RESUMO
The main objective of this study was to verify the superimposition of light and radiation field automatically using image processing technique. For radiotherapy machines [Co-60 and linear accelerator], each film scanned using digitizer scanner then treat using image processing program MatLab, where the congruence of the light and radiation field should be determined. The scanned image saved in a TIFF file format to preserve the quality of the image. The data analyzed include upper, lower, right, and left borders of the light and radiation field in megavoltage films. The result showed that the mean light field size was 10.0 X 10.1 cm, medical physicist score was 10.2 +/- 0.11608 cm X 10.2 +/- 0.099861 cm, and the field size that calculated by computerized score using MatLab program was 9.9 +/- 0.36049 cm X 9.9 +/- 0.1123 cm, the result also showed that the computerized score is more accurate in determining of borders and penumbra than medical physicist score