Abstract:
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Abstract
This Study was performed to evaluate the linear accelerator performance in
radiation and isotopes center Khartoum (RICK) concerning the mechanical tests
done according to AAPM protocol and Canadian protocol. The result showed that
the collimator isocenter rotation was optimum at 0 mm shift, Gantryisocenter
rotation was at 2 mm shift and the table rotation was optimum at 0 mm shift i.e. all
parameters were within the tolerance.Also the light and radiation field congruence
showed 2 mm shift, the laser beam coincidence showed 2mm shift, the variation of
field size (20x20, 14x14, 12x12, 10x10, 8x8, 6x6, 4x4 and 2x2cm2) versus SSD
was optimum and the correlation was so significant at R2 =0.998. The Dose rate
increase with Field sizes increment due to scatter from collimator, in the other
hand the dose decreases with SSD increment according to inverse square law
which was verified for field size 10x10 cm2 and 2x2 cm2.
The temperature effect causes change in the output measurement according to the
following equation: Y = 0.0041X+1.093, where Y refers to output in Gy/MU and
X refers to temperature, while the pressure leading to change in the output
measurement according to the following equation: Y = 0.063X + 7.298, where Y
refers to output and X refers to pressure.ix
The effect (temperature and pressure correction factor) the output varies linearly
according to the following equation: Y = 1.0129X + 0.2901, where Y refers to
output and X refers to temperature pressure correction factor.