1. Method of improving the resolution of SPECT imaging of a region of interest of a biological object comprising: performing a first MRI scan on a biological object to determine a limited field of view (LFOV); moving the region of interest into the LFOV of an MRI imaging system and SPECT imaging system based on the first MRI scan; simultaneously performing a second MRI and first SPECT scan on the LFOV to acquire second MRI data and first SPECT data; generating an adaptive system matrix using average intensities generated from the second MRI and first SPECT data, wherein the adaptive system matrix is defined by S i , j ′ = ∑ k ⁢ S i , k ⁢ ξ k , j ⁢ ⁢ where ( 1 ) ξ k , j = { T / B if ( k , j ) ∈ target 1 if ( k , j ) ∈ LFOV ⋂ target c ⁢ ⁢ … 0 if ( k , j ) ∈ LFOV c ( 2 ) where Si,j is the system matrix, where T/B is the target-to-background value, where ξ k,j is the elements of the weighting matrix within the LFOV, where target C is a region outside the target region and where LFOV C is a region outside the LFOV; and generating an image of the region of interest in the LFOV using the adaptive system matrix.