Comparative study of a low-Z cone-beam computed tomography system.
Roberts, DA, Hansen, VN, Thompson, MG, Poludniowski, G, Niven, A, Seco, J and Evans, PM (2011) Comparative study of a low-Z cone-beam computed tomography system. Phys Med Biol, 56 (14). 4453 - 4464. ISSN 0031-9155
Available under License : See the attached licence file.
Computed tomography images have been acquired using an experimental (low atomic number (Z) insert) megavoltage cone-beam imaging system. These images have been compared with standard megavoltage and kilovoltage imaging systems. The experimental system requires a simple modification to the 4 MeV electron beam from an Elekta Precise linac. Low-energy photons are produced in the standard medium-Z electron window and a low-Z carbon electron absorber located after the window. The carbon electron absorber produces photons as well as ensuring that all remaining electrons from the source are removed. A detector sensitive to diagnostic x-ray energies is also employed. Quantitative assessment of cone-beam computed tomography (CBCT) contrast shows that the low-Z imaging system is an order of magnitude or more superior to a standard 6 MV imaging system. CBCT data with the same contrast-to-noise ratio as a kilovoltage imaging system (0.15 cGy) can be obtained in doses of 11 and 244 cGy for the experimental and standard 6 MV systems, respectively. Whilst these doses are high for everyday imaging, qualitative images indicate that kilovoltage like images suitable for patient positioning can be acquired in radiation doses of 1-8 cGy with the experimental low-Z system.
|Divisions :||Faculty of Engineering and Physical Sciences > Electronic Engineering > Centre for Vision Speech and Signal Processing|
|Date :||21 July 2011|
|Identification Number :||10.1088/0031-9155/56/14/014|
|Uncontrolled Keywords :||Cone-Beam Computed Tomography, Humans, Phantoms, Imaging|
|Additional Information :||Copyright 2011 Institute of Physics. This is the author's accepted manuscript.|
|Depositing User :||Symplectic Elements|
|Date Deposited :||07 Dec 2012 17:38|
|Last Modified :||23 Sep 2013 19:52|
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