A staggered array of pinhole cameras for dedicated breast SPECT

A staggered detector geometry is proposed for pinhole camera SPECT imaging of breast cancer. Several such systems are simulated in two dimensions, with reconstructed images evaluated for spatial resolution, noise, and artifacts. Designs for dedicated breast SPECT scanners generally involve moving a detector around the breast. Multiple detectors have greater detection efficiency. With enough detectors, a static array can be used. Imaging detectors are expensive, but advancing technology continues to reduce costs. However, for a given object size and camera size, a limited number of cameras can be placed around the object. This in turn limits the achievable combination of sensitivity and spatial resolution. A second row of pinhole detectors may be placed so as to image through small gaps between the detectors in the first row. This could double the number of cameras, although the sensitivity would be less than doubled as the second row of cameras would be farther from the object. This arrangement would also have better tomographic ray coverage than a single row. The front row of cameras could also be moved closer to the object, for improved spatial resolution and/or sensitivity. Parts of the object´s periphery might not imaged by the front row of cameras, but these would be imaged by the second row, albeit with less sensitivity and resolution. A staggered pinhole array could be built in a planar arrangement, suitable for imaging a compressed breast. Slit-slat collimators could be used in such a configuration. Other applications suggest themselves as well, e.g. small animal imaging. We evaluate several staggered arrays and compare them with corresponding single-row arrays. Initial studies are in two dimensions, representing either a central slice from a pinhole array, or a single plane in a slit-slat array (neglecting axial blurring). In simulation, test objects are imaged using different camera arrays, and the projections are used to reconstruct images for analysis.