A MONTE-CARLO PROGRAM FOR THE CALCULATION OF CONTRAST, NOISE AND ABSORBED DOSE IN DIAGNOSTIC-RADIOLOGY

A Monte Carlo computer program has been developed for the simulation o f X-ray photon transport in diagnostic X-ray examinations. The simulat ion takes account of the incident photon energy spectrum and includes a phantom (representing the patient), an anti-scatter grid and an imag e receptor. The primary objective for developing the program was to st udy and optimise the design of anti-scatter grids. The program estimat es image quality in terms of contrast and signal-to-noise ratio, and r adiation risk in terms of mean absorbed dose in the patient. It theref ore serves as a tool for the optimisation of the radiographic procedur e. A description is given of the program and the variance-reduction te chniques used. The computational method was validated by comparison wi th measurements and other Monte Carlo simulations.