HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Brown, J. K. Articles by Botvinick, E. H. Search for Related Content PubMed PubMed Citation Articles by Brown, J. K. Articles by Botvinick, E. H.

Intrinsic Dual-Energy Processing of Myocardial Perfusion Images

Physics Research Laboratory, University of California, San Francisco, South San Francisco
Joint Bioengineering Graduate Group
Nuclear Medicine Section, Cardiovascular Division
Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California

Correspondence: For correspondence or reprints contact: Elias H. Botvinick, MD, Nuclear Medicine Section, Box 0252, L340, University of California, San Francisco, San Francisco, CA 94143.

ABSTRACT

We have developed a software-based method for processing dual-energy ²⁰¹Tl SPECT emission projection data with the goal of calculating a spatially dependent index of the local impact of -ray attenuation. We refer to this method as intrinsic dual-energy processing (IDEP). Methods: IDEP exploits the differential attenuation of lower energy emissions (69–83 keV) and higher energy emissions (167 keV) resulting from the decay of ²⁰¹ to characterize the relative degree of low-energy -ray attenuation throughout the myocardium. In particular, IDEP can be used to estimate the relative probability that a low-energy -ray emitted from a particular region of the myocardium is detected during the acquisition of SPECT projection data. Studies on phantoms and healthy human volunteers were performed to determine whether the IDEP method yielded detection probability images with systematic structure visible above the noise of these images and whether the systematic structure in the detection probability images could be rationalized physically. In patient studies, the relative regional detection probabilities were applied qualitatively to determine the likely effects of attenuation on the distribution of mapped photon emissions. Results: Measurements of the detection probability in uniform phantoms showed excellent agreement with those obtained from computer simulations for both 180° and 360° acquisitions. Additional simulations with digital phantoms showed good correlation between IDEP-estimated detection probabilities and calculated detection probabilities. In patient studies, the IDEP-derived detection probability maps showed qualitative agreement with known nonuniform attenuation characteristics of the human thorax. When IDEP data were integrated with the findings on the emission scan, the correlation with coronary anatomy (known in 6 patients and hypothesized on the basis of clinical and electro-cardiographic parameters in 5 patients) was improved compared with evaluating the mapped emission image alone. Conclusion: The IDEP method has the potential to characterize the attenuation properties of an object without use of a separate transmission scan. Coupled with the emission data, it may aid coronary diagnosis.

Key Words: attenuation correction • myocardial perfusion • SPECT • ²⁰¹Tl

This article has been cited by other articles:

				P. P. Steele, D. L. Kirch, and J. E. Koss Comparison of Simultaneous Dual-Isotope Multipinhole SPECT with Rotational SPECT in a Group of Patients with Coronary Artery Disease J. Nucl. Med., July 1, 2008; 49(7): 1080 - 1089. [Abstract] [Full Text] [PDF]