Abstract:
The verification of light and radiation field is essential for radiotherapy
process if the light field does not match the radiation field that resulting from
central axis dose measurements and treatment planning account to about 5%
of an optimal situation which the uncertainties so an effective quality
assurance program should include port film reviews, and tests of machines
for beam alignment.
This study was performed in Radiation and Isotopes Center of Khartoum
(RICK) in period of May 2013 to September 2013. The main objective of
this study was to verify the superimposition of light and radiation field
automatically by using image processing technique.
For radiotherapy machines (Co-60 and linear acceralator) each film
scanned using digitizer scanner then treat by using image processing
program Mat Lab, where the congruence of the light and radiation field
should be determined. The scanned image will be 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 and standard deviation light field size was
(10.0 X 10.1cm), Medical physicist score was (10.2 ± 0.11608 X 10.2 ±
0.099861 cm) and the field size that calculate by computerized score using
Mat Lab program was (9.9 ± 0.36049 X 9.9 ± 0.1123cm), the result also
showed that the Computerized score is more accurate in determining of
borders and Penumbra than medical physicist score. The computerized score
technique, even in relatively simple images, could be disturbed by noise,
creating some small regions that required additional processing. On the
contrary, the manual method ignored those details to focus only on the
expected boundaries which were determinate incorrect.
