Effects of source spot size and scatter on imaging in radiography
The profile and its detail information of the center projecting line of the radiographic image is interpreted with the results of the Monte Carlo simulation.It is found that the scatter,the source spot size and the shape of H-D characteristic curve all affect the experimental gray curve and its detail information of the center projecting line.The more the scatter exposure is,the lower the amplitude of the center signal is.The severer the non-linearity on the toe of H-D curve is,the lower the amplitude of the center signal is.It is pointed out that comparing the experimental gray curve with the Monte Carlo simulation results can ensure the scatter level and the source spot size half-quantitatively.When the exposure is being measured,the scatter interference should be removed.It is proposed to move the step farther away from the detector when the step method is used to measure the H-D characteristic curve.