Abstract：Objective In this study, the relationship between the iterative reconstruction parameters of Ordered Subset Maximum (OSEM)
and the quantitative accuracy of 99mTcO4
- SPECT/CT was analyzed to optimize the parameter setting of SPECT image reconstruction.
Methods Using NEMA/IEC image quality model, six hot spheres and background were infused with 126.54 KBq/mL and
7.03 KBq/mL 99mTcO4
- (hot spheres to background ratio was 18:1), respectively. SPECT was used for sectional image collection, and
Q. Metrix software was used for post-processing and quantitative analysis of sectional images. OSEM algorithm was used to reconstruct
all the fault images (i=2, 10, 20, 30, 40, 50, 60 and 70) and subsets (s=5, 10, 15, 20 and 25). The mean recovery coefficients (RCmean)
were calculated to evaluate the quantitation accuracy of SPECT/CT with different reconstruction parameter Settings. Results RCmean
of all hot spheres increased with the increase of iteration number, especially for 13 mm, 17 mm and 22 mm hot spheres. After 50
iterations, RCmean reached a plateau. When the number of iterations increased from 2 to 10, RCmean increased most obviously. However,
different subsets had no significant effect on RCmean. The RCmean value of the hot sphere and the volume of the hot sphere had nonlinear
changes according to the curve regression analysis, and the function relationship was in the form of logarithmic function, and the
logarithmic function of the estimated curve model is y=0.167ln(x)+0.486, R2=0.93 (P<0.05). Conclusion The quantitation accuracy of
99mTcO4
- SPECT/CT was improved with increased of OSEM iteration numbers, especially for small spheres, the maximum convergence
was achieved when the number of iterations was 50. The subsets number has no significant effect on the quantitative accuracy. There is a
definite logarithmic function relationship between RCmean and sphere size, which provides a reliable theoretical basis for the calibration
of quantitative parameters of 99mTCO4
-SPECT /CT in different lesions.
邓惠兴，杨爱民，杨路路，王岐. OSEM重建的设置对于99mTcO4 SPECT/CT定量准确性的影响[J]. 中国医疗设备, 2021, 36(11): 67-70.
DENG Huixing, YANG Aimin, YANG Lulu, WANG Qi. Impact of OSEM Iterations and Subsets on Quantitative Accuracy of 99mTcO4
- SPECT/CT. China Medical Devices, 2021, 36(11): 67-70.
