1-D interpolation method for the HRRT PET sinogram gap-filling

The ECAT High Resolution Research Tomograph (HRRT) (CTI PET Systems, Knoxville, TN, USA) is a positron emission tomography (PET) scanner producing PET sinogram data with gaps. These gaps are areas of nonexisting sinogram data formed due to the physical limitations of the HRRT scanner detector block configuration. We present a simple non-interative and fast 1-D cubic convolution based interpolation scheme to fill the gaps of the data. The scheme is based on the idea of shrinking and resizing of previously introduced gap-filling by using the slices in the direction of the radial samples. This method shrinks the data by taking the gaps away, resizes it by bicubic interpolation back to the original size and fills the gaps by the resized data. The new scheme is a symmetric version of it using 1-D cubic interpolation in the resizing. The results obtained by the proposed method are shown to be comparable to those of the current state of the art methods.