Polymer gel dosimetry using x-ray computed tomography: Investigation of the effect of reconstruction technique

X-ray computed tomography (XCT) imaging of gel dosimeters is a promising technique that may make gel dosimetry more practical for medical physicists to use clinically. One of the issues limiting its use is the dose resolution of the system, which is determined by the system's noise and ability to resolve low contrast objects. Alternative reconstruction of CT data is shown to approximately halve the minimum detectable change in signal and increase, by up to double, the signal to noise ratio for small low contrast objects when compared with the vendor reconstruction. This has the potential to reduce the number of averages required in XCT gel dosimetry imaging protocols as well as improving dose resolution.