Scatter and detecability in lung SPECT: a Monte Carlo study
(English)Manuscript (preprint) (Other academic)
The image quality in SPECT is degraded by scattered photons. The finite energy resolution of the gamma camera makes the detection of scattered photons unavoidable. The effect on the image is impaired contrast and a reduction in the possibilities of detecting small lesions.
The detectability of cold lesions above statistical noise and normal variations in the activity distribution was evaluated using the Monte Carlo technique. A SPECT study of a digital thorax phantom was simulated with cold lesions of different sizes positioned inside the homogeneous activity distribution in the lungs. The contrast-to-noise for a number of energy window settings were assessed, with and without three different scatter correction methods: the dual-window, the triple-energy-window and the Klein-Nishina method.
The contrast was improved by using scatter corrections and the TEW and KN scatter corrections showed the best result. The detectability was not improved by using scatter corrections when normal variations in the lung activity are small compared with the statistical noise level. Lesions of about 2 cm in diameter are detectable. The optimum energy window was found to be 128-154 keV, both with and without scatter corrections.
Scatter correction, detectability, SPECT, Monte Carlo, lung
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-89581OAI: oai:DiVA.org:liu-89581DiVA: diva2:608336