An ionizing radiation detector arrangement includes scintillator crystals and respective photodiodes of elongate form and mountings to assemble these in sub-arrays of, for example, four, units. The mountings are shaped to permit assembly around a ring with radially extending cards bearing circuit components. Assembly is made accurately by including skewed lugs in the mountings.

An articulating detector array for gamma cameras is disclosed which is adaptable to perform different imaging techniques in a single apparatus. The articulating detector array is adapted to detect incident gamma radiation from diverse directions as well as Compton scattering thereof without the need of a collimator, as so has improved gamma ray detection efficiency. The detector array includes radiation detectors in an array and movable to a plurality of positions, in which each radiation detector is responsive to gamma radiation from a target for generating detection signals for use in tomographic imaging of the source. The detector array includes articulating support structures for mounting the detectors to the base and for moving the detectors from a first position to a second position. In one embodiment, the articulating support structures includes a first portion connected to a detector; and a second portion connected to the base, in which the first portion is adapted to extend from the second portion from the first position to the second position. In another embodiment, the articulating support structures include a pivot for pivotably mounting the detectors and for rotating the detectors from a first position to a second position.

A radiation detector or detector array which has a non-constant spatial response individually and in combination with a tomographic scanner. The detector has a first dimension which is oriented parallel to the plane of the scan circle in the scanner. Along the first dimension, the detector is most responsive to radiation received along a centered segment of the dimension and less responsive to radiation received along edge segments. This non-constant spatial response can be achieved in a detector comprised of a scintillation crystal and a photoelectric transducer. The scintillation crystal in one embodiment is composed of three crystals arranged in layers, with the center crystal having the greatest light conversion efficiency. In a preferred embodiment, the non-constant spatial response is achieved in a detector comprised of a single scintillation crystal whose response is shaped by inducing along said first dimension a scintillation conversion efficiency gradient. In the single crystal embodiment, the gradient is chosen so that the crystal has greater conversion efficiency centrally than peripherally.

In an exemplary embodiment, a measuring arrangement comprises a radiation source emitting a radiation beam which penetrates the body layer to be examined, and a radiation receiver which supplies electrical output signals corresponding to the radiation intensity measured, a computer being connected with the radiation receiver for computing from the output signals of the radiation receiver the attenuation values of specific image points of the body layer. There is a collimator with a collimator grid forming a shielding compartment for each detector. Each detector is arranged in its collimator grid compartment and can be secured to a plate forming part of the grid, the plate being removably inserted in two parallel side portions forming the sides of each grid compartment. Furthermore, each plate with the detector secured thereto can project slightly beyond the radiation exit side of the side portions, so that a simple electrical connection to the detectors is possible.

A radiation detector, particularly suitable for use in computerized tomographic scanning systems, comprising a scintillator crystal having one window surface optically connected with a photodetector, preferably a semiconductor device, and having other surfaces diffused and tapered whereby the window surface is enabled to see all other surfaces so as to provide efficient passage of light photons from the crystal through the polished surface to the photodetector.