Dual gated PET/CT imaging of small targets of the heart: Method description and testing with a dynamic heart phantom

Tommi Kokki M.Sc., Hannu T. Sipilä M.Sc., Mika Teräs PhD, Tommi Noponen Lic. Tech., Nicolas Durand-Schaefer M.Sc., Riku Klén PhD, Juhani Knuuti MD, PhD
Original Article
Volume 17, Issue 1 / February , 2010

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Abstract

Background

In PET imaging respiratory and cardiac contraction motions interfere the imaging of heart. The aim was to develop and evaluate dual gating method for improving the detection of small targets of the heart.

Methods

The method utilizes two independent triggers which are sent periodically into list mode data based on respiratory and ECG cycles. An algorithm for generating dual gated segments from list mode data was developed.

Results

The test measurements showed that rotational and axial movements of point source can be separated spatially to different segments with well-defined borders. The effect of dual gating on detection of small moving targets was tested with a moving heart phantom. Dual gated images showed 51% elimination (3.6 mm out of 7.0 mm) of contraction motion of hot spot (diameter 3 mm) and 70% elimination (14 mm out of 20 mm) of respiratory motion. Averaged activity value of hot spot increases by 89% when comparing to non-gated images. Patient study of suspected cardiac sarcoidosis shows sharper spatial myocardial uptake profile and improved detection of small myocardial structures such as papillary muscles.

Conclusions

The dual gating method improves detection of small moving targets in a phantom and it is feasible in clinical situations.

Keywords

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