PET attenuation correction for flexible MRI surface coils in hybrid PET/MRI using a 3D depth camera.

PET attenuation correction for flexible MRI surface coils in hybrid PET/MRI using a 3D depth camera.
Phys Med Biol. 2017 Nov 29;:
Authors: Frohwein LJ, Hess M, Schlicher D, Bolwin K, Büther F, Jiang X, Schäfers KP
Abstract
PET attenuation correction for flexible MRI radio frequency surface coils in hybrid PET/MRI is still a challenging task, as position and shape of these coils conform to large inter-patient variabilities. 
 The purpose of this feasibility study is to develop a novel method for the incorporation of attenuation information about flexible surface coils in PET reconstruction using the Microsoft Kinect V2 depth camera. The depth information is used to determine a dense point cloud of the coil's surface representing the shape of the coil.
 From a CT template - acquired once in advance - surface information of the coil is extracted likewise and converted into a point cloud. The two point clouds are then registered using a combination of an iterative-closest-point (ICP) method and a partially rigid registration step. Using the transformation derived through the point clouds, the CT template is warped and thereby adapted to the PET/MRI scan setup.
 The transformed CT template is converted into an attenuation map from Hounsfield Units (HU) into linear attenuation coefficients (LAC). The resulting fitted attenuation map is then integrated into the MRI-based patient-specific DIXON-based attenuation map...

Source: Physics in Medicine and Biology - November 29, 2017 Category: Physics Authors: Frohwein LJ, Hess M, Schlicher D, Bolwin K, Büther F, Jiang X, Schäfers KP Tags: Phys Med Biol Source Type: research