1. A single photon nuclear imaging system, the system comprising: a detector for detecting gamma photons; and a multi-pinhole collimator having at least four pinholes for single photon nuclear imaging an object under study with the detector, wherein all of the pinholes of the multi-pinhole collimator are displaced from each other by a substantially equal distance along a first direction perpendicular to an axis-of-rotation of the object under study, wherein the multi-pinhole collimator comprises: a collimator plate having the plurality of patterned pinholes; and a support base for suspending the plurality of patterned pinholes of the collimator plate between the object under study and the detector, and wherein four of the pinholes of the multi-pinhole collimator are symmetrical pinholes, the four symmetrical pinholes being patterned such that an angle in a range from about 15° to about 30° is formed between a first reference line and a second reference line, the first and second reference lines diverging from a center point of the collimator plate, wherein the first reference line intersects the center point and two of the four symmetrical pinholes, wherein the second reference line intersects the center point and does not intersect the four symmetrical pinholes, wherein the second reference line is perpendicular to a first edge of the collimator plate and parallel to a second edge of the collimator plate, and wherein the four symmetrical pinholes are all configured to focus a volume-of-interest of the object under study across a plurality of transaxial planes of the volume-of-interest along the axis-of-rotation of the object under study.