of lead (Pb) Reduction in In-air Collision Kerma 0.04 0.5 0.13 10 -1 0.77 10 -2 2.16 10 -3 3.67 10 -4