Patent Number: 
Section: claims

1. A SPECT apparatus comprising:a two-dimensional detector that detects radiations from RIs in a patient via a collimator;a correction processing unit that corrects, in order to reduce a fall in spatial resolution having dependency on distances between the respective RIs and the detector, plural two-dimensional projection distributions with different projection angles, which are detected by the detector, on a three-dimensional frequency space according to plural correction functions corresponding to plural distances, respectively; anda reconfiguring unit that reconfigures a three dimensional RI distribution from the plural two-dimensional projection distributions corrected;wherein the correction processing unit includes:a coordinate transforming unit that transforms the plural two-dimensional projection distributions into a three-dimensional projection distribution represented by a three-dimensional actual space formed by a projection angle axis, a slice axis and a channel axis;a transforming unit that transforms the three-dimensional projection distribution into a representation of a frequency space according to three-dimensional Fourier transformation;a correcting unit that corrects values of respective points of the transformed three-dimensional projection distribution according to any one of the plural correction functions corresponding to distances of the respective points; anda transforming unit that transforms the corrected three-dimensional projection distribution into a representation of the actual space according to the three-dimensional Fourier transformation. 2. A SPECT apparatus comprising:a two-dimensional detector that detects radiations from RIs in a patient via a collimator;a correction processing unit that corrects, in order to reduce a fall in spatial resolution having dependency on distances between the respective RIs and the detector, plural two-dimensional projection distributions with different projection angles, which are detected by the detector, on a three-dimensional frequency space according to plural correction functions corresponding to plural distances, respectively; anda reconfiguring unit that reconfigures a three dimensional RI distribution from the plural two-dimensional projection distributions corrected;wherein the correction function is an inverse function of a point spread function represented by the frequency space. 3. A SPECT apparatus according to claim 2, further comprising a storing unit that stores the plural correction functions. 4. A SPECT apparatus according to claim 2, wherein the point spread function is a modulation transfer function. 5. A SPECT apparatus according to claim 2, wherein the collimator is a parallel hole collimator. 6. A SPECT apparatus according to claim 2, further comprising a storing unit that stores data of the plural correction functions. 7. A SPECT apparatus according to claim 6, wherein the distances are associated with the data of each of the plural correction functions. 8. A SPECT apparatus according to claim 6, wherein parameters concerning the distances and filter characteristics are associated with the data of each of the plural correction functions. 9. A SPECT apparatus according to claim 8, wherein the reconfiguring unit reconfigures plural three-dimensional RI distributions on the basis of two-dimensional projection distributions corrected for each of the correction functions with the different filter characteristics. 10. A SPECT apparatus according to claim 9, further comprising a display unit that displays the plural three-dimensional RI distribution as a list. 11. A processing method for a SPECT comprising:correcting plural two-dimensional projection distributions with different projection angles concerning RIs in a patient, which are detected by a two-dimensional detector, on a three-dimensional frequency space according to plural correction functions corresponding to plural distances between the RIs and the detector, respectively; andreconfiguring a three-dimensional RI distribution from the plural two-dimensional projection distributions corrected;wherein the correction function is an inverse function of a point spread function represented by the frequency space. 12. A processing method for a SPECT according to claim 11, whereinin the correcting,the plural two-dimensional projection distributions are transformed into a three-dimensional projection distribution represented by a three-dimensional actual space formed by a projection angle axis, a slice axis and a channel axis,the three-dimensional projection distribution is transformed into representation of a frequency space according to three-dimensional Fourier transformation,values of respective points of the transformed three-dimensional projection distribution are corrected according to any one of the plural correction functions corresponding to distances of the respective points, andthe corrected three-dimensional projection distribution is transformed into representation of the actual space according to the three-dimensional inverse Fourier transformation. 13. A processing method for a SPECT according to claim 11, wherein the point spread function is a modulation transfer function. 14. A program for SPECT processing for causing a computer to realize:means for correcting plural two-dimensional projection distributions with different projection angles concerning RIs in a patient, which are detected by a two-dimensional detector, on a three-dimensional frequency space according to plural correction functions corresponding to plural distances between the RIs and the detector, respectively; andmeans for reconfiguring a three-dimensional RI distribution from the plural two-dimensional projection distributions corrected;wherein the correction function is an inverse function of a point spread function represented by the frequency space.