Tungsten alloy focusing collimator can improve the resolution and detection efficiency of SPECT system. The alignment direction of the holes of this type of collimator is directed to converge on a point in front of the collimator. The focusing collimator can get an enlarged image, but the reconstruction algorithm is complicated and the image is easy to distort.
More details, please visit:
http://www.tungsten-alloy.com/tungsten-alloy-radiation-shielding.html
According to the experts, focusing collimator choosing tungsten alloy as the radiation shielding material as it has the characteristics of high density, good machinability, good mechanical properties, high modulus of elasticity, and high absorption capacity against X-rays and γ-rays. Also, tungsten alloy is non-toxic, so it is harmless to the human health and environment. It has been reported that for the dynamic study of cerebral circulation using technetium 99m, multihole collimators were required for two pairs of scintillation detectors. One pair was to be situated over the cerebral hemispheres to cover the region served by the middle cerebral arteries. Parallel-hole collimators were considered satisfactory for this purpose. The other pair was to be placed over the carotid arteries. In this case, well-shielded focusing collimators were required. For low energy rays like those of 99Tcm, a honeycomb arrangement of hexagonal holes with thin-walled septa combines maximum sensitivity with good resolution.
