Acquisition and Processing Methods for a Bedside Cardiac SPECT Imaging System

Abstract

We have developed a compact and mobile gamma imaging system that is designed for both PET and SPECT acquisitions within a bedside environment, such as an intensive care unit, surgical suite, or emergency room. This paper describes the SPECT performance evaluation of the system for cardiac imaging, including both Tc-99m and F-18 radionuclides. For cardiac F-18 imaging in a bedside environment, the 511 keV SPECT approach using high energy collimation and anterior 180 degree acquisition has the advantages of not requiring a detector to be positioned beneath the bed and greatly reducing attenuation effects. In this study, we evaluated SPECT reconstructed image quality using an anthropomorphic dynamic cardiac phantom filled with Tc-99m and F-18 separately. The specific issues that were addressed in this study included the following: 1) mitigating septal penetration effects with the 511 keV photons using de-convolution filtering, 2) reducing truncation effects due to the relatively small field-of-view of the camera using angle-dependent center-of-rotation shifts, and 3) investigating the effects of reduced angular sampling and angular range. We found that reducing angular sampling to 28 projections through 135 degrees with Tc-99m and 25 projections through 180 degrees with F-18 showed all features of the myocardium.

Effective dose to patients and staff when using a mobile PET/SPECT system

“…Although reducing the activity administered to the patient is a simple means of reducing dose, there will be degradation in the quality of the image. The main cause of image degradation would be increased noise from reduced counts in the projection images (2) . One way to alleviate this effect is to increase the scan time.…”

“…This selection resulted in reduced sensitivity at high energies, a limited field‐of‐view, and reduced spatial resolution when compared to a dedicated clinical system. The details of the performance evaluation of the system and a description of the acquisition procedure can be found in the literature (1,2) . Although conventional systems can achieve better performance parameters, these conventional systems are often not a viable option for patients in an ICU or emergency room or are not economically feasible.…”

Advances in Biomedical Imaging and Image Fusion

“…For example, brain injuries have reduced or increased blood flow to some parts, which can be easily detected with SPECT. Figure 8 shows some SPECT images of the brain [55][56][57][58].…”