Calculation of lung-heart ratios for single-photon emission computed tomography
- Univ. of Massachusetts Medical Center, Worcester, MA (United States). Dept. of Nuclear Medicine
The authors investigate the effectiveness of simple iterative reconstruction techniques in calculating lung-heart activity ratios (LHRs). The LHR has been shown to be an effective indicator of the severity of coronary artery disease in cardiac SPECT. A study was conducted with a mathematical cardiac torso phantom that modelled uptake of {sup 201}Tl in the heart and lung regions. The projection data included only the effects of nonuniform photon attenuation. The data were first reconstructed with zeroth-order Chang and a variant of the Bellini method, both of which utilize information from the nonuniform attenuation map. This nonuniform (NU) Bellini method compensates exactly for attenuation in the heart region, but is incorrect for other regions in the medium. These reconstructions were then used as the initial estimates in the iterative Chang, variable step-size (VSS) Chang, and Morozumi methods,m for one and five iterations. The average heart count (AHC) and average lung count (ALC) were calculated using region-of-interest (ROI) templates derived from the true activity map. The population mean LHR was tabulated as the ratio of the ALC to AHC. Using the same reconstruction procedure, the authors also calculated the sample mean LHR and standard deviation from 21 noisy 3D reconstructions.
- OSTI ID:
- 267971
- Report Number(s):
- CONF-951073-; ISSN 0018-9499; TRN: 96:016648
- Journal Information:
- IEEE Transactions on Nuclear Science, Vol. 43, Issue 3Pt2; Conference: IEEE nuclear science symposium and medical imaging conference, San Francisco, CA (United States), 21-28 Oct 1995; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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