Effective and organ doses during CT scanning.

Abstract

Purpose: This study was set up to measure the values of body effective doses and absorbed stomach and colon doses during abdo-pelvic CT examinations of adult patients at a general hospital in Malta, compare the mean values with corresponding values found in the literature and observe how these values varied with patient mass, patient girth patient diameter. Method: Effective dose, absorbed stomach and colon dose, DLP and CTDivoL were calculated by means of the ImPACT dosimetry software. DLP and CTDivoL values were also collected from anonymized dose reports. The degree of correlation between effective dose and absorbed stomach and colon doses, against patient mass, girth and diameter was investigated. The machine and ImPACT values of DLP and CTDivoL were compared. Results: The mean body effective dose and absorbed stomach and colon doses, obtained from the study were 12.2mSv, 24.0mGy, 22.9mGy respectively. There was a strong linear correlation linking body effective dose and absorbed stomach and colon doses with patient mass and diameter, whilst a medium linear correlation was obtained with patient girth. DLP and CTDIVOL values from the ImPACT software were in general higher than those given by the machine dose report. Conclusion: The mean values of body effective doses and absorbed stomach and colon doses, in certain cases, compared favourably with those found in the literature but not in others. Further optimization of the standard protocol used in the facility should be carried out to reduce patient radiation doses further.

Keywords: Computed Tomography; Effective Dose; Absorbed Organ Dose; Volume CT Dose Index; Dose Length Product.