Comparative Study on performance of Co 60 telethetherapy units in radiation isotope center Khartoum

Abstract

The aim of the current study is to assess and compare the performance of the Co-60 teletherapy units (MDS and Equinox) that installed in RICK. The assessed parameters were the field size (FS) versus SSD, Isocenter of machines, couch vertical isocenter, collimator rotation isocenter, penumbra profile and laser beams intersect. The field size (FS) of MDS machine is more adjusted to the standard FS of the inverse square law (theoretical one) with a correlation coefficient of R2 = 0.99. While the Equinox machine has significant discrepancy from the standard FS and with a coefficient of R2 = 0.86; and the equation of fitting as , where y refers to FS and x refers to SSD in cm. The test of Gantry angles and the machine iso-center shift in cm revealed that the MDS machine isocenter is approaching to the standard with a coefficient at R2 = 0.8 and the average shift of isocenter relative to Gantry angulations was 0.2±0.1. While the Equinox machine it is isocenter significantly changed as Gantry angulations at with significant coefficient of R2 = 0.97 and it is equation correlation could be given by: , where y refers to