[The Image Noise Effect on the Results of Gamma Knife Dosimetry Parameters Test].

In order to analyze the image noise effect on the results of Gamma knife dosimetry parameter test, we tested the dosimetry parameters of the Gamma knives according to GBZ 168-2005. Radiological protection standards of X (gamma)-ray stereotactic radiosurgery for head treatment. Dose analysis software was applied to examine the testing film before and after image denoising, and SPSS 11.0 software was used for statistical analysis. The results showed that there was a significant difference in the results of the maximum deviation between radiation field size and its nominal value (t = 7.600, P < 0.01) and the radiation field's penumbra region width of collimators also had significantly different sizes (t = 5.334, P < 0.01) before and after image denoising. This study indicated that the image noise could influence the results of testing Gamma knife dosimetry parameters, so as to cause deviations.