Gamma | The usefulness of a 3-dimensional reconstruction method with resolutio…

1Jong Min Seung, 2Joong Hyun Kim, 1Hyeong Jin Lee, 1Jin Eui Kim, 1Hyun Joo Kim, 1,2Jae Sung Lee,

1,2Dong Soo Lee

1Dept. of Nuclear Medicine, Seoul National Univ. Hospital

2Dept. of Nuclear Medicine, Seoul National U

Objective

The 3-dimensional  reconstruction  method  with  resolution  recovery modeling  has advantages of high spatial resolution  and contrast because of its precise modeling  of spatial blurring  according to the distance from detector plane.  The aim of this study was to evaluate one of the resolution recovery reconstruction methods (Astonish, Philips Medical), compare it to other iterative reconstructions, and verify its clinical usefulness.

Methods

Flanges Jaszczak  ECT  phantom  and NEMA IEC  PET  body  phantom  (Data Spectrum Corp., USA) studies  were performed  using  Skylight  SPECT  (Philips) system under  four  different  conditions; short or long (2 times of short) distance, and half or full (105 cts/view) acquisition counts. Astonish reconstruction  method  was compared  with  two  other  iterative  reconstructions; MLEM and  3D- OSEM which  vendor  supplied.  For  quantitative  analysis,  the  contrast  ratios  obtained  from  IEC phantom  test were compared. Reconstruction parameters were determined  by optimization  study using  graph  of  contrast  ratio  versus background  variability.  The  qualitative  comparison  was performed with Jaszczak ECT phantom and human myocardial data.

Results

For largest hot sphere of 37 mm diameter, the Astonish showed 26.5% and 18.4% higher contrast ratio than MLEM and 3D-OSEM,  in short distance study.  For long distance,  the Astonish showed

47.3% and 38.6% higher contrast ratio than MLEM and 3D-OSEM.  The effect of acquired counts was insignificant.  In the qualitative  studies with  Jaszczak  phantom  and human  myocardial data, the Astonish showed best image quality.

Conclusion

In this study,  we have found  out that the ASTONISH can provide more reliable clinical results by better image quality compared to other iterative reconstruction methods.