High-resolution versus high-sensitivity SPECT imaging with geometric blurring compensation for various parallel-hole collimation geometries.

Recent studies have shown that trading efficiency for improved resolution may be a good choice for small lesion detection, but utilizing collimator with high efficiency may be more favorable for cardiac single photon emission computed tomography (SPECT). This paper investigates the tradeoffs of geometric-blurring compensation for high-resolution (HR) and high-sensitivity (HS) SPECT imaging with various parallel-hole collimators in terms of noise reduction and resolution recovery. Five types of collimators were investigated and compared with a general all purpose collimator using computer simulations. It is shown that less noisy SPECT images can be achieved with unchanged spatial resolution using large collimator holes with blurring compensation. The optimal collimator hole found in the computer simulation is the one with a hole acceptance angle in the range from 6.3 degrees to 9.4 degrees. Phantom experiments with two cardiac-insert phantoms show that the resolution of the image obtained using the HS collimator can be successfully recovered by blurring compensation, and the image is less noisy compared to the one obtained using the HR collimator.