A nonlinear spatially variant object-dependent system model for prediction of partial volume effects and scatter in PET

• Published in: IEEE transactions on medical imaging Vol. 17; no. 2; pp. 214 - 227
• Main Authors: Chi-Hsien Chen, Muzic, R.F., Nelson, A.D., Adler, L.P.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-04-1998; Institute of Electrical and Electronics Engineers
• Subjects: Algorithms; Biological and medical sciences; Biomedical engineering; Biomedical measurements; Computer Simulation; Engine cylinders; Error correction; Forecasting; Functions; Hospitals; Humans; Image Enhancement - methods; Image Processing, Computer-Assisted - methods; Investigative techniques, diagnostic techniques (general aspects); Mathematical models; Measurement errors; Medical sciences; Miscellaneous. Technology; Models, Biological; Models, Statistical; Monte Carlo Method; Neoplasms; Nonlinear Dynamics; Normal Distribution; Phantoms, Imaging; Positron emission tomography; Predictive models; Radiology; Radionuclide investigations; Radiopharmaceuticals; Reproducibility of Results; Scattering; Scattering, Radiation; Spatial resolution; Thorax - diagnostic imaging; Tomography, Emission-Computed - methods; Tomography, Emission-Computed - statistics & numerical data; Radionuclide study; Volume; Technique; Scattering factor; Corrections; Point spread function; Quantitative analysis; Positron; Emission tomography
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/42.700733

Accurate quantitation of small lesions with positron emission tomography (PET) requires correction for the partial volume effect. Traditional methods that use Gaussian models of the PET system were found to be insufficient. A new approach that models the non-Gaussian object-dependent scatter was developed. The model consists of eight simple functions with a total of 24 parameters. Images of line and disk sources in circular and elliptical cylinders, and an anthropomorphic chest phantom were used to determine the parameter values. Empirical rules to determine these parameter values for various objects based on those for a reference object, a 21.5-cm circular cylinder, were also proposed. For seven spheroids and a 3.4-cm cylinder, pixel values predicted by the model were compared with the measured values. The model-to-measurement-ratio was 1.03/spl plusmn/0.07 near the center of the spheroids and 0.99/spl plusmn/0.03 near the center of the 3.4-cm cylinder. In comparison, the standard single Gaussian model had corresponding ratios of 1.27/spl plusmn/0.09 and 1.24/spl plusmn/0.03, respectively, and the corresponding ratios for a double Gaussian model were 1.13/spl plusmn/0.09 and 1.05/spl plusmn/0.01. Scatter fraction (28.5%) for a line source in the 21.5-cm cylinder was correctly estimated by our model. Because of scatter. The authors found that errors in the measurement of activity in spheroids with diameters from 0.6 to 3.4 cm were more significant than previously appreciated.