The physical performance of different x-ray contrast agents: calculations using a Monte Carlo model of the imaging chain.
A Monte Carlo computational model of the imaging chain has been used to investigate the performance of x-ray contrast agents with atomic number, Z, 53 < or = Z < or = 90 with respect to physical image quality descriptors (contrast and signal to noise ratio, SNR) and patient mean absorbed dose. Contrast agents of equal molar concentrations were used within a water slab (simulating the patient). The imaging conditions were chosen to represent adult and paediatric examinations. For all tube potentials studied (40-140 kV), the contrast agents with the highest atomic numbers (bismuth and thorium) gave the highest contrast. In analogue screen-film imaging, several other contrast agents could produce a higher image contrast than iodine in a limited range of tube potentials. This advantage could alternatively be effected as a reduced amount of administered contrast agent, or as a reduced mean absorbed dose in the patient. In digital imaging, a lower mean absorbed dose for a constant SNR than that with iodine can be achieved for ranges of tube potentials and contrast agents. Bismuth and thorium yield a lower dose than iodine at all studied tube potentials. Gadolinium and erbium could alternatively be used at a broad range of tube potentials above 90 kV with a dose penalty of only 5-20%.
Sandborg
M
M
Department of Radiation Physics, Faculty of Health Sciences, Linköping University, Sweden.
Christoffersson
J O
JO
Carlsson
G A
GA
Almén
T
T
Dance
D R
DR
D000328:Adult; D001729:Bismuth; D003287:Contrast Media; D004871:Erbium; D005682:Gadolinium; D006801:Humans; D007455:Iodine; D008961:Models, Structural; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D017785:Photons; D011859:Radiography / Q000379:methods*; D013910:Thorium; D014965:X-Rays
D003287:Contrast Media; D013910:Thorium; D004871:Erbium; D007455:Iodine; D005682:Gadolinium; D001729:Bismuth