Radiation Dose Optimization in Computed Tomography Examinations: A comparative Analysis of Body and Head phantoms in some Radiological Units of Abuja Hospitals

The increasing use of Computed Tomography (CT) as a diagnostic modality in the country has raised a major concern of delivering high radiation dose and potential source of increased cancer risk. To address this concern, CT patient absorbed dose and Quality Control (QC) parameters during CT examinations at various radiological centres in Abuja were investigated using a Polymethyl Methacrylate (PTW chamber type 30009, Freiburg, Germany), 100 mm pencil ion chamber with PTW DIA DOS E integrated electrometer and a Victoreen CT probe, model 6000-100 for head and body phantoms respectively for ten hospitals in Abuja. The electrometer and ion chamber techniques were applied on ten (10) various CT scanners and were used to estimate the computed tomography dose index (CTDIW) and the results compared to the computed tomography dose index (CTDI) values for accuracy and validation purposes. The results showed the body phantom doses ranged from 0.31±0.01 mGy to 1.58± 0.002 mGy, while the head phantom doses ranged from 1.30±0.001 mGy to 1.94± 0.3 mGy. The mean dose ratios for head and body phantom were 1.67± 0.15Gy and 1.23±0.03Gy, respectively. The results indicate that the body phantom doses were within the acceptable limits of 1Gray, whereas the head phantom doses exceeded the recommended limits. The differences in CT doses between CT machines suggest a need for optimization of CT examinations protocol and QC measures in some CT establishments in Abuja hospitals.