PMID- 3494970
OWN - NLM
STAT- MEDLINE
DCOM- 19870601
LR  - 20190903
IS  - 0143-3636 (Print)
IS  - 0143-3636 (Linking)
VI  - 8
IP  - 1
DP  - 1987 Jan
TI  - Influence of zoom factor on centre-of-rotation of the SPECT system and on the 
      resolution of tomographic images.
PG  - 3-10
AB  - The influence of zooming on centre-of-rotation (COR) of the rotating camera-based 
      SPECT system and on the resolution of tomographic images was investigated. COR 
      values were measured as a function of zoom factor varying from x1.0 to x3.0. 
      Measurements were performed using two SPECT systems collimated with three 
      collimators. In this study, the COR was observed to shift linearly with zoom 
      factor. The influence of zooming on COR depends on the location and the deviation 
      of the COR from the axis-of-rotation (AOR). We recommend that the deviation of 
      the COR from the AOR be kept to within 0.4 pixels corresponding to 2.4 mm. Unlike 
      zooming, the magnitude of COR shift is uncorrelated to the type of collimator 
      used. Contrast and spatial resolution variations of the tomographic images were 
      quantitated as a function of COR shift for clinical data acquired using no zoom 
      factor and a zoom factor of 2.50. The resolution indices were observed to be more 
      sensitive to COR shift for clinical data acquired using no zoom factor. The 
      sensitivity appeared to be inversely dependent on the zoom factor utilized. 
      However, zooming was found not to preserve the same resolution degradation. 
      Optimum resolution images can be reconstructed by requiring the COR be determined 
      and clinical study be acquired using the same zoom factor and collimator. For 
      qualitative evaluation of tomographic images, the zoom factor requirement can be 
      removed provided that the deviation of the COR from the AOR is within the 
      recommended limit. This limit allows for a maximum spatial resolution degradation 
      of 5%.(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Saw, C B
AU  - Saw CB
FAU - Clarke, L P
AU  - Clarke LP
FAU - Serafini, A N
AU  - Serafini AN
LA  - eng
PT  - Journal Article
PL  - England
TA  - Nucl Med Commun
JT  - Nuclear medicine communications
JID - 8201017
SB  - IM
MH  - *Image Enhancement
MH  - Rotation
MH  - *Tomography, Emission-Computed
EDAT- 1987/01/01 00:00
MHDA- 1987/01/01 00:01
CRDT- 1987/01/01 00:00
PHST- 1987/01/01 00:00 [pubmed]
PHST- 1987/01/01 00:01 [medline]
PHST- 1987/01/01 00:00 [entrez]
AID - 10.1097/00006231-198701000-00002 [doi]
PST - ppublish
SO  - Nucl Med Commun. 1987 Jan;8(1):3-10. doi: 10.1097/00006231-198701000-00002.