Conceptual Study of a New X-Ray Volumetric Imaging Modality Based On Compton Scattering: Compton Coincident Volumetric Imaging
X Xu*, D Yan, William Beaumont Hospital, Royal Oak, MISU-C-144-5 Sunday 1:00PM - 1:55PM Room: 144
Purpose: Compton scattering is a dominant interaction during the x-ray imaging of radiography and x-ray CT. However, these scattered photons are not used for extracting imaging information; but considered as a major deteriorating factor for image qualities. Here we introduce a new design and attempt to show that the Compton scattered photons can be effectively used for imaging.
Methods: In the design of Compton Coincident Volumetric Imaging (CCVI), a collimated monoenergetic x-ray beam is directed onto a thin silicon detector. Besides detecting the energy lost by the photons, this detector also acts as the imaging source of CCVI. A small portion of the photons are Compton scattered by the detector. This detector records the energies and the traveling directions of the scattered photons (with an azimuthal angle ambiguity). Among those scattered photons whose traveling paths intersect the imaging object, a portion of them are Compton scattered within the object for the second time. The finally scattered photons are recorded by an areal energy resolving detector panel behind the object. The two detectors work in coincident mode.
CCVI images the spatial electron density distribution in the imaging object. The location of the scattering(3D spatial information) can be determined within a curve, but the exact location is not determined.This is similar to the case of the PET imaging. Therefore the imaging reconstruction algorithms are also similar.A statistical iterative imaging reconstruction algorithm was tested.
Results: The CCVI device was simulated, and volumetric images of a numerical phantom were successfully reconstructed.An order of magnitude analysis of the imaging dose shows a dose reduction up to the order of a hundred times compared with the typical clinical CT imaging protocol.
Conclusion: CCVI offers an enormous potential on imaging dose reduction.Furthermore,a CCVI modality will have no moving parts,which potentially offers cost reduction and faster imaging speed.