Reproducibility is defined as the ability of a radiographic unit to produce the same exposure values in short intervals of time (Bontrager, 2013). During testing when a unit is malfunctioning it manifests as inconsistent exposure readings in the RadCheck meter. The Purpose of this Reproducibility lab was to test the consistency of the output intensity after multiple exposures. This was done by taking several exposures with different combinations of mA and time, then recording what was detected by the RadCheck meter. Once all the results were gathered the coefficient of radiation was calculated. The coefficient was then compared to the Healing Art and Radiation Protection Act (HARP) and Safety Code 35 (SC35) to ensure that it was within standards. If the coefficient of radiation is not within standards, this would mean that the unit needs to be replaced. Not being within standards can lead to detriment in terms of image quality ultimately leading to extra unwanted dose to the patient. This lab was performed in room 6, by first placing a lead apron overtop of the detector to ensure no unnecessary exposures hit the detector. A RadCheck meter was then placed on the center of the lead apron. The x-ray tube was set to an SID of 100cm and was collimated to include the entirety of the meter. Once the room was setup 10 subsequent exposures were taken, for each exposure the factors were kept constant at 60kVp and 5mAs. However before each of these exposures the mA and time were changed to provide different combinations that would achieve 5mAs. After each exposure, the reading on the RadCheck meter was recorded and reset in preparation for the next exposure. The results were recorded in the chart below: RadCheck readingsOnce the results were recorded and averaged the next step was to calculate the Coefficient of Radiation to compare to HARP and SC35 standards. The formula used is stated below. X = Mean Value of Exposure Measurements Xi = ith Exposure Measurement n = Number of Exposure Measurements Therefore the Coefficient of Radiation is 0.0232 The calculation for the range is stated below When looking at HARP regulations the Coefficient of radiation for any 10 consecutive exposures taken within an hour should not be greater than 0.08 and for SC35 it should not exceed 0.05 (Service Ontario, 2011; Health Canada, 2008). When compared to the calculated coefficient of 0.0232 it is clear that it falls within regulation for both HARP and SC35. However when calculating the ranges HARP states the mean value should be within 20% and SC35 states it should be within 15%. This is not the case as the calculations above indicate. In short room 6 does not meet the required regulations for HARP and SC35. This is indicative of some problem within the x-ray tube, in a clinical setting a service technician would be called to find and correct the issue as it may be harmful to patients.
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