title: A four-pixel matched collimator for high-sensitivity SPECT imaging.
abstract: We propose a wide aperture parallel-hole collimator that we call a 4-pixel matched collimator (4-PMC) for high-sensitivity SPECT imaging. The hole size of the 4-PMC is matched to four detector pixels; that is, there are four (2 × 2) pixels per collimator hole. By contrast, a 1-pixel matched collimator (1-PMC) is defined as a collimator whose hole size is matched to one detector pixel. We evaluated four types of collimator (high-resolution collimator versions and high-sensitivity collimator versions of both 4-PMC and 1-PMC) by simulation. SPECT images of a cylindrical phantom with cold spots in the noise-free condition demonstrated that the 4-PMC provided a higher-contrast image than the 1-PMC for the same collimator version. In addition, SPECT images at the noise level corresponding to a human cerebral blood flow study suggested that the high-sensitivity version of the 4-PMC provided the highest contrast image among the four collimator types. In conclusion, the high-sensitivity SPECT system using the 4-PMC can improve the trade-off between spatial resolution and sensitivity and will consequently provide improved image contrast for clinical studies of the human brain compared with the SPECT system using the 1-PMC.
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Hitachi-shi, Ibaraki-ken, Japan. atsuro.suzuki.rc@hitachi.com
authors.forename: Atsuro
authors.initials: A
authors.lastname: Suzuki
authors.forename: Wataru
authors.initials: W
authors.lastname: Takeuchi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ishitsu
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Ueno
authors.forename: Keiji
authors.initials: K
authors.lastname: Kobashi
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019047:Phantoms, Imaging; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*