OPTIMIZATION OF THE DESIGN OF ANTISCATTER GRIDS BY COMPUTER MODELING

A Monte Carlo computer program has been developed to model diagnostic radiological examinations, and has been used to study and optimise the design of antiscatter grids. This is important because the use of an inappropriate or poorly designed grid can lead to increased patient do se. Optimal grid parameters may be different for large and small scatt ering volumes. The program treats the patient as a rectangular block o f tissue and takes account of the grid and image receptor. Image quali ty is measured in terms of contrast and signal-to-noise ratio and pati ent risk in terms of mean absorbed dose. Test objects of appropriate s ize and composition are used in the calculation of these image quality parameters. A new performance comparison and optimisation procedure h as been developed, and the program has been used to study grid design in screen-film and digital radiology for small, medium and large scatt ering volumes.