GB2014749A - Tomosynthesis of sectional images of a three-dimensional object - Google Patents

Abstract

In a method of tomosynthesis of a body section, a body 51 is irradiated from different directions 44, 45, 46 to form a composite multiperspective image 50. A selected layer is tomosynthesised by multiple superposition 63, 64, 65 of the composite image 57, with appropriate lateral displacement related to the multisource geometry 43, on a display screen 68 so that corresponding image points relating to the selected layer in each of the component perspective images are aligned. it is desirable, e.g. to reduce dosage, to convert and intensify the composite image 50 in an image relaying system 49, 55, 56 but this can introduce image distortion (Figure 3 not shown) which reduces the definition of the resultant tomosynthesised image. The improvement comprises using a diaphragm with pinhole aperture located in the object region to form a point image of the radiation source group 43 on the input screen 48 of the image relaying system, and employing the corresponding output point image to correct the image- forming process, for example by correcting the multiple image superposition process. Thus when using an image multiplying point hologram 64, the point hologram can be formed using the output point image. Alternatively a multi-lens projector can be set up using the output point image so that for a selected layer corresponding to the position of the diaphragm, all the point images are made to coincide in the superposition region. In a further alternative of electronic synthesis, the layer dependant shift signals are corrected using the output point image in a similar manner. <IMAGE>