The primary goal of a radiology quality assurance (QA) program is to ensure adequate clinical diagnostic information and low dose (ALARA principle). This can be achieved by optimum operating parameters such as kVp (peak voltage the highest kilo voltage used in producing a radiograph), Entrance skin dose ESD, linearity of tube current and exposure time and beam quality assess of x-ray machine. Six conventional X-ray instruments in medical city at Baghdad from different origins and different manufacturing time. Protocol for QA was perform to measure different parameter such as patient entrance surface dose air kerma ESD, reproducibility of peak tube voltage, linearity of tube current, linearity of exposure time, and the filtration. The mean (ESD) were measured for different organ using (Dosimax), (Unfors) ionization chamber and thermoluminance dosimeter (TLD). (TLD) reading was higher than average value of ionization chamber because the scattering of radiation inpatient body, the scattering coefficient were range between (1.1 – 1.05). The voltage stability for the machine were tested for three machines (A, B, and C) and found the percentage of voltage ripple to machine (B and C) is (3.79) and (4.856) respectively and for machines A was 11.4. The Linearity of current and exposure time exposure were assess, and found that this relationship is linear for the machines (B and C) but not for the machine (A). Half Value Layer (HVL) test for the three machines was measured.
 

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