title: Gadolinium concentration analysis in brain phantom by X-ray fluorescence.
abstract: We have measured the X-ray fluorescence from gadolinium as a function of concentration and position in tumors of different sizes and shapes in a head phantom. The gadolinium fluorescence was excited with a 36 GBq Am-241 source. The fluorescence signal was detected with a CdTe detector and a multi-channel analyzer. The fluorescence peak was clearly separated from the scattered X-rays. Concentrations of 5.62-78.63 mg/ml of Gd ion were used in 1, 2, and 3 cm diameter spherical tumors and a 2x4 cm oblate spheroid tumor. The data show trends approaching saturation for the highest concentrations, probably due to reabsorption in the tumor. A comparison of X-ray photographic imaging and densitometer measurements to determine concentration is also presented.
authors.affiliation: Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand.
authors.forename: Musaed
authors.initials: M
authors.lastname: Almalki
authors.forename: Samir Abdul
authors.initials: SA
authors.lastname: Majid
authors.forename: Philip H
authors.initials: PH
authors.lastname: Butler
authors.forename: Lou
authors.initials: L
authors.lastname: Reinisch
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000528:radiation effects; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000532:radiotherapy; D005682:Gadolinium / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D019786:Gadolinium DTPA / Q000493:pharmacokinetics / Q000627:therapeutic use; D006801:Humans; D008954:Models, Biological; D017247:Neutron Capture Therapy; D019047:Phantoms, Imaging; D011859:Radiography; D013052:Spectrometry, X-Ray Emission
chemical_list: D005682:Gadolinium; D019786:Gadolinium DTPA