A specially designed high resolution converging collimator having a focal length of 50 cm has been evaluated for cone beam single photon emission computed tomography (SPECT). The focal region was investigated by imaging a point source placed at the expected focal point and along the central ray of the collimator in front of and behind the focal point. Technetium-99m point source sensitivities m...

Purpose A pinhole collimator is routinely used to increase the resolution of scintigraphy. This prospective study was conducted to determine the interest of Tc-MIBI pinhole SPECT for the preoperative localization of parathyroid lesions in primary hyperparathyroidism. Methods All patients underwent a neck US, TcO4 and Tc-MIBI planar images, and two consecutive SPECT with a parallel (C-SPECT) and...

PURPOSE The use of the low-energy high-resolution (LEHR) collimator for lymphoscintigraphy causes the appearance of star-shaped artifacts at injection sites. The aim of this study was to confirm whether the lower resolution of the low- to medium-energy general-purpose (LMEGP) collimator is compensated by decrease in the degree of septal penetration and the reduction in star-shaped artifacts. ...

UNLABELLED Myocardial perfusion imaging with SPECT remains critically important for diagnosing, assessing, and evaluating treatment of coronary artery disease. However, conventional rotational SPECT suffers from prolonged study times because of relatively low detection efficiency. We therefore have investigated a multipinhole collimator that could improve the detection efficiency in cardiac SPE...

UNLABELLED (99m)Tc-sestamibi dual-phase scintigraphy is currently established for parathyroid localization. However, the imaging technique is not standardized, and the role of the pinhole collimator, especially, is not fully recognized in the imaging protocol. The aim of this study was to check whether the use of a pinhole collimator in parathyroid scintigraphy would enhance lesion detectabilit...

Introduction: Image quality and accuracy of in vivo activity quantification in SPECT are affected by collimator penetration and scatter components, especially in high energy imaging. These phenomena highly depend on the collimator characteristic and photon energy. The presence of penetrated and scattered photons from collimator in SPECT images degrades spatial resolution, contr...

Due to the collimator aperture, spatial resolution of SPECT data varies with source-to-detector distance. Since the radius of detector rotation is bigger when scanning larger patients, spatial resolution is degraded in these cases. Emitted gamma rays travel not only along the central axis of the collimator hole but also off-axis due to the collimator aperture. However, an off-axis ray at one an...

Background. Bremsstrahlung (BS) imaging during radioembolization (RE) confirms the deposition of radiotracer in hepatic/extrahepatic tumors. The aim of this study is to demonstrate (32)P images and to optimize the imaging parameters. Materials and Methods. Thirty-nine patients with variable types of hepatic tumors, treated with the intra-arterial injection of (32)P, were included. All patients ...

UNLABELLED We present a new rodent SPECT system (U-SPECT-II) that enables molecular imaging of murine organs down to resolutions of less than half a millimeter and high-resolution total-body imaging. METHODS The U-SPECT-II is based on a triangular stationary detector set-up, an XYZ stage that moves the animal during scanning, and interchangeable cylindric collimators (each containing 75 pinho...