title: Intrasubject comparison between technetium-99m-ECD and technetium-99m-HMPAO in healthy human subjects.
abstract: The pharmacokinetics and quality of planar and SPECT brain imaging of two 99mTc-labeled brain perfusion agents, d,l-hexamethyl propylene amine oxime (HMPAO) and ethyl cysteinate dimer (ECD), were compared in seven healthy, normal subjects. Both radiopharmaceuticals showed rapid brain uptake and had a net brain washout of less than 5% during the first 20 min after drug administration. However, during the same time period, 99mTc-ECD images of the head showed significantly less background facial uptake and retention when compared to 99mTc-HMPAO images. The brain-to-background contrast ratio of 99mTc-ECD (brain/neck) continued to improve over time and by 5 hr postadministration was 17 to 1 versus 2 to 1 for 99mTc-HMPAO. SPECT brain images of both agents show gray/white matter ratios that were unchanged over time and an intracerebral distribution consistent with blood flow. A blind read of these SPECT images also shows 99mTc-ECD to produce images that were "easier to interpret" with less extracerebral activity as compared to 99mTc-HMPAO. Repeat, whole-body planar spot imaging suggests that 99mTc-ECD was cleared more rapidly from the body than was 99mTc-HMPAO.
authors.affiliation: Médecine Nucléaire, Hotel-Dieu de Montréal, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Léveillé
authors.forename: G
authors.initials: G
authors.lastname: Demonceau
authors.forename: R C
authors.initials: RC
authors.lastname: Walovitch
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D003545:Cysteine / Q000031:analogs & derivatives*; D006801:Humans; D008297:Male; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D012016:Reference Values; D019690:Technetium Tc 99m Exametazime; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; C059659:technetium Tc 99m bicisate; D003545:Cysteine