A nuclear scanner includes an annular support structure (12) which supports a plurality of radiation detector units (14), each detector unit including crystals (52), tiles (66) containing an array of crystals, or modules (14) of tiles. The detector units define annular ranks of crystals, and the annular ranks of crystals define spaces between the ranks. In another embodiment, the crystals define axial spaces between crystals. Separate rings of crystals have axial spaces that are staggered such that no area of the imaging region is missed. The spaces between the detector units may be adjusted to form uniform or non-uniform spacing. Moving the patient through the annular support structure compensates for reduced sampling under the spaces between ranks.
